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GIFT   OF 
MICHAEL  REESE 


ALUMINIUM: 


ITS  HISTORY,  OCCURRENCE,  PROPERTIES, 

METALLURGY  AND  APPLICATIONS, 

INCLUDING  ITS  ALLOYS. 


BY 


JOSEPH  W.  RICHARDS,  A.C., 

CHEMIST   AND   PRACTICAL   METALLURGIST  ;   MEMBER   OF   THE   DEUTSCHE 
CHEMISCHE   GESELLSCHAFT. 


ILLUSTRATED  BY  SIXTEEN   ENGRAVINGS. 


PHILADELPHIA  : 
HENRY  CAREY  BAIRD  &  CO., 

INDUSTRIAL  PUBLISHERS,  BOOKSELLERS  AND  IMPORTERS, 
810  WALNUT  STREET. 

LONDON: 

SAMPSON  LOW,  MARSTON,  SEARLE  &  RIVINGTON, 
CROWN  BUILDINGS,  188  FLEET  STREET. 

1887, 


COPYRIGHT  BT 
JOSEPH  W.  RICHARDS, 


COLLINS   PRINTING   HOUSE, 

705  Jayne  Street. 


PREFACE. 


Xo  apology  is  necessary  in  presenting  a  work  on 
aluminium  in  English.  In  1858  Tissier  Bros,  pub- 
lished in  France  a  small  book  on  the  subject.  H. 
St.  Claire  Deville,  the  originator  of  the  aluminium 
industry,  published  a  treatise,  also  in  French,  in 
1859.  Deville's  book  is  still  the  standard  on  the 
subject.  Until  December,  1885,  we  have  an  inter- 
mission, and  then  a  work  by  Dr.  Mierzinski, 
forming  one  of  Hartleben's  Chemisch-Techuische 

o 

Bibliothek,  which  is  a  fair  presentation  of  the 
industry  up  to  about  1883,  this  being  a  German 
contribution.  Probably  because  the  English- 
speaking  people  have  taken  comparatively  little 
hand  in  this  subject  we  find  no  systematic  trea- 
tise on  aluminium  in  our  language.  The  present 
work  aims  to  present  the  subject  in  its  entirety  to 
the  English  reader. 

Tissier,  Deville,  Mierzinski,  and  the  German, 
French,  and  English  scientific  periodicals  have 


IV  PREFACE. 

been  freely  consulted  and  extracted  from,  full 
credit  being  given  in  each  case  to  the  author  or 
journal.  As  this  art  has  of  late  advanced  so 
rapidly  it  has  been  a  special  aim  to  give  every- 
thing that  has  been  printed  up  to  the  time  of  pub- 
lication. 

The  different  parts  of  the  work  are  arranged  in 
what  seemed  their  logical  order,  corresponding 
closely  to  that  followed  by  Deville.  The  Appendix 
contains  an  account  of  laboratory  experiments,  etc., 
several  of  which,  it  is  trusted,  may  be  of  value. 

In  conclusion,  the  author  wishes  to  thank  the 
faculty  of  his  "Alma  Mater,"  Lehigh  University, 
for  their  permission  to  use  his  Thesis  on  Alumin- 
ium as  the  basis  of  this  treatise ;  also,  to  acknowl- 
edge his  indebtedness  to  Dr.  Wm.  H.  Greene,  of 
Philadelphia,  for  assistance  rendered  in  the  prep- 
aration of  the  work  for  the  press. 

J.  W.  R. 

PHILADELPHIA,  November  25,  1886. 


LIST  OF  REFERENCES. 


Tissier Recherche  de  1' Aluminium.    C.  &  H. 

Tissier.     Paris,  1858. 
Deville De  1' Aluminium.     H.  St.  Claire  De- 

ville.     Paris,  1859. 
Watts Watts' s     Dictionary    of    Chemistry, 

vol.  i. 
Mierzinski     ....     Die    Fabrikation    des    Aluminiums. 

Dr.  Mierzinski.     Vienna,  1885. 
Compt.  Rend.    .     .     .     Comptes  Rendus  de  les  Sciences  de 

1'Academie.     Paris. 
Wagner's  Jahresb.       .     Wagner's    Jahresbericht   der   Chem 

ische  Technologic. 

Phil.  Mag The  London  and   Edinburgh  Philo- 
sophical Magazine. 
Mon.  Scientif.    .     .     .     Le      Moniteur      Scientifique.        Dr. 

Quesnesville. 
Fremy Encyclopedic     Chemique.       Fremy. 

Paris,  1883. 

Dingl.  Joul Dingler's  Polytechnisches  Journal. 

Pogg.  Ann Poggendorff''s  Annalen. 

Jrnl.  der  Pharm.     .     .     Journal  der  Pharmacie. 

Bull,  de  la  Soc.  Chem.     Bulletin  de  la  Soci6t6  Chemique  de 

Paris. 

Sci.  Am.  (Suppl.)  .     .     Scientific  American  (Supplement). 
Eng.  and  Mng.  Jrnl.   .     The  Engineering  and  Mining  Journal. 
Chem.  News      .     .     .     The  Chemical  News. 
Jahresb.  der  Chem.      .     Jahresbericht  ueber  die   Fortschritte 

der  Chemie. 


FO  RMU  L  JE. 


Al   .     .     .  .  Aluminium. 

A12O3  .     .  .  Alumina. 

A12C16  .     .  .  Aluminium  chloride. 

K     .     .     .  .  Potassium. 

KOH   .     .  .  Caustic  Potash. 

KC1      .     .  .  Potassium  chloride. 

Na.       .     .  .  Sodium. 

Al2Cl6.2NaCl.  Aluminium-sodium  double  chloride. 

Si    ...  .  Silicon. 

Fe  .     .     .  .  Iron. 

Cu  .     .     .  .  Copper. 


TEMPERATURES. 

Unless  stated  otherwise,  all  temperatures  given  are  in  Centi- 
grade degrees. 


CONTENTS. 


PART  I. 
HISTORY  OF  ALUMINIUM. 

PAGE 

Lavoisier's  suggestion  of  the  existence  of  metallic  bases 
of  the  earths  and  alkalies ;  Researches  in  preparation 
of  aluminium,  by  Davy,  Oerstedt,  and  Wohler   .         .       25 
Isolation  of  aluminium,  by  H.  St.  Claire  Deville,  in  1854       26 
Patronage  of  Emperor  Napoleon  III.  ;  Aluminium  at  the 
Paris   Exhibition,  1855;    Its  manufacture  on  a  large 
scale  at   Glaciere,  Nanterre,  and    Salindres ;    Tissier 
Bros.'  book  on  aluminium  in  1858       ....       28 
Deville' s  book,  1859  ;  History  of  the  works  near  Rouen        29 
Deville's  explanation  of  the  uses  of  the  new  metal          .       30 
Alfred  Monnier's  production  of  aluminium  at  Camden, 

N.  J.,  1856 31 ' 

W.  J.  Taylor  claiming  the  possible  cost  of  aluminium  at 
§1  per  pound;    Kerl  and    Stohman's  r£sum£  of  the 
manufacture  of  aluminium  up  to  1874          ...       32 
Dr.  Clemens  Winckler's  retrospect  of  the  development  of 

aluminium,  1879 33 

Manufacture  of  aluminium  in  England,  France,  and  Ger- 
many ;  Aluminium  beams  for  balances,  made  by  Sar- 
torius  of  Gottingen;  Difficulties  in  using  aluminium  for 
mathematical  instruments ;  Action  of  molten  aluminium 
upon  earthen  crucibles  ......  35 


Vlll  CONTENTS. 

PAGE 

Prices  of  aluminium  and  of  aluminium  bronze  in  France  ; 
Webster's  aluminium  works  in  England  .  .  .36 

Col.  William  Frishmuth's  invention  for  producing  alu- 
minium at  reduced  cost;  Opinion  of  his  invention  by 
Major  Ricarde-Seaver,  F.R.S.E 37 

Col.  Frishmuth's  works  in  Philadelphia ;  Aluminium  cast- 
ing for  the  Washington  Monument,  made  by  Col.  Frish- 
muth  ;  Census  report  of  his  annual  production ;  His 
price  in  bars  ........  39 

Imports  and  consumption  of  aluminium  in  the  United 
States  from  1870  to  1884  ;  Its  production  in  Philadel- 
phia by  Col.  Frishmuth  in  1883,  1884  ...  40 

Cowle's  process  for  making  aluminium  bronze  at  Cleve- 
land, Ohio ;  Present  state  of  aluminium  industry  as 
described  by  Prof.  Charles  F.  Mabery,  of  Cleveland, 
Ohio,  and  Dr.  T.  Sterry  Hunt,  of  Montreal  .  .41 

PART  II. 
OCCURRENCE  OF  ALUMINIUM  IN  NATURE. 

Combinations  of  aluminium  with  oxygen,  alkalies,  and 
acids,  etc.  ;  Formulae  of  aluminium  silicates  .  .  43 

Appearance  of  most  of  the  aluminium  compounds ;  For- 
mulae of  some  of  the  precious  stones  ....  44 

Minerals  most  used  for  producing  aluminium;  Beauxite  .       45 

Analyses  of  beauxite 46 

Cryolite ;  Where  found,  description,  and  general  uses  ; 
Its  importation  by  the  Pennsylvania  Salt  Co.,  of  Phila- 
delphia ;  Native  cryolite  in  the  United  States  .  .  48 

Imports  of  cryolite  into  the  United  States  ;  Corundum  ; 
Its  great  source  of  supply 49 

Probable  sources  of  supplies  of  materials  for  production 
of  aluminium  in  the  United  States  and  Great  Britain  .  50 


CONTENTS.  IX 

PART  III. 
PHYSICAL  PROPERTIES  OF  ALUMINIUM. 

PAGE 

Table  of  analyses  of  commercial  aluminium    ...       51 

Free  and  combined  silicon  in  aluminium  ;  Gases  in  alu- 
minium .........  52 

Composition  of  the  aluminium  apex  of  the  Washington 
Monument  at  Washington,  D.  C.,  cast  by  Col.  Frish- 
muth ;  Color  of  aluminium  ;  As  described  by  Deville, 
Fremy,  Mallet,  and  Mierzinski  .....  53 

Mat ;  As  described  by  Deville,  Mierzinski,  and  Bell  Bros.       54 

Polish  and  lustre ;  Processes  for  producing  as  given  by 
Deville,  Bell  Bros,  and  Kerl  and  Stohman  .  .  55 

Odor  ;  As  given  by  Deville  and  Watts   ....       56 

Taste — Deville;  Malleability — Deville  and  Mallet  on  this 
subject  .........  57 

M.  Degousse's  success  in  beating  aluminium  into  leaves; 
Substitution  of  aluminium  for  silver  leaf;  Kerl  & 
Stohman  on  rolling  and  annealing  aluminium  .  .  58 

Bell  Bros,  on  beating  aluminium  ;  Mierzinski  on  extensi- 
bility of  aluminium  .......  59 

Aluminium  leaf  first  made  by  C.  Falk  &  Co.,  Vienna; 
Ductility  ;  Drawing  aluminium  wire  ;  Results  obtained 
by  Deville,  Vangeois,  and  Bell  Bros.  ...  60 

Elasticity,  Tenacity,  Hardness — Deville,  Wertheim,  Mul- 
let, Fremy;  Kerl  &  Stohman  on  engraving  aluminium  61 

Mierzinski  and  W.  H.  Barlow  on  tensile  strength; 
Tables ;  Comparative  mechanical  value  of  aluminium, 
steel,  etc 62 

Table  of  strength  of  aluminium  wire;  Sonorousness;  Re- 
sults obtained  by  Deville  and  M.  Lissajous  in  making 
bells  and  tuning-forks  ......  63 

Results  obtained  by  Faraday  and  Watts  ;  Density ;  De- 
ville's  table  of  comparison  with  other  metals  .  .  64 


X  CONTENTS. 

PAGE 

Comparative  value  of  equal  volumes  of  aluminium  and 
silver ;  Specific  gravity  of  absolutely  pure  aluminium, 
Mallet ;  Fusibility  ;  As  given  by  Deville,  Mallet,  and 
Mierzinski  ......  65 

Fixity  ;  As  given  by  Deville,  Watts,  and  Fremy  ;  Elec- 
tric conductivity  ;  Results  obtained  by  Deville  and  M. 
Buff ,  ...  .66 

Comparison  with  copper  and  magnesium,  Fremy  ;  Ther- 
mal conductivity;  Deville,  Faraday,  and  Watts,  etc., 
on  this  subject  .  .  .  .  •  .  .  .  .67 

Mierzinski,  Calvert,  and  Johnson  on  this  subject ;  Spe- 
cific heat ;  Deville,  Regnault,  Paul  Morin,  Mallet,  and 
Fremy  on  this  subject 68 

Magnetism;  Deville,  MM.  Poggendorff  and  Reiss ;  Crys- 
talline Form  ;  Deville  on  this  subject  ...  69 

PART  IV. 
CHEMICAL  PROPERTIES  OF  ALUMINIUM. 

Remark;  Action  of  air;  Deville' s  observations       .         .       70 
Cupellation  of  aluminium ;   Observations  of  Wohler,  Peli- 

got,  Watts,  etc. 71 

Action  of  water  ;  Deville  on  this  subject          .         .         .72 
Mierzinski  and  the  Chemical  News  ;    Action  of  hydro- 
gen sulphide  and  sulphur  ;  Deville  and  Fremy     .         .       73 
Sulphuric  acid  ;  Deville,  M.  de  la  Rive,  and  Fremy        .       74 
Nitric  acid  ;  Deville  and  M.  Hulot ;  Hydrochloric  acid  ; 

Deville,  M.  Favre,  and  others     .....       75 
Potash,  soda,  and  lime  ;  Deville,  Mallet,  Mierzinski        .       77 
Aqua  ammonia ;    Deville   and  Wohler ;   Organic   acids, 
vinegar,  etc.  ;  Deville,  M.  Paul  Morin ;  Use  of  Alu- 
minium for  culinary  articles          .....        78 
Solutions  of  metallic  salts  ;  Precipitation  of  other  metals 
by  aluminium  ;    Deville,  Tissier,  Paul  Morin,  Mourey, 
Christofle,  Hulot .79 


CONTENTS.  XI 

PAGE 

Mierzinski.  Fremy  and  Watts 81 

Nitre  ;  Purification  by  nitre  ;  Deville,  Fremy,  and  Mier- 
zinski on  this  subject 83 

Silicates  and  borates  ;  Action  on  glass  and  crucible  clay  ; 
Deville  and  Tissier ;  Fluorspar ;  Tissier  on  its  use  as 
a  flux 84 

Phosphate  of  lime,  Tissier  on  this  subject ;  Sodium  chlo- 
ride and  chlorides,  Deville;  Tissier  on  their  use  as 
fluxes 85 

Metallic  oxides ;  Tissier' s  experiments  ....       86 

Mierzinski ;  Beketoff 's  experiments  ;  Animal  matters  ; 
Deville  and  M.  Charriere  on  the  use  of  aluminium  in 
surgery  .  .  .  .  .  .  .  .  .87 

Miscellaneous  agents;  Tissier  and  Mierzinski  on  this 
subject .88 

General  observations  on  the  properties  of  aluminium, 
Deville  88 


PART   V. 
METALLURGY  OF  ALUMINIUM. 

.Oerstedt's  original  paper  on  isolation  of  aluminium,  1824  90 
AYohler,  the  true  discoverer  of  the  metal ;  Wohler's  first 

paper .         .91 

Wohler's  second  paper  .......  93 

Deville' s  remarks  on  the  metal  obtained  by  Wohler         .  95 

Deville' s  improvement,  1854-55      .....  96 

Deville' s  apparatus  at  Javel  and  Glaciere  described  and 

illustrated  .........  98 

Deville's  experiments  with  sodium  vapor        .         .         .  100 
Reduction  from  cryolite ;  H.  Rose's  entire  paper    .         .  103 
Dr.  Percy's  investigations  as  laid  before  the  Royal  Insti- 
tution            115 

Allan  Dick's  paper,  November,  1855      .         .         .         .116 


Xll  CONTENTS. 

PAGE 

Deville's  account  of  his  researches         .         .         .  .118 

Wohler's  improvement  on  Deville's  process;    Watts  on 

the  reduction  of  cryolite  ;   Gerhard's  furnace         .  .126 

Watts's  summary  of  the  use  of  cryolite           .          .  .127 

General  remarks    .         .         .                   .         .         .  .128 

PART   VI. 
THE  MANUFACTURE  or  SODIUM. 

Preliminary  observations         .          .         .          .          .          .130 

Summary,  taken  principally  from  Mierzinski ;   Efforts  of 
Davy,    Gay    Lussac,    Thenard,    Curaudau,     Brunner, 
Donny,  and  Mareska          .         .         .         .         .         .131 

Donny  and  Mareska's  condenser,  illustrated;   Deville's 

account  of  its  operation       .          .          .         .  •        .          .     132 

Object  of  and  disadvantage  in  use  of  chalk  ;  Preliminary 
calcination  of  the  mixture  ;   Illustration  of  the  furnace.     133 

Decomposition  retorts,  illustrated 134 

Operation  in  the  retorts  .          .          .          .          .          .135 

Deville,  Rivot,  and  Tissier  on  the  temperature         .          .      137 
Wagner's  improvement;  Attempts  to  reduce  potassium 

and  sodium  together   .          . 138 

Weldon's  calculation  of  the  cost  of  sodium  ;  Making  of 
sodium  in  New  York  City,  N.  Y. ;  Castner's  Ameri- 
can patent  process       .         .         .         .         •         •         .139 
Claims  made  in  Castner's  patent     ...  .     141 

Reduction  of  sodium  by  electricity,  Mierzinski,   Davy; 

Jablochoff's  apparatus  described  and  illustrated   .          .     142 

PART   VII. 
MANUFACTURE  OF  ALUMINA. 

Present  state  of  the  industry  ;  Tilghman's  process  .         .     144 
Manufacture  from  cryolite ;  Dry  way      .         .         .         .     146 


CONTENTS.  Xlll 

PAGB 

Thomson's  furnace  described  and  illustrated    .         .         .147 
Preference  for  mechanical  furnaces  as  used  in  manufac- 
ture of  soda,  potash,  etc 148 

Precipitation  of  solution  of  sodium  aluminate,  according 

to  Lowig 151 

Wet  way 152 

Manufacture  from  alum-stone  or  shales    .         .         .         .153 


PART  VIII. 

MANUFACTURE  OF  THE  DOUBLE  CHLORIDE  OF  ALUMINIUM 
AND  SODIUM. 

Preliminary  remarks 154 

Mierzinski,  Deville,  and  M.  Dullo  on  this  subject    .         .  155 
Manufacture  by  using  hydrochloric  acid  and  carbon  di- 

sulphide 157 


PART  IX. 
MANUFACTURE  OF  ALUMINIUM  AT  SALINDRES  (GARD). 

Aluminium  as  made  by  A.  R.  Pechiney  &  Co.,  successors 

to  Henry  Merle  &  Co 158 

Reactions  involved  in  and  outline  of  the  process      .         .158 
Preparation  of  the  aluminate  of  soda ;    Material  used ; 
Composition  of  mixture  ;  Calcination,  washing,  filter- 
ing, with  illustration  of  filtering  apparatus    .         .         .     159 
Preparation  of  the  alumina ;  Description  of  precipitating 
tank  and  method  of  precipitation,  washing,  and  dry- 
ing, illustrated 163 

Preparation  of  aluminium — sodium  double  chloride          .     166 
Illustration  of  furnace  ;  Mixing  and  shaping  the  charge  ; 
Condenser  .         .         .         .         .         .         .         .167 

2 


XIV  CONTENTS. 

PAGE 

Reduction  of  the  double  chloride  by  sodium  ;  Illustration 
of  furnace  ;  Difficulties  met ;  Method  of  charging,  re- 
ducing, and  running  out 168 

Average  cost  of  manufacture  at  Salindres  in  1872.         .     172 
Later  improvements  in  Deville's  process  ;  Webster's  pro- 
cess;  History  and  description  of  the  plant ;   Where  its 
advantages  lie ;  Utilization  of  bye  products          .         .173 
Frishmuth's  process ;  Patent  claims         .          .          .          .178 
Other  processes;  Niewerth's  method  of  reduction  by  nas- 
cent sodium  ;  Grousillier's  reduction  under  pressure     .      179 

PART  X. 

REDUCTION  OF  ALUMINIUM  BY  OTHER  REDUCING  AGENTS 
THAN  SODIUM. 

Reduction  by  Cyanogen;    Knowles's  patent;    Corbelli's 

patent 180 

Deville's  and  Watts' s  comments  ;  Reduction  by  hydrogen  ; 

Process  of  F.  W.  Gerhard;  Comment  by  Watts  .  181 
Reduction  by  carburetted  hydrogen  ;  Process  of  A.  L. 

Fleury,  of  Boston 182 

^Petitjean's    process         .          .          .          .          .          .          .183 

Reduction  by  double  reaction  ;  Processes  of  M.  Comenge 

and  Johnson        .          .          .          .         .          .          .          .     1 84 

Process  of  Niewerth        .         .         .         .         .         .         .185 

Reduction  by  carbon  and  carbon  dioxide  ;  Process  of  J. 

Morris,  of  Uddington 187 

Reduction  by  carbon  ;  Article  by  M.  Chapelle  .  .188 
Statement  of  G.  W.  Reinar  ;  Cowles  Bros.'  process  .  189 

Patent  claim  of  Messrs.  Cowles 190 

Prof.  Charles  F.  Mabery's  official  account  of  Cowles  Bros.' 

process 191 

Dr.  T.  Sterry  Hunt's  paper  read  before  the  American 

Institute  of  Mining  Engineers     .         .         .          .          .194 


CONTENTS.  XV 

PAOB 

Dr.    Hunt's   address   before  the   National   Academy    of 

Science 196 

W.  P.  Thompson's  complete  description  of  the  process  .     197 
Illustrative  description  of  the  furnace  ;  Mode  of  operat- 
ing furnace,   and  improvements  thereon ;  Amount  re- 
duced ;  Ores  used 199 

Reduction  by  iron  ;   Lauterborn's  process  not  new  ;    Pa- 
tents of  F.  Lauterborn  and  of  H.  Niewerth         .         .     206 
Preparation  of  aluminium   and  sodium  in  the   Bessemer 

converter;  W.  P.  Thompson's  experiments         .         .207 
Calvert  and  Johnson's  experiments         ....     209 
Reports  of  Fremy,  Watts,  Benzon,  Evrard    .          .         .211 
Silicon  bronze,  by  Evrard;  Ostberg's  statement  of  the 
iron-aluminium  alloy  used  in  the  mitis  process ;    Re- 
duction with  copper  ;  Calvert  and  Johnson's  process    .     212 
Kerl  and  Stohman's  account  of  Benzon's  process     .         .213 
Laboratory   tests  of  this   process  ;  Reduction   by   zinc ; 

Dullo's  observations    .         .         .         .         .         .         .214 

Patent  of  M.  N.  Basset 215 

Wedding's  remarks  on  Basset's  process         .         .         .217 
Kagensbusch's singular  proposition;  Fred'k  J.  Seymour's 

patent 218 

Extraordinary  claim  in  Seymour's  second  patent     .          .     220 
American  Aluminium  Co.,  Detroit;   Reduction  by  lead; 

Wilde's  invention 221 

Reduction  by  manganese ;  Claims  of  W.  Weldon,  Bur- 
stow,  England  ;  Reduction  by  electricity     .         .          .     222 
Deville's  account  of  the  process       .....     223 
Sectional  illustration  of  the  crucibles       ....     224 

Bunsen  and  Deville  on  the  subject 225 

Mierzinski's  practical  remarks         .          .          .          .          .226 
Patented   improvement  by  Richard  Gratzel,   Germany, 

illustrated 228 

Duvivier's  experiment  with  electric  current    .         .         .     229 


XVI  CONTENTS. 

PAGE 

Kagensbusch's  proposition  ;  Gaudin's  "  economic"  reduc- 
tion of  aluminium  .......  230 

Metals  coated  with  aluminium  by  Thomas  and  Tilly  ; 
Depositing  of  aluminium  by  Corbelli  and  J.  B. 
Thompson 231 

Patented  process  by  J.  A.  Jeancon  ;  Experiments  by  M. 
A.  Bertrand,  C.  Winkler,  and  Sprague  .  .  .232 

Electrolyses  of  M.  L.  Senet,  Gerhard,  and  Smith  ;  De- 
composition of  a  solution  of  alum  by  J.  Braun  ;  Moses 
G.  Farmer's  patent  for  obtaining  aluminium  .  .  233 

Mierzinski's  denial  of  the  successful  deposition  of  alu- 
minium from  an  aqueous  solution  of  its  salt ;  Alumin- 
ium and  nickel  plating  at  Frishmuth's  works  .  .234 

PART  XI. 
WORKING  IN  ALUMINIUM. 

Melting  aluminium ;  Deville's  instructions       .         .         .     235 

Kerl  and  Stohman's  instructions 236 

Mierzinski's  instructions;  Casting  aluminium;  Deville's 

instructions 237 

Purification  of  aluminium  ;  Freeing  from  slag,  Deville    .     238 

Process  of  Paul  Morin 239 

Watts' s  suggestion  ;  Freeing  from  impurities,  Deville     .     240 
Mierzinski's  recommendation  .         .         .         .         .242 

Buchner's  treatment  of  commercial  aluminium  to  elimi- 
nate silicon;  Mallet's  process  of  obtaining  pure  from 
commercial  aluminium  ;  Uses  of  aluminium          .         .     243 
Aluminium  plating  and  aluminium  leaf  .         .         .         .246 
Aluminium    coins  ;      Soldering    aluminium  ;      Deville's 
views  on     .         .         .         .         .         .         .         .         .247 

Hulot's  process  ;  Monrey's  solder 248 

Mierzinski's  statements  as  to  Mourey's  solder;  Improve- 
ments of  Schwarz  ;  Formulae  for  these  solders  .  .249 


CONTENTS.  XV11 

PAGE 

Frishmuth's   solders;  Kerl   and    Stohman  on   Mourey's 
solders,  with  formulae  ......     250 

Process  of  Bell  Bros 252 

Veneering  with    aluminium;  Deville's   account   of- the 

success  of  M.  Sevrard  in  1854 253 

Dr.  Clemens  Winckler  on  this  subject  .  .  .  .254 
Gilding  and  silvering  ahminium  ;  Failures  of  Deville 

and  Morin ;  Success  of  Mourey  and  Christofle  .  .  256 
Watts,  and  Kerl  and  Stohman,  on  this  subject  .  .257 

PART  XII. 
ALLOYS  OF  ALUMINIUM. 

General  remarks,  Mierzinski  .....  258 

Aluminium  and  silicon  ;  Tissier  and  Deville  .  .  .  259 
Aluminium  and  mercury ;  Statements  of  Deville  and 

Watts ;  Aluminium  amalgam  made  by  Caillet  with  the 

battery 261 

Joules' s  method  of  electrolyzing 262 

Properties  of  aluminium  amalgam ;  Fremy,  Tissier, 

Gmelin  on  this  subject         ......     263 

Aluminium  and  copper;  Tissier  Bros.,  18e8  .  .  .  264 
Deville,  1859  ;  Use  of  the  alloy  by  Christofle  ;  Alloy  de- 
scribed by  Debray  ;  Composition  of  aluminium  bronze  265 
Properties  of  aluminium  bronze  ;  M.  Lechatelier's  table 

of  its  strength ;  Experiments  by  A.  Gordon  .  .  266 
M.  Boudaret  on  its  malleability ;  Mierzinski  on  points  to 

be  attended  to  in  making  the  aluminium  bronze  .  .267 
Directions  to  be  observed  in  casting ;  Comparative 

strength  of  the  bronze 268 

Hulot's  solder ;  Fremy's  instructions  ;  Kerl  and  Stohman's 

directions 269 

Bronze  for  philosophical  instruments;  Specific  gravity 

and  strength ;    Comparative    strength  of   the   alloys ; 

Their  specific  gravities 270 


XVlll  CONTENTS. 

PAOE 

Melting  point  of  10  per  cent,  bronze  ;  B.  S.  Procter's  ex- 
periments .          .          .          .          .          .          .          .          .271 

Thurston  on  the  properties  of  aluminium  bronze     .          .     272 
Strange   and   Knight   on   the   properties    of    aluminium 

bronze 273 

Alloys  made  by  Cowles  Bros. 274 

Strength  of  these  alloys  by  the  testing  machine        .          .     27G 
Alloys    of    aluminium    and   copper   with    other   metals; 
Neogen  made  by  F.  H.  Sauvage          .         .         .         .277 

Minargent ;     P.     Baudrin's     alloy ;     James     Webster's 
patent  bronze     .          .         .         .          .          .          .          .278 

Phosphor   aluminium   bronze   made   by  Thomas   Shaw, 
Newark,  N.  J.;  Cowles  Bros.'  reports  of  the  strength 
of  aluminium  silver  castings ;   Solders  for  aluminium 
bronze  for  jeweller's  use     ......     279 

Silicon  and  aluminium  bronze,  Cowles  Bros.;  Aluminium 

and  iron;  Tissier  Bros.'  alloy;  Deville,  Rogers  .     280 

Fremy  and  Mierzinski  on  aluminium  alloys     .          .          .     282 
Ostberg's  mitis  castings,  with  description  of  the  process  .     283 
Alloy  used  by  Ostberg,  Worcester,  llass.        .         .         .     285 

Ostberg's  note  to  the  Engineering  and  Mining  Journal ; 

Watts's  note;  Mr.  Sellers's  series  of  experiments        .     286 
Aluminium  and  zinc;  Tissier  Bros.,   Deville,  Kerl  and 
Stohman,  and  Fremy  on  these  alloys  .          .          .          .287 

Aluminium  and  tin  ;   Tissier  Bros.,   Deville,   and  Keii 
and  Stohman  on  this  subject         .....     289 

Fremy,  Mierzinski,  and  M,  Bourbouze  .         .         .     290 

Aluminium  and  lead;  Tissier,  Deville,  Kerl  and  Stohman, 
and  Mierzinski  .          .         .          .          .         .          .          .291 

Aluminium  and  antimony  ;  Tissier,  and  Kerl  and  Stoh- 
man;  Aluminium  and  bismuth  ;  Tissier  and  Watts      .     292 
Aluminium  and  nickel ;  Tissier  and  Mierzinski        .          .     293 
Argentan        .....'....     294 

Minargent      .         .          . 295 

Aluminium  and  silver ;  Tissier  on  this  subject         .         .     295 


CONTENTS.  XIX 

PAflB 

Deville  ;  Kerl  and  Stohman  ;  Fremy      ....     296 

Mierzinski ;  "Tiers  Argent;"  Cowles  Bros,  on  "Alu- 
minium silver" 297 

Aluminium  and  gold ;  Tissier,  Fremy,  and  Mierzinski 
on  these  alloys 298 

Aluminium  and  platinum  ;  Tissier  ;  Aluminium  and  Cad- 
mium, Deville;  Aluminium  and  boron,  Deville  on  this 
subject 299 

Aluminium  and  carbon,  Deville  and  Cowles  ;  Aluminium 
and  gallium,  Watts,  Lecoq  de  Boisbaudran  .  .300 

Aluminium  and  titanium,  TVohler 301 

Aluminium  and  tungsten,  by  Michel,  in  Wb'hler's  labora- 
tory ;  Aluminium  and  molybdenum  ;  Experiments  by 
Michel;  Aluminium  and  manganese ;  Experiments  by 
Michel 302 

Aluminium  and  sodium  ;  Deville  and  Fremy  on  these 
alloys  ;  Aluminium  and  nitrogen,  Dr.  Hunt  .  .  303 

APPENDIX. 

Native  sulphate  of  alumina  ;    Account  of  a  deposit  in 

New  Mexico 305 

Decomposition   of    cryolite;     F.    Lauterborn's    patent; 

American  aluminium  ;   Frishmuth's  metal    .         .          .     306 
Analyses  of  same  ;  Specific  gravity  of  aluminium  ;  Gravity 
calculated  from  analyses      ......     307 

Amalgamation  of  aluminium  ......     308 

Theory  of  the  rapid  oxidation  of  aluminium  amalgam  ; 
Reduction  of  alumina ;   Experiment  on  reduction  with 
copper;  Production  and  reduction  of  aluminium  sul- 
phide ;  Fremy 's  researches  .....     309 

Investigations  by  Reichel         .          .          .          .          .          .312 

Than's  remarks 314 

Reichel's  experiments  in  reducing  aluminium  sulphide  ; 
Petitjean's  patent  .  .  .  .  .  .  315 


XX  CONTENTS. 

PAGE 

Reich  el*  8  summary         .         .         .         .         .         .         .316 

Aluminium  chloride  formed  from  the  sulphide  ;  F.  Laut- 
erborn-'s  patent 317 

Niewerth ;  Reichel ;  A.  Orlowski ;  Experiments  on  mak- 
ing aluminium  sulphide  .  .  .  .  .  .318 

Tabulated  results  ;  Remarks  and  suggestions  of  a  practical 
process 321 

Reducing  the  aluminium  sulphide 322 

Experiments  with  lead,  copper,  tin,  antimony,  and  iron ; 
Review  of  these  experiments  and  suggestions  of  a  prac- 

,    tical  process 323 


ADDENDA. 

Additional  details  of  Castner's  sodium  process  .  .324 
New  process  for  making  aluminium  chloride ;  Remarks  on 

the  mitis  process          .         .         .         .         .         .         .326 

Production  of  aluminium  in  1885;  Low  price  of  aluminium 

in  October,  1886 327 

INDEX  328 


ALUMINIUM 


PART  I. 

HISTORY  OF  ALUMINIUM. 

LAVOISIER*  first  suggested  the  existence  of  metal- 
lic bases  of  the  earths  and  alkalies.  The  first 
researches  in  the  preparation  of  aluminium  date 
back  to  1807.  Davy  tried,  but  in  vain,  to  decom- 
pose A1208  by  an  electric  current,  or  to  reduce  it 
by  vapor  of  potassium.  Oerstedt,  in  1824,  believed 
he  had  isolated  aluminium.  He  decomposed  anhy- 
drous A12C16  by  K  amalgam,  and  he  obtained, 
along  with  some  KC1,  an  amalgam  which  decom- 
posed by  heat  furnished  him  a  metal  resembling 
tin.  It  is  probable  that  he  employed  either  some 
moist  APC16  or  K  amalgam  which  contained  KOH, 
for  it  is  only  when  wetted  with  a  solution  of  KOH 
that  aluminium  alloys  with  mercury;  for,  when 
AVohler,  later,  wished  to  prepare  aluminium  by 
this  method,  he  found  it  impossible  to  obtain  an 
Al  amalgam  when  he  employed  materials  pure 

*  Fremy,  Ency. 


26  ALUMINIUM. 

and  dry.  Nevertheless,  the  method  of  Oerstedt 
marks  an  epoch  in  the  history  of  the  science,  for 
in  1827  Wohler  isolated  aluminium  by  decomposing 
APC16  by  K.  The  metal  first  isolated  by  Wohler 
was  a  gray  powder,  taking  under  the  polisher  the 
brilliancy  of  tin.  It  was  very  easily  changed, 
because  of  its  extreme  division,  and  also  because 
it  was  mixed  with  the  K  or  A12C16  used  in  excess. 
At  that  time  no  further  use  was  made  of  these 
facts.  Later,  in  1845,  on  making  vapor  of  AP016 
pass  over  potassium  placed  in  platinum  boats, 
Wohler  obtained  the  metal  in  small,  malleable 
globules  of  metallic  appearance,  from  which  he 
was  able  to  determine  the  principal  properties  of 
aluminium.  But  the  metal  thus  obtained  was 
scarcely  as  fusible  as  cast  iron,  without  doubt 
because  of  the  platinum  with  which  it  had  alloyed 
during  its  preparation.  In  addition  to  this,  it 
decomposed  water  at  100°,  from  which  we  suppose 
that  it  was  still  impregnated  with  K  or  APC16.  It 
is  to  H.  St.  Claire  Devil le  that  the  honor  belongs 

o 

of  having  in  1854  isolated  aluminium  in  a  state  of 
almost  perfect  purity,  determining  its  true  proper- 
ties. In  commencing  researches  on  aluminium, 
Deville,  while  he  applied  the  method  of  Wohler, 
was  ignorant  of  the  latter's  results  of  1845.  Besides, 
he  was  not  seeking  to  produce  aluminium  that  he 
might  turn  its  valuable  properties  to  practical  ac- 
count, but  that  it  might  serve  for  the  production 
of  A10,  which  he  believed  could  exist  as  well  as 


HISTORY   OF   ALUMINIUM.  27 

FeO.  The  aluminium  he  wished  to  prepare  would, 
he  thought,  by  its  further  reaction  on  APC16  form 
A1C12,  from  which  he  might  derive  A1O  and  the 
other  proto-salts.  But  this  proto-chloride  was  not 

thus  produced ;  he  obtained,  enclosed  in  a  mass  of 

A12C16.2KC1,  fine  globules  of  a  brilliant  substance,  - 
ductile,  malleable,  and  very  light,  capable  of  being 
melted  in  a  muffle   without  oxidizing,  attacked 
by  H^TO3  with  difficulty,  but  dissolved  easily  by 
HC1  or  KOH  with  evolution  of  hydrogen.     Recog- 
nizing the  importance  of  these  properties,  which 
he   proceeded   to   investigate  and    establish,   and 
fearing  to  see  the  honor  of  his  discovery  pass  into 
other    hands,    Deville    immediately    commenced 
research  for  an  economic  process  to  produce  alumi- 
nium.    The  task  was  difficult,  for  the  metal  could 
only  be  isolated  from  its  chloride  or  fluoride  by  ~ 
potassium  or  sodium,  of  which  only  the  former 
was  known  at  that  time.     Moreover,  potassium   I 
cost  then  900  fr.  per  kilo,  was  extremely  dangerous,    • 
and    gave    only   a   small    return   of    aluminium. 
Deville    succeeded    in    advantageously   replacing    \ 
potassium   by   sodium,  and   introduced  such   im- 
provements into  the  manufacture  of  the  latter  that 
he  reduced  the  cost  of  a  kilo  from  2000  fr.  in  1855 
to  10  fr.  in  1859.     In  order  to  produce  aluminium 
cheaply,  he  busied  himself  also  in  the  economic 
production   of  A1203,  which   gave  later  a  lively 
impulse  to  the  cryolite  and  beauxite  industries. 
The  researches  of  Deville,  at  first  undertaken  in  I 


28  ALUMINIUM. 

the  laboratory  of  the  Normal  School,  Paris,  were 
afterwards  continued  on  a  larger  scale,  thanks  to 
the  liberality  of  the  Emperor  Napoleon  III.,  at 
the  chemical  works  of  Javel.  At  this  works  were 
made  the  ingots  and  divers  objects  of  aluminium 
which  figured  at  the  Paris  Exhibition  in  1855. 
Later,  after  new  experiments  made  together  at  the 
Normal  School,  Deville,  H.  Debray,  and  P.  Morin 
set  up  a  plant  to  make  aluminium  on  a  large  scale 
at  Messrs.  Rousseau  Brothers'  works  at  Glaciere. 
The  primary  method  there  received  many  improve- 
ments. Later  on  it  was  still  further  improved 
under  the  direction  of  P.  Morin  at  the  works  in 
Nanterre.  At  last,  in  the  works  of  Messrs.  Merle 
&  Co.,  at  Salindres,  it  has  reached  its  present  stage 
^of  advancement. 

Tissier  Bros,  wrote  and  published  a  book  entitled 
'  Recherches  sur  1'Aluminium'  in  1858.  These 
brothers  were  employed  in  the  experiments  which 
Deville  superintended  at  the  laboratory  of  the 
Normal  School,  Paris,  and  Deville  charges  that 
after  learning  the  important  results  of  his  experi- 
ments they  suddenly  left  him,  taking  drawings  of 
furnaces,  details  of  processes,  etc.,  and  started  works 
themselves.  Deville  was  very  bitter  against  them, 
and  this  ill-feeling  was  increased  by  the  following 
incident :  Deville  was  collecting  material  to  write 
a  book  on  the  subject,  which  he  almost  regarded  as 
his  prerogative,  seeing  that  he  had,  so  to  speak, 
created  the  industry  ;  but,  before  he  had  completed 


HISTORY    OF    ALUMINIUM.  29 

it,  Tissier  Bros,  published  theirs.  In  order  not  to 
be  too  far  behind,  Deville  hastened  the  comple- 
tion of  his  book,  by  doing  which  he  was  unable 
to  make  it  as  full  as  he  had  wished,  and  published 
it  in  September,  1859.  Several  sharp  letters  passed 
between  Deville  and  the  Tissiers,  which  may  be 
seen  in  the  Compt.  Rend,  or  Ann.  de  Chem.  et  de 
Fhys.  A.  Tissier,  in  his  book,  thus  describes  the 
formation  and  history  of  his  works :  In  July,  1855, 
Messrs.  Maletra,  Chanu,  and  Davey,  of  Rouen, 
formed  a  company  to  produce  aluminium,  and  we 
were  entrusted  with  the  organization  and  special 
charge  of  the  industry.  The  commencement  was 
beset  with  difficulties,  not  only  in  producing,  but 
in  using  the  metal.  It  then  sold  at  §200  per  kilo, 
the  price  being  an  insurmountable  obstacle  to  its 
employment  in  the  arts.  The  small  capital  at  our 
disposal  was  not  enough  to  start  the  industry,  to 
pay  general  expenses,  and  the  losses  occasioned  by 
the  many  experiments  necessary.  On  February 
28, 1856,  the  society  was  dissolved.  In  April,  the 
same  year,  Mr.  William  Martin,  struck  by  the 
results  already  obtained,  and  sanguine  of  greater 
success,  united  with  us.  From  that  time  daily 
improvements  confirmed  M.  Martin's  hopes,  and 
in  1857  the  works  at  Amfreville-la-mi-Voie,  near 
Rouen,  sold  the  metal  at  §60  per"  kilo  (§2.00  per 
oz.).  The  laboratory  of  this  works  was  devoted 
to  researches  on  everything  concerning  the  produc- 
tion and  application  of  aluminium.  M.  Martin 

3* 


30  ALUMINIUM. 

has  our  sincere  gratitude  for  the  kindness  with 
which  he  so  willingly  encouraged  and  contributed 
to  the  progress  of  the  manufacture  of  "this  won- 
derful metal." 

Deville,  as  stated  above,  published  his  book  in 
September,  1859,  and  he  concludes  it  with  these 
words :  "  I  have  tried  to  show  that  aluminium  may 
become  a  useful  metal  by  studying  with  care  its 
physical  and  chemical  properties,  and  showing  the 
actual  state  of  its  manufacture.  As  to  the  place 
which  it  may  occupy  in  qur  daily  life,  that  will 
depend  on  the  public's  estimation  of  it  and  its 
commercial  price.  The  introduction  of  a  new 
metal  into  the  usages  of  man's  life  is  an  operation 
of  extreme  difficulty.  At  first,  aluminium  was 
spoken  of  too  highly  in  some  publications,  which 
made  it  out  to  be  a  precious  metal ;  but  later  these 
estimates  have  depreciated  even  to  the  point  of 
considering  it  attackable  by  pure  water.  The 
cause  of  this  is  the  desire  which  many  have  to  see 
taken  out  of  common  field  mud  a  metal  superior 
to  silver  itself;  the  opposite  opinion  established 
itself  because  of  very  impure  specimens  of  the 
metal  which  were  put  in  circulation.  It  seems 
now  that  the  intermediate  opinion,  that  which  I 
have  always  held  and  which  I  express  in  the  firsf 
lines  of  my  book,  is  becoming  more  public,  and 
will  stop  the  illusions  and  exaggerated  beliefs 
which  can  only  be  prejudicial  to  the  adoption  of 
aluminium  as  a  useful  metal.  Moreover,  the  in- 


HISTORY    OF   ALUMINIUM.  31 

dustry,  established  as  it  now  is,  can  be  the  cause 
of  loss  to  no  one ;  as  for  myself,  I  take  no  account 
of  the  large  part  of  my  estate  which  I  have  devoted, 
but  am  only  too  happy,  if  my  efforts  are  crowned 
with  definite  success,  in  having  made  fruitful  the 
work  of  a  man  whom  I  am  pleased  to  call  my 
friend — the  illustrious  Wohler." 

As  early  as  1856  we  find  an  article  in  an  Ameri- 
can magazine*  showing  that  there  were  already 
chemists  in  the  United  States  spending  time  and 
money  on  this  subject.  The  following  is  the  sub- 
stance of  the  article  alluded  to:  "Within  the 
last  two  years  Deville  has  extracted  50  to  60  Ibs. 
of  aluminium.  At  the  present  time,  M.  Rousseau, 
the  successor  of  Deville  in  this  manufacture,  pro- 
duces aluminium  which  he  sells  at  §100  per  pound. 
Xo  one  in  the  United  States  has  undertaken  to 
make  the  metal  until  recently  Mons.  Alfred  Mon- 
nier,  of  Camden,  X.  J.,  has,  according  to  the 
statement  of  Prof.  James  C.  Booth  in  the  c  Penn. 
Inquirer/  been  successful  in  making  sodium  by  a 
continuous  process,  so  as  to  procure  it  in  large  bars, 
and  has  made  aluminium  in  considerable  quantity, 
specimens  of  which  he  has  exhibited  to  the  Frank- 
lin Institute.  Mons.  Monnier  is  desirous  of  forming 
a  company  for  tjie  manufacture  of  aluminium,  and 
is  confident  that  by  operating  in  a  large  way  he 
can  produce  it  at  a  much  less  cost  than  has  hereto- 

*  Mining  Magazine,  1856,  vii.  317. 


32  ALUMINIUM. 

fore  been  realized.  We  would  suggest  the  pro- 
priety of  giving  aid  to  this  manufacturer  at  the 
expense  of  the  government,  for  the  introduction  of 
a  new  metal  into  the  arts  is  a  matter  of  national 
importance,  and  no  one  can  yet  realize  the  various 
and  innumerable  uses  to  which  this  new  metal  may 
be  applied.  It  would  be  quite  proper  and  consti- 
tutional for  Congress  to  appropriate  a  sum  of 
money,  to  be  expended  under  the  direction  of  the 
Secretary  of  the  Treasury  in  the  improvement  of 
this  branch  of  metallurgy,  and  in  testing  the  value 
of  the  metal  for  coinage  and  other  public  use." 

In  the  next  volume  of  the  '  Mining  Magazine'* 
there  is  a  long  article  by  Mr.  W.  J.  Taylor,  con- 
taining nothing  new  in  regard  to  the  metallurgy 
of  aluminium,  but  chiefly  concerned  in  calculating 
theoretically  the  cost  of  the  metal  from  the  raw 
materials  and  labor  required  by  Deville's  processes, 
and  concluding  that  it  is  quite  possible  to  make  it 
for  $1,00  per  pound. 

In  1874  we  have  the  following  resume  by  Kerl  & 
Stohman :  "  Deville  first  worked  under  the  direc- 
tion of  the  Paris  Academy ;  later,  the  Emperor 
Napoleon  gave  him  great  encouragement,  by  means 
of  which  he  succeeded  in  producing  several  kilos 
of  aluminium,  which  were  shown  at  the  exhibition 
in  Paris,  1855.  With  the  experience  thus  gained, 
Deville  took  possession  of  Rousseau  Bros.'  cherni- 

*  Mining  Magazine,  viii.  167  and  228.  Proc.  Ac.  Nat.  Sci., 
Jan.  1857. 


HISTORY    OF   ALUMINIUM.  66 

cal  works  at  La  Glaciere,  near  Paris.  It  soon  fol- 
lowed that  the  price  of  aluminium  was  reduced 
from  1000  fr.  per  kilo  to  300  fr.  After  a  short 
time  the  undertaking  was  enlarged,  and  the  manu- 
facture removed  to  Nanterre  and  Salindres.  The 
last  named  works,  under  the  management  of 
Usiglio,  went  into  the  possession  of  Merle.  !N"ew 
advances  made  a  further  reduction  in  price  to 
200  fr.  possible.  In  1862  the  price  was  put  down 
to  130  fr.  Another  works  was  then  established  at 
Amfrcville,  near  Rouen.  This  was  on  a  larger 
scale  than  that  at  Kauterre,  for  while  in  1859  the 
latter  produced  60  kilos,  the  former  produced  80. 
In  England  the  first  manufactory  was  established  in 
1859,  at  Battersea,  London  ;  and  the  next  year  Bell 
Bros,  started  at  Kewcastle-on-Tyne.  Germany  as 
yet  possesses  no  aluminium  works." 

The  further  we  get  away  from  an  age  the  better 
able  are  we  to  write  the  true  history  of  that  age. 
And  so,  as  years  pass  since  the  labors  of  AVohler, 
Deville,  and  Tissier,  we  are  now  able  to  see  better 
the  whole  connected  history  of  the  development 
of  this  art.  Dr.  Clemens  Winckler  gives  us  a 
comprehensive  retrospect  of  the  field  seen  from  the 
standpoint  of  1879,  from  which  we  condense  the  fol- 
lowing :*  The  history  of  the  art  of  working  in  alu- 
minium is  a  very  short  one,  so  short  that  the  present 
generation,  with  which  it  is  contemporary,  is  in 

*  Industrie  Blatter,  1879  ;  Sci.  Am.  Suppl.,  Sept.  G,  1879. 


34  ALUMINIUM. 

danger  of  overlooking  it  altogether.  The  three 
international  exhibitions  which  have  been  held  in 
Paris  since  aluminium  first  began  to  be  made  on  a 
commercial  scale  form  so  many  memorials  of  its 
career,  giving,  as  they  did,  at  almost  equal  intervals, 
evidence  of  the  progress  made  in  its  application. 
In  1855,  we  meet  for  the  first  time,  in  the  Palais  de 
1'Industrie,  with  a  large  bar  of  the  wonderful 
metal,  docketed  with  the  extravagant  name  of  the 
"  silver  from  clay."  In  1867  we  meet  with  it 
again,  worked  up  in  various  forms,  and  get  a  view 
of  the  many  difficulties  which  had  to  be  overcome 
in  producing  it  on  a  large  scale,  purifying,  and 
moulding  it.  We  find  it  present  as  sheets,  wire, 
foil,  or  worked-up  goods,  polished,  engraved,  and 
soldered,  and  see  for  the  first  time  its  most  impor- 
tant alloy — aluminium  bronze.  After  a  lapse  of 
almost  another  dozen  years  we  see  at  the  Paris 
exhibition  of  1878  the  maturity  of  the  industry. 
"We  have  passed  out  of  the  epoch  in  which  the 
metal  was  worked  up  in  single  specimens,  showing 
only  the  future  capabilities  of  the  metal,  and  we 
see  it  accepted  as  a  current  manufacture,  having  a 
regular  supply  and  demand  and  being  in  some 
regards  commercially  complete.  The  despair  which 
has  been  indulged  in  as  to  the  future  of  the  metal 
is  thus  seen  to  have  been  premature.  The  manu- 
facture of  aluminium  and  goods  made  of  it  has 
certainly  not  taken  the  extension  at  first  hoped 
for  in  its  behalf;  the  lowest  limit  of  the  cost  of 


HISTORY   OF   ALUMINIUM.  35 

manufacture  was  soon  reached,  and  aluminium 
remains  as  a  metal  won  by  expensive  operations 
from  the  cheapest  of  raw  materials. 

To  France  is  due  the  merit  of  having  been  the 
first  country  to  carry  out  Wohler's  process  on  a 
practical  scale,  and  to  have  created  the  aluminium 
industry.  France  seems  to  be  the  only  country  in 
which  the  industry  is  able  to  prosper.  The  English 
establishment  at  Newcastle-on-Tyne  by  Bell  &  Co. 
did  not  succeed,  and  has  been  shut  up  now  for 
about  live  years.  The  German  manufactory,  set 
up  in  Berlin  by  Wirz  &  Co.,  cannot  be  said  really 
to  have  lived  at  all ;  it  drooped  before  it  was  well 
started.  In  France,  the  great  chemical  works  of 
H.  Merle  &  Co.,  Salindres,  carries  on  the  extraction 
of  aluminium,  and  the  Societe  Anonyme  de  1'Alu- 
rninium,  at  Nanterre,  works  up  the  metal.  Both 
firms  were  represented  at  the  exhibition  in  1878. 

The  most  rational  use  indicated  for  aluminium 
by  reason  of  its  low  specific  gravity  is  the  making 
of  beams  for  balances.  Sartorius,  of  Gottingen, 
was  the  first  to  make  these  light  and  unalterable 
beams  of  an  alloy  of  96  aluminium  and  4  silver. 
He  has  had  but  few  imitators.  There  are  several 
reasons  why  the  metal  is  shown  so  little  favor  by 
mathematical  instrument  makers  and  others.  First 
of  all,  there  is  the  price ;  then  the  methods  of 
working  it  are  not  everywhere  known  ;  and  further, 
no  one  knows  how  to  cast  it.  Molten  aluminium 
attacks  the  common  earthen  crucible,  reduces  silicon 


36  ALUMINIUM. 

from  it,  and  becomes  gray  and  brittle.  This  incon- 
venience is  overcome  by  using  Jirne  crucibles,  or 
by  lining  an  earthen  crucible  with  carbon  or  strongly 
burnt  cryolite  clay.  If  any  one  would  take  up  the 
casting  of  aluminium  and  bring  it  into  vogue  as  a 
current  industrial  operation,  there  is  no  doubt  that 
the  metal  would  be  more  freely  used  in  the  finer 
branches  of  practical  mechanics.  The  prices  per 
kilo  quoted  in  the  last  list  issued  by  the  Societe 
Anonyme  are  as  follows : — 

ALUMINIUM. 

Bars 130  fr. 

Sheets  (0.5  to  0.1  mm.  thick)         .  135  "  to  160  fr. 

Wire  (2  to  3  mm.  diam.)         .        .  170  "   "  200  " 

ALUMINIUM  BRONZE  (10  per  cent,  aluminium). 

Bars 18  fr. 

Sheets  (2  to  0.5  mm.  thick)       .        .     24  "  to  30  fr. 
Wire  (7  to  1  mm.  diam.)  .        .        .     28  "  to  39  " 

The  preceding  paper  of  Dr.  Winckler,  as  he  re- 
marks, chronicles  the  perfection  of  Deville's  pro- 
cesses, when  aluminium  was  made  as  cheaply 
as  it  could  possibly  be  by  these  methods.  But, 
about  this  time  an  aluminium  works  was  started 
in  Birmingham,  England,  by  Mr.  Webster,  which 
has  grown  to  be  one  of  the  largest  in  the  world. 
Mr.  Webster  owns  several  patents  on  processes  of 
his  own,  which  will  be  found  described  in  their 
proper  places. 

In  the  United  States  one  of  the  most  prominent 


HISTORY    OF   ALUMINIUM. 

chemists  engaged  on  aluminium  is  Colonel  William 
Frishmuth,  of  Philadelphia.  The  following  article 
gives  an  account  of  his  invention  :*  "  Some  months 
ago,  we  published  in  the  '  Star7  the  fact  that  Colonel 
"William  Frishmuth,  well  known  in  this  city  for 
many  years,  has  discovered  a  method  for  producing 
aluminium  at  reduced  cost.  Comments  were  made 
in  various  quarters  as  to  the  real  value  of  the  discov- 
ery, some  of  which  even  questioned  the  possibility 
of  producing  the  metal  by  this  process,  which  is 
stated  to  produce  it  from  South  Carolina  corundum, 
using  sodium  as  a  reagent.  Meanwhile  patents 
have  been  taken  out  in  this  and  foreign  countries, 
and  preliminaries  are  fairly  under  way  to  test  the 
process  practically.  It  did  not  seem  too  much  to 
hope  when  the  publication  was  made  that  Ameri- 
can capitalists  would  at  once  make  investigation  of 
Colonel  Frishmuth's  discovery,  learn  whether  the 
results  were  even  measurably  up  to  the  promise, 
and  in  that  event  secure  to  themselves  a  commercial 
plant  so  extremely  important.  It  has,  however, 
fallen  to  capitalists  abroad  to  obtain  control  of  the 
patent.  At  the  present  time  Major  Ricarde-Seaver, 
F.R.S.E.,  late  Government  Inspector  of  Mines, 
London,  is  in  this  city  as  an  expert  to  examine  the 
process  and  its  practicability  on  behalf  of  these 
capitalists.  A  reporter  endeavored  to  obtain  from 
Major  Seaver  his  opinion  of  the  process,  but  he 

*  Philadelphia  Evening  Star,  November  15,  1884. 

4 


38  ALUMINIUM. 

stated  that  his  opinion  could  not  be  made  public. 
Mr.  Seaver  said  in  reference  to  aluminium  :  '  Some 
of  the  best  minds  in  Europe  have  been  studying 
for  years  the  problem  of  producing  the  metal 
cheaply.  Scientists  in  France  and  Germany  and  one 
in  Geneva  have  been  at  work  on  it  a  long  time. 
As  to  the  possibility  of  producing  it  so  that  it 
could  be  used  as  an  alloy  for  iron  and  steel,  that  is  not 
to  be  expected  unless  it  could  be  produced  at  much 
less  than  a  dollar  per  pound.  As  to  the  possibility 
of  doing  that  by  this  process,  I  am  not  at  liberty 
to  speak.  The  work  here  has  so  far  been  merely 
on  an  experimental  scale.  As  scientific  men  know 
by  many  experiences,  disappointments  are  some- 
times met  with  when  they  leave  the  experimental 
field  and  work  is  attempted  on  a  commercial  scale 
for  business  purposes.  I  am,  however,  very  much 
pleased  with  what  I  have  seen  here,  and,  as  I  have 
said,  while  scientific  men  all  over  Europe  have  been 
investigating  the  problem,  it  seems  to  be  solved 
here.  I  am  certainly  satisfied  that  aluminium  can 
be  produced  by  Frishmuth's  process,  there  is  some 
metal  made  by  it,  and  there  will  be  a  display  of  it 
at  the  NQW  Orleans  exhibition.  Even  if  it  can  be 
made  very  cheap  by  this  process,  it  is  not  probable 
that  anything  more  would  be  done  by  the  parties  I 
represent  than  to  supply  the  market  at  a  fair  price, 
just  as  the  Rothschilds,  who  own  the  great  quick- 
silver mines  of  the  world,  regulate  the  supply  by 
the  demand.' " 


HISTORY   OF   ALUMINIUM.  39 

Colonel  Frishmuth's  works  are  at  Rush  and 
Amber  streets,  near  the  Richmond  coal  wharves, 
Philadelphia.  lie  seems  to  be  kept  busy,  and  his 
metal  is  on  the  market ;  an  analysis  of  it  will  be  found 
in  the  Appendix.  It  can  be  bought  from  Bullock 
&  Crenshaw,  Philadelphia.  He  cast  the  tip  of  the 
AVashington  Monument,  which  weighs  one  hundred 
ounces,  one  of  the  largest  single  castings  of  alumin- 
ium ever  made.  As  far  as  is  known,  he  is  at  pres- 
ent the  only  producer  of  pure  aluminium  in  the 
United  States.  His  metal  is  sold  in  bars  at  about 
fifteen  dollars  per  pound.  In  the  Philadelphia  city 
census  of  1884  he  is  placed  as  employing  ten  men, 
and  his  annual  product  is  valued  at  §18,000.  Mr. 
Frishmuth  melts  down  quantities  of  aluminium 
scrap,  and  the  author  has  been  unable  to  learn,  ex- 
cept from  Mr.  Seaver's  statement,  that  Mr.  Frish- 
muth produces  any  aluminium  by  his  process.  Mr. 
Seaver  represented  an  English  syndicate  which 
stands  ready  to  buy  out  all  patents  of  any  value 
which  appear  on  aluminium ;  they  possess  large 
capital,  and  are  said  to  be  ready  to  pay  an  immense 
sum  for  any  practical,  cheap  process  for  producing 
the  metal. 

In  the  Mineral  Resources  of  the  United  States, 
1883-4,  we  find  a  few  statistics  as  to  the  amount 
of  aluminium  made  in  recent  years.  It  is  there 
stated  that  in  1882  there  were  2350  kilos  made  in 
France.  The  price  of  the  American  metal  ranged 
from  §0.75  to  §1.00  per  troy  ounce  in  1883  ;  and 


40  ALUMINIUM. 

from  $0.50  to  $1.00  per  ounce  in  1884,  according 
to  quantity.  The  amount  imported  and  entered  for 
consumption  in  the  United  States  from  1870  to  1884 
is  as  follows : — 


Year  ending  June  30, 

Quantity  (pounds). 

Value. 

1870   . 

$  98 

1871 

•        .... 

341 

1872 

. 

1873   . 

2 

22 

1874 

.  683 

2125 

1875   . 

.  434 

1355 

1876   . 

.    .    .139 

1412 

1877 

.  131 

1551 

1878   . 

.  251 

2978 

1879 

.  284 

3423 

1880 

.  341 

4042 

1881   .    .    . 

.  517 

6071 

1882   . 

.  566 

6459 

1883 

.  436 

5079 

1884'   . 

.  590 

8416 

Until  recently  the  aluminum  sold  in  the  United 
States  was  entirely  of  foreign  origin,  but  it  is  now 
produced  in  this  country  by  Colonel  Frishmuth, 
of  Philadelphia,  who  turned  out  1000  ounces  of 
the  metal  in  1883,  and  1800  ounces  in  1884.  The 
aluminium  cap  or  apex  of  the  Washington  Monu- 
ment was  cast  by  him  ;  it  is  of  pyramidal  form, 
10  inches  high,  6  inches  on  a  side  of  its  base,  and 
weighs  8J  pounds  (see  p.  53). 

Within  the  last  two  years  a  process  has  been 
invented  and  brought  into  practical  use  which  has 
served  to  bring  the  metallurgy  of  aluminium  into 


HISTORY   OF  ALUMINIUM.  41 

very  general  attention.  The  Cowles'  process,  the 
discovery  and  details  of  which  will  be  given  further 
on,  is  due  to  two  Cleveland  gentlemen,  and  they 
seem  to  be  developing  all  that  is  in  their  process. 
They  make  no  pure  metal,  but  sell  the  alloys, 
principally  aluminium  bronze,  the  latter  of  good 
quality,  and  at  a  much  lower  price  than  it  was 
ever  sold  before.  If  they  can  make  it  profitable 
to  sell  the  bronze  at  the  price  which  they  now 
quote,  the  permanent  success  of  their  process  is 
assured.  Mr.  Charles  F.  Mabery,  of  the  Case 
School  of  Applied  Science,  Cleveland,  is  their  con- 
sulting chemist,  and  Dr.  T.  Sterry  Hunt,  of  Mon- 
treal, seems  to  be  very  much  interested  in  the  pro- 
cess from  a  scientific  point  of  view.  Mr.  Mabery 
gives  his  views  as  to  the  present  state  of  the  alumi- 
nium industry  as  follows:  "The  aluminium  of 
commerce  has  been  made  chiefly  in  France  by 
Deville's  old  method.  Several  patents  have  been 
issued  for  its  prod  uction  by  electrolysis,  and  although 
it  can  be  deposited  in  small  quantities  from  solu- 
tions, there  is  but  one  electrolytic  method  that 
can  be  worked  on  a  commercial  basis,  and  that  is 
Bunsen  &  Deville's  method  of  electrolysing  molten 
Al2Cl6.2XaCl.  Large  works  have  recently  been 
erected  in  France  for  obtaining  the  metal  by  this 
method,  and  it  is  claimed  that  it  can  be  produced 
for  about  $7  per  pound.  A  company  has  recently 
been  formed  in  London  to  manufacture  aluminium 
alloys  on  the  basis  of  the  Webster  patents.  The 

4* 


42  ALUMINIUM. 

chief  improvement  on  the  old  process,  according 
to  the  patent  specifications,  is  in  the  preparation  of 
the  pure  A1203.  Frishmuth,  of  Philadelphia, 
attempts  to  produce  sodium  in  one  retort,  volatilize 
aluminium  chloride  from  another,  and  allow  the 
vapors  to  meet  in  a  third.  The  assertion  made  by 
him  at  first  that  he  could  place  the  metal  on  the 
market  at  $1.25  per  pound  has  not  been  verified." 
Dr.  Hunt,  in  reply  to  an  inquiry  as  to  the  present 
state  of  the  industry,  replies :  "  Webster,  of  Eng- 
land, is  the  chief,  perhaps  the  only,  manufacturer 
in  that  country  of  the  metal  and  its  alloys.  Messrs. 
Cowles  manufacture  the  alloys,  and  they  can  now 
make  pure  aluminium,  but  the  method  is  not  yet 
perfected  or  made  public.  The  process  of  Frish- 
muth is  not  new,  but  is  mentioned  in  Watts'  Dic- 
tionary. So  far  as  I  can  learn,  and  so  far  as  Messrs. 
Cowles  are  informed,  there  has  been  no  pure  alu- 
minium made  commercially  save  from  the  chloride 
by  use  of  sodium.  Messrs.  Cowles'  work  with 
their  large  new  dynamo  has  been  very  satisfac- 
tory." 


PART  II. 

OCCURRENCE  OF  ALUMINIUM  IN  NATURE. 

THERE  is  no  other  metal  on  the  earth  which  is 
so  widely  scattered  and  occurs  in  such  abundance. 

Al  is  not  found  metallic.  Stocker*  made  the 
statement  that  Al  occurred  as  shining  scales  in  an 
alumina  formation  at  St.  Austel,  near  Cornwall, 
but  he  was  in  error.  But  the  combinations  of  Al 
with  oxygen,  the  alkalies,  fluorine,  silicon,  and 
the  acids,  etc.,  are  so  numerous  and  occur  so  abun- 
dantly as  not  only  to  form  mountain  masses,  but  to 
be  also  the  bases  of  soils  and  clays.  Especially 
numerous  are  the  combinations  with  Si  and  other 
bases,  which,  in  the  form  of  felspar  and  mica, 
mixed  with  quartz,  form  granite.  Mierzinski 
gives  the  formulae  of  a  few  of  these  silicates  as:  — 


Orthoclase  .  .  K2Si3O"  + 

Albite  .  .  .  Na2Si3O7  +  Al2Si3O9 

Anorthite  .  .  CaSiOS-f  Al2SiO5 

K  Mica  .  .  (HK)*Al*Si*08+  (HK)2Al2Si4O'5 

Na  Mica  .  .  (HNa)2Al2Si2O8-f-  (HNa)2Al2Si4O« 

Li  Mica  .  .  (Li^KXFe^.AlWSSiO2. 

Mg  Mica  .  .  m(HK)4SiO4-f-n(Mg.Fe.H.)2SiO4-f 


*  Jrnl.  fr.  prakt.  Chenu,  06,  470. 


44  ALUMINIUM. 

These  combinations,  by  the  influence  of  the 
atmosphere,  air,  and  water,  are  decomposed,  the 
alkali  is  replaced  or  carried  away,  and  the  residues 
form  clays.  The  clays  form  soils,  and  thus  the 
surface  of  the  earth  becomes  porous  to  water  and 
fruitful.  It  is  a  curious  fact  that  Al  has  never 
been  found  in  animals  or  plants,  which  would  seem 
to  show  that  it  is  not  necessary  to  their  growth, 
and  perhaps  would  act  injuriously,  if  it  were  present, 
by  its  influence  on  the  other  materials.  Most  of  the 
Al  compounds  appear  dull  and  disagreeable,  such 
as  felspar,  mica,  pigments,  gneiss,  amphibole,  por- 
phyry, eurite,  trachyte,  etc. ;  yet  there  are  others 
possessing  extraordinary  lustre,  and  so  beautiful  as 
to  be  classed  as  precious  stones.  Some  of  these, 
with  their  formulae,  are — 

Ruby    .        .         .        .  A12Q3 

Sapphire       .         .         .  A12O3 

Garnet  ....  (Ca.Mg.Fe.Mn)3Al2Si3Oi2 

Cyanite          .        .         .  APSiO5 

Some  other  compounds  occurring  frequently 
are — 

Turquoise  .  .  .  A12P2O8.H6A12O6.2H20 

Lazulite  .  .  .  (MgFe)Al2P2O9  + Aq 

Wavellite  .  .  .  2A12P2O8.H6AK)5.9H2O 

Topaz  ....  5Al2SiO5.Al2SiF10 

Cryolite  .  .  .  Al2F3.6NaF 

Diaspore  .  .  .  H2A12O4 

Beauxite  .  .  .  H6A12O6 

Aluminite  .  .  .  A12SO6.9H2O 

Aluuite  K*SO4.A1*S3012.2H2AKO3 


OCCURRENCE   OF    ALUMINIUM    IN   NATURE.          45 

One  would  suppose  that  since  aluminium  occurs 
in  such  ahundance  over  the  whole  earth,  since  we 
literally  tread  it  under  foot,  that  it  would  he  ex- 
tracted and  applied  to  numberless  uses,  being 
made  as  abundant  and  useful  as  iron ;  but  such  is 
not  the  case. 

Beauxite  and  cryolite  are  the  minerals  most 
used  for  producing  aluminium,  and  their  preference 
lies  mainly  in  their  purity.  Native  alums  gene- 
rally contain  Fe,  which  must  be  removed  by  ex- 
pensive processes.  Some  observations  on  a  native 
alum  deposited  in  New  Mexico  will  be  found  in 
the  Appendix.  WQ  will  here  consider  at  greater 
length  only  beauxite  and  cryolite. 

BEAUXITE. 

Beauxite  is  a  combination  between  diaspor, 
A1203.3H20,  and  brown  hematite,  Fe*0».3EPO ;  or, 
it  is  diaspor  with  Al  replaced  more  or  less  by  Fe ; 
the  larger  the  amount  of  Fe  the  more  its  color 
changes  from  white  to  brown.  It  was  first  found 
in  France,  near  the  town  of  Beaux,  large  deposits 
occurring  in  the  departments  Yar  and  Benches  du 
Rhon,  extending  from  Tarascon  to  Antibes.  Seve- 
ral of  these  beds  are  a  dozen  yards  thick,  and .  160 
kilometres  in  length.  Deposits  are  also  found  in 
the  departments  of  1'Herault  and  1'Arriege.  Very 
important  beds  are  found  in  Styria,  at  Wochein, 
and  at  Freibriss,  in  Austria,  a  newly  discovered 


46 


ALUMINIUM. 


locality  where  the  mineral  is  called  Wochehrite. 
Here  it  has  a  dense,  earthy  structure,  while  that  of 
France  is  conglomerate  or  oolitic.  Deposits  similar 
to  those  of  France  are  found  in  Ireland  at  Irish 
Hill,  Straid,  and  Glenravel.  Further  deposits  are 
found  in  Hadamar  in  Hesse,  at  Klein-Steinheim, 
Langsdorff,  and  in  French  Guiana. 

The  following  analyses  give  an  idea  of  the  pecu- 
liar composition  of  this  mineral ;  besides  the  in- 
gredients given  there  are  also  traces  of  CaO,  MgO, 
SO3,  P205,  TiO2,  and  Ya203. 


a. 

b. 

c. 

d. 

e. 

/. 

A12O3    .     .     . 

60.0 

75.0 

63.16 

72.87 

44.4 

54.1 

Fe2O3    .     .     . 

25.0 

12.0 

23.55 

13.49 

30.3 

10.4 

SiO2      .     .     . 

3.0 

1.0 

4.15 

4.25 

15.0 

12.0 

K*0  and  Na2O 

... 

... 

0.79 

0.78 

... 

... 

H20      ... 

12.0 

12.0 

8.34 

8.50 

9.7 

29.9 

9- 

h. 

i. 

k. 

L 

m. 

A12O3  .  .  . 
Fe2O3  .  .  . 
SiO2  .  .  . 
K2O  and  Na2O 

64.6 
20 

7.5 

29.80 
3.67 
44.76 

48.12 
2.36 
7.95 

43.44 
2.11 
15.05 

61.89 
1.96 
6.01 

45.76 
18.96 
6.41 
0  38 

H20  .  .  . 

24.7 

13.86 

40.33 

35.70 

27.82 

27.61 

. 

n. 

0. 

P- 

1- 

r. 

A1203    .     .     . 

55.61 

76.3 

50.85 

49.02 

73.00 

FC2O3    .     .     . 

7.17 

6.2 

14.36 

12,90 

4.26 

SiO2      .     .     . 

4.41 

11.0 

5.14 

10.27 

2.15 

K2O  and  Na2O 

0.26 

0.31 

H20      ... 

32.33 

26.4 

28.38 

25.91 

18.66 

OCCURRENCE   OF   ALUMINIUM   IN   NATURE.          47 

Index : — 
a  and  b.  from  Beaux  (Deville). 

c.  dark  \  Woclieinite  (Drechsler). 

d.  light  J 

e.  red  brown  \ 

f.  yellow        >  Beauxite  from  Feisstritz  (Schnitzer). 

g.  white 

h.  white  Wocheinite  (L.  Mayer  and  O.  Wagner). 

*.  Beauxite  from  Irish  Hill. 

k.  "  "    Co.  Antrine  (Spruce). 

I  "  "    Glenravel  (F.  Hodges). 

raandw.         "  "     Hadamar  (Hesse)  (Retzlaff). 

o.  from  Klein-Steinheim  (Bischof  ). 

p  and  q.  from  LangsdorfF  (I.  Lang). 

r.  Beauxite  from  Dublin,  Ireland,  brought  to  the  Laurel 

Hill  Chemical  Works,  Brooklyn,  L.  I.,  and  there 
used  for  making  alums.  It  is  dirty  white,  hard, 
dense,  compact,  and  in  addition  to  the  ingredients 
given  above  contains 0.59  percent.  CaO,  and  some 
TiO2.  It  costs  $6  per  ton  laid  down  in  the  works. 
The  above  analysis,  made  by  Mr.  Joiiet,  is  fur- 
nished me  by  the  kindness  of  the  superintendent 
of  the  works,  Mr.  Herreshoff. 

As  is  seen  from  the  above  analyses,  the  percentage 
of  A1203  is  very  variable,  and  cannot  be  determined 
at  all  simply  by  inspection  but  only  by  an  analysis, 
for  often-  the  best-looking  specimens  are  the  lowest 
in  APO3.  For  instance,  a  beauxite  containing  62.10 
A1203,  6.11  Fe203,  5.06  SiO2,  and  20.83  H*0  was 
much  darker  and  more  impure  looking  than  that 
from  Wochein  (h)  which  contained  only  29.8  per 
cent.  APO3. 


48  ALUMINIUM. 

CRYOLITE. 

Cryolite  was  first  found  at  Ivigtuk,  in  Arksut- 
fiord,  west  coast  of  Greenland,  where  it  constitutes 
a  large  bed  or  vein  in  gneiss.  It  is  a  semi-trans- 
parent, snow-white  mineral.  When  impure  it  is 
yellowish  or  reddish,  even  sometimes  almost  black. 
It  is  shining,  sp.  gr.  2.95,  and  hardness  2.5  to  3. 
It  is  brittle,  not  infrequently  contains  FeCO3,  PbS, 
SiO2,  and  sometimes  columbite.  It  is  fusible  in 
the  flame  of  a  candle,  and  on  treatment  with  sul- 
phuric acid  yields  hydrofluoric  acid.  As  will  be 
seen  further  on,  cryolite  was  first  used  by  the  soap- 
makers  for  its  soda;  it  is  still  used  for  making  soda 
and  alumina  salts,.and  to  make  a  white  glass  which 
is  a  very  good  imitation  of  porcelain.  The  Penn- 
sylvania Salt  Company  in  Philadelphia  import  it 
from  Ivigtuk  by  the  ship-load  for  these  purposes ; 
lately  they  have  discontinued  making  the  glass. 
Cryolite  is  in  general  use  as  a  flux.  A  very  com- 
plete description  of  the  deposit  at  Ivigtuk  can  be 
found  in  Hoffman's  '  Chemische  Industrie.' 

The  only  known  deposit  of  cryolite  in  the  United 
States  is  that  found  near  Pike's  Peak,  Colorado, 
and  described  by  W.  Cross  and  W.  F.  Hillebrand 
in  the  '  American  Journal  of  Science,'  October, 
1883.  It  is  purely  of  mineralogical  importance 
and  interest,  occurring  in  small  masses  as  a  sub- 
ordinate constituent  in  certain  quartz  and  feld- 
spar veins  in  a  country  rock  of  coarse  reddish 


OCCURRENCE    OF    ALUMINIUM    IN   NATURE.          49 

granite.  Zircon,  astrophyllite,  and  columbite  are 
the  primary  associated  minerals,  the  first  only 
being  abundant. 

There  -is  no  duty  on  the  imports  of  cryolite  into 
the  United  States,  and  they  have  varied  from 
10,000  tons  in  1869  to  9000  in  1884,  costing  $9  to 
$10  per  ton. 

CORUNDUM. 

"  Till  1869,  the  sole  sources  of  corundum  were 
a  few  river  washings  in  India  and  elsewhere. 
It  was  found  in  scattered  crystals,  and  cost  twelve 
to  twenty-five  cents  per  pound.  In  1869,  in 
riding  over  a  spur  of  the  Alleghenies  in  northern 
Georgia,  I*  found  what  has  proven  to  be  an 
almost  inexhaustible  mine  of  corundum  in  the 
crysolite  serpentine,  the  first  instance  on  record  of 
the  mineral  being  found  in  situ.  Previously  it  had 
been  washed  out  of  debris  at  Cripp's  Hill,  N".  C., 
and  at  a  mine  in  West  Chester,  Pa.,  both  on  the 
slopes  of  the  crysolite  serpentine.  The  clue  being 
thus  obtained  accidentally,  about  thirty  mines  were 
shortly  afterwards  discovered  in  the  same  forma- 
tion ;  but  of  the  thousands  of  tons  thus  far  dug 
out,  the  larger  portion  has  come  from  the  mines  I 
discovered. 

"  At  present  it  can  be  bought  at  about  ten  dollars 
per  ton  at  the  mines.  It  is  nearly  pure  A12O3. 


.  W.  P.  Thompson. 


50  ALUMINIUM. 

Disapore,  a  hydrated  alumina,  is  also  found  in  the 
same  region  and  locality.  Corundum  will  proba- 
bly always  be  the  principal  source  in  America  of 
material  from  which  to  manufacture  pure  Al. 
But  in  Great  Britain,  in  all  probability,  manufac- 
turers must  look  to  alumina  prepared  artificially 
from  cryolite  or  from  Mr.  Kynaston's  sulphate  of 
alumina."* 

*  Journal  of  the  Society  of  Chemical  Industry,  April,  1886. 


PART  III. 


PHYSICAL  PROPERTIES  OF  ALUMINIUM. 

COMMERCIAL  aluminium  is  never  chemically  pure, 
and  therefore  displays  properties  varying  more  or 
less  from  those  of  the  pure  metal  according  to  the 
character  and  amount  of  impurities  present.  In 
this  treatise,  whenever  the  properties  of  aluminium 
are  mentioned,  they  must  be  understood  to  refer  to 
the  chemically  pure  metal,  and  not  to  the  commer- 
cial article,  unless  specifically  stated.  As  prelimi- 
nary to  the  presentation  of  these  properties  we  will 
here  make  some  observations  on  the  commercial 
metal  and  the  impurities  generally  found  in  it. 

In  whatever  way  aluminium  may  be  reduced, 
still  it  is  always  far  from  being  pure,  being  con- 
taminated with  iron,  silicon,  or  even  sodium  and 
lead,  as  is  shown  by  the  following  analyses : — 


Al. 

Si. 

2149 
0.454 
1.270 
0.2o 
0.70 
0.47 
2.87 
0.45 
3.70 
0.04 
0.12 
1.00 
0.40 

Fe. 

<7tt. 

P6. 

Ara. 

1    Parisian  (Salvetat)        .              ... 

92.969 
96.253 
96.890 
97.200 
92.500 
96.160 
8S.330 
92.000 
94.700 
98.290 
97.680 
97.400 
97.600 

4.882 
3.293 
1.840 
2.40 
6.80 
3.37 
2.40 
7.55 
1.60 
1.67 
2.20 
1.30 
1.40 

trace 
63*8 

o'l'o 

0.40 

trace 
trace 

0*20 
0.20 

trace 
trace 

trace 

o'  *  Berlin  (Mallet)      

4.  Mo  fin  &  Co.,  Nanterre  (Sauerwein)    . 
**'  [  Parisian  (Dumas) 

7.  Parisian  (Salvetat)     ...          ... 

9    Bonn  (Kraut)          .          ...          .     . 

}}•  j  Morin  &  Co.,  Nanterre,  1862  (Kraut) 

12.  )  (Hampe)  the  purest  he  could  buy 
13.  $     Wagner's  Jahresb.,  1877    .... 

52  ALUMINIUM. 

According  to  Rammelsberg  (Kerl's  Handbuch) 
the  Si  which  is  always  found  in  aluminium  is  in 
part  combined  with  it,  and  this  combined  Si 
changes  by  treatment  with  HC1  into  either  SiO2, 
which  remains,  or  into  SiH4,  which  escapes  ;  while 
another  part  of  the  Si  is  combined  with  the  alu- 
minium just  as  graphite  is  with  Fe ;  and  this  part 
of  the  Si  remains  on  treatment  with  acid  as  a  black 
mass,  not  oxidized  by  ignition  in  the  air.  Two 
analyses  of  aluminium  reduced  from  cryolite  by 
sodium  in  a  porcelain  crucible  gave— 


SiO2 

1. 
.     9.55 

2. 
1.85 

Free  Si    . 
Si  in  SiH4 

.     0.17 
.     0.74 

0.12 
0.58 

One  sample  of  aluminium  analyzed  by  Professor 
Rammelsburg contained  as  much  as  10.46  percent. 
Si,  and  another  sample  even  13.9  per  cent.  The 
quantity  of  Fe  varies  from  2.9  to  7.5  per  cent. 

M.  Dumas  has  found  that  aluminium  usually 
contains  gases,  about  which  he  makes  the  follow- 
ing statements  :*  "  On  submitting  aluminium  in 
a  vacuum  to  the  action  of  a  gradually  increasing 
temperature  up  to  the  softening  point  of  porcelain, 
and  letting  the  mercury  pump  continue  acting  on 
the  retort  until  it  was  completely  exhausted,  con- 
siderable quantities  of  gas  were  withdrawn.  The 
liberation  of  the  gas  from  the  metal  seems  to  take 

*  Sci.  Am.  Suppl.,  Aug.  7,  1880. 


PHYSICAL   PROPERTIES   OF  ALUMINIUM.  53 

place  suddenly  towards  a  red-white  heat.  200 
grammes  of  aluminium,  occupying  80  c.  c.,  gave 
89.5  c.  c.  of  gas,  measured  at  17°  and  755  mm. 
pressure.  The  gas  consisted  of  1.5  c.  c.  CO2  and 
88  c.  c.  H.  CO,  £T,  and  0  were  absent," 

*The  aluminium  apex  or  cap  of  the  Washington 
Monument  cast  by  Colonel  Frishmuth,of  Philadel- 
phia, has  the  following  composition : — 

Al 97.75 

Fe        .        .        .        .        .        .      1.70 

Si 0.55 

COLOR. 

Deville:  The  color  of  aluminium  is  a  beautiful 
white  with  a  slight  blue  tint,  especially  when  it  has 
been  strongly  worked.  Being  put  alongside  silver, 
their  color  is  sensibly  the  same.  However,  common 
silver,  and  especialh7  that  alloyed  with  copper,  has  a 
yellow  tinge,  making  the  aluminium  look  whiter  by 
comparison.  Tin  is  still  yellower  than  silver,  so 
that  aluminium  possesses  a  color  unlike  any  other 
useful  metal. 

Fremy :  Aluminium  has  a  fine  white  color,  just 
a  little  blue  when  compared  with  silver.  When  it 
has  been  worked,  or  when  it  contains  Fe  or  Si,  its 
blue  tint  acquires  greater  intensity.  The  commer- 
cial aluminium  resembles  silver. 


*  Mineral  Resources  of  the  United  States,  1883-84. 
5* 


54  ALUMINIUM. 

Mallet:  Absolutely  pure  aluminium  is  percepti- 
bly whiter  than  the  commercial  metal ;  on  a  cut 
surface  very  nearly  pure  tin-white,  without  bluish 
tinge,  as  far  as  could  be  judged  from  the  small 
pieces  examined. 

Mierzinski :  The  pure  white  color  of  aluminium 
is  very  brilliant ;  it  has  a  tint  lying  between  the 
color  of  tin  and  zinc,  although  on  account  of  its 
usual  blue  shading,  even  in  a  poor  light,  it  cannot 
be  confounded  with  them  or  with  any  white  metal. 

MAT. 

Deville:  Aluminium  like  silver  is  able  to  take  a 
very  beautiful  mat  which  keeps  indefinitely  in  the 
air.  It  is  obtained  easily  by  plunging  the  surface 
for  an  instant  in  a  very  dilute  solution  of  caustic 
soda,  washing  in  a  large  quantity  of  water  and  at 
last  dipping  in  strong  nitric  acid.  Under  these 
conditions,  all  the  foreign  materials  which  might 
contaminate  it,  except  silicon  in  large  proportion, 
dissolve  and  leave  the  metal  quite  white  and  with 
a  very  pleasing  appearance. 

Mierzinski:  The  peculiar  lustre  of  aluminium, 
however,  is  not  permanent.  With  time,  the  objects 
take  on  their  plain  faces  an  olive  green  coloration, 
and  look  much  less  agreeably.  Their  former  white 
color  can  be  restored  by  Mourey's  receipt,  by  placing 
them  first  in  dilute  hydrofluoric  acid,  1000  parts 


PHYSICAL   PROPERTIES   OF   ALUMINIUM.  55 

water  to  2  of  acid,  and  then  dipping  them  in  nitric 
acid. 

Bell  Bros.:  They  recommend  first  washing  the 
objects  in  benzole  or  essence  of  turpentine,  before 
treating  with  NaOH  and  HNO3,  as  above. 

POLISH  AND  LUSTRE. 

Deville:  Aluminium  may  be  polished  and  bur- 
nished easily,  but  it  is  necessary  to  employ  as  an 
intermediate  material  between  the  stone  and  polish- 
ing powder  a  mixture  of  stearic  acid  and  essence  of 
turpentine,  finishing  with  pure  essence  of  turpen- 
tine. In  general,  the  polished  surfaces  are  of  a  less 
agreeable  appearance  than  the  mat,  the  blue  tint  of 
the  metal  becoming  more  manifest.  But,  in  this 
work,  the  experience  and  practice  of  the  workers 
in  aluminium  is  far  from  being  complete ;  each  metal 
requires  a  special  way  of  working,  and  we  may  ex- 
pect yet  for  a  material  so  new  that  progress  will  be 
made  in  this  direction. 

Bell  Bros. :  Aluminium  is  easily  polished  and 
burnished.  Use  a  mixture  of  equal  parts  of  rum 
and  olive  oil  as  an  intermediate  substance  between 
the  polishing  stone  and  the  powder  used.  The 
polishing  stone  is  steeped  in  this  mixture,  and  will 
then  burnish  the  metal  as  silver  and  copper  are  bur- 
nished, care  being  taken  not  to  press  too  heavily  on 
the  burnishing  instrument. 

Kerl  &  Stohman :    The  use  of  the  old  means  of 


56  ALtMINIUM. 

polishing  and  burnishing  metals,  such  as  soap,  wine, 
vinegar,  linseed-oil,  decoction  of  marshmallow,  etc., 
is  not  effective  with  aluminium, but, on  the  contrary, 
is  even  harmful ;  because,  using  them,  the  blood 
stone  arid  the  burnishing  iron  tear  the  metal  as 
fine  stone  does  glass.  Oil  of  turpentine  has  also 
been  used,  but  with  no  good  effect.  Mourey  found, 
after  many  attempts,  that  a  mixture  of  equal  weights 
of  olive  oil  and  rum,  which  were  shaken  in  a  bottle 
till  an  emulsified  mass  resulted,  gave  a  very  bril- 
liant polish.  The  polishing  stone  is  dipped  in  this 
liquid,  and  the  metal  polished  like  silver,  except 
that  one  must  not  press  so  hard  in  shining  up. 
The  peculiar  black  streaks  which  form  under  the 
polishing  stone  need  cause  no  trouble ;  they  do  not 
injure  the  polish  in  the  least,  and  can  be  removed 
from  time  to  time  by  wiping  with  a  lump  of  cotton. 
The  best  way  to  clean  a  soiled  surface  and  remove 
grease  is  to  dip  the  object  in  benzine,  and  dry  it  in 
fine  sawdust.  Hammered  and  pressed  objects  of 
aluminium  may,  before  polishing,  be  very  easily 
ground  by  using  olive  oil  and  pumice. 

ODOR. 

Deville:  The  odor  of  pure  aluminium  is  sensibly 
nothing,  but  the  metal  strongly  charged  with 
silicon  will  exhale  the  odor  of  silicuretted  hydro- 
gen, exactly  represented  by  the  odor  of  cast  iron. 
But,  even  under  these  unfavorable  circumstances, 


PHYSICAL   PROPERTIES   OF   ALUMINIUM.  57 

the  smell  of  the  metal  is  only  appreciable  to  persons 
experienced  in  judging  very  slight  sensations  of 
this  kind. 

"Watts:  When  pure,  aluminium  is  quite  desti- 
tute of  taste  or  odor. 


TASTE. 

Deville :  Pure  aluminium  has  no  tast£,  but  the 
impure  and  odorous  metal  may  have  a  taste  like 
iron,  in  any  case  only  very  slight. 

MALLEABILITY. 

Deville:  Aluminium  may  be  forged  or  rolled 
with  as  much  perfection  as  gold  or  silver.  It  is 
beaten  into  leaves  as  easily  as  they,  and  a  very 
experienced  gold  beater,  M.  Rousseau,  has  made 
leaves  as  fine  as  those  of  gold  or  silver,  which  are 
put  up  in  books.  I  know  of  no  other  useful 
metal  able  to  stand  this  treatment.  Before  rolling 
a  bar  of  aluminium  it  is  well  to  prepare  the  metal 
by  forging  it  on  all  sides,  and  commencing  work 
with  a  hammer.  Aluminium  is  tempered  at  a 
very  low  red  heat ;  or  the  plate  is  heated  just  until 
the  black  trace  left  on  its  surface  by  a  drop  of  oil 
put  there  and  which  is  carbonized  has  entirely  dis- 
appeared. 

Mallet:  With  absolutely  pure  aluminium  the 
malleability  was  undoubtedly  improved,  the  metal 


58  ALUMINIUM. 

yielding  easily  to  the  hammer,  bearing  distortion 
well,  and  flattening  in  two  or  three  directions 
without  cracking.  It  seemed  to  be  sensibly  less 
hardened  by  hammering  than  the  ordinary  metal 
of  commerce. 

'Chemical  News,'  1859:  M.  Degousse  has  suc- 
ceeded in  beating  aluminium  into  leaves  as  thin  as 
those  obtained  of  gold  or  silver.  The  operation  is 
attended  with  a  certain  difficulty,  and  it  is  neces- 
sary to  temper  the  metal  frequently.  This  can- 
not be  done,  however,  in  the  ordinary  manner 
as  with  gold  or  silver;  only  a  very  slight  heat 
must  be  employed.  The  beating  is  done  as  usual. 
These  thin  aluminium  leaves  can  be  substituted  for 
silver  leaf.  They  have  a  less  brilliant  color,  but 
are  much  more  durable,  and  may  be  employed 
advantageously  for  decorative  purposes.  A  very 
thin  leaf  will  burn  like  paper  when  made  into  a 
roll,  with  a  brilliant  white  flame. 

Kerl  &  Stohman :  Aluminium  may  be  rolled  as 
easily  as  other  metals,  but  it  must  be  annealed 
oftener.  The  annealing  of  objects  made  of  it  is 
not  more  difficult  than  that  of  other  metals.  The 
moment  the  metal  begins  to  glow  its  annealing  is 
complete.  Those  metal-workers  who  are  anxious 
about  the  exact  point  of  time  can  rub  the  top  of 
the  article  to  be  annealed  with  a  lump  of  fat,  the 
disappearance  of  the  fat  shows  the  moment  in 
which  the  object  is  to  be  removed  from  the  anneal- 
ing oven.  Aluminium  can  also  be  pressed  or 


PHYSICAL    PROPERTIES   OF   ALUMINIUM.  59 

stamped  into  all  forms  of  hollow  and  round  vessels, 
in  a  stamping  press.  But  there  must  be  used  a 
kind  of  varnish  of  4  parts  of  oil  of  turpentine  and 
1  part  of  stearic  acid. 

Bell  Bros. :  Aluminium  can  be  beaten  out,  hot 
or  cold,  to  the  same  extent  and  as  perfectly  as  gold 
and  silver,  and  may  be  rolled  in  much  the  same 
way.  Thin  leaves  may  be  used  in  the  same  man- 
ner as  gold  and  silver  leaf.  Covered  iron  ingot 
moulds  serve  best  for  casting  bars  of  the  metal  to 
be  rolled.  Aluminium  quickly  loses  its  temper, 
and  therefore  requires  frequent  reheating  at  a  dull 
red  heat ;  when  the  plates  are  very  thin  this  de- 
mands great  attention. 

Mierzinski:  The  extensibility  of  aluminium  is 
quite  high,  standing  near  to  gold  and  silver.  It 
may  easily  be  beaten  out  or  rolled  without  tearing. 
In  beating  to  leaf  it  should  at  first  be  warmed  only 
to  100°  or  150°,  an  actual  glowing  heat  has  proved 
to  be  very  unsuitable.  Such  leaves  are  especially 
suitable  for  showing  the  characteristic  qualities  of 
the  metal ;  for  instance,  it  dissolves  with  extraor- 
dinary quickness  in  caustic  alkali,  leaving  the  iron, 
which  is  always  present.  This  leaf  is  also  very 
combustible,  even  in  a  gas  flame,  burning  with  a 
brilliant,  sparkling  light ;  the  resulting  A1203  is 
melted,  and  as  hard  as  corundum.  While  water 
does  not  appear  to  be  decomposed  by  aluminium 
in  compact  masses  at  100°,  yet  it  does  so  when  in 
the  extremely  attenuated  form  of  leaf.  In  pure, 


60  ALUMINIUM. 

boiling  water  the  leaf  slowly  evolves  hydrogen, 
after  several  hours  the  leaves  are  half  gone,  being 
changed  into  hydrated  alumina.  Aluminium  leaf 
was  first  made  by  C.  Falk  &  Co.,  Vienna. 

.    DUCTILITY. 

Deville :  Aluminium  behaves  very  well  at  the 
drawing  plate.  M.  Yangeois  obtained  in  1855, 
with  a  metal  far  from  being  pure,  wires  of  extreme 
tenuity,  which  were  used  to  make  aluminium  pas- 
sementere.  However,  the  metal  deteriorates  much 
in  the  operation,  and  the  threads  become  flexible 
again  only  after  an  annealing  very  delicately  per- 
formed, because  of  the  fineness  of  the  threads  and 
the  fusibility  of  the  metal.  The  heat  of  the  air 
coming  from  the  top  of  the  chimney  over  an  Ar- 
gand  burner  is  sufficient  to  anneal  them. 

Bell  Bros. :  Aluminium  is  easily  drawn  into 
wire.  Run  the  metal  into  an  open  mould,  so  as  to 
form  a  flat  bar  of  about  one-half  inch  section,  the 
edges  of  which  are  beaten  very  regularly  with  a 
hammer.  The  diameter  should  be  very  gradually 
reduced  at  first,  with  frequent  heating.  When  the 
threads  are  required  very  fine  the  heating  becomes 
a  very  delicate  operation,  on  account  of  the  fine- 
ness of  the  threads  and  the  fusibility  of  the  metal. 


PHYSICAL  PROPERTIES  OF  ALUMINIUM.        61 

ELASTICITY — TENACITY — HARDNESS. 

Deville:  The  elasticity  of  aluminium,  according 
to  M.  Wertheirn,  is  sensibly  the  same  as  that  of 
silver;  its  tenacity  is  also  nearly  the  same.  The 
moment  after  being  cast  it  has  the  hardness  of  virgin 
silver ;  when  it  has  been  worked  it  resembles  that 
of  soft  iron,  becomes  elastic  by  becoming  much  more 
rigid,  and  gives  the  sound  of  steel  when  dropped 
on  a  hard  body. 

Mallet:  Absolutely  pure  aluminium  was  dis- 
tinctly softer  than  before  purification.  Hence  its 
fracture  was  not  easily  observed,  but  seemed  to  be 
very  fine  grained  with  some  appearance  of  fibrous 
silkiness.  It  seemed  to  be  sensibly  less  hardened 
by  hammering  than  the  ordinary  metal  of  com- 
merce. 

Fremy :  Aluminium  just  cast  is  scratched  by  a 
wire  or  edge  of  silver,  but  by  hammering  it  be- 
comes as  hard  as  iron  and  elastic.  The  tenacity  of 
aluminium  wire  is  between  that  of  zinc  and  tin, 
but  by  hammering  it  attains  that  of  hardened  cop- 
per. When  cast  carefully  it  can  be  easily  filed 
without  fouling  the  tool. 

Kerl  &  Stohman  :  Aluminium  resists  the  action 
of  the  engraving  tool,  which  slides  upon  the  sur- 
face of  the  metal  as  upon  hard  glass.  But  as  soon 
as  one  uses  the  varnish  of  4  parts  of  oil  of  turpen- 
tine and  1  of  stearic  acid,  or  some  olive  oil  mixed 
with  rum,  the  tool  cuts  into  it  like  pure  copper. 


62  ALUMINIUM. 

Mierzinski :  The  tenacity  of  aluminium  is  very 
remarkable,  and,  according  to  Barlow,  is  1892  kilos 
per  square  centimetre ;  the  extensibility  2.5  per  cent. 

W.  H.  Barlow  :*  A  ba-r  of  aluminium  three  feet 
long  and  one-quarter  inch  square  was  obtained,  and 
different  parts  of  it  subjected  to  tests  for  tension, 
compression,  and  transverse  strain,  elasticity,  elastic 
range,  and  ductility.  It  will  be  seen  on  reference 
to  the  results  that  the  weight  of  a  cubic  inch  was 
0.0275  pound,  showing  a  specific  gravity  of  2.688, 
and  its  ultimate  tensile  strength  was  about  twelve 
tons  per  square  inch.  The  range  of  elasticity  is 
large,  the  extreme  to  the  yielding  point  being  one- 
two  hundredth  of  the  length.  The  modulus  of 
elasticity  is  10,000.  The  ductility  in  samples  two 
inches  long  was  2.5  per  cent.  Taking  the  tensile 
strength  of  the  metal  in  relation  to  its  weight,  it 
shows  a  high  mechanical  value.  These  results  are 
thus  tabulated : — 

Weight  of       Tensile        Length  of  a 
1  cubic  foot    strength  bar  able  to  sup- 
in  pounds,   persq.in.  port  its  weight, 
in  pounds.          in  feet. 

Cast  Fe      .         .        .        .444  16,500  5351 

Bronze       .         .        .        .525  36,000  9893 

Wrought  Fe       .                      480  50,000  15,000 

Steel 490  78,000  23,040 

Al 168  26,800  23,040 

It  thus  appears  that  taking  the  strength  of  alu- 
minium in  relation  to  its  weight,  it  possesses  a 

*  Rpt.  Brit.  A.  A.  S.,  1882,  p.  668. 


PHYSICAL   PROPERTIES   OF    ALUMINIUM.  63 

mechanical  value  about  equal  to  that  of  steel  of 
35  tons  per  square  inch  tensile  strength. 

Mierzinski:  Kamarsch  (Dingier  172,  55)  obtains 
the  following  results  as  the  strength  of  aluminium 
wire : — 

DIAMETER.  TBKSII.E  STRENGTH,  GRAMMES.  TENACITY. 

Millimetres.  1st  trial.  2d  trial.     Mean.     Kilos  per  sq.  millimetre. 

0.225  661  653  657  12.975 

0.205  524  506  515  12.255 

0.160  307  311  309  12.700 

0.145  246  252  249  11.845 


SONOROUSNESS. 

Deville:  A  very  curious  property,  which  alumi- 
nium shows  the  more  the  purer  it  is,  is  its  excessive 
sonorousness,  so  that  a  bar  of  it  suspended  by  a 
fine  wire  and  struck  sounds  like  a  crystal  bell. 
M.  Lissajous,  who  with  me  observed  this  property, 
has  taken  advantage  of  it  to  construct  tuning  forks 
of  aluminium,  which  vibrate  very  well.  I  also 
tried  to  cast  a  bell,  which  has  been  sent  to  the 
Royal  Institution  at  London  at  the  request  of  my 
friend  Rev.  J.  Barlow,  vice-president  and  secretary 
of  the  institution.  This  bell,  cast  on  a  model  not 
well  adapted  to  the  qualities  of  the  metal,  gives  a 
sharp  sound  of  considerable  intensity,  but  which 
is  not  prolonged,  as  if  the  clapper  or  support  hin- 
dered the  sound,  which,  thus  hindered,  becomes 
far  from  agreeable.  The  sound  produced  by  the 
ingots  is,  on  the  contrary,  very  pure  and  prolonged. 


64  ALUMINIUM. 

Ill  the  experiments  made  in  Mr.  Faraday's  labora- 
tory, this  celebrated  physicist  has  remarked  that 
the  sound  produced  by  an  ingot  of  aluminium  is 
riot  simple.  One  can  distinguish,  by  turning  the 
vibrating  ingot,  two  sounds  very  near  together 
and  succeeding  each  other  rapidly,  according  as  one 
or  the  other  face  of  the  ingot  faces  the  observer. 

Watts:  Aluminium  is  highly  sonorous,  but  a 
bell  cast  of  it  gave  a  sound  like  a  cracked  pot. 

DENSITY. 

Deville  :  The  density  of  aluminium  is  2.56  ;  by 
rolling  this  is  considerably  increased,  so  as  to  become 
2.67,  indicating  a  considerable  approaching  of  the 
molecules  to  each  other;  which  may  explain  the 
differences  existing  in  its  properties  after  being 
annealed  or  worked.  Heated  to  100°  and  cooled, 
it  changes  very  little,  for  its  specific  gravity  is 
still  2.65.  The  following  table  compares  it  with 
the  other  metals  :  —  • 


Pt 

Au 
Pb 
Hg 
Cu 
Fe 
Sn 
Zn 
Al 


Sp.Gr. 

21.5 

Sp.Gr.  Al.= 
8  6 

19.3 
11.4 

7.7 
4.8 

10.5 
8.9 

4.2 

3.6 

7.8 
7.3 

2.9 

2  8 

7.1 
2.5 

2.8 
1.0 

PHYSICAL    PROPERTIES    OF   ALUMINIUM.  65 

Since  the  metal  has  been  in  commerce  it  has 
been  sold  at  a  high  price ;  at  present  (1859)  it  can 
be  bought  in  large  quantities  at  300  fr.  per  kilo ; 
it  is,  therefore,  much  dearer  than  silver.  But, 
because  of  the  difference  in  their  densities,  for 
equal  volumes  of  aluminium  and  silver,  the  value 
of  the  former  must  be  divided  by  4  in  order  to 
compare  them;  making  a  volume  of  aluminium 
much  cheaper  than  an  equal  volume  of  silver, 
while,  besides,  it  is  much  stronger.  So,  to-day, 
Al  may  be  considered  as  costing  75  fr.  to  Ag 
220  fr. 

Mallet:  The  specific  gravity  of  absolutely  pure 
aluminium  was  carefully  determined  at  4°  C.,  and 
the  mean  of  three  closely  agreeing  observations 
gave  2.583. 

FUSIBILITY. 

Deville:  Aluminium  melts  at  a  temperature 
higher  than  that  of  zinc,  lower  than  that  of  silver, 
but  approaching  nearer  to  that  of  zinc  than  silver. 
It  is,  therefore,  quite  a  fusible  metal. 

Mallet :  It  seems  that  pure  aluminium  is  a  little 
less  fusible  than  the  commercial  metal. 

Mierzinski:  The  melting  point  of  aluminium 
can  be  taken  as  about  700°  C. 


66  ALUMINIUM. 

FIXITY. 

Deville:  Aluminium  is  absolutely  fixed,  and 
loses  no  part  of  its  weight  when  it  is  violently 
heated  in  a  forge  fire  in  a  carbon  crucible. 

Watts:  Aluminium  heated  in  a  closed  vessel 
does  not  exhibit  the  slightest  tendency  to  volatilize. 

Fremy :  Aluminium  is  fixed  at  all  temperatures. 

ELECTRIC  CONDUCTIVITY. 

Deville:  Aluminium  conducts  electricity  #rith 
great  facility,  so  that  it  may  be  considered  as  one 
of  the  best  conductors  known,  and  perhaps  equal 
to  silver.  I  found  by  Wheatstone's  Bridge  that 
it  conducts  eight  times  better  than  iron.  M.  Buff* 
has  arrived  at  results  evidently  different  from 
mine  because  we  have  not  taken  the  same  ground 
of  comparison.  The  difference  is  due,  without 
doubt,  to  the  metal  which  he  employed  containing, 
as  is  easily  found  in  many  specimens,  a  little  cryo- 
lite and  fusible  materials,  the  density  of  which  is 
near  that  of  the  metal,  and  which  were  employed 
in  producing  it.  The  complete  separation  of  the 
metal  and  flux  is  a  difficult  mechanical  operation, 
but  which  is  altogether  avoided  by  using  a  vola- 
tile flux.  This  is  a  condition  which  must  be  sub- 
mitted to  in  order  to  get  the  metal  absolutely 
pure. 

'  Jahresb.  der  Chemie,'  1881,  p.  94:  Aluminium 


PHYSICAL    PROPERTIES   OF   ALUMINIUM.  67 

thus  compares  with  copper  and  magnesium  in  elec- 
tric conductivity : — 

At  0°.  At  100°. 

Cu  ....     45.74  33.82 

Mg  ....    24.47  17.50 

Al  ....     22.46  17.31 

After  Al  come  red  brass,  Cd,  yellow  brass,  Fe, 
Zn,  Pb,  Ag,  Sb,  Bi,  in  the  order  given. 

Fremy :  The  electric  conductivity  of  aluminium 
is  51.5,  copper  being  100 ;  or  33.74,  silver  being 
100. 

THERMAL  CONDUCTIVITY. 

Deville:  It  is  generally  admitted  that  conductiv- 
ity for  heat  and  electricity  correspond  exactly  in 
the  different  metals.  A  very  simple  experiment 
made  by  Mr.  Faraday  in  his  laboratory  seems  to 
place  aluminium  very  high  among  metallic  con- 
ductors. He  found  that  it  conducted  heat  better 
than  silver  or  copper. 

Watts:  Aluminium  conducts  heat  better  than 
silver. 

4  Jahresb.  der  Chemie,'  1881,  p.  94:  Aluminium 
has  the  following  conductivity  for  heat: — 

AtO°.  At  100°. 

Cu         ....     0.7198  0.7226 

Mg  0.3760  0.3760 

Al          ....     0.3435  0.3619 

After  Al  come  red  brass,  Cd,  yellow  brass,  Fe, 
Zn,  Pb,  Ag,  Sb,  Bi  in  the  order  given. 


68  ALUMINIUM. 

Mierzinski:  No  less  remarkable  than  the  con- 
ductivity of  aluminium  for  electricity  is  that  for 
heat.  According  to  Calvert  and  Johnson  (Dingier, 
153,  285),  that  of  silver  being  1000,  aluminium  is 
665. 

SPECIFIC  HEAT. 

Deville:  According  to  the  experiments  of  M. 
Regnault,  the  specific  heat  of  aluminium  corre- 
sponds to  its  equivalent  13.75,  from  which  we  may 
conclude  that  it  must  be  very  large  when  compared 
with  all  the  other  useful  metals.  One  can  easily 
perceive  this  curious  property  by  the  considerable 
time  which  it  takes  an  ingot  of  the  metal  to  get 
cold.  We  might  even  suggest  that  a  plate  of  alu- 
minium would  make  a  good  chafing  dish.  Another 
experiment  makes  this  conclusion  very  evident. 
M.  Paul  Morin  had  the  idea  to  use  aluminium  for 
a  plate  on  which  to  cook  eggs,. the  sulphur  of  which 
attacked  silver  so  easily ;  and  he  obtained  excellent 
results.  He  noticed,  also,  that  the  plate  kept  its 
heat  a  much  longer  time  than  the  silver  one.  This 
exceptional  property  should  be  utilized  for  some- 
thing. 

Mallet:  The  specific  heat  of  absolutely  pure 
aluminium  was  0.2253,  therefore  the  atomic  heat 
is  0.2253  times  27.02  or  6.09. 

Fremy :     The    specific   heat   of   aluminium    is 


PHYSICAL   PROPERTIES   OF   ALUMINIUM.  69 

0.2181 ;  larger  than  that  of  any  other  useful  metal, 
which  accords  with  its  small  atomic  weight. 

MAGNETISM. 

Deville:  I  have  found,  as  also  MM.  Poggen- 
dorfF  and  Reiss,  that  aluminium  is  very  feebly 
magnetic. 

CRYSTALLINE  FORM. 

Deville :  Aluminium  often  presents  a  crystalline 
appearance  when  it  has  been  cooled  slowly.  When 
it  is  not  pure  the  little  crystals  which  form  are 
needles,  and  cross  each  other  in  all  directions. 
When  it  is  almost  pure  it  still  crystallizes  by 
fusion,  but  with  difficulty,  and  one  may  observe 
on  the  surface  of  the  ingots  hexagons  which  ap- 
pear regularly  parallel  along  lines  which  centre  in 
the  middle  of  the  polygon.  It  is  an  error  to  con- 
clude from  this  observation  that  the  metal  crystal- 
lizes in  the  rhombohedral  system.  It  is  evident 
that  a  crystal  of  the  regular  system  may  present  a 
hexagonal  section ;  while,  on  the  other  hand,  in 
preparing  aluminium  by  the  battery  at  a  low  tem- 
perature, I  have  observed  complete  octahedrons, 
which  were  impossible  of  measurement,  it  is  true, 
but  their  angles  appeared  equal. 


PART  IV. 

CHEMICAL  PROPERTIES  OF  ALUMINIUM. 

REMARK:  Unless  specifically  stated  otherwise, 
the  properties  here  mentioned  are  those  of  the 
pure  metal  and  not  of  the  commercial,  the  impuri- 
ties of  which  generally  modify  the  properties  of 
the  aluminium  more  or  less. 

ACTION  OF  AIR. 

Deville:  Air,  wet  or  dry,  has  absolutely  no 
action  on  aluminium.  No  observation  which  has 
come  to  my  knowledge  is  contrary  to  this  assertion, 
which  may  easily  be  proved  by  any  one.  I  have 
known  of  beams  of  balances,  weights,  plaques, 
polished  leaf,  reflectors,  etc.,  of  the  metal  exposed 
for  months  to  moist  air  and  sulphur  vapors,  and 
showing  no  trace  of  alteration.  We  know  that 
aluminium  may  be  melted  in  the  air  with  impun- 
ity. Therefore  air  and  also  oxygen  cannot  sensi- 
bly affect  it ;  it  resisted  oxidation  in  the  air  at  the 
highest  heat  I  could  produce  in  a  cupel  furnace,  a 
heat  much  higher  than  that  required  for  the  assay 
of  gold.  This  experiment  is  interesting,  especially 


CHEMICAL   PROPERTIES   OF   ALUMINIUM.  71 

when  the  metallic  button  is  covered  with  a  layer 
of  oxide  which  tarnishes  it,  the  expansion  of  the 
metal  causes  small  branches  to  shoot  from  its  sur- 
face, which  are  very  brilliant,  and  do  not  lose  their 
lustre  in  spite  of  the  oxidizing  atmosphere.  M. 
Wbhler  has  also  observed  this  property  on  trying 
to  melt  the  metal  with  a  blowpipe.  M.  Peligot 
has  profited  by  it  to  cupel  aluminium.  I  have 
seen  buttons  of  impure  metal  cupelled  with  lead 
and  become  very  malleable. 

With  pure  aluminium  the  resistance  of  the  metal 
to  direct  oxidation  is  so  considerable  that  at  the 
melting  point  of  platinum  it  is  hardly  appreciably 
touched,  and  does  not  lose  its  lustre.  It  is  well 
known  that  the  more  oxidizable  metals  take  this 
property  away  from  it.  But  silicon  itself,  which 
is  much  less  oxidizable,  when  alloyed  with  it 
makes  it  burn  with  great  brilliancy,  because  there 
is  formed  a  silicate  of  aluminium. 

Watts :  Aluminium  may  be  heated  intensely  in 
a  current  of  air  in  a  muffle  without  undergoing 
more  than  superficial  oxidation.  When  heated  as 
foil  with  a  splinter  of  wood  in  a  current  of  oxygen 
it  burns  with  a  brilliant,  bluish-white  light. 

1  Chemical  News,'  1859 :  Wohler  finds  that  alu- 
minium leaf  burns  brightly  in  air  and  in  oxygen 
with  a  brilliant  light.  The  A1203  formed  is  as 
hard  as  corundum.  Wire  burns  in  oxygen  like 
iron  wire,  but  the  combustion  cannot  continue  be- 
cause the  wire  fuses. 


72  ALUMINIUM. 

Mterzinski:  Aluminium  does  not  change  at  a 
somewhat  high  temperature  in  the  air;  hut  if 
heated  to  whiteness  it  burns,  with  the  production 
of  strong  light,  to  A1203,  which  covers  the  surface 
of  the  bath. 

ACTION  OF  WATER  (H20). 

Deville:  "Water  has  no  action  on  aluminium, 
either  at  ordinary  temperatures,  or  at  100°,  or  at 
a  red  heat  bordering  on  the  fusing  point  of  the 
metal.  I  boiled  a  fine  wire  in  water  for  half  an 
hour  and  it  lost  not  a  particle  in  weight.  The 
same  wire  was  put  in  a  glass-tube  heated  to  red- 
ness by  an  alcohol  lamp  and  traversed  by  a  current 
of  steam,  but  after  several  hours  it  had  not  lost  its 
polish,  and  had  the  same  weight.  To  obtain  any 
sensible  action  it  is  necessary  to  operate  at  the 
highest  heat  of  a  reverberatory  furnace,  a  white 
heat.  Even  then  the  oxidation  is  so  feeble  that  it 
develops  only  in  spots,  producing  almost  inappre- 
ciable quantities  of  APO3.  This  slight  alteration 
and  the  analogies  of  the  metal  allow  us  to  admit 
that  it  decomposes  water,  but  very  feebly.  If, 
however,  metal  produced  by  M.  Rose's  method 
was  used,  which  is  almost  unavoidably  contami- 
nated with  slag 'composed  of  chlorides  of  alumin- 
ium and  sodium,  the  A12C16,  in  presence  of  water, 
plays  the  part  of  an  acid  towards  aluminium,  dis- 
engaging hydrogen  with  the  formation  of  a  sub- 


CHEMICAL    PROPERTIES   OF   ALUMINIUM.  73 

chlorhydrate  of  alumina,  whose  composition  is  not 
known,  and  which  is  soluble  in  water.  When  the 
metal  thus  tarnishes  in  water  one  may  be  sure  to 
find  chlorine  in  the  water  on  testing  it  with  nitrate 
of  silver. 

Mierzinski:  Cold  and  warm  water  have  no 
influence  on  aluminium  even  if  it  is  heated  to 
redness. 

4  Chemical  Xews,'  1859 :  Aluminium  leaf  will 
slowly  decompose  water  at  100° ;  at  first  it  takes 
a  bronze  color,  and  after  boiling  some  hours  it 
becomes  translucent. 

ACTION  OF  HYDROGEN  SULPHIDE  AND  SULPHUR 
(H2S  and  S). 

Deville:  Sulphuretted  hydrogen  exercises  no 
action  on  aluminium,  as  may  be  proved  by  leaving 
the  metal  in  an  aqueous  solution  of  the  gas.  In 
these  circumstances  almost  all  the  metals,  and 
especially  silver,  blacken  with  great  rapidity. 
Sulph-hydrate  of  ammonia  may  be  evaporated  on 
an  aluminium  leaf,  leaving  on  the  metal  only  a 
deposit  of  sulphur  which  the  least  heat  drives 
away. 

Aluminium  may  be  heated  in  a  glass  tube  to  a 
red  heat  in  vapor  of  sulphur  without  altering  the 
metal.  This  resistance  is  such  that  in  melting 
together  poly  sulphide  of  potassium  and  some 
aluminium  containing  copper  or  iron,  the  latter  are 
7 


74  ALUMINIUM. 

attacked  without  the  aluminium  being  sensibly 
affected.  Unhappily,  this  method  of  purification 
may  not  be  employed  because  of  the  protection 
which  aluminium  exercises  over  foreign  metals. 
Under  the  same  circumstances  gold  and  silver  dis- 
solve up  very  rapidly.  However,  at  a  high  tempera- 
ture I  have  observed  that  it  combines  directly  with 
sulphur  to  give  A12S3.  These  properties  varying 
so  much  with  the  temperature  form  one  of  the 
special  characteristics  of  the  metal  and  its  alloys. 

Fremy :  H2S  is  without  action  on  aluminium, 
acting  towards  it  as  towards  the  sulphides  of  iron, 
zinc,  or  copper.  It  is  true  that  aluminium  decom- 
poses Ag2S,  but  it  sets  the  sulphur  at  liberty  and 
combines  with  the  silver.  These  facts  are  in  ac- 
cordance with  the  resistance  the  metal  offers  to 
free  sulphur. 

SULPHURIC  ACID  (H2S04). 

Deville :  Sulphuric  acid,  diluted  in  the  propor- 
tion most  suitable  for  attacking  the  metals  which 
decompose  water,  has  no  action  on  aluminium ;  and 
contact  with  a  foreign  metal  does  riot  help,  as  with 
zinc,  the  solution  of  the  metal,  according  to  M.  de 
la  Rive.  This  singular  fact  tends  to  remove  alu- 
minium considerably  from,  those  metals.  To 
establish  it  better,  I  left  for  several  months  some 
globules  weighing  only  a  few  milligrammes  in  con- 
tact with  weak  H2S04,  and  they  showed  no  visible 


CHEMICAL   PROPERTIES   OF   ALUMINIUM.  75 

alteration;  however  the  acid  gave  a  faint  precipi- 
tate with  aqua  ammonia. 

Fremy  :  H2S04,  dilute  or  concentrated,  exercises 
in  the  cold  only  a  very  slight  sensible  action  on 
aluminium,  the  pure  metal  is  attacked  more  slowly 
than  when  it  contains  foreign  metals.  The  presence 
of  silicon  gives  rise  to  a  disengagement  of  Sill4, 
which  communicates  to  the  hydrogen  set  free  a 
tainted  odor.  Concentrated  H2S04  dissolves  it 
rapidly  with  the  aid  of  heat,  disengaging  sulphurous 
acid  gas  (SO2). 

NITRIC  ACID  (UNO3). 

Deville:  Nitric  acid,  weak  or  concentrated,  does 
not  act  on  aluminium  at  the  ordinary  temperature. 
In  boiling  HXO3  the  solution  takes  place,  but  with 
such  slowness  that  I  had  to  give  up  this  mode  of  dis- 
„  solving  the  metal  in  my  analyses.  By  cooling  the 
solution  all  action  ceases.  M.  Hulot  has  obtained 
good  results  on  substituting  aluminium  for  plati- 
num in  the  Grove  battery. 

HYDROCHLORIC  ACID  (HC1). 

Deville:  The  true  solvent  of  aluminium  is  HC1, 
weak  or  concentrated ;  but,  when  the  metal  is  per- 
fectly pure,  the  reaction  takes  place  so  slowly  that 
M.  Favre,  of  Marseilles,  had  to  give  up  this  way  of 
attack  in  determining  the  heat  of  a  combination  of 


76  ALUMINIUM. 

the  metal.  But  impure  aluminium  is  dissolved 
very  rapidly.  At  a  very  low  temperature  gaseous 
HC1  attacks  the  metal  and  changes  it  into  A12C16. 
Under  these  circumstances  iron  does  not  seem  to 
alter;  able,  no  doubt,  to  resist  by  covering  itself 
with  a  very  thin  protecting  layer  of  FeCl2.  This 
experiment  would  lead  me  to  admit  that  it  is  the 
HC1  and  not  the  water  which  is  decomposed  by 
aluminium;  and,  in  fact,  the  metal  is  attacked 
more  easily  as  the  acid  is  more  concentrated.  This 
explains  the  difference  of  the  action  of  solutions  of 
HC1  and  H2S04,  the  latter  being  almost  inactive. 
This  reasoning  applies  also  to  tin. 

When  the  metal  contains  silicon,  it  disengages 
hydrogen  of  a  more  disagreeable  smell  than  that 
given  out  by  iron  under  similar  circumstances. 
The  reason  of  this  is  the  production  of  that  remark- 
able body  recently  discovered  by  MM.  Wohler 
and  Buff — Sill4.  "When  the  proportion  of  silicon  is 
small,  the  whole  is  evolved  as  gas ;  when  in- 
creased a  little,  some  remains  in  solution  with  the 
aluminium,  and  then  it  requires  great  care  to 
separate  the  metal  exactly,  even  when  the  solution 
is  evaporated  to  dryness.  If  3  to  5  per  cent,  of  Si 
is  present,  it  remains  insoluble  mixed  with  a  little 
SiO2,  as  has  been  cleverly  proven  by  Wohler  and 
Buff  by  the  action  of  hydrofluoric  acid,  which  dis- 
solves the  SiO2  with  evolution  of  H  without  attack- 
ing the  Si  itself.  On  dissolving  commercial  alu- 
minium there  is  sometimes  obtained  a  black, 


CHEMICAL    PROPERTIES   OF    ALUMINIUM.  77 

crystalline  residue,  which,  separated  on  a  filter  and 
dried  at  200°  to  300°  takes  fire  in  places;  this 
residue  is  Si  mixed  with  some  SiO2.  The  presence 
of  Si  augments  very  much  the  facility  with  which 
Al  is  attacked  by  HC1. 

Mierzinski:  If  HC1  is  present  in  a  mixture  of 
acids,  it  begins  the  destruction  of  the  metal.  HI, 
HBr,  and  HF  act  similarly  to  HC1. 


POTASH,  SODA,  AND  LIME  (KOH,  ^"aOH,  Ca(OH)2). 

Deville  :  Alkaline  solutions  act  with  great  energy 
on  the  metal,  transforming  it  into  aluminate  of 
potash  or  soda,  setting  free  hydrogen.  However, 
it  is  not  attacked  by  KOH  or  !N"aOH  in  fusion  ; 
one  may,  in  fact,  drop  a  globule  of  the  pure  metal 
into  melted  caustic  st>da  raised  almost  to  a  red 
heat  in  a  silver  vessel,  without  observing  the  least 
disengagement  of  hydrogen.  Silicon,  on  the  con- 
trary, dissolves  with  great  energy  under  the  same 
circumstances.  I  have  employed  melted  £TaOH  to 
clean  siliceous  aluminium.  The  piece  is  dipped 
into  melted  XaOH  kept  almost  at  red  heat.  At 
the  moment  of  immersion  several  bubbles  of  H 
disengage  from  the  metallic  surface,  and  when  they 
have  disappeared,  all  the  Si  of  the  superficial  layer 
of  Al  has  been  dissolved.  It  only  remains  to  wash 
well  with  water  and  dip  it  into  nitric  acid,  when 
the  aluminium  takes  a  beautiful  mat. 

Mallet  :  The  pure  metal  presents  greater  resist- 
7* 


78  ALUMINIUM. 

ance  to  the  prolonged  action  of  alkalies  than  the 
impure. 

Mierzinski :  Lime-water  acts  similarly  to  NaOH 
or  KOH,  with  the  difference  that  the  resulting 
calcium  compound  is  precipitated. 

I 
AQUA  AMMONIA  (NH4OH). 

Deville:  Aqua  ammonia  acts  only  feebly  on 
aluminium,  producing  a  little  A1203,  which,  accord- 
ing to  a  very  curious  observation  of  Wohler,  has 
the  property  of  partly  dissolving  in  the  ammonia. 
In  an  atmosphere  in  which  ammonia  was  present, 
the  metal  did  not  lose  its  lustre,  which  is  easily 
explained,  because  it  is  only  in  contact  with  water 
that  the  oxidization  of  the  metal  takes  place,  with 
disengagement  of  hydrogen. 

ORGANIC  ACIDS,  VINEGAR,  ETC. 

Deville :  Weak  acetic  acid  acts  oh  aluminium  in 
the  same  way  as  H2S04,  i.  e.,  in  an  inappreciable 
degree  or  with  extreme  slowness.  I  used  for  the 
experiment  acid  diluted  to  the  strength  of  strongest 
vinegar.  M.  Paul  Morin  left  a  plaque  of  the  metal 
a  long  time  in  wine  which  contained  tartaric  acid 
in  excess  and  acetic  acid,  and  found  the  action  on  it 
quite  inappreciable.  The  action  of  a  mixture  of 
acetic  acid  and  NaCl  in  solution  in  pure  water  on 
pure  aluminium  is  very  different,  for  the  acetic 


CHEMICAL    PROPERTIES    OF    ALUMINIUM.  79 

acid  replaces  a  portion  of  the  HC1  existing  in  the 
NaCl,  rendering  it  free.  However,  this  action  is 
very  slow  on  the  Al,  especially  if  it  is  pure. 

The  practical  results  flowing  from  these  observa- 
tions deserve  to  be  clearly  defined,  because  of  the 
applications  which  may  be  made  of  aluminium  to 
culinary  vessels.  I  have  observed  that  the  tin  so 
often  used,  and  which  each  day  is  put  in  contact 
with  ivTaCl  and  vinegar,  is  attacked  much  more 
rapidly  than  aluminium  under  the  same  circum- 
stances. Although  the  salts  of  tin  are  very  poison- 
ous, and  their  action  on  the  economy  far  from 
being  negligible,  the  presence  of  tin  in  our  food 
passes  unperceived  because  of  its  minute  quantity. 
Under  the  same  circumstances,  aluminium  dissolves 
in  less' quantity;  the  acetate  of  Al  formed  resolves 
itself  on  boiling  into  insoluble  APG3  or  an  insoluble 
sub-acetate,  having  no  more  taste  or  action  on  the 
body  than  clay  itself.  It  is  for  that  reason,  and 
because  it  is  known  that  the  salts  of  the  metal  have 
no  appreciable  action  on  the  body,  that  aluminium 
may  be  considered  as  an  absolutely  harmless  metal. 

SOLUTIONS  OF  METALLIC  SALTS. 

Deville :  The  action  of  any  salt  whatever  may 
be  easily  deduced  from  the  action  of  the  acids  on 
the  metal.  We  may,  therefore,  predict  that  in  acid 
solutions  of  sulphates  and  nitrates  aluminium  will 
precipitate  no  metal,  not  even  silver,  as  Wohler  has 


80  ALUMINIUM. 

observed.  But  the  hydrochloric  solutions  of  the 
same  metals  will  be  precipitated,  as  MM.  Tissier 
have  shown.  Likewise,  in  alkaline  solutions,  Ag, 
Pb,  and  metals  high  in  the  classification  of  the 
elements  are  precipitated. 

It  may  be  concluded  from  this  that'  to  deposit 
aluminium  on  other  metals  by  means  of  the  bat- 
tery, it  is  always  necessary  to  use  acid  solutions  in 
which  IIC1,  free  or  combined,  should  be  absent. 
For  similar  reasons  the  alkaline  solutions  of  the 
same  metals  cannot  be  employed,  although  they 
give  such  good  results  in  plating  common  metals 
wnth  gold  and  silver.  It  is  because  of  these  curious 
properties  that  gilding  and  silvering  aluminium 
are  so  difficult.  M.  Paul  Morin  and  I  have  often 
tried  a  bath  of  basic  sulphide  of  gold,  or  hyposul- 
phite of  silver,  with  a  large  excess  of  sulphurous 
acid,  with  no  good  results.  But  M.  Mourey,  who 
has  already  rendered  great  services  in  galvanoplasty, 
readily  gilds  and  silvers  aluminium  for  commerce 
with  astonishing  skill  when  we  consider  the  short 
time  he  has  had  to  study  this  question.  I  know 
also  that  M.  Christofle  has  gilded  it,  but  I  am 
entirely  ignorant  of  the  processes  employed  by  these 
gentlemen.  The  coppering  of  aluminium  by  the 
battery  is  effected  very  easily  by  means  of  M.  Hulot's 
process.  He  uses  simply  a  bath  of  acid  sulphate 
of  copper.  The  layer  of  copper,  if  well  prepared, 
is  very  solid. 

All  that  I  have  said  on  the  subject  of  the  action 


CHEMICAL    PROPERTIES    OF    ALUMINIUM.  81 

of  metallic  salts  is  true  only  for  pure  aluminium. 
Impure  metal,  especially  if  it  contains  iron  or  sodium, 
acts  then  in  producing  in  the  copper  salts  with  which 
I  operate  a  deposit  of  metallic  Cu.  But  this  phe- 
nomenon, even  in  the  most  unfavorable  cases,  is 
produced  very  slowly,  and  if  a  leaf  of  aluminium 
is  used  one  may  see  at  the  end  of  several  weeks 
the  texture  of  the  metal  etched  with  red  fibres,  as 
if  the  Fe  and  Al  were  only  in  juxtaposition,  and 
the  ferruginous  fibres  acted  alone.  Moreover,  the 
deposit  is  only  local,  and  little  by  little  becomes 
complete ;  but  it  is  slower  as  the  metal  is  purer. 

Mierziuski:  Silver  is  precipitated  by  Al  from  a 
nitrate  solution,  feebly  acid  or  neutral,  in  dendrites  ; 
the  separation  begins  after  six  hours ;  from  an  am- 
moniacal  solution  of  AgCl  or  Ag2Cr04,  Al  precipi- 
tates the  metal  immediately  as  a  crystalline  powder. 

From  CuSO4  or  Cu(N03/  solution,  Al  separates 
Cu  only  after  two  days,  in  dendrites  or  octahedra  ; 
from  the  latter  it  also  precipitates  a  basic  salt  as  a 
green,  insoluble  powder;  from  a  CuCl2  solution  the 
Cu  falls  immediately  ;  somewhat  slower  from  solu- 
tion of  acetate  of  copper.  The  sulphate  or  nitrate 
solution  behaves  similarly  if  a  little  KC1  is  added 
to  it,  and  the  precipitation  is  complete  in  presence 
of  excess  of  Al. 

From  Hg2Cl2,  Hg2Cy2,  and  Hg2(X03)2,  Hg  sepa- 
rates first,  and  then  forms  an  amalgam  with  the 
Al  which  decomposes  water  at  ordinary  tempera- 
tures or  oxidizes  in  the  air  with  development  of 


82  ALUMINIUM. 

much  heat ;  the  same  qualities  are  possessed  by  the 
amalgam  formed  by  warming  the  two  metals  to- 
gether in  an  atmosphere  of  CO2. 

From  Pb(N03)2  and  Pb(C2H302/  the  metal  sepa- 
rates slowly  in  crystals  ;  from  PbCl2  immediately ; 
an  alkaline  solution  of  PbCrO  gives  Pb  and  Cr203. 

From  an  alcoholic  solution  of  HgCl2  the  Hg  is 
precipitated  much  quicker  with  a  gentle  heat.  Al 
also  reduces  Hg  from  a  solution  of  Hgl2  in  KI. 
Al  separates  Hg  from  HgCl2  vapors,  and  A12C16 
deposits  in  the  cooler  part  of  the  tube,  the  remain- 
ing Al  being  melted  by  the  heat  of  the  reaction. 
Al  acts  likewise  toward  melted  As^Cl,  the  silver 

£5          / 

set  free  being  melted  by  the  heat  of  the  reaction. 
Zn  is  easily  thrown  down  from  alkaline  solution. 

Fremy:  Aluminium  decomposes  a  very  large 
number  of  metallic  solutions,  which  takes  place 
especially  easily  if  the  solution  is  made  alkaline 
or  ammoniacal.  Acid,  and  especially  neutral  solu- 
tions, are  less  favorable  for  the  experiment.  All 
the  chlorides,  excepting  KC1  and  NaCl,are  reduced 
by  it.  A12C16  is  no  exception,  for  the  solution  is 
decomposed  with  evolution  of  hydrogen.  Alu- 
minium easily  resists  solutions  of  Nad  and  alum 
separately,  but  dissolves  in  a  mixed  solution  of 
these  two  salts.  In  alkaline  solution,  the  metals 
are  precipitated  because  of  the  facility  with  which 
aluminates  of  the  alkalies  are  formed. 

Watts  (2d  Supplement) :  The  action  of  alumin- 
ium on  metallic  solutions  is  as  follows :  Cu  is  pre- 


CHEMICAL    PBOPERTIES    OF    ALUMINIUM.  83 

cipitated  from  copper  salts  ;  Pb  is  slowly  precipi- 
tated from  lead  salts ;  Ag  is  precipitated  from  a 
slightly  acid  or  neutral  solution  of  Ag^O3 ;  Zn  is 
readily  precipitated  from  zinc  salts. 

NITRE. 

Deville:  Aluminium  may  be  melted  in  nitre 
without  undergoing  the  least  alteration,  the  two 
materials  rest  in  contact  without  reacting,  even  at 
a  red  heat,  at  which  temperature  the  salt  is  plainly 
decomposed,  disengaging  oxygen  actively.  But  if 
the  heat  is  pushed  to  the  point  where  nitrogen 
itself  is  disengaged,  there  the  nitre  becomes  potassa, 
a  new  affinity  becomes  manifest,  and  the  phenomena 
change.  The  metal  then  combines  rapidly  with 
the  K2O  to  give  aluminate  of  potash.  The  accom- 
panying phenomenon  of  flagration  often  indicates  a 
very  energetic  reaction.  Aluminium  is  continually 
melted  with  nitre  at  a  red  heat  to  purify  it  by  the 
oxygen  disengaged,  without  any  fear  of  loss.  But 
it  is  necessary  to  be  very  careful  in  doing  it  in  an 
earthen  crucible.  The  SiO2  of  the  crucible  is  dis- 
solved by  the  nitre,  the  glass  thus  formed  is  decom- 
posed by  the  aluminium,  and  the  silicide  of  alu- 
minium formed  is  then  very  oxidizable,  especially 
in  the  presence  of  alkalies.  The  purification  by 
nitre  ought  to  be  made  in  an  iron  crucible  well 
oxidized  by  nitre  inside. 

Fremy  :  At  the  melting  point,  aluminium  is  not 


84  ALUMINIUM. 

attacked  by  nitre ;  this  property  has  been  at  times 
utilized  to  oxidize  and  then  remove  the  metals 
alloyed  with  it,  but  it  is  now  demonstrated  that 
this  mode  of  purification  is  very  imperfect. 

Mierzinski :  Heated  to  redness  with  nitre,  alu- 
minium burns  with  a  fine  blue  flame. 

SILICATES  AND  BORATES. 

Deville :  By  treating  silicates  and  borates  with 
aluminium  silicon  and  boron  may  be  obtained. 
The  process  is  described  at  the  end  of  Deville's 
book,  but  is  too  long  and  foreign  to  the  subject  in 
hand  to  be  given  here. 

Tissier  :  Aluminium  melted  in  an  ordinary  white 
glass  vessel  oxidizes  itself  at  the  expense  of  the 
SiO2,  setting  free  silicon,  and  the  alumina  formed 
combines  with  the  alkali  forming  an  alurninate. 
In  experiments  which  we  have  made,  the  metal 
became  covered  with  a  thin  layer  of  silicon,  while  the 
metal  which  remained  underneath  was  still  malle- 
able and  did  not  appear  to  be  combined  with  Si. 

FLUORSPAR. 

Tissier:  This  salt  is  without  action  on  the  metal 
and  makes  its  best  flux,  especially  so  because  of  the 
property  which  it  has  of  dissolving  the  alumina 
with  which  the  metal  may  be  contaminated  and 


CHEMICAL    PROPERTIES    OF    ALUMINIUM.  85 

which  encrusts  little  globules.     The  fluorspar,  by 
dissolving  this  crust,  facilitates  their  reunion. 

PHOSPHATE  OF  LIME. 

Tissier :  We  have  heated  to  white  heat  a  mixture 
of  pure  Ca3(P04)2  and  aluminium  leaf,  without  the 
metal  losing  its  metallic  appearance.  This  material 
thus  appears  to  have  no  action  on  the  metal. 

SODIUM  CHLORIDE  (NaCl)  AND  CHLORIDES. 

Deville :  A  solution  of  sodium  or  potassium 
chloride,  in  which  is  put  a  pure  aluminium  wire, 
seemed  to  me  to  exercise  no  sensible  action  on  the 
metal,  either  cold  or  warm.  It  is  not  the  same 
with  the  other  metallic  chlorides,  and  we  may 
state  that,  as  a  general  rule,  these  are  decomposed 
by  aluminium  with  greater  facility  as  the  metal 
which  they  contain  belongs  to  a  higher  order.  The 
chlorhydrate  of  A\  itself  dissolves  aluminium 
forming  a  sub-chlorhydrate  with  evolution  of  hy- 
drogen. 

Tissier:  KaCl  is  employed  as  a  flux  for  Al  in 
remelting  it.  It  does  not  possess  the  property,  like 
CaF2,  of  dissolving  the  A1203,  and  has  the  incon- 
venience of  producing  with  the  clay  of  the  crucible 
a  sensible  quantity  of  A12C16,  which  may  on  con- 
tact with  the  air  act  in  promoting  the  loss  of  a 
certain  quantity  of  metal. 

8 


86  ALUMINIUM. 

METALLIC  OXIDES. 

Tissier  :  We  made  our  experiments  in  this  way : 
The  Al  leaf  was  mixed  carefully  with  the  oxide 
on  which  we  experimented,  then  the  mixture  was 
placed  in  a  small  porcelain  capsule  and  heated  in  a 
small  earthen  crucible  which  served  as  a  muffle. 
Our  results  were  as  follows : — 

MnO2 — Aluminium  has  no  action  on  manganese 

o 

dioxide. 

Fe203 — By  heating  to  white  heat  1  equivalent  of 
Fe203  and  3  of  Al,  the  reaction  took  place  with 
detonation,  and  by  heating  sufficiently  we  obtained 
a  metallic  button,  well  melted,  and  containing  69.3 
per  cent.  Fe  and  30.7  per  cent.  Al,  being  as  hard 
and  brittle  as  cast-iron.  Its  composition  is  nearly 
AlFe.  It  would  thus  appear  that  the  decomposition 
of  Fe203  will  not  pas's  the  limit  where  the  quantity 
of  iron  reduced  is  sufficient  to  form  with  the  alu- 
minium the  alloy  AlFe. 

ZnO:  A  mixture  of  aluminium  leaf  and  zinc 
oxide  heated  to  whiteness  did  not  appear  to  present 
the  least  indication  of  decomposition. 

PbO:  We  mixed  2  equivalents  of  litharge  with  1 
of  aluminium,  and  heated  the  mixture  slowly  up  to 
white  heat,  when  the  Al  reacted  on  the  PbO  with 
such  intensity  as  to  produce  a  strong  detonation. 
We  made  an  experiment  writh  50  grammes  of  PbO 
and  2.9  grammes  of  Al  leaf,  when  the  crucible  was 


CHEMICAL    PROPERTIES   OF   ALUMINIUM.  87 

broken  to  pieces  and  the  doors  of  the  furnace  blown 
off. 

CuO :  3  grammes  of  black  oxide  of  copper  mixed 
with  1.03  grammes  of  aluminium  detonated  pro- 
ducing a  strong  explosion  when  the  heat  reached 
whiteness. 

Mierzinski:  Aluminium  reduces  CuO  and  PbO 
with  explosion,  Fe203  only  in  part,  forming  the 
alloy  AlFe.  ZnO  and  MnO  are  not  reduced  by 
aluminium. 

Beketoff  :*  He  reduced  baryta  (BaO)  with  metal- 
lic aluminium  in  excess,  and  obtained  alloys  of 
aluminium  and  barium  containing  in  one  case  24 
per  cent,  in  another  33  per  cent,  of  Ba. 

ANIMAL  MATTERS. 

Deville:  Among  the  animal  matters  produced 
by  the  organism,  some  are  acid,  as  sweat.  These 
appear  to  have  no  sensible  action  on  aluminium. 
Alkaline  materials,  as  the  saliva,  have  a  greater 
tendency  to  oxidize  it,  but  the  whole  effect  produced 
is  insignificant.  M.  Charriere  has  made  for  a  patient 
on  whom  he  practised  tracheotomy  a  small  tube 
of  the  metal,  which  remained  almost  unaltered 
although  in  contact  with  purulent  matter.  After 
a  long  time  a  little  alumina  was  formed  on  it, 
hardly  enough  to  be  visible. 

*  Bull,  de  la  Soc.  Chem.,  1857,  p.  22. 


88  ALUMINIUM. 

MISCELLANEOUS  AGENTS. 

Tissier:  Only  2.65  grammes  of  aluminium  intro- 
duced into  melted  red  hot  sodium  sulphate  (Na2S04) 
decomposed  that  salt  with  such  intensity  that  the 
crucible  was  broken  into  a  thousand  pieces,  and 
the  door  of  the  furnace  blown  to  a  distance. 
Heated  to  redness  with  alkaline  carbonate,  the 
Al  wTas  slowly  oxidized  at  the  expense  of  the  CO2, 
C  was  set  free,  and  an  aluminate  formed.  The 
reaction  takes  place  without  deflagration. 

Mierzinski :  Heated  to  redness  with  potassium 
or  sodium  sulphate,  aluminium  gives  a  strong 
detonation.  Potassium  carbonate  quickly  destroys 
the  metal  with  separation  of  carbon.  Hydrogen, 
nitrogen,  sulphur,  and  carbon  are  without  any 
influence  on  aluminium,  but  chlorine,  iodine,  bro- 
mine, and  fluorine  attack  it  rapidly. 

GENERAL  OBSERVATIONS  ON  THE  PROPERTIES  OF 
ALUMINIUM. 

Deville:  Aluminium,  at  a  low  temperature,  con- 
ducts itself  as  a  metal  which  can  give  a  very  weak 
base ;  in  consequence,  its  resistance  to  acids,  IIC1 
excepted,  is  very  great.  It  conducts  itself  with 
the  alkalies  as  a  metal  capable  of  giving  a  quite 
energetic  acid,  it  being  attacked  by  K20  and  Na20 

O  O  v 

dissolved    in   water.      But,   this   affinity   is   still 
insufficient    to   determine    the    decomposition    of 


CHEMICAL   PROPERTIES   OF   ALUMINIUM.  89 

melted  KOH.  For  a  stronger  reason  it  does  not 
decompose  metallic  oxides  at  a  red  heat.  This  is 
why,  in  the  muffle,  the  alloy  of  aluminium  and 
copper  gives  black  CuO,  and  this  also  accounts  for 
the  alloy  of  aluminium  and  lead  being  capable  of 
being  cupelled.  But,  by  a  strange  exception,  and 
which  does  not  appertain  solely,  I  believe,  to  alu- 
minium, as  soon  as  the  heat  is  above  redness  the 
affinities  are  quickly  inverted,  and  the  metal  takes 
all  the  properties  of  silicon,  decomposing  the  oxides 
of  lead  and  copper  with  the  production  of  alumin- 
ates. 

From  all  the  experiments  which  have  been  re- 
ported and  from  all  the  observations  which  have 
been  made,  we  can  conclude  that  aluminium  is  a 
metal  which  has  complete  analogies  with  no  one  ot 
the  simple  bodies  which  we  consider  metals.  In 
1855  I  proposed  to  place  it  along  side  of  chromium 
and  iron,  leaving  zinc  out  of  the  group  with  which 
aluminium  had  been  until  then  classed.  Zinc  is 
placed  very  well  beside  magnesium,  there  being 
intimate  analogies  between  these  two  volatile 
metals.  There  may  be  found  at  the  end  of  a  memoir 
which  M.  AVohler  and  I  published  in  the  '  Compt 
Rendue'  and  the  '  Ami.  de  Chem.  et  de  Phys.'  the 
reasons  why  we  are  tempted  to  place  aluminium 
near  to  silicon  and  boron  in  the  carbon  series,  on 
grounds  analogous  to  those  on  which  antimony  and 
arsenic  are  placed  in  the  nitrogen  series. 


PART  V. 

METALLURGY  OF  ALUMINIUM. 

As  has  been  remarked  in  the  historical  section, 
Davy  was  the  first  to  try  to  isolate  aluminium. 
His  attempts  were  unsuccessful.  The  next  chemist 
to  publish  an  account  of  attempts  in  this  direction 
was  Oerstedt,  who  published  a  paper  in  1824  in  a 
Swedish  periodical.*  Oerstedt's  original  paper  is 
thus  translated  into  Berzelius'  '  Jahresbericht  :'f 

"  Oerstedt  mixes  calcined  and  pure  alumina,  quite 
freshly  prepared,  with  powdered  charcoal,  puts  it 
in  a  porcelain  retort,  ignites  and  leads  Cl  gas 
through.  The  coal  then  reduces  the  alumina,  and 
there  results  A12C16  and  CO,  and  perhaps  also  some 
phosgene,  COC12 ;  the  A12C16  is  caught  in  the  con- 
denser and  the  gases  escape.  The  A12C16  is  white, 
crystalline,  melts  about  the  temperature  of  boiling 
water,  easily  attracts  moisture,  and  evolves  heat 
when  in  contact  with  water.  If  it  is  mixed  with 
a  concentrated  potassium  amalgam  and  heated 
quickly,  it  is  transformed ;  there  results  KC1,  and 

*  Oversigt  over  clct  K.  Danske  Videnskabemes  Sclkabs 
Forhandlingar  og  dets  Medlemmers  Arbeider.  May,  1824,  to 
May,  1825,  p.  15. 

t  Berz.  Jahresb.  der  Chemie,  1827,  vi.  118. 


METALLURGY    OF   ALUMINIUM.  91 

the  aluminium  unites  with  the  mercury.  The  new 
amalgam  oxidizes  in  the  air  very  quickly,  and 
gives  as  residue  when  distilled  in  a  vacuum  a  lump 
of  metal  resembling  tin  in  color  and  lustre.  In 
addition,  Oerstedt  found  many  remarkable  prop- 
erties of  the  metal  and  of  the  amalgam,  but  he 
holds  them  for  a  future  communication  after  further 
investigation." 

I  have  not  been  able  to  find  any  other  paper  by 
Oerstedt,  but  the  next  advance  in  the  science  is  by 
Wohler,  and  all  agree  in  naming  him  as  the  true 
discoverer  of  the  metal.  The  following  is  taken 
from  Poggendorf.* 

Wohler  reviews  the  article  which  we  have  just 
given,  and  then  continues  as  follows: — 

"  I  have  repeated  this  experiment  of  Oerstedt, 
but  achieved  no  very  satisfactory  result.  By  heat- 
ing potassium  amalgam  with  APC16  and  distilling 
the  product,  there  remained  behind  a  gray  melted 
mass  of  metal,  but  which,  by  raising  the  heat  to 
redness,  went  off  as  green  vapor  and  distilled  as 
pure  potassium.  I  have  therefore  looked  around 
for  another  method  or  way  of  conducting  the  ope- 
ration, but,  unpleasant  as  it  is  to  say  it,  the  reduc- 
tion of  the  aluminium  fails  each  time.  Since,  how- 
ever, Herr  Oerstedt  remarks  at  the  end  of  his  paper 
that  he  did  not  regard  his  investigations  in  alu- 
minium as  yet  ended,  and  already  several  years 

*  Pogg.  Ann.,  1827,  ii.  147. 


92  ALUMINIUM. 

have  passed  since  then,  it  looks  as  if  I  had  taken 
up  one  of  those  researches  begun  auspiciously  by 
another  (but  not  finished  by  him)  because  it  prom- 
ised new  and  splendid  results.  I  must  remark,  how- 
ever, that  Herr  Oerstedt  has  indirectly  by  his  silence 
encouraged  me  to  try  to  attain  to  further  results  my- 
self. Before  I  give  the  art  how  one  can  quite 
easily  reduce  the  metal,  I  will  say  a  few  words 
about  APCl6  and  its  production. 

"  I  based  the  method  of  reducing  aluminium  on 
the  reaction  of  A12C16  on  potassium,  and  on  the 
property  of  the  metal  not  to  oxidize  in  water.  I 
warmed  in  a  glass  retort  a  small  piece  of  APCl6 
with  some  potassium,  and  the  retort  was  shattered 
with  a  strong  explosion.  I  tried  then  to  do  it  in  a 
small  platinum  crucible,  in  which  it  succeeded  very 
well.  The  reaction  is  always  so  violent  that  the 
cover  must  be  weighted  down,  or  it  will  be  blown 
off';  and  at  the  moment  of  reduction,  although  the 
crucible  be  only  feebly  heated  from  outside,  it  sud- 
denly glows  inside,  and  the  platinum  is  almost  torn 
by  the  sudden  shocks.  In  order  to  avoid  any 
mixture  of  platinum  with  the  reduced  aluminium, 
I  next  made  the  reduction  in  a  porcelain  crucible 
and  succeeded  then  in  the  following  manner :  Pat 
in  the  bottom  of  the  crucible  a  piece  of  potassium 
free  from  carbon  and  oil,  and  cover  this  with  an 
equal  volume  of  pieces  of  APCl6.  Cover,  and  heat 
over  a  spirit  lamp,  at  first  gently,  that  the  crucible 
be  not  broken  by  the  production  of  heat  inside, 


METALLURGY   OF   ALUMINIUM. 

and  then  heat  stronger,  at  last  to  redness. 
and  when  fully  cold  put  it  into  a  glass  of  cold  water. 
A  gray  powder  separates  out  which  on  nearer  ob- 
servation, especially  in  sunlight,  is  seen  to  consist 
of  little  flakes  of  metal.  After  it  has  separated, 
pour  off  the  solution,  filter,  wash  with  cold  water, 
and  dry  ;  this  is  the  aluminium." 

In  reality  this  powder  possessed  no  metallic 
properties,  and,  moreover,  it  contained  potassium 
and  APC16,  which  gave  to  it  the  property  of  de- 
composing water  at  100°.  To  avoid  the  loss  of 
A12C16  by  volatilization  at  the  high  heat  developed 
during  the  reaction,  Liebig  afterwards  made  the 
vapor  of  APC16  pass  slowly  over  some  potassium 
placed  in  a  long  glass  tube.  This  device  of  Liebig 
is  nearly  the  arrangement  which  Wohler  adopted 
later,  in  1845,  and  which  gave  him  much  better 
results.  The  following  is  W6hler's  second  paper, 
published  in  1845  : — * 

"  On  account  of  the  violent  incandescence  with 
which  the  reduction  of  A  PCI6  by  potassium  is  ac- 
companied, this  operation  requires  great  precau- 
tions, and  can  be  carried  out  only  on  a  small  scale. 
I  took  for  the  operation  a  platinum  tube,  in  which 
I  placed  A12C16  and  near  it  some  potassium  in  a 
platinum  boat.  I  heated  the  tube  gently  at  first, 
then  to  redness.  But  th£  reduction  may  also  be 
done  by  putting  potassium  in  a  small  crucible 

*  Liebig's  Annalen,  53,  422. 


•  94  ALUMINIUM. 

which  is  placed  inside  a  larger  one,  and  the  space 
between  the  two  filled  with  APC16.  A  close  cover 
is  put  over  the  whole  and  it  is  heated.  Equal 
volumes  of  potassium  and  A12C16  are  the  best  pro- 
portions to  employ.  After  cooling,  the  tube  or 
crucible  is  put  in  a  vessel  of  water.  The  metal  is 
obtained  as  a  gray,  metallic  powder,  but  on  closer 
observation  one  can  see  even  with  the  naked  eye 
small  tin-white  globules  some  as  large  as  pins'  heads. 
Under  a  microscope  magnifying  two  hundred  diam- 
eters the  whole  powder  resolves  itself  into  small 
globules,  several  of  which  may  sometimes  be  seen 
sticking  together,  showing  that  the  metal  was 
melted  at  the  moment  of  reduction.  A  beaten-out 
globule  may  be  again  melted  to  a  sphere  in  a  bead 
of  borax  or  salt  of  phosphorus,  but  rapidly  oxidizes 
during  the  operation,  and  if  the  heat  is  continued, 
disappears  entirely,  seeming  either  to  reduce  boron 
in  the  borax  bead  or  phosphorus  or  P205in  the  salt 
of  phosphorus  bead.  I  did  not  succeed  in  melting 
together  the  pulverulent  aluminium  in  a  crucible 
with  borax,  at  a  temperature  which  would  have 
melted  cast  iron,  for  the  metal  disappeared  entirely 
and  the  borax  became  a  black  slag.  It  seems  prob- 
able that  aluminium,  being  lighter  than  molten 
borax,  swims  on  it  and  burns.  The  white  metallic 
globules  had  the  color  and  lustre  of  tin.  It  is  per- 
fectly malleable  and  can  be  hammered  out  to  the 
thinnest  leaves.  Its  specific  gravity,  determined 
with  two  globules  weighing  32  milligrammes,  was 


METALLURGY   OF   ALUMINIUM.  95 

2.50,  and  with  three  hammered-out  globules  weigh- 
ing 34  milligrammes,  2.67.  Ou  account  of  their 
lightness  these  figures  can  only  be  approximate. 
It  is  not  magnetic,  remain's  white  in  the  air,  de- 
composes water  at  100°,  not  at  usual  temperatures, 
and  dissolves  completely  in  caustic  potash  (KOH). 
When  heated  in  oxygen  almost  to  melting,  it  is 
only  superficially  oxidized,  but  it  burns  like  zinc 
in  a  blast-lamp  flame." 

These  results  of  Wbhler's,  especially  the  deter- 
mination of  sp.  gr.,  were  singularly  accurate  when 
we  consider  that  he  established  them  working  with 
microscopic  bits  of  the  metal.  It  was  just  such 
work  that  established  Wohler's  fame  as  an  investi- 
gator. However,  we  notice  that  his  metal  differed 
from  aluminium  as  we  know  it  in  several  important 
respects,  in  speaking  of  which  Deville  says:  "All 
this  time  the  metal  obtained  by  Wohler  was  far 
from  being  pure;  it  was  very  difficultly  fusible, 
owing  without  doubt  to  the  fact  that  it  contained 
platinum  taken  from  the  vessel  in  which  it  had 
been  prepared.  It  is  well  known  that  these  two 
metals  combine  very  easily  at  a  gentle  heat.  More- 
over, it  decomposed  water  at  100°,  which  must  be 
attributed  either  to  the  presence  of  some  potassium 
or  to  APC16,  with  which  the  metal  might  have 
been  impregnated ;  for  aluminium  in  presence  of 
APCl6  in  effect  decomposes  water  with  evolution  of 
hydrogen. 

After  AYohler's  paper  in  1845,  the  next  improve- 


96  ALUMINIUM. 

ment  is  that  introduced  by  Deville,  in  1854-55, 
and  this  is  really  the  date  at  which  aluminium,  the 
metal,  became  known  and  its  true  properties  estab- 
lished. He  first  read  to  the  Academy  an  account  of 
his  laboratory  process,  by  which  he  obtained  a 
pencil  of  the  metal.  The  following  is  his  account:* 
"The  following  is  the  best  method  for  obtaining 
aluminium  chemically  pure  in  the  laboratory. 
Take  a  large  glass  tube  about  four  centimetres  in 
diameter,  and  put  into  it  pure  APC16  free  from 
iron,  and  isolate  it  between  two  stoppers  of  ami- 
anthus (tine,  silky  asbestos).  Hydrogen,  well  dried 
and  free  from  air,  is  brought  in  at  one  end  of  the 
tube.  The  APC16  is  heated  in  this  current  of  gas 
by  some  lumps  of  charcoal,  in  order  to  drive  off 
hydrochloric  acid  or  sulphides  of  chlorine  or  of 
silicon,  with  which  it  is  always  impregnated.  Then 
there  are  introduced  into  the  tube  porcelain  boats, 
as  large  as  possible,  each  containing  several  grammes 
of  sodium,  which  was  previously  rubbed  quite  dry 
between  leaves  of  filter  paper.  The  tube  being  full 
of  hydrogen  the  sodium  is  melted,  the  A12C16  is 
heated  and  distils,  and  decomposes  in  contact  with 
the  sodium  with  incandescence,  the  intensity  of 
which  can  be  moderated  at  pleasure.  The  operation 
is  ended  when  all  the  sodium  has  disappeared,  and 
when  the  sodium  chloride  formed  has  absorbed  so 
much  A12C16  as  to  be  saturated  with  it.  The  Al 

*  Ann.  de.  Pays,  et  de  Chem.,  xliii.  24. 


METALLURGY   OP   ALUMINIUM.  97 

which  has  been  formed  is  held  in  the  douhle 
chloride  of  sodium  and  aluminium,  Al2Cl6.2!N"aCl, 
a  compound  very  fusihle  and  very  volatile.  The 
boats  are  then  taken  from  the  glass  tube,  and  their 
entire  contents  put  in  boats  made  of  retort  carbon, 
which  have  been  previously  heated  in  dry  chlorine 
in  order  to  remove  all  silicious  and  ferruginous 
matter.  These  are  then  introduced  into  a  large 
porcelain  tube,  furnished  with  a  prolongation  and 
traversed  by  a  current  of  hydrogen,  dry  and  free 
from  air.  This  tube  being  then  heated  to  redness, 
the  Al2Cl6.2XaCl  distils  without  decomposition 
and  condenses  in  the  prolongation.  There  is  found 
in  the  boats,  after  the  operation,  all  the  Al  which 
had  been  reduced,  collected  in  at  most  one  or  two 
small  buttons.  The  boats  when  taken  from  the 
tube  should  be  nearly  free  from  Al2Cl6.2]N"aCl  and 
also  from  ^aCl.  The  buttons  of  aluminium  are 
united  in  a  small  earthen  crucible  which  is  heated 
as  gently  as  possible,  just  sufficient  to  melt  the 
metal.  The  latter  is  pressed  together  and  skimmed 
clean  by  a  small  rod  or  tube  of  clay.  The  metal 
thus  collected  may  be  very  suitably  cast  in  an 
ingot  mould." 

The  later  precautions  added  to  the  above  given 
process  were  principally  directed  towards  avoiding 
the  attacking  of  the  crucible,  which  always  takes 
place  when  the  metal  is  melted  with  a  flux,  and  the 
aluminium  thereby  made  more  or  less  siliceous. 
The  next  improvement  was  the  introduction  by 
9 


98 


ALUMINIUM. 


Deville  of  an  application 
on  a  large  scale  of  the  lab- 
oratory method  just  de- 
scribed. He  first  put  it 
up  at  the  chemical  works 
of  M.  du  Sussex,  at  Javel, 
and  later  at  the  works  of 
MM.  Rousseau  Bros.,  at 
Glaciere.  It  has  at  pre- 
sent only  an  historic  inter- 
est, as  it  was  soon  modi- 
fied in  its  details  so  as  to 
be  almost  entirely  chang- 
ed, but  I  give  it  here  so 
as  to  show  the  different 
phases  through  which  the 
industry  has  passed.  The 
text  is  not  given  in  full  as 
Deville  describes  it,  which 
would  be  unnecessary ;  but 
the  condensed  account 
gives  a  clear  idea  of  the 
process.  The  full  descrip- 
tion may  be  found  in  De- 
ville'shook,  or  in  the 'Ann. 
de  Chem.  et  de  Phys.'  [3] 
xlvi.  445,  where  it  first 
appeared. 

The  crude  APC16,  placed 
in  the  cylinder  A,  is  vap- 


METALLURGY   OF   ALUMINIUM.  99 

orized  by  the  fire  and  passes  through  the  tube  to 
the  cylinder  B  containing  60  to  80  kilos  of  iron 
nails  heated  to  a  dull-red  heat.  The  iron  retains 
as  relatively  fixed  ferrous  chloride,  the  ferric 
chloride  and  hydrochloric  acid  which  contaminate 
the  APC16,  and  likewise  transforms  any  sulphur 
dichloride  (SCI2)  in  it  into  ferrous  chloride  and  sul- 
phide of  iron.  The  vapors  on  passing  out  of  B 
through  the  tube,  which  is  kept  at  about  300°, 
deposit  spangles  of  ferrous  chloride,  which  is  with- 
out sensible  tension  at  that  temperature.  The 
vapors  then  enter  D,  a  cast-iron  cylinder  in  which 
are  three  cast-iron  boats  each  containing  300  grms. 
of  sodium.  It  is  sufficient  to  heat  this  cylinder 
barely  to  a  dull-red  heat  in  its  lower  part,  for  the 
reaction  once  commenced  disengages  enough  heat 
to  complete  itself,  and  it  is  often  necessary  to  take 
away  all  the  fire  from  it.  There  is  at  first  pro- 
duced in  the  first  boat  some  aluminium  and  some 
sodium  chloride,  which  latter  combines  with  the 
excess  of  .A12C1'  to  form  the  volatile  chloride 
Al2Cl6.2NaCl.  These  vapors  of  double  chloride 
condense  on  the  second  boat  and  are  decomposed 
by  the  sodium  to  aluminium  and  sodium  chloride. 
A  similar  reaction  takes  place  in  the  third  boat 
when  all  the  sodium  of  the  second  has  disappeared. 
When  on  raising  the  cover  it  is  seen  that  the  reac- 
tions are  over,  the  boats  are  taken  out,  immedi- 
ately replaced  by  others,  and  are  allowed  to  cool 
covered  by  empty  boats.  In  this  first  operation 


100  ALUMINIUM. 

the  reaction  is  rarely  complete,  for  the  sodium  is 
protected  by  the  layer  of  NaCl  formed  at  its 
expense.  To  make  this  disappear,  the  contents  of 
the  hoats  are  put  into  cast  iron  pots  or  earthen 
crucibles,  which  are  heated  until  the  APC16  begins 
to  volatilize.  Then  the  pots  or  crucibles  are  cooled 
and  there  is  taken  from  the  upper  part  of  their 
contents  a  layer  of  ISTaCl,  almost  pure,  while  under- 
neath are  found  globules  of  aluminium,  which  are 
separated  from  the  residue  by  washing  with  water. 
Unfortunately,  the  water  in  dissolving  the  A12C16 
of  the  flux  exercises  on  the  metal  a  very  rapid 
destructive  action,  and  only  the  globules  larger 
than  the  head  of  a  pin  are  saved  from  this  washing. 
These  are  gathered  together,  dried,  melted  in  an 
earthen  crucible,  and  pressed  together  with  a  clay 
rod.  The  button  is  then  cast  in  an  ingot  mould. 
It  is  important  in  this  operation  to  employ  only  well 
purified  sodium,  and  not  to  melt  the  aluminium  if  it 
still  contains  any  sodium,  for  in  this  case  the  metal 
takes  fire  and  burns  as  long  as  any  of  the  alkaline 
metal  remains  in  it.  In  such  a  case  it  is  necessary  to 
remelt  in  presence  of  a  little  Al2Cl6.2JSTaCl." 

Deville  says  later,  "Such  was  the  detestable  pro- 
cess by  means  of  which  we  made  the  ingots  of 
aluminium  which  were  sent  to  the  Exposition." 

Deville,  after  this,  tried  some  experiments  in 
which  he  used  sodium  vapor,  and  he  thus  reports 
his  results  in  his  book:  "This  process,  which  I 
have  not  perfected,  is  very  easy  to  operate,  and  gave 


METALLURGY  OF  ALUMINIUM.        101 

me  very  pure  metal  at  the  first  attempt.  I  operate 
as  follows :  I  fill  a  mercury  bottle  with  a  mixture 
of  chalk,  carbon,  and  carbonate  of  soda,  in  the 
proportions  best  for  generating  sodium.  An  iron 
tube  about  ten  centimetres  long  is  screwed  to  the 
bottle,  and  the  whole  placed  in  a  wind  furnace, 
so  that  the  bottle  is  heated  to  red-white  and  the 
tube  is  red  to  its  end.  The  end  of  the  tube  is 
then  introduced  into  a  hole  made  in  a  large  earthen 
crucible  about  one-fourth  way  from  the  bottom, 
so  that  the  end  of  the  tube  just  reaches  the  inside 
surface  of  the  crucible.  The  carbonic  oxide  (CO) 
disengaged  burns  in  the  bottom  of  the  crucible, 
heating  and  drying  it;  afterwards  the  sodium  flame 
appears,  and  then  pieces  of  A12C16  are  thrown  into 
the  crucible  from  time  to  time.  The  salt  volatilizes 
and  decomposes  before  this  sort  of  tuyere  from 
which  issues  the  reducing  vapor.  APC16  is  added 
when  the  vapors  coming  from  the  crucible  cease  to 
be  acid,  and  when  the  flame  of  sodium  burning  in 
the  atmosphere  of  A12C16  loses  its  brightness.  AV  hen 
the  operation  is  finished,  the  crucible  is  broken  and 
there  is  taken  from  the  walls  below  the  entrance 
of  the  tube  a  saline  mass  composed  of  N"aCl,  a 
considerable  quantity  of  globules  of  aluminium, 
and  some  sodium  carbonate,  which  latter  is  in 
larger  quantity  the  slower  the  operation  wras  per- 
formed. The  globules  are  detached  by  plunging  the 
saline  mass  into  water,  when  it  becomes  necessary 
to  notice  the  reaction  of  the  water  on  litmus.  If  the 

9* 


102  ALUMINIUM. 

water  becomes  acid,  it  is  renewed  often ;  if  alkaline., 
the  mass  impregnated  with  metal  must  be  digested 
in  nitric  acid  diluted  with  three  or  four  volumes  of 
water,  and  so  the  metal  is  left  intact.  The  globules 
are  reunited  by  melting  with  the  precautions  before 
given." 

Deville  modified  these  methods  in  various  ways. 
APC16  is  a  deliquescent  salt,  difficult  of  preservation, 
and  so  was  soon  replaced  by  Al2Cl6.2NaCl,  which 
does  not  present  these  inconveniences.  The  double 
chloride,  however,  does  draw  some  moisture  and 
holds  it  energetically,  from  which  it  results  that  at 
a  high  temperature  it  will  give  rise  to  some  alumina, 
which  encloses  the  globules  of  metal  with  a  thin 
coating  and  so  hinders  their  easy  reunion  into  a 
button.  Deville  remarked  that  the  presence  of 
fluorides  facilitated  the  reunion  of  these  globules, 
which  he  attributed  to  their  dissolving  the  coat  of 
A1203  on  them.  Since  then,  the  employment  of  a 
fluoride  as  a  flux  is  considered  necessary  to  over- 
come the  effect  produced  primarily  by  the  APC16.- 
2NaCl  holding  moisture  so  energetically.  The  first 
fluoride  employed  by  Deville  was  fluorspar,  which 
was  soon  replaced  by  cryolite.  This  opens  up  the 
subject  of  the  reduction  of  aluminium  from  cryolite, 
and  since  Percy  and  Rose  both  preceded  Deville  in 
using  it,  I  will  first  give  their  investigations,  follow- 
ing with  those  which  Deville  published  in  1859. 


METALLURGY  OF  ALUMINIUM.  103 

REDUCTION  FROM  CRYOLITE. 

We  will  here  give  H.  Rose's  entire  paper,  as  an 
account  of  this  eminent  chemist's  investigations 
written  out  by  himself  with  great  detail,  describ- 
ing failures  as  well  as  successes,  cannot  but  be  of 
value  to  all  interested  in  the  production  of  alu- 
minium.* 

u  Since  the  discovery  of  aluminium  by  Wohler, 
Deville  has  recently  devised  the  means  of  procuring 
the  metal  in  large,  solid  masses,  in  which  condition 
it  exhibits  properties  with  which  we  were  previ- 
ously unacquainted  in  its  more  pulverulent  form 
as  procured  by  Wohler's  method.  While,  for  in- 
stance, in  the  latter  state  it  burns  vividly  to  white 
earthy  alumina  on  being  ignited,  the  fused  globules 
may  be  heated  to  redness  without  perceptibly  oxi- 
dizing. These  differences  may  be  ascribed  to  the 
greater  amount  of  division  on  the  one  hand  and  of 
density  on  the  other.  According  to  Deville,  how- 
ever, Wohler 's  metal  contains  platinum,  by  which 
he  explains  its  difficulty  of  fusion,  although  it 
affords  white  alumina  by  combustion.  Upon  the 
publication  of  Deville's  researches  I  also  tried 
to  produce  aluminium  by  the  decomposition  of 
Al2Cl6.2XaCl  by  means  of  sodium.  I  did  not, 
however,  obtain  satisfactory"  results.  Moreover, 
Prof.  Rammelsberg,  who  followed  exactly  the 

*  Pogg.  Annalen,  Sept.  1855. 


104  ALUMINIUM. 

method  of  Deville,  obtained  but  a  very  small  pro- 
duct, and  found  it  very  difficult  to  prevent  the 
cracking  of  the  glass-tube  in  which  the  experiment 
was  conducted  by  the  action  of  the  vapor  of  sodium 
on  A12C16.  It  appeared  to  me  that  a  great  amount 
of  time,  trouble,  and  expense,  as  well  as  long  prac- 
tice, was  necessary  to  obtain  even  small  quantities 
of  this  remarkable  metal. 

"  The  employment  of  A12C16  and  its  compounds 
with  alkali  chlorides  is  particularly  inconvenient, 
owing  to  their  volatility,  deliquescence,  and  to  the 
necessity  of  preventing  all  access  of  air  during 
their  treatment  with  sodium.  It  very  soon  occurred 
to  me  that  it  would  be  better  to  use  the  fluoride  of 
aluminium  instead  of  the  chloride ;  or  rather  the 
combination  of  the  fluoride  with  alkaline  fluorides, 
such  as  we  know  them  through  the  investigations 
of  Berzelius,  who  pointed  out  the  strong  affinity 
of  A12F6  for  NaF  and  KF,  and  that  the  mineral 
occurring  in  nature  under  the  name  of  Cryolite 
was  a  pure  compound  of  A12F6  and  ]S"aF. 

"  This  compound  is  as  well  fitted  for  the  prepara- 
tion of  aluminium  by  means  of  sodium  as  A12C16 
or  Al2Cl6.2NaCl.  Moreover,  as  cryolite  is  not  vola- 
tile, is  readily  reduced  to  the  most  minute  state  of 
division,  is  free  from  water  and  does  not  attract 
moisture  from  the  air,  it  affords  peculiar  advan- 
tages over  the  above-mentioned  compounds.  In 
fact,  I  succeeded  with  much  less  trouble  in  prepar- 
ing aluminium  by  exposing  cryolite  together  with 


METALLURGY    OF   ALUMINIUM.  105 

sodium  to  a  strong  red  heat  in  an  iron  crucible, 
than  by  using  A12C16  and  its  compounds.  But  the 
scarcity  of  cryolite  prevented  my  pursuing  the  ex- 
periments. In  consequence  of  receiving,  however, 
from  Prof.  Krantz,  of  Bonn,  a  considerable  quan- 
tity of  the  purest  cryolite  at  a  very  moderate  price 
(S2  per  kilo),  I  was  enabled  to  renew  the  investi- 
gation. 

"  I  was  particularly  stimulated  by  finding,  most 
unexpectedly,  that  cryolite  was  to  be  obtained  here 
in  Berlin  commercially  at  an  inconceivably  low 
price.  Prof.  Krantz  had  already  informed  me  that 
cryolite  occurred  in  commerce  in  bulk,  but  could 
not  learn  where.  Shortly  after,  M.  Rudel,  the 
manager  of  the  chemical  works  of  H.  Kunheim, 
gave  me  a  sample  of  a  coarse  white  powder,  large 
quantities  of  which  were  brought  from  Greenland, 
by  way  of  Copenhagen,  to  Stettin,  under  the  name 
of  mineral  soda,  and  at  the  price  of  $3  per  centner. 
Samples  had  been  sent  to  the  soap  boilers,  and  a 
soda-lye  had  been  extracted  from  it  by  means  of 
quicklime,  especially  adapted  to  the  preparation  of 
many  kinds  of  soap,  probably  from  its  containing 
alumina.  It  is  a  fact,  that  powdered  cryolite  is 
completely  decomposed  by  quicklime  and  water. 
The  fluoride  of  lime  formed  contains  no  alumina, 
which  is  all  dissolved  by  the  caustic  soda  solution; 
and  this,  on  its  side,  is  free  from  fluorine,  or  only 
contains  a  minute  trace.  I  found  this  powder  to 
be  of  equal  purity  to  that  received  from  Prof. 


106  ALUMINIUM. 

Krantz.  It  dissolved  without  residue  in  HC1  (in 
platinum  vessels);  the  solution  evaporated  to  dry- 
ness  with  H2S04,  and  heated  till  excess  of  acid  was 
dissipated,  gave  a  residue  which  dissolved  com- 
pletely in  water,  with  the  aid  of  a  little  HC1. 
From  this  solution,  ammonia  precipitated  a  con- 
siderable quantity  of  alumina.  The  sol  ution  filtered 
from  the  precipitate  furnished,  on  evaporation,  a 
residue  of  sulphate  of  soda,  free  from  potash. 
Moreover,  the  powder  gave  the  well-known  re- 
actions of  fluorine  in  a  marked  degree.  This 
powder  was  cryolite  of  great  purity:  therefore  the 
coarse  powder  I  first  obtained  was  not  the  form 
in  which  it  was  originally  produced.  It  is  now 
obtainable  in  Berlin  in  great  masses ;  for  the  prepa- 
ration of  aluminium  it  must,  however,  be  reduced 
to  a  very  fine  powder. 

"  In  my  experiments  on  the  preparation  of  alu- 
minium, which  were  performed  in  company  with 
M.  Weber,  and  with  his  most  zealous  assistance,  I 
made  use  of  small  iron  crucibles,  If  inches  high 
and  If  inches  upper  diameter,  which  I  had  cast 
here.  In  these  I  placed  the  finely  divided  cryolite 
between  thin  layers  of  sodium,  pressed  it  down 
tight,  covered  with  a  good  layer  of  potassium 
chloride  (KC1),  and  closed  the  crucible  with  a  well- 
fitting  porcelain  cover.  I  found  KC1  the  most 
advantageous  flux  to  employ;  it  has  the  lowest 
specific  gravity  of  any  which  could  be  used,  an 
important  point  when  the  slight  density  of  the 


METALLURGY   OF   ALUMINIUM.  107 

metal  is  taken  into  consideration.  It  also  increases 
the  fusibility  of  the  sodium  fluoride.  I  usually 
employed  equal  weights  of  cryolite  and  KC1,  and 
for  every  five  parts  of  cryolite  two  parts  of  sodium. 
The  most  fitting  quantity  for  the  crucible  was 
found  to  be  ten  grammes  of  powdered  cryolite. 
The  whole  was  raised  to  a  strong  red  heat  by 
means  of  a  gas-air  blowpipe.  It  was  found  most 
advantageous  to  maintain  the  heat  for  about  half 
an  hour,  and  not  longer,  the  crucible  being  kept 
closely  covered  the  whole  time ;  the  contents  were 
then  found  to  be  well  fused.  When  quite  cold  the 
melted  mass  is  removed  from  the  crucible  by  means 
of  a  spatula,  this  is  facilitated  by  striking  the 
outside  with  a  hammer.  The  crucible  may  be 
employed  several  times,  at  last  it  is  broken  by  the 
hammer  blows.  The  melted  mass  is  treated  with 
water,  when,  at  times  only,  a  very  minute  evolu- 
tion of  hydrogen  gas  is  observed,  which  has  the 
same  unpleasant  odor  as  the  gas  evolved  during 
solution  of  iron  in  HC1.  The  carbon  contained  in 
this  gas  is  derived  from  a  very  slight  trace  of 
naphtha  adhering  to  the  sodium  after  drying  it. 
On  account  of  the  difficult  solubility  of  ISTaF,  the 
mass  is  very  slowly  acted  on  by  water,  although 
the  insolubility  is  somewhat  diminished  by  the 
presence  of  the  KC1.  After  twelve  hours  the  mass 
is  softened  so  far  that  it  may  be  removed  from  the 
liquid  and  broken  down  in  a  porcelain  mortar. 
Large  globules  of  aluminium  are  then  discovered, 


108  ALUMINIUM. 

weighing  from  0.8  to  0.4  or  even  0.5  gramme, 
which  may  be  separated  out.  The  smaller  globules 
cannot  well  be  separated  from  the  undecomposed 
cryolite  and  the  alumina  always  produced  by 
washing,  owing  to  their  being  specifically  lighter 
than  the  latter.  The  whole  is  treated  with  UNO3 
in  the  cold.  The  APO3  is  not  dissolved  thereby, 
but  the  little  globules  then  first  assume  their  true 
metallic  lustre.  They  are  dried  and  rubbed  on  fine 
silk  muslin ;  the  finely-powdered,  undecomposed 
cryolite  and  A1203  pass  through,  while  the  globules 
remain  on  the  gauze.  The  mass  should  be  treated 
in  a  platinum  or  silver  vessel,  a  porcelain  vessel 
would  be  powerfully  acted  on  by  the  NaF.  The 
solution,  after  standing  till  clear,  may  be  evapo- 
rated to  dryness  in  a  platinum  capsule,  in  order  to 
obtain  the  !NaF,  mixed,  however,  with  much  KC1. 
The  small  globules  may  be  united  by  fusion  in  a 
small,  well-covered,  porcelain  crucible,  under  a 
layer  of  KC1.  They  cannot  be  united  without  a 
flux.  They  cannot  be  united  by  mere  fusion,  like 
globules  of  silver,  for  instance,  for,  though  they  do 
not  appear  to  oxidize  on  ignition  in  the  air,  yet 
they  become  coated  writh  a  scarcely  perceptible  film 
of  oxide,  which  prevents  their  running  together 
into  a  mass.  This  fusion  with  KC1  is  always  at- 
tended with  loss  of  aluminium.  Buttons  weighing 
0.85  grm.  lost,  when  so  treated,  0.05  grm.  The 
KC1  when  dissolved  in  water  left  a  small  quantity 
of  A1203  undissolved,  but  the  solution  contained 


METALLURGY  OF  ALUMINIUM.         109 

none.  Another  portion  of  the  metal  had  un- 
doubtedly decomposed  the  KC1 ;  and  a  portion  of 
the  A12C16  and  KC1  must  have  been  volatilized 
during  fusion  (other  metals,  as  copper  and  silver, 
behave  in  a  similar  manner — Pogg.  Ixviii.  287). 
I  therefore  followed  the  instructions  of  Deville, 
and  melted  the  globules  under  a  stratum  of 
Al2Cl6.2NaCl  in  a  covered  porcelain  crucible.  The 
salt  was  melted  first,  and  then  the  globules  of 
metal  added  to  the  melted  mass.  There  is  no  loss, 
or  a  very  trifling  one  of  a  few  milligrammes  of 
metal,  by  this  proceeding.  "When  the  aluminium 
is  fused  under  KC1  its  surface  is  not  perfectly 
smooth,  but  exhibits  minute  concavities;  with 
Al2Cl6.2XaCl  this  is  not  the  case.  The  readiest 
method  of  preparing  the  Al2Cl6.2]STaCl  for  this  pur- 
pose is  by  placing  a  mixture  of  alumina  and  carbon 
in  a  glass  tube,  as  wide  as  possible,  and  inside  this  a 
tube  of  less  diameter,  open  at  both  ends,  and  contain- 
ing XaCl.  If  the  spot  where  the  mixture  is  placed 
be  very  strongly  heated,  and  that  where  the  NaCl 
is  situated,  more  moderately,  while  a  current  of 
chlorine  is  passed  through  the  tube,  the  vapor  of 
A12C1*  is  so  eagerly  absorbed  by  the  !N"aCl  that  no 
A12C16,  or,  at  most,  a  trace,  is  deposited  in  any  other 
part  of  the  tube.  If  the  smaller  tube  be  weighed 
before  the  operation,  the  amount  absorbed  is  readily 
determined.  It  is  not  uniformly  combined  with 
the  EaCl,  for  that  part  which  is  nearest  to  the 

10 


110  ALUMINIUM. 

mixture  of  charcoal  and  alumina  will  be  found  to 
have  absorbed  the  most. 

"  I  have  varied  in  many  ways  the  process  for  the 
preparation  of  aluminium,  but  in  the  end  have 
returned  to  the  one  just  described.  I  often  placed 
the  sodium  in  the  bottom  of  the  crucible,  the  pow- 
dered cryolite  about  it,  and  the  KC1  above  all.  On 
proceeding  in  this  manner,  it  was  observed  that 
much  sodium  was  volatilized, burning  with  a  strong, 
yellow  flame,  which  never  occurred  when  it  was  cut 
into  thin  slices  and  placed  in  alternate  layers  with 
the  cryolite,  in  which  case  the  process  goes  on  quietly. 
When  the  crucible  begins  to  get  red  hot,  the  tempera- 
ture suddenly  rises,  owing  to  the  commencement  of 
the  decomposition  of  the  compound  ;  no  lowering 
of  the  temperature  should  be  allowed,  but  the 
heat  should  be  steadily  maintained,  not  longer, 
however,  than  half  an  hour.  By  prolonging  the 
process  a  loss  would  be  sustained,  owing  to  the 
action  of  the  KC1  on  the  aluminium.  Nor  does 
the  size  of  the  globules  increase  on  extending  the 
time  even  to  two  hours;  this  effect  can  only  be 
produced  by  obtaining  the  highest  possible  tempera- 
ture. If  the  process  be  stopped,  however,  after  five 
or  ten  minutes  of  very  strong  heat,  the  production 
is  very  small,  as  the  metal  has  not  had  sufficient 
time  to  conglomerate  into  globules,  but  is  in  a  pul- 
verulent form  and  burns  to  APO3  during  the  cooling 
of  the  crucible.  No  advantage  is  gained  by  mixing 
the  cryolite  with  a  portion  of  chloride  before  plac- 


METALLURGY  OF  ALUMINIUM.        Ill 

ing  it  between  the  layers  of  sodium,  neither  did  I 
increase  the  production  by  using  Al2Cl6.2NaCl  to 
cover  the  mixture  instead  of  KC1.  I  repeatedly 
employed  Nad,  decrepitated,  as  a  flux  in  the 
absence  of  KC1,  without  remarking  any  important 
difference  in  the  amount  of  metal  produced,  although 
a  higher  temperature  is  in  this  case  required.  The 
operations  may  also  be  conducted  in  refractory 
unglazed  crucibles  made  of  stoneware,  and  of  the 
same  dimensions,  although  they  do  not  resist  so 
well  the  action  of  the  sodium  fluoride  at  any  high 
heats,  but  fuse  in  one  or  more  places.  The  iron 
crucibles  fuse,  however,  when  exposed  to  a  very 
high  temperature  in  a  charcoal  fire.  The  product 
of  metal  was  found  to  vary  very  much,  even  when 
operating  exactly  in  the  manner  recommended  and 
with  the  same  quantities  of  materials.  I  never 
succeeded  in  reducing  the  whole  amount  of  metal 
contained  in  the  cryolite  (which  contains  only  13 
per  cent.  Al).  By  operating  on  10  grammes  of 
cryolite,  the  quantity  I  always  employed  in  the 
small  Fe  crucible,  the  most  successful  result  was 
0.8  grm.  But  0.6  or  even  0.4  grm.  may  be  con- 
sidered favorable ;  many  times  I  obtained  only  0.3 
grm.,  or  even  less.  These  very  different  results 
depend  on  various  causes,  more  particularly,  how- 
ever, on  the  degree  of  heat  obtained.  The  greater 
the  heat  the  greater  the  amount  of  large  globules, 
and  the  less  amount  of  minutely  divided  metal  to 
oxidize  during  the  cooling  of  the  crucible.  I  sue- 


112  ALUMINIUM. 

ceeded  once  or  twice  in  reducing  nearly  the  whole 
of  the  metal  to  one  single  button,  weighing  0.5 
grm.,  at  a  very  high  heat  in  a  stoneware  crucible. 
I  could  not  always  obtain  the  same  heat  with  the 
blowpipe,  as  it  depended  in  some  degree  on  the 
pressure  in  the  gasometer  in  the  gasworks,  which 
varies  at  different  hours  of  the  day.  The  follow- 
ing experiment  will  show  how  great  the  loss  of 
metal  may  be  owing  to  oxidation  during  the 
slow  cooling  of  the  crucible  and  its  contents :  In  a 
large  iron  crucible  were  placed  35  grms.  of  cryolite 
in  alternate  layers  with  14  grms.  of  sodium  and 
the  whole  covered  with  a  thick  stratum  of  KC1. 
The  crucible,  covered  by  a  porcelain  cover,  was 
placed  in  a  larger  earthen  one,  also  covered,  and 
the  whole  exposed  to  a  good  heat  in  a  draft  furnace 
for  one  hour  and  cooled  as  slowly  as  possible.  The 
product  in  this  case  was  remarkably  small,  for 
0.135  grm.  of  aluminium  was  all  that  could  be 
obtained  in  globules.  The  differences  in  the  amounts 
reduced  depend  also  in  some  degree  on  the  more  or 
less  successful  stratification  of  the  sodium  with  the 
powered  cryolite,  as  much  of  the  latter  sometimes 
escapes  decomposition.  The  greater  the  amount  of 
sodium  employed,  the  less  likely  is  this  to  be  the 
case  ;  however,  owing  to  the  great  difference  in  their 
prices,  I  never  emploj^ed  more  than  4  grms.  of 
sodium  to  10  grms.  of  cryolite.  In  order  to  avoid 
this  loss  by  oxidation  I  tried  another  method  of 
preparation  :  Twenty  grms.  of  cryolite  were  heated 


METALLURGY    OF    ALUMINIUM.  113 

intensely  in  a  gun-barrel  in  a  current  of  hydrogen, 
and  then  the  vapor  of  8  grms.  of  sodium  passed 
over  it.  This  was  effected  simply  by  placing  the 
sodium  in  a  little  iron  tray  in  a  part  of  the  gun- 
barrel  without  the  fire,  and  pushing  it  forward 
when  the  cryolite  had  attained  a  maximum  tempe- 
rature. The  operation  went  on  very  well,  the 
whole  being  allowed  to  cool  in  a  current  of  hydro- 
gen. After  the  treatment  with  water,  in  which 
the  sodium  fluoride  dissolved  very  slowly,  I  ob- 
tained a  black  powder,  consisting  for  the  most  part 
of  iron.  Its  solution  in  HC1  gave  small  evidence 
of  Al.  The  small  amounts  I  obtained,  however, 
should  not  deter  others  from  making  these  experi- 
ments. These  are  the  results  of  first  experiments 
on  which  I  have  not  been  able  to  expend  much 
time.  Now  that  cryolite  can  be  procured  at  so 
moderate  a  price,  and  sodium,  by  Deville's  improve- 
ments, will  in  future  become  so  much  cheaper,  it  is 
in  the  power  of  every  chemist  to  engage  in  the 
preparation  of  aluminium,  and  I  have  no  doubt 
that  in  a  short  time  methods  will  be  found  afford- 
ing a  much  more  profitable  result. 

"  For  the  rest,  I  am  of  opinion  that  cryolite  is  the 
best  adapted  of  all  the  compounds  of  aluminium 
for  the  preparation  of  this  metal.  It  deserves  the 
preference  over  Al2Cl6.2XaCl  or  A12C16,  and  it  might 
still  be  employed  with  great  advantage  even  if  its 
price  were  to  rise  considerably.  The  attempts  at 
preparing  aluminium  direct  from  A1203  have  as 

10* 


114  ALUMINIUM. 

yet  been  unattended  with  success.  Potassium  and 
sodium  appear  only  to  reduce  metallic  oxides  when 
the  potash  and  soda  produced  are  capable  of  forming 
compounds  with  a  portion  of  the  oxide  remaining 
as  such.  Pure  potash  and  soda,  with  whose  pro- 
perties we  are  very  slightly  acquainted,  do  not 
appear  to  be  formed  in  this  case.  Since,  however, 
alumina  combines  so  readily  with  the  alkalies  to 
form  aluminates,  one  would  be  inclined  to  believe 
that  the  reduction  of  APO3  by  the  alkali  metals 
should  succeed.  But  even  were  it  possible  to  ob- 
tain the  metal  directly  from  A1203,  it  is  very  prob- 
able that  cryolite  would  long  be  preferred  should 
it  remain  at  a  moderate  price,  for  it  is  furnished 
by  nature  in  a  rare  state  of  purity,  and  the  alumi- 
nium is  combined  in  it  with  sodium  and  fluorine 
only,  which  exercise  no  prejudicial  influence  on  the 
properties  of  the  metal,  whereas  A1203  is  rarely 
found  in  nature  in  a  pure  state  and  in  a  dense, 
compact  condition,  and  to  prepare  A1203  on  a  large 
scale,  freeing  it  from  those  substances  which  would 
act  injuriously  on  the  properties  of  the  metal, 
would  be  attended  with  great  difficulty. 

"  The  buttons  of  aluminium  which  I  have  pre- 
pared are  so  malleable  that  they  may  be  beaten 
and  rolled  out  into  the  finest  foil  without  cracking 

O 

on  the  edges.  They  have  a  strong  metallic  lustre. 
Some  small  pieces,  not  globular,  however,  were 
found  in  the  bottom  of  the  crucible,  and  occasion- 
ally adhering  to  it,  which  cracked  on  being  ham- 


METALLURGY  OF  ALUMINIUM.        115 

mered,  and  were  different  in  color  and  lustre  from 
the  others.  They  were  evidently  not  so  pure  as 
the  greater  number  of  the  globules,  and  contained 
iron.  On  sawing  through  a  large  button  weighing 
3.8  grms.,  it  could  readily  be  observed  that  the 
metal  for  about  half  a  line  from  the  exterior  was 
brittle,  while  in  the  interior  it  was  soft  and  malle- 
able. Sometimes  the  interior  of  a  globule  contained 
cavities.  AVith  Deville,  I  have  occasionally  observed 
aluminium  crystallized.  A  large  button  became 
striated  and  crystalline  on  cooling.  Deville  believes 
he  has  observed  regular  octahedra,  but  does  not 
state  this  positively.  According  to  my  brother's 
examination,  the  crystals  do  not  belong  to  any  of 
the  regular  forms.  As  I  chanced  on  one  occasion 
to  attempt  the  fusion  of  a  large,  flattened-out  but- 
ton of  rather  impure  aluminium,  without  a  flux,  I 
observed,  before  the  heat  was  sufficient  to  fuse  the 
mass,  small  globules  sweating  out  from  the  surface. 
The  impure  metal  being  less  fusible  than  pure 
metal,  the  latter  expands  in  fusing  and  comes  to 
the  surface." 

Such  were  the  results  given  to  the  world  by  H. 
Rose.  After  their  publication,  many  minds  were 
turned  towards  this  field,  and  it  was  discovered 
that  some  six  months  previously  Dr.  Percy  had 
accomplished  the  same  results,  and  had  even  shown 
them  to  the  Royal  Institution,  but  with  the  singu- 
lar fact  of  exciting  very  little  attention.  These 
facts  are  stated  at  length  in  the  following  paper, 


116  ALUMINIUM. 

written  by  Allan  Dick,  Esq.,  which  appeared  in 
November,  1855,  two  months  after  the  publication 
of  H.  Rose's  paper :  — * 

"In  the  last  number  of  this  magazine  was  the 
translation  of  a  paper  by  H.  Rose,  of  Berlin,  de- 
scribing a  method  of  preparing  aluminium  from 
cryolite.  Previously,  at  the  suggestion  of  Dr. 
Percy,  I  had  made  some  experiments  on  the  same 
subject  in  the  metallurgical  laboratory  of  the 
School  of  Mines,  and  as  the  results  obtained  agree 
very  closely  with  those  of  Mr.  Rose,  it  may  be 
interesting  to  give  a  short  account  of  them  now, 
though  no  detailed  description  was  published  at 
the  time,  a  small  piece  of  metal  prepared  from 
cryolite  having  simply  been  shown  at  the  weekly 
meeting  of  the  Royal  Institution,  March  30,  1855, 
accompanied  by  a  few  words  of  explanation  by 
Faraday. 

"  Shortly  after  the  publication  of  Mr.  Deville's 
process  for  preparing  aluminium  from  A12C16,  I 
tried,  along  with  Mr.  Smith,  to  make  a  specimen 
of  the  metal,  but  we  found  it  much  more  difficult 
to  do  than  Deville's  paper  had  led  us  to  antici- 
pate, and  had  to  remain  contented  with  a  much 
smaller  piece  of  metal  than  we  had  hoped  to  obtain. 
It  is,  however,  undoubtedly  only  a  matter  of  time, 
skill,  and  expense  to  join  successful  practice  with 
the  details  given  by  Deville.  Whilst  making 

*  Phil.  Mag.,  Nov.  1855. 


METALLURGY   OF   ALUMINIUM.  117 

these  experiments  Dr.  Percy  had  often  requested 
us  to  try  whether  cryolite  could  be  used  instead  of 
the  chlorides,  but  some  time  elapsed  before  we 
could  obtain  a  specimen  of  the  mineral.  The  first 
experiments  were  made  in  glass  tubes  sealed  at  one 
end,  into  which  alternate  layers  of  finely  powdered 
cryolite  and  sodium  cut  into  small  pieces  were 
introduced,  and  covered  in  some  instances  with  a 
layer  of  cryolite,  in  others  by  KaCl.  The  tube 
was  then  heated  over  a  gas  blowpipe  for  a  few 
minutes  till  decomposition  had  taken  place  and 
the  product  was  melted.  When  cold,  on  breaking 
the  tube,  it  was  found  that  the  mass  was  full  of 
small  globules  of  aluminium,  but  owing  to  the 
specific  gravity  of  the  metal  and  flux  being  nearly 
alike,  the  globules  had  not  collected  into  a  button 
at  the  bottom.  To  effect  this,  long  continued 
heat  would  be  required,  which  cannot  be  given  in 
glass  tubes  owing  to  the  powerful  action  of  the 
melted  fluoride  on  them.  To  obviate  this  difficulty 
a  platinum  crucible  was  lined  with  magnesia  by 
ramming  it  in  hard,  and  subsequently  cutting  out 
all  but  a  lining.  In  this,  alternate  layers  of  cryolite 
and  sodium  were  placed,  with  a  thickish  layer  of 
cryolite  on  top.  The  crucible  was  covered  with  a 
tight-fitting  lid,  and  heated  to  redness  for  about 
half  an  hour  over  a  gas  blowpipe.  When  cold  it 
was  placed  in  water,  and  after  soaking  for  some 
time  the  contents  were  dug  out,  gently  crushed  in 
a  mortar,  and  washed  by  decantation.  Two  or 


118  ALUMINIUM. 

three  globules  of  aluminium,  tolerably  large  con- 
sidering the  size  of  the  experiment,  were  obtained, 
along  with  a  large  number  of  very  small  ones. 
The  larger  ones  were  melted  together  under  KOI. 
Some  experiments  made  in  iron  crucibles  were  not 
attended  with  the  same  success  as  those  of  Rose, 
no  globules  of  any  considerable  size  remained  in 
the  melted  fluorides ;  the  metal  seemed  to  alloy  on 
the  sides  of  the  crucible,  which  acquired  a  color 
like  zinc.  It  is  possible  that  this  difference  may 
have  arisen  from  using  a  higher  temperature  than 
Rose,  as  we  made  these  experiments  in  a  furnace, 
not  over  the  blowpipe.  Porcelain  and  clay  cruci- 
bles were  also  tried,  but  laid  aside  after  a  tew  ex- 
periments, owing  to  the  action  of  the  fluorides 
upon  them,  which  in  most  cases  was  sufficient  to 
perforate  them  completely." 

The  above  papers,  Rose's  and  Dick's,  contain  all 
the  published  researches  with  cryolite  until  Deville's 
attention  was  turned  towards  it.  He  then  took 
up  the  subject  with  his  accustomed  thoroughness. 
The  following  pages  are  taken  from  his  '  De  1' Alu- 
minium,' the  subject  not  being  given  in  its  entirety, 
but  only  the  most  important  points.  He  published 
the  first  account  of  these  researches  in  '  Ann.  de 
Chem.  et  de  Phys.'  [3],  xlvi.  451  :- 

"  I  have  repeated  and  confirmed  all  the  experi- 
ments of  Dr.  Percy  and  H.  Rose,  using  the  specimens 
of  cryolite  which  I  obtained  from  London  through 
the  kindness  of  MM.  Rose  and  Hofmann.  I  have, 


METALLURGY    OF   ALUMINIUM.  119 

furthermore,  reduced  cryolite  mixed  with  !N"aCl  by 
the  battery,  and  I  believe  that  this  will  be  an  ex- 
cellent method  of  covering  with  aluminium  all  the 
other  metals,  copper  in  particular.  Anyhow,  its 
fusibility  is  considerably  increased  by  mixing  it 
with  A12C16.2KC1.  Cryolite  is  a  double  fluoride  of 
aluminium  and  sodium,  containing  13  per  cent. 
Al,  32.5  per  cent.  Xa,  and  54.5  per  cent.  F.  Its 
formula  is  Al2F6.6NaF.  I  have  verified  these  facts 
myself  by  many  analyses." 

Deville  then  gives  a  description  of  methods  of 
making  cryolite  artificially,  which  is  unnecessary 
to  repeat  here,  for  natural  cryolite  is  so  cheap  that 
these  methods  are  of  no  practical  importance.  He 
continues : — 

"In  reducing  the  cryolite  I  placed  the  finely-pul- 
verized mixture  of  cryolite  and  XaCl  in  alternate 
layers  with  sodium  in  a  porcelain  crucible.  The 
uppermost  layer  is  of  pure  cryolite,  covered  with 
XaCl.  The  mixture  is  heated  just  to  complete  fu- 
sion, and,  after  stirring  with  a  pipe-stem,  is  let  cool. 
On  breaking  the  crucible,  the  aluminium  is  often 
found  united  in  large  globules  easy  to  separate  from 
the  mass.  The  metal  always  contains  silicon,  which 
increases  the  depth  of  its  natural  blue  tint  and 
hinders  the  whitening  of  the  metal  by  nitric  acid, 
because  of  the  insolubility  of  the  silicon  in  that 
acid.  M.  Rose's  metal  is  very  ferruginous.  I  have 
verified  all  M.  Rose's  observations,  and  I  agree 
with  him  concerning  the  return  of  metal,  which  I 


120  ALUMINIUM. 

have  always  found  very  small.  There  are  always 
produced  in  these  operations  brilliant  flames,  which 
are  observed  in  the  scoria  floating  on  the  alumin- 
ium, and  which  are  due  to  gas  burning  and 
exhaling  a  very  marked  odor  of  phosphorus.  In 
fact,  P206  exists  in  cryolite,  as  one  may  find  by 
treating  a  solution  of  the  mineral  in  sulphuric  acid 
with  molybdate  of  ammonia,  according  to  H. 
Rose's  reaction. 

"The  facility  with  which  aluminium  unites  in 
fluorides  is  due  without  doubt  to  the  property  which 
these  possess  of  dissolving  the  alumina  on  the  surface 
of  the  globules  at  the  moment  of  their  formation, 
and  which  the  sodium  is  unable  to  reduce.  I  had 
experienced  great  difficulty  by  obtaining  small 
quantities  of  metal  poorly  united,  when  I  reduced 
the  Al2Cl6.2]N"aCl  by  sodium ;  M.  Ramrnelsberg,  who 
often  made  the  same  attempts,  tells  me  he  has  had  a 
like  experience.  But,  I  am  assured  by  a  scrupulous 
analysis  that  the  quantity  of  metal  reduced  by  the 
sodium  is  exactly  that  which  theory  indicates, 
although  after  many  operations  there  is  found  only 
a  gray  powder,  resolving  itself  under  the  micro- 
scope into  a  multitude  of  small  globules.  The  fact 
is  simply  that  Al2Cl6.2NaCl  is  a  very  poor  flux 
for  aluminium.  MM.  Morin,  Debray,  and  myself 
have  undertaken  to  correct  this  bad  eflect  by  the 
introduction  of  a  solvent  for  the  A1203  into  the 
saline  slag  which  accompanies  the  aluminium  at 
the  moment  of  its  formation.  At  first,  we  found 


METALLURGY   OF   ALUMINIUM.  121 

it  an  improvement  to  condense  the  vapors  of  A12C16, 
previously  purified  by  iron,-directly  in  NaCl,  placed 
for  this  purpose  in  a  crucible  and  kept  at  a  red 
heat.  We  produced  in  this  way , from  highly  colored 
material,  a  double  chloride  very  white  and  free  from 
moisture,  and  furnishing  on  reduction  a  metal  of 
fine  appearance.  We  then  introduced  fluorspar 
(CaF2)  into  the  composition  of  the  mixture  to  be 
reduced,  and  we  obtained  good  results  with  the 
following  proportions : — 

Al*Cl6.2NaCl        ....  400  grammes. 

NaCl 200 

CaF2 200          " 

Na        .        .        .        .        .        .  75  to  80  " 

The  double  chloride  ought  to  be  melted  and  heated 
almost  to  low  red  heat  at  the  moment  it  is  em- 
ployed, the  NaCl  calcined  and  at  a  red  heat  or 
melted,  and  the  CaF2  pulverized  and  well  dried. 
The  double  chloride,  NaCl  and  CaF2  are  mixed  and 
alternated  in  layers  in  the  crucible  with  sodium. 
The  top  layer  is  of  the  mixture,  and  the  cover  is 
XaCl.  Heat  gently,  at  first,  until  the  reaction  ends, 
and  then  to  a  heat  about  sufficient  to  melt  silver. 
The  crucible,  or  at  least  that  part  of  it  which  con- 
tains the  mixture,  ought  to  be  of  a  uniform  red  tint, 
and  the  material  perfectly  liquid.  It  is  stirred  a 
long  time  and  cast  on  a  well-dried,  chalked  plate. 
There  flows  out  first  a  very  limpid  liquid,  colorless 
and  very  fluid,  then  a  gray  material,  a  little  more 
pasty,  which  contains  aluminium  in  little  grains, 
11 


122  ALUMINIUM. 

and  is  set  aside,  and  finally  a  button  with  small, 
metallic  masses  which  of  themselves  ought  to  weigh 
20  grms.  if  the  operation  has  succeeded  well.  On 
pulverizing  and  sieving  the  gray  slag,  5  or  6  grms.  of 
small  globules  are  obtained,  wrhich  may  be  pressed 
together  by  an  earthen  rod  in  an  ordinary  crucible 
heated  to  redness.  The  globules  are  thus  reunited, 
and  when  a  sufficient  quantity  is  collected  the  metal 
is  cast  into  ingots.  In  a  well-conducted  operation, 
75  grms.  of  Na  ought  to  give  a  button  of  20  grms. 
and  5  grms.  in  grains,  making  a  return  of  one  Al 
from  three  of  Na.  Theory  indicates  one  to  two 
and  a  half,  or  30  grms.  of  Al  from  75  of  Na.  But 
all  the  efforts  which  have  been  made  to  recover  from 
the  insoluble  slag  the  4  or  5  grms.  of  metal  not 
united  but  easily  visible  with  a  glass,  have  been  so 
far  unsuccessful:  There  is,  without  doubt,  a  knack, 
a  particular  manipulation  on  which  depends  the 
success  of  an  operation  which  would  render  the 
theoretical  amount  of  metal,  but  we  lack  it  yet. 
These  operations  take  place,  in  general,  with  more 
facility  on  a  large  scale,  so  that  we  may  consider 
fluorspar  as  being  suitable  for  serving  in  the  manu- 
facture of  aluminium  in  crucibles.  We  employed 
very  pure  fluorspar,  and  our  metal  was  quite  exempt 
from  silicon.  It  is  true  that  we  took  a  precaution 
which  is  necessary  to  adopt  in  operations  of  this 
kind;  we  plastered  our  crucibles  inside  with  a  layer 
of  aluminous  paste,  the  composition  of  which  has 
been  given  in  '  Ann.  de  Chem.  et  de  Phys.,'  xlvi. 


METALLURGY  OF  ALUMINIUM.        123 

195.  This  paste  is  made  of  calcined  alumina  and 
an  aluminate  of  lime,  the  latter  obtained  by  heating 
together  equal  parts  of  chalk  and  alumina  to  a  high 
heat.  By  taking  about  four  parts  calcined  alumina 
and  one  of  aluminate  of  lime  well  pulverized  and 
sieved,  moistening  with  a  little  water,  there  is 
obtained  a  paste  with  which  the  inside  of  'an 
earthen  crucible  is  quickly  and  easily  coated.  The 
paste  is  spread  evenly  with  a  porcelain  spatula,  and 
compressed  strongly  until  its  surface  has  become 
well  polished.  It  is  allowed  to  dry,  and  then  heated 
to  bright  redness  to  season  the  coating,  which  does 
not  melt,  and  protects  the  crucible  completely 
against  the  action  of  the  aluminium  and  fluorspar. 
A  crucible  will  serve  several  times  in  succession 
provided  that  the  new  material  is  put  in  as  soon  as 
the  previous  charge  is  cast.  The  advantages  of 
doing  this  are  that  the  mixture  and  the  sodium  are 
put  into  a  crucible  already  heated  up,  and  so  lose 
less  by  volatilization  because  the  heating  is  done 
more  quickly,  and  the  crucible  is  drier  than  if  a  new 
one  had  been  used  or  than  if  it  had  been  let  cool. 
A  new  crucible  should  be  heated  to  at  least  300° 
or  400°  before  being  used.  The  saline  slag  contains 
a  large  quantity  of  calcium  chloride,  which  can  be 
washed  away  by  water,  and  an  insoluble  material 
from  which  aluminium  fluoride  can  be  volatilized. 
"  Yet  the  operation  just  described,  which  was  a 
great  improvement  on  previous  ones,  requires  many 
precautions  and  a  certain  skill  of  manipulation  to 


124  ALUMINIUM. 

succeed  every  time.  But,  nothing  is  more  easy  or 
simple  than  to  substitute  cryolite  for  the  fluorspar. 
Then  the  operation  is  much  easier.  The  amount  of 
metal  produced  is  not  much  larger,  although  the 

-IT  O        7  O 

button  often  weighs  22  grammes,  yet  if  cryolite  can 
only  be  obtained  in  abundance  in  a  continuous  sup- 
ply, the  process  which  I  will  describe  will  become 
most  economical.  The  charge  is  made  up  as  before, 
except  introducing  cryolite  for  CaF2.  In  one  of 
our  operations  we  obtained,  with  76  grrns.  of  sodi- 
um, a  button  weighing  22  grms.  and  4  grms.  in 
globules,  giving  a  yield  of  one  Al  to  two  and  ei^ht- 
tenths  parts  sodium,  which  is  very  near  to  that 
indicated  by  theory.  The  metal  obtained  was  of 
excellent  quality.  However,  it  contained  a  little 
iron  coming  from  the  A12C16,  W7hich  had  not  been 
purified  perfectly.  Bat  iron  does  not  inj  ure  the  prop- 
erties of  the  metal  as  copper  does ;  and,  save  a  little 
bluish  coloration,  it  does  not  alter  its  appearance  or 
its  resistance  to  physical  and  chemical  agencies. 

"Process  with  cryolite  alone:  The  process  adopted 
in  the  works  at  Amfreville,  near  Rouen,  directed 
by  Tissier  Bros.,  is  the  same  as  that  described  by 
Percy  and  Rose.  The  details  which  I  give  are 
taken  from  MM.  Tissier's  own  account  of  their  pro- 
cess." (Deville  then  gives  the  details  of  the  process 
outlined  by  Rose  (see  p.  103),  of  reducing  in  iron 
crucibles ;  which  it  is  not  necessary  to  repeat.) 

"  I  obtained  a  good  specimen  of  commercial  alu- 
minium thusextracted  from  cryolite ;  and  M.  Demon- 


METALLURGY  OF  ALUMINIUM.        125 

deur  has  been  so  kind  as  to  make  an  analysis  of  it, 
with  the  following  results:  Si  4.4;  FeO.8;  A!  94.8. 
"  M.  Rose  has  recommended  iron  vessels  for  this 
operation,  because  of  the  rapidity  with  which  alka- 
line fluorides  attack  earthen  crucibles  and  so  intro- 
duce considerable  silicon  into  the  metal.  Unfortu- 
nately, these  iron  crucibles  introduce  iron  into  the 
metal.  This  is  an  evil  inherent  to  this  method,  at 
least  in  the  present  state  of  the  industry.  The 
inconveniences  of  this  method  result  in  part  from 
the  high  temperature  required  to  complete  the  ope- 
ration, and  from  the  crucible  being  in  direct  contact 
with  the  fire,  by  which  its  sides  are  heated  hotter 
than  the  metal  in  the  crucible.  The  metal  itself, 
placed  in  the  lower  part  of  the  fire,  is  hotter  than 
the  slag.  This,  according  to  my  observations,  is  an 
essentially  injurious  condition.  The  slag  ought  to 
be  cool,  the  metal  still  less  heated,  and  the  sides  of 
the  vessel  Avhere  the  fusion  occurs  ought  to  be  as 
cold  as  possible.  The  yield  from  cryolite,  accord- 
ing to  Rose's  and  my  own  observations,  is  also  very 
small.  M.  Rose  obtained  from  10  of  cryolite  and 
4  of  Xa  about  0.5  of  Al.  This  is  due  to  the 
affinity  of  aluminium  for  fluorine,  which  must  be 
very  strong  not  only  with  relation  to  its  affinity 
for  sodium  but  even  for  calcium,  and  this  affinity 
appears  to  increase  with  the  temperature,  as  was 
found  in  my  laboratory.  Cryolite  is  convenient  to 
employ  as  a  flux  to  add  to  the  mixture  which  is 
fused,  especially  when  operating  on  a  small  scale; 

11* 


126  ALUMINIUM. 

but  it  is  fortunate  that  it  is  not  indispensable,  for 
no  one  would  wish  to  establish  an  industry  on  the 
employment  of  a  material  wThich  is  of  uncertain 
supply." 

We  here  close  what  Deville  has  written  on  the 
use  of  cryolite.  The  process  was  that  used  by 
Tissier  Bros,  at  Rouen,  but  was  finally  abandoned 
there  and  the  works  closed.  We  find  a  little 
improvement  on  Deville's  process  suggested  by 
Wohler,*  in  which  he  shows  how  to  perform  the 
reduction  in  an  earthen  crucible.  The  finely  pul- 
verized cryolite  is  mixed  with  an  equal  weight  of 
a  flux  containing  7  NaCI  to  9  KC1.  This  mixture' 
is  then  placed  in  alternate  layers  with  sodium  in 
the  crucible,  50  parts  of  the  mixture  to  10  of 
sodium,  and  heated  gradually  just  to  its  fusing 
point.  The  metal  thus  obtained  is  free  from 
silicon,  but  only  one-third  of  the  aluminium  in  the 
cryolite  is  obtained.  In  spite  of  the  small  yield, 
this  method  was  used  for  some  time  by  Tissier 
Bros.  Cryolite  has  also  been  treated  at  ]^"anterre, 
by  a  different  process,  but  the  aluminium  produced 
contained  phosphorus.  So,  while  the  exclusive 
use  of  cryolite  in  the  preparation  of  aluminium  is 
now  renounced,  it  has  retained  the  office  of  a  flux. 

Watts  gives  the  following  paragraph  in  connec- 
tion with  the  reduction  of  cryolite :  "A  peculiar 
apparatus  for  effecting  the  reduction  of  aluminium, 

*  Ann.  der  Cbem.  und  Pharm.  99,  255. 


METALLURGY   OF   ALUMINIUM.  127 

either  from  Al2Cl6.2NaCl  or  from  cryolite,  the 
object  of  which  is  to  prevent  loss  of  sodium  by 
ignition,  has  been  invented  and  patented  by  W.  F. 
Gerhard.*  It  consists  of  a  reverberatory  furnace 
having  two  hearths,  or  of  two  crucibles,  or  of  two 
reverberatory  furnaces,  placed  one  above  the  other 
and  communicating  by  an  iron  pipe.  In  the  lower 
is  placed  a  mixture  of  sodium  with  the  aluminium 
compound,  and  in  the  upper  a  stratum  of  !NaCl,  or 
of  a  mixture  of  NaCl  and  cryolite,  or  of  the  slag 
obtained  in  a  previous  operation.  This  charge, 
when  melted,  is  made  to  run  into  the  lower  furnace 
•in  quantity  sufficient  to  completely  cover  the  mix- 
ture contained  therein,  and  so  to  protect  it  from 
the  air.  The  mixture  thus  covered  is  reduced  as 
by  the  usual  operation." 

Watts  thus  summarizes  the  use  of  cryolite : 
"  The  chief  inducement  for  using  it  as  a  source  of 
aluminium  is  that  it  is  a  natural  product  obtained 
with  tolerable  facility,  and  enables  the  manufact- 
urer to  dispense  with  the  troublesome  and  costly 
preparation  of  Al2Cl6.2^"aCl.  But  the  metal  thus 
obtained  is  less  pure  than  that  obtained  by  other 
processes.  If  earthenware  crucibles  are  used,  the 
metal  is  contaminated  with  silicon,  because  the 
sodium  fluoride  produced  acts  strongly  on  the 
siliceous  matter  of  the  crucible,  while  if  an  iron 
crucible  be  used,  the  metal  takes  up  some  iron. 

*  Eng.  Pat.  1858,  No.  2247. 


128  ALUMINIUM. 

The  best  use  of  cryolite  is  as  a  flux  in  the  prepara- 
tion of  aluminium  from  Al2Cl6.2JN"aCl,  in  which 
case  the  slag  is  not  sodium  fluoride  but  aluminium 
fluoride,  which  acts  but  slightly  on  the  containing 
vessel." 

GENERAL  REMARKS. 

I  have  now  given  the  metallurgy  of  aluminium 
through  what  may  be  called  its  experimental  stage 
up  to  its  practical  industrial  manufacture.  Up  to 
this  period,  which  I  will  place  at  about  1859,  the 
object  has  been  to  produce  the  metal  at  any  cost, 
only  produce  it.  "  To  learn  how"  engrossed  the 
attention  of  the  investigators,  who  troubled  them- 
selves very  little  about  the  ultimate  cost.  They 
must  learn  first  how  to  do  the  thins:  and  afterwards 

O 

devote  their  energies  to  cheapening  the  process 
discovered.  But,  in  1859,  the  works  at  Amfreville, 
near  Rouen,  under  the  direction  of  the  Tissiers,  is 
producing  aluminium  from  cryolite;  Morin  &  Co., 
at  Nanterre,  are  making  it,  though  not  in  such 
large  quantities  as  Tissier,  but  they  soon  after 
move  to  Salindres,  and  set  up  so  large  a  plant  that 
a  year  or  so  afterwards  the  Tissiers  were  driven 
from  the  business.  Such  is  then  the  state  of  the 
industry.  We  iind  that  in  the  next  fifteen  or 
twenty  years  very  little  advance  is  chronicled.  At 
Salindres,  the  processes  given  by  Deville  were  used 
somewhat  improved  and  perfected,  but  yet  the 


METALLURGY  OF  ALUMINIUM.        129 

same  processes.  It  is  only  within  the  last  ten 
years  that  any  improvements  of  a  radical  nature, 
such  as  Webster's,  Frishmuth's,  and  Cowles,  have 
been  brought  into  the  industry. 

So,  from  now  on  we  will  treat  the  subject  in  the 
order  usually  adopted  in  presenting  it ;  i.  e.,  first 
give  a  short  sketch  of  the  metallurgy  of  sodium 
up  to  the  present  time,  then  a  review  of  the  manu- 
facture of  alumina  and  its  conversion  into 
Al2Cl6.2XaCl,  ending  with  a  full  description  of  the 
process  as  now  carried  on  at  Salindres,  and  a  fewr 
attempts  which  have  been  made  to  improve  it. 
Afterwards,  leaving  the  old  Deville  process  and  its 
improvements,  I  will  give  as  full  an  account  as  I 
have  been  able  to  gather  of  the  various  methods 
proposed  to  produce  aluminium  without  the  use  of 
sodium. 


PART  VI. 

THE  MANUFACTURE  OF  SODIUM. 

As  already  observed,  we  will  not  go  extensively 
into  the  metallurgy  of  this  metal.  Some  years 
ago,  in  order  to  treat  fully  of  the  metallurgy  of 
aluminium,  it  would  have  been  as  necessary  to  ac- 
company it  with  all  the  details  of  the  manufacture  of 
sodium  as  to  give  the  details  of  the  reduction  of  the 
aluminium,  because  the  manufacture  of  the  former 
was  carried  on  solely  in  connection  with  that  of  the 
latter.  But  now  sodium  has  come  out  of  the  list  of 
chemical  curiosities  and  has  become  an  article  of 
commerce,  used  for  many  other  purposes  than  the 
reduction  of  aluminium,  though  that  is  still  its 
chief  use.  So  we  regard  the  manufacture  of  sodium 
as  a  separate  metallurgical  subject,  still  intimately 
connected  with  that  of  aluminium,  but  yet  so  far 
distinct  from  it  as  to  deserve  a  metallurgical  trea- 
tise of  its  own.  Moreover,  the  metallurgy  of  sodium 
is  very  much  as  Deville  left  it,  it  has  been  very 
little  improved  since  then,  and  so  almost  all  the 
details  of  its  manufacture  are  to  be  found  in  Eng- 
lish in  any  good  book  on  chemistry.  To  such 
works  I  refer  the  reader  for  fuller  accounts  than  are 


THE  MANUFACTURE   OF   SODIUM.  131 

given  here.  The  following  summary  is  taken  prin- 
cipally from  Mierzinski. 

Sodium  was  first  isolated  by  Davy  by  the  use  of 
electricity  in  the  year  1808.*  Later,  Gay  Lussac 
and  Thenard  made  it  by  decomposing  at  a  very 
high  temperature  a  mixture  of  Na2C03  and  iron 
filings/)-  On  April  30, 1808,  Curaudau  announced 
that  he  had  succeeded  in  producing  potassium  or 
sodium  without  using  iron,  simply  by  decomposing 
K2C03  or  ^a2COs  by  means  of  animal  charcoal. 
Briinner  continuing  this  investigation  used  instead 
of  animal  charcoal  the  so-called  black  flux,  the  pro- 
duct obtained  by  calcining  crude  tartar  from  wine 
barrels.  He  was  the  first  to  use  the  w rough t-iron 
mercury  bottles.  The  mixture  was  heated  white 
hot  in  a  furnace,  the  sodium  volatilized  and  was 
condensed  in  an  iron  tube  screwed  into  the  top  of 
the  flask,  which  projected  from  the  furnace  and 
was  cooled  with  water.  In  Briinners  experiments 
he  only  obtained  three  per  cent,  of  the  weight  of 
the  mixture  as  metallic  sodium,  the  rest  of  the 
metal  being  lost  as  vapor. 

Donny  and  Mareskagave  the  condenser  the  form 
which  with  a  few  modifications  it  retains  to-day. 
It  was  of  iron,  4  millimetres  thick,  arid  was  made 
in  the  shape  of  a  book,  having  a  length  of  about 
100  centimetres,  breadth  50,  and  depth  6  (see  Fig. 
2).  This  form  is  now  so  well  known  that  a  further 

*  Phil.  Trans.,  1808. 

|  Recherches  Physico-chemiques,  1810. 


132  ALUMINIUM. 

description  is  unnecessary.  With  this  condenser 
the  greatest  difficulty  of  the  process  was  removed, 
and  the  operation  could  be  carried  on  in  safety. 

Fig.  2. 


This  apparatus  was  devised  and  used  by  Donny  and 
Mareska  in  1854,  with  the  supervision  of  Deville, 
and  the  whole  process  as  used  by  them  is  the  same 
that  the  Tissier  Bros,  took  with  them  and  operated 
at  their  works  at  Rouen,  and  their  description  ac- 
cords with  that  given  by  Deville,  which  is  as  fol- 
lows : — 

The  Na2C03  is  first  well  dried  at  a  high  tempera- 
ture, then  mixed  with  well  dried  pulverized  char- 
coal and  chalk,  ground  to  the  finest  powder,  the 
success  of  the  operation  depending  on  the  fineness  of 
this  mixture.  The  proportions  of  these  to  use  is 
various.  One  simple  mixture  is  of 

Na2CO* 30 

Coal  .        .        .     '   .        .        .        .13 

Chalk  .        .        .        .               ".."       .       5 

Coke  5 


THE  MANUFACTURE   OF   SODIUM. 


Devil le  recommends  taking — 


Coal     . 
Chalk  . 


1000 
450 
175 


The  addition  of  chalk  has  the  object  of  making  the 
mixture  less  fusible  and  more  porous,  but  has  the 
disadvantage  that  the  residue  remaining  in  the  re- 
tort after  the  operation  is  very  impure,  and  it  is 
impossible  to  add  any  of  it  to  the  succeeding  charge ; 
and  also,  some  of  it  being  reduced  to  caustic  lime 
forms  caustic  alkali  with  some  Na'CO8,  which  is 
then  lost.  When  the  mixture  is  well  made  it  is 
subjected  to  a  preliminary  calcination.  This  is 
done  in  cast-iron  cylinders,  two  of  which  are  placed 
side  by  side  in  a  furnace  and  heated  to  redness  (see 
Fig.  3).  This  is  continued  till  all  the  moisture, 

Fig.  3. 


carbonic  acid,  and  any  carburetted  hydrogen  rforn 
the  coal  cease  coming  oft'.  The  mass  contracts,  be- 
comes white  and  somewhat  dense,  so  that  a  larger 

12 


134 


ALUMINIUM. 


amount  of  the  mixture  can  now  be  treated  in  the 
retorts  where  the  sodium  is  evolved.  As  soon  as 
the  outcorning  gases  burn  with  a  yellow  flame, 
showing  sodium  coming  off,  the  calcination  is 
stopped.  The  mixture  is  then  immediately  drawn 
out  on  to  the  stone  floor  of  the  shop,  wThere  it  cools 
quickly  and  is  then  ready  for  the  next  operation. 
This  calcination  yields  a  mixture  which  without 
any  previous  reactions  is  just  ready  to  evolve  sodium 
when  brought  to  the  necessary  temperature.  This 
material  is  made  into  a  sort  of  cylinder  or  cartridge 
and  put  into  the  decomposition  retorts  (see  Fig.  4). 

Fig.  4. 


The  charging  should  be  done  quickly.     The  final 
retorts  are  120  centimetres  long,  12  to  14  centime- 


THE   MANUFACTURE   OF  SODIUM.  135 

tres  diameter,  with  walls  10  to  30  millimetres  thick. 
These  are  of  wrought  iron,  since  cast  iron  would 
not  stand  the  heat.  At  each  end  this  retort  is 
closed  with  wrought-iron  stoppers  and  made  tight 
with  fire-clay.  Through  one  stopper  leads  the  pipe 
to  the  condenser,  the  other  stopper  is  the  one  re- 
moved when  the  retort  is  to  be  recharged.  These 
retorts  are  placed  horizontally  in  rows  in  a  furnace. 
Usually  four  are  placed  in  a  furnace,  preferably 
heated  by  gas,  such  as  the  Siemens  regenerative 
furnace  or  Bicheroux's,  these  being  much  more  eco- 
nomical. In  spite  of  all  these  precautions  the  re- 
torts will  be  strongly  attacked,  and  in  order  to  pro- 
tect them  from  the  destructive  action  of  a  white 
heat  for  seven  or  eight  hours  they  are  coated  with 
some  kind  of  fire-proof  material.  The  best  for 
this  purpose  is  graphite,  which  is  made  into  cylin- 
ders inclosing  the  retorts,  and  which  can  remain  in 
place  till  the  furnace  is  worn  out.  These  graphite 
cylinders  not  only  protect  the  iron  retorts,  but  pre- 
vent the  diffusion  of  the  gaseous  products  of  the 
reaction  into  the  hearth,  and  so  support  the  retorts 
that  their  removal  from  the  furnace  is  easily  ac- 
complished. Instead  of  these  graphite  cylinders 
the  retorts  may  be  painted  with  a  mixture  that 
melts  at  white  heat  and  so  enamels  the  outside.  A 
mixture  of  alumina,  sand,  yellow  earth,  borax,  and 
water-glass  will  serve  very  well  in  many  cases.  We 
would  remark  that  the  waste  gases  from  this  fur- 
nace can  be  used  for  the  calcining  of  the  mixture,  or 


136  ALUMINIUM. 

even  for  the  reduction  of  the  aluminium  by  sodium, 
where  the  manufacture  of  the  former  is  connected 
with  the  making  of  the  sodium.  Donny  and 
Mareska's  condenser  is  the  best  to  use. 

As  for  the  reduction  of  the  sodium,  the  retort  is 
first  heated  to  redness,  during  which  the  stopper 
at  the  condenser  end  of  the  retort  is  left  off.  The 
charge  is  then  rapidly  put  in,  and  the  stopper  at 
once  put  in  place.  The  reaction  begins  almost  at 
once  and  the  operation  is  soon  under  full  headway, 
the  gases  evolved  burning  from  the  upper  slit  of 
the  condenser  tube  with  a  flame  a  foot  long.  The 
gases  increase  in  volume  as  the  operation  continues, 
the  flame  becoming  yellower  from  sodium  and  so 
intensely  bright  as  to  be  insupportable  to  look  at. 
Now  has  come  the  moment  when  the  workman 
must  quickly  adapt  the  condenser  to  the  condenser 
tube  projecting  from  the  retort,  the  joint  being 
greased  with  tallow  or  paraffine.  The  sodium 
collects  in  this  in  a  melted  state  and  trickles  out. 
The  length  of  the  operation  varies,  depending  on 
the  intensity  of  the  heat  and  the  quantity  of  the 
mixture  ;  a  charge  may  sometimes  be  driven  over 
in  two  hours,  and  sometimes  it  takes  eight.  We 
can  say,  in  general,  that  if  the  reaction  goes  on 
quickly  a  somewhat  larger  amount  of  sodium  is 
obtained.  The  higher  the  heat  used,  however,  the 
quicker  the  retorts  are  destroyed.  The  operation 
requires  continual  attention.  From  time  to  time, 
a  workman  with  a  prod  opens  up  the  neck  of  the 


THE   MANUFACTURE   OF  SODIUM.  137 

condenser.  But,  if  care  is  not  taken  the  metal 
overflows :  if  this  happens,  the  metal  overflowing 
is  thrown  into  some  petroleum,  while  another  man 
replaces  the  condenser  with  an  empty  one.  The 
operation  is  ended  when  the  evolution  of  gas  ceases 
and  the  flame  becomes  short  and  feeble,  while  the 
connecting  tube  between  the  retort  and  condenser 

O 

keeps  clean  and  does  not  stop  up.  As  soon  as  this 
occurs,  the  stopper  at  the  charging  end  is  removed, 
the  charge  raked  out  into  an  iron  car,  and  a  new 
charge  being  put  in,  the  operation  continues. 
After  several  operations  the  retorts  must  be  well 
cleaned  and  scraped  out.  The  sodium  thus  ob- 
tained is  in  melted  bits  or  drops,  mixed  with  carbon 
and  Na2C03.  It  must  therefore  be  cleaned,  which 
is  done  by  melting  it  in  a  wrought-iron  kettle 
under  paraffin  with  a  gentle  heat,  and  then  casting 
it  into  the  desired  shapes.  The  sodium  is  kept 
under  a  layer  of  oil  or  any  hydrocarbon  of  high 
boiling  point  containing  no  oxygen. 

Deville  says  that  the  temperature  necessary  for 
the  reduction  of  sodium  from  Na2C03  and  carbon 
is  not  so  high  as  is  generally  supposed.  He  says 
that  it  was  M.  Bivot's  opinion  that  the  retorts  were 
not  heated  higher  than  the  retorts  at  Veille-Mon- 
tague  used  for  reducing  zinc.  Tissier  gives  the 
reaction  as 

:NTa2C03  -f  2C  =  SCO  4-  2^a. 
The  sodium   is   condensed,  while  the  carbonic 

12* 


138  ALUMINIUM. 

oxide,  carrying  over  some  sodium,  burns  at  the 
end  of  the  apparatus.  This  would  all  be  very 
simple  if  the  reaction  of  carbonic  oxide  on  sodium 
near  the  condensing  point  did  not  complicate 
matters,  producing  a  black,  infusible  deposit  of 
Na?0  and  C,  which  on  being  melted  always  gives 
rise  to  a  loss  of  sodium. 

The  foregoing  is  the  process  as  perfected  by 
Donny  and  Mareska,  Deville,  and  Tissier.  Only  a 
few  improvements  have  been  made,  the  most  im- 
portant are  the  following: — 

R.  Wagner*  uses  paraffin  in  preference  to  paraf- 
fin oil  in  which  to  keep  the  sodium  after  making 
it.  Only  pure  paraffin  which  has  been  melted  a 
long  time  on  a  water  bath  and  all  its  water  driven 
off  can  be  used.  The  sodium  to  be  preserved  is 
dipped  in  the  paraffin  melted  on  a  water  bath  and 
kept  at  no  higher  heat  than  55°,  and  the  metal  is 
thereby  covered  with  a  thick  coat  of  paraffin 
which  protects  it  from  oxidation,  and  may  then  be 
put  up  in  wooden  or  paper  boxes.  When  the 
metal  is  to  be  used,  it  is  easily  freed  from  paraffin 
by  simply  warming  it,  since  sodium  melts  at  95° 
to  96°  C.  and  the  paraffin  at  50°  to  60°. 

The  reduction  of  K2CG3  by  carbon  requires  much 
less  heat  than  that  of  Na2C03,  and,  therefore,  many 
attempts  have  been  made  to  reduce  potassium  and 
sodium  together,  tinder  circumstances  where  so- 

*  Dingier,  1883,  p.  252. 


THE  MANUFACTURE  OF   SODIUM.  139 

dium  alone  would  not  be  reduced.  Dumas*  added 
some  K2C03  to  the  regular  sodium  mixture ;  and 
separated  the  sodium  and  potassium  from  each 
other  by  a  slow,  tedious  oxidation.  R.  Wagnerf 
made  a  similar  attempt.  He  says  that  not  only 
does  the  reduction  of  both  metals  from  a  mixture 
of  K2C03,  Xa2C03,  and  carbon  work  easier  than 
Xa2C03  and  carbon,  but  even  caustic  soda  (XaOH) 
may  be  used  with  K2COS  and  carbon.  Also,  the 
melting  point  of  potassium  and  sodium  alloyed  is 
much  lower  than  that  of  either  one  alone,  in  con- 
sequence of  which  their  boiling  point  and  the  tem- 
perature required  for  reduction  are  lower. 

"W.  Weldon  calculated  the  cost  of  sodium  as 
seven  to  eight  marks  per  kilo.  The  greater  part 
of  this  is  for  retorts  in  which  the  operation  takes 
place,  and  which  are  so  quickly  destroyed  that  the 
replacing  of  them  forms  half  the  cost  of  the  metal. 
Compare  with  p.  172. 

The  latest  announcement  of  advance  in  making 
sodium  is  from  New  York  City,  and  is  thus  de- 
scribed in  a  New  York  paper: — % 

"  When  sodium  was  reduced  in  price  to  $1.50  per 
pound,  it  was  thought  to  have  touched  a  bottom 
figure,  and  all  hope  of  making  it  any  cheaper  seemed 
fruitless.  This  cheapening  was  not  brought  about 

*  Handbuch  der  Angewandten  Chemie,  1830,  ii.  345. 

t  Dingier,  143,  343. 

t  New  York  World,  May  16,  1886. 


140  ALUMINIUM. 

by  any  improved  or  new  process  of  reduction,  but 
was  owing  simply  to  the  fact  that  the  aluminium 
industry  required  sodium,  and  by  making  it  in 
large  quantities  its  cost  does  not  exceed  the  above- 
mentioned  price.  The  retail  price  is  now  $4.00 
per  pound.  The  process  now  used  was  invented 
by  Briinner,  in  1808,  and  up  to  the  present  time 
nothing  new  or  original  has  been  patented  except 
three  or  four  modifications  of  his  process  which 
have  been  adopted  to  meet  the  requirements  of 
using  it  on  a  large  scale.  Mr.  H.  Y.  Castner,  whose 
laboratory  is  at  218  West  Twentieth  Street,  New 
York,  has  the  first  patent  ever  granted  on  this  sub- 
ject in  the  United  States,  and  the  only  one  taken 
out  in  the  world  since  1808.  Owing  to  negotia- 
tions being  carried  on,  Mr.  Castner  having  filed 
applications  for  patents  in  various  foreign  countries, 
but  not  having  the  patents  granted  there  yet,  we 
are  not  at  liberty  to  state  his  process  fully.  The 
metal  is  reduced  and  distilled  in  large  iron  cruci- 
bles, which  are  raised  automatically  through  aper- 
tures in  the  bottom  of  the  furnace,  where  they  remain 
until  the  reduction  is  completed  and  the  sodium 
distilled.  Then  the  crucible  is  lowered,  a  new  one 
containing  a  fresh  charge  is  substituted  and  raised 
into  the  furnace,  while  the  one  just  used  is  cleaned 
and  made  ready  for  use  again.  The  temperature 
required  is  very  moderate,  the  sodium  distilling  as 
easy  as  zinc  does  when  being  reduced.  Mr.  Cast- 
ner expects  to  produce  it  at  25  cents  per  pound, 


THE  MANUFACTURE  OF  SODIUM.  141 

thus  solving  the  problem  of  cheap  aluminium,  and 
with  it  magnesium,  silicon,  and  boron,  all  of  which 
depend  on  sodium  for  their  manufacture.  Thus 
the  production  of  cheap  sodium  means  much  more 
than  cheap  aluminium.  Mr.  Castner  is  well  known 
in  New  York  as  a  chemist  of  good  standing,  and 
has  associated  with  him  Mr.  J.  H.  Booth  and  Mr. 
Henry  Booth,  both  well  known  as  gentlemen  of 
means  and  integrity." 

Mr.  Benjamin,  in  a  letter  to  the  '  Engineering 
and  Mining  Journal,'  gives  the  following  details 
in  addition  to  those  above:*  The  pots  used  are 
cast  iron,  8  inches  in  diameter  and  14  inches  deep. 
They  are  kept  at  bright  red,  or  about  1000°,  at 
which  temperature  the  decomposition  takes  place. 
Whereas,  by  previous  processes  only  one-third  of 
the  sodium  in  the  charge  is  obtained,  Mr.  Castner 
gets  nearly  all,  for  the  pots  are  nearly  entirely 
empty  when  withdrawn  from  the  furnace.  Thus 
the  great  items  of  saving  are,  two  or  three  times 
as  much  metal  extracted  from  a  given  amount  of 
salt,  and  cheap  cast-iron  crucibles  used  instead  of 
expensive  wrought-iron  retorts. 
•  The  following  are  the  claims  which  Mr.  Castner 
makes  in  his  patent :  — f 

Claim  1.  In  a  process  for  manufacturing  potas- 
sium or  sodium,  performing  the  reduction  by  diflus- 

*  Eng.  and  Min.  Journ.,  May  29,  1886. 
t  U.  S.  Pat.  No.  342,897,  June  1, 1886.     Hamilton  Y.  Cast- 
ner,  New  York. 


142  ALUMINIUM. 

ing  carbon  in  a  body  of  alkali  in  a  state  of  fusion 
at  moderate  temperatures. 

2.  Performing  the  reduction  by  means  of  the 
carbide  of  a  metal  or  its  equivalent. 

3.  Mechanically  combining  a  metal  and  carbon 
to  increase  the  weight  of  the  reducing  material, 
and  then  mixing  this  product  with  the  alkali  and 
fusing  the  latter,  whereby  the  reducing  material  is 
held  in  suspension  throughout  the  mass  of  fused 
alkali. 

4.  Performing  the  deoxidation  by  the  carbide  of 
a  metal  or  its  equivalent. 

We  learn  later  that  Mr.  Castner  cokes  a  mixture 
of  fine  iron  and  gas-tar,  grinds  the  coke,  and  uses 
this  as  the  reducing  material ;  caustic  soda  is  used 
on  account  of  its  low  fusing  point. 

REDUCTION  OF  SODIUM  BY  ELECTRICITY. 

Mierzinski :  In  order  to  lower  the  cost  of  sodium 
efforts  have  been  made  to  obtain  it  by  means  of 
electricity.  Davy  has  shown  that  its  production 
in  this  way  is  possible,  for  he  first  obtained  the 
metal  by  electrolizing  a  solution  of  Na2C03.  P. 
Jablochoff  uses  the  following  arrangement  to  de- 
compose Nad  or  KC1 : — 

The  arrangement  is  easily  understood.  The  salt 
to  be  decomposed  is  fed  in  by  the  funnel  into  the 
kettle  heated  by  a  fire  beneath.  The  positive  pole 
evolves  chlorine  gas,  and  the  negative  pole  evolves 


THE  MANUFACTURE   OF   SODIUM. 


143 


vapor  of  the  metal,  for,  as  the  salt  is  melted,  the 
heat  is  sufficient  to  vaporize  the  metal  liberated. 
The  gas  escapes  through  one  tube  and  the  metallic 

Fig.  5. 


anrrm  «•?**• 


vapor  by  the  other.     The  vapor  is  led  into  a  con- 
denser and  solidified. 


PAUT  VII. 

MANUFACTURE  OF  ALUMINA. 

I  DO  not  propose  to  give  here  all  the  methods 
.which  have  been  employed  to  get  good  clean  alu- 
mina (APO3),  but  only  those  which  may  be  recom- 
mended as  being  practical  and  economical  on  a 
large  scale,  not  repeating  the  methods  used  at  Sal- 
indres  or  by  Mr.  Webster,  which  will  be  found  in 
connection  with  the  full  description  of  the  processes 
used  at  Salindres  and  Birmingham.  Most  of  the 

O 

following  is  from  Mierzinski,  and  may  be  taken  as 
representing  the  present  state  of  the  industry. 

By  igniting  an  alum  salt,  as  ammonia  alum,  there 
remains  either  a  white  powder  or  shining,  sticky 
pieces  which  are  very  hard  and  dissolve  with  dif- 
ficulty in  weak  acid  or  in  concentrated  solutions  of 
alkali.  Large  quantities  of  this  alumina  may  be 
obtained  by  calcining  the  salt  in  an  oven  similar  in 
its  principal  details  to  a  soda  furnace. 

Mierzinski  then  gives  Mr.  Webster's  process  of 
mixing  the  powdered  alum  with  coal-tar,  etc., 
which  is  given  in  full  in  Part  IX. 

Tilghman  decomposes  commercial  sulphate  of 
alumina,  AP(S04)3.18H20,  by  filling  a  red-hot  fire- 


MANUFACTURE  OF  ALUMINA.         145 

clay  cylinder  with  it.  This  cylinder  is  lined  inside 
with  a  magnesia  fettling,  is  kept  at  a  red  heat,  the 
sulphate  put  in  in  large  lumps,  and  steam  is  passed 
through  the  retort,  carrying  with  it  vapor  of  XaCl. 
This  last  arrangement  is  effected  by  passing  steam 
into  a  cast-iron  retort  in  which  ^N"aCl  is  kept  melted, 
and  as  the  steam  leaves  this  retort  it  carries  vapor 
of  the  salt  with  it.  It  is  preferable,  however,  to 
make  a  paste  of  the  sulphate  of  alumina  and  the 
sodium  chloride,  forming  it  into  small  hollow  cyl- 
inders, which  are  well  dried,  and  then  the  fire-clay 
cylinder  filled  with  these.  Then,  the  cylinder  being 
heated  to  whiteness,  highly  superheated  steam  is 
passed  over  it.  The  HC1  which  is  formed  is 
caught  in  a  condensing  apparatus,  and  there  remains 
a  mass  of  aluminate  of  soda,  which  is  moistened 
with  water  and  treated  with  a  current  of  carbon 
dioxide  and  steam.  By  washing  the  mass,  the  soda 
goes  into  solution  and  hydrated  alumina  remains, 
which  is  washed  well  arid  is  ready  for  use. 

Most  of  the  alumina  is  now  made  from  the 
natural  aluminous  earths,  beauxite  and  cryolite, 
the  occurrence  and  properties  of  which  have  been 
already  described.  The  manufacture  from  beauxite 
is  fully  described  in  the  account  of  the  process  used 
at  Salindres,  on  p.  158.  "We  will  give  here  the 
modern  methods  of  making  it  from  cryolite. 


146  ALUMINIUM. 

MANUFACTURE  FROM  CRYOLITE. 

Dry  Way. — The  cryolite  is  pulverized,  an  easy 
operation,  and  to  every  100  parts,  130  to  150  parts  of 
chalk  are  added,  and  a  suitable  quantity  of  fluorspar 
is  also  used,  which  remains  in  the  residue  on  wash- 
ing after  ignition.  More  chalk  is  used  than  is  theo- 
retically necessary,  in  order  to  make  the  mass  less 
fusible  and  keep  it  porous.  But,  to  avoid  using 
too  much  chalk  merely  for  this  purpose,  a  certain 
quantity  of  coke  may  be  put  into  the  mixture.  It 
is  of-the  first  importance  that  the  mixture  be  very 
intimate  and  finely  pulverized.  It  is  of  greater 
importance  that  the  mixture  be  subjected  to  just 
the  proper  wTell-regulated  temperature  while  being 
calcined.  The  cryolite  will  melt  very  easily,  but 
this  is  to  be  avoided.  On  this  account,  the  calci- 
nation cannot  take  place  in  an  ordinary  smelting 
furnace,  because,  in  spite  of  stirring,  the  mass  will 
rnelt  at  one  place  or  another,  while  at  another  part 
of  the  hearth  it  is  not  even  decomposed,  because 
the  heat  at  the  fire-bridge  is  so  much  higher  than 
at  the  farther  end  of  the  hearth.  Thomson  con- 
structed a  furnace  for  this  special  purpose  (see 
Figs.  6  and  7),  in  which  the  flame  from  the  fire 
first  went  under  the  bed  of  the  furnace,  then  over 
the  charge  spread  out  on  the  bed,  and  finally  in  a 
flue  over  the  roof  of  the  hearth.  The  hearth  has 
an  area  of  nearly  9  square  metres,  being  4  me- 
tres long  and  2.5  metres  wride.  It  is  charged 


MANUFACTURE  OF  ALUMINA. 


147 


twelve  times  each  day,  each  time  with  500  kilos  of 
mixture,  thus  roasting  6000  kilos  daily,  with  a 

Fig.  6. 


consumption  of  800  kilos  of  coal.     The  waste  heat 
of  the  gases  escaping  from  the  furnace  is  utilized 


for  drying  the  soda  solution  to  its  crystallizing 
point,  and  the  gases  finally  pass  under  an  iron 
plate  on  which  the  chalk  is  dried.  In  this  fur- 


148  ALUMINIUM. 

nace  the  mass  is  ignited  thoroughly  without  a  hit 
of  it  melting,  so  that  the  residue  can  be  fully 
washed  with  water.  The  reaction  commences  at 
a  gentle  heat,  hut  is  not  completed  until  a  red  heat 
is  reached.  Here  is  the  critical  point  of  the  whole 
process,  since  a  very  little  raising  of  the  tempera- 
ture ahove  a  red  heat  causes  it  to  melt.  However, 
it  must  not  he  understood  that  the  forming  of 
lumps  is  altogether  to  be  avoided.  These  lumps 
would  be  very  hard  and  unworkable  when  cold, 
but  they  can  be  broken  up  easily  while  hot,  so 
that  they  may  be  drawn  out  of  the  furnace  a  few 
minutes  before  the  rest  of  the  charge  is  removed, 
and  broken  up  while  still  hot  without  any  trouble. 
The  whole  charge,  on  being  taken  out,  is  cooled 
and  sieved,  the  hard  lumps  which  will  not  pass  the 
sieve  arc  ground  in  a  mill  and  again  feebly  ignited, 
when  they  will  become  porous  and  may  be  easily 
ground  up.  However,  the  formation  of  these 
lumps  can  be  avoided  by  industrious  stirring  of 
the  charge  in  the  furnace.  A  well-calcined  mix- 
ture is  porous,  without  dust  and  without  lumps 
which  are  too  hard  to  be  crushed  between  the 
fingers.  We  would  here  remark  that  mechani- 
cal furnaces  of  similar  construction  to  those  used 
in  the  manufacture  of  soda,  potash,  sulphate  of 
soda,  etc.,  are  more  reliable  and  give  the  best 
results  if  used  for  this  calcination.  The  mixture, 
or  ashes,  as  the  workmen  call  it,  is  drawn  still  hot, 
and  washed  while  warm  in  conical  wooden  boxes 
with  double  bottoms,  or  the  box  may  have  but  one 


MANUFACTURE  OF  ALUMINA.         149 

bottom,  with  an  iron  plate  about  76  millimetres 
above  it.  A  series  of  such  boxes,  or  a  large  appa- 
ratus having  several  compartments,  may  be  so 
arranged  that  the  washing  is  done  methodically, 
i.  £.,  the  fresh  water  comes  first  in  contact  with  a 
residue  which  is  already  washed  nearly  clean,  and 
the  fresh  charge  is  washed  by  the  strong  liquor. 
This  is  known  as  the  "  Lessiveur  methodique," 
and  an  apparatus  constructed  especially  for  this 
purpose  is  described  in  Dingier  186,  370,  by  P.  J. 
Havrez,  but  the  subject  is  too  general  and  the  de- 
scription too  long  to  be  given  here.  A  very  suit- 
able washing  apparatus  is  also  that  of  Schank, 
used  in  the  soda  industry  for  washing  crude  soda, 
and  described  in  '  Lunge's  Handbook  of  the  Soda 
Industry,'  Book  II.  p.  410.  Since  the  ashes  are 
taken  warm  from  the  furnace  the  washing  water 
need  not  be  previously  heated,  but  the  final  wash- 
water  must  be  warmed  as  the  ashes  have  been 
cooled  down  by  the  previous  washings.  As  soon 
as  the  strong  liquor  does  not  possess  a  certain 
strength,  say  20°  B.,  it  is  run  over  a  fresh  charge 
and  so  brought  up.  The  solution  contains  sodium 
aluminate. 

Xow,  whether  the  sodium  aluminate  solution  is 
made  from  beauxite  or  cryolite,  it  is  treated  further 
in  the  same  way  in  either  case  to  get  the  hyd rated 
alumina  and  the  soda  solution.  Carbon  dioxide  is 
next  passed  through  the  solution. 

The  carbon  dioxide  necessary  for  precipitating  the 
13* 


150  ALUMINIUM. 

by  d  rated  alumina  may  be  made  in  different  ways. 
The  gases  coming  from  the  furnace  in  calcining  the 
cryolite  might  be  used  if  they  were  not  contaminated 
with  dust ;  and  there  is  also  the  difficulty  that  ex- 
hausting the  gases  from  the  furnace  would  interfere 
with  the  calcination.  It  has  also  been  recommended 
to  use  the  gases  from  the  fires  under  the  evapora- 
ting pans,  by  exhausting  the  air  from  the  flues  and 
purifying  it  by  washing  with  water.  This  can 
only  be  done  where  the  pans  are  fired  with  wood 
or  gas.  However,  the  lime-kiln  is  almost  exclu- 
sively used  to  furnish  this  gas.  The  kiln  used  is 
shaped  like  a  small  blast  furnace.  Leading  in  at  the 
boshes  are  two  flues  from  five  fire-places  built  in 
the  brickwork  of  the  furnace,  and  the  heat  from 
these  calcines  the  limestone.  The  gases  are  taken 
off  by  a  cast-iron  down-take  at  the  top.  At  the 
bottom  of  the  furnace,  corresponding  with  the  tap 
hole  in  a  blast  furnace,  is  an  opening,  kept  closed, 
from  which  lime  is  withdrawn  at  intervals.  A 
strong  blast  is  blown  in  just  above  the  entrance  of 
the  side  flues,  and  by  keeping  up  a  pressure  in  the 
furnace,  leakings  into  it  may  be  avoided.  The 
gas  is  sucked  away  from  the  top  by  a  pump,  which 
forces  it  through  a  cleaning  apparatus  constructed 
like  a  wash  bottle,  and  it  is  then  stored  in  a  ga- 
someter. Instead  of  the  pump,  a  steam  aspirator 
may  be  used,  which  is  always  cheaper  and  takes  up 
less  room. 

The  precipitation  with  CO2  is  made  by  simply 


MANUFACTURE  OF  ALUMINA.        151 

forcing  it  through  a  tube  into  the  liquid.  The 
apparatus  used  at  Salindres  is  one  of  the  most  im- 
proved forms.  (See  p.  163.)  The  precipitate  is 
granular,  and  settles  easily.  However,  it  is  not 
pure  hydrated  alumina,  hut  a  compound  of  alumina, 
soda,  carbonic  acid,  and  water,  containing  usually 
about  45  per  cent,  APO3,  20  per  cent,  Na^O3,  and 
35  per  cent,  H20.  The  sodium  carbonate  can  be 
separated  by  long-continued  boiling  with  water, 
but  by  this  treatment  the  alumina  becomes  very 
gelatinous  and  very  difficult  of  further  treatment. 
The  precipitate  was  formerly  separated  on  linen 
filters,  but  centrifugal  machines  are  now  preferred. 
The  evaporated  solution  gives  a  high  grade  of  car- 
bonate of  soda  free  from  iron.  The  heavy  residue 
which  is  left  after  the  ashes  have  been  lixiviated 
consists  of  Fe*03,  CaO,  undecomposed  cryolite,  and 
aluminate  of  Na,  and  has  not  been  used  for  any- 
thing. 

According  to  Lo wig's  experiments,  the  solution 
of  sodium  aluminate  can  be  precipitated  by  cal- 
cium, barium,  strontium,  or  magnesium,  hydrates, 
forming  caustic  soda  and  hydrated  alumina,  the 
latter  being  precipitated  with  the  CaO,  BaO,  SrO, 
or  MgO.  The  precipitate  is  washed  by  decantation 
and  then  divided  into  two  portions,  one  of  which 
is  dissolved  in  HC1,  the  other  made  into  a  mush 
with  water  and  gradually  added  to  the  solution  of 
the  other  half  until  the  nitrate  shows  only  a  very 
little  APO3  in  solution.  CaCP,  EaCP,  SrCP,  or 


152  ALUMINIUM. 

MgCl2  has  been  formed,  and  the  alumina  all  pre- 
cipitated. 

Wet  way. — The  decomposition  of  cryolite  in  the 
wet  way  is  operated  as  follows:  The  finely 
powdered  cryolite  is  boiled  with  dried  burnt  lime 
in  the  proportion  of  three  parts  cryolite  to  two  of 
lime.  There  results  a  precipitate  of  calcium  fluor- 
ide, CaF2,  while  sodium  aluminate  is  in  the 
solution.  The  reaction  takes  place  quite  easily. 
The  solution  is  settled,  washed  by  decaritation, 
and  these  washings  put  with  the  strong  solution 
first  poured  off;  the  next  washings  are  reserved 
for  the  fresh  wash-water  of  another  operation. 
The  solution  of  sodium  aluminate  is  then  boiled 
with  a  quantity  of  cryolite  equal  to  the  amount 
first  used,  when  sodium  fluoride  is  formed  and 
alumina  precipitated.  This  operation  is  in  noway 
difficult,  only  requiring  a  little  more  attention 
than  the  first.  The  alumina  thus  made  is  very 
finely  divided.  The  reactions  involved  are : — 

Al2F6.6^NTaF  +  6CaO=  AP03.3^"a20  4-  6CaF2. 
Al2F6.6STaF  +  Al203.3£Ta20  +  6H20= 2(A1203.3H20) 
+  121STaF. 

During  this  last  operation  it  is  best  to  add  an 
excess  of  cryolite,  and  keep  the  liquid  in  motion 
to  prevent  the  cryolite  from  caking  at  the  bottom. 
Lead  is  the  best  material  to  make  these  precipitat- 
ing tanks  of,  since  iron  would  contaminate  the 
alumina.  The  precipitate  is  washed  as  in  the 


MANUFACTURE  OF  ALUMINA.        153 

previous  operation.  The  solution  of  sodium  fluor- 
ide, XaF,  is  boiled  with  the  requisite  quantity  of 
burnt  lime,  which  converts  it  into  caustic  soda, 
KaOH,  which  is  separated  from  the  precipitated 
CaF2  by  decantation  and  washing.  The  solution 
is  evaporated  down  to  a  concentrated  solution  of 
XaOH,  or  to  dryness,  as  desirable.  The  lime  used 
should  be  as  pure  and  free  from  iron  as  possible,  to 
avoid  contaminating  the  alumina. 

Alumina  may  also  be  obtained  from  alum  stone 
or  alum  shales;  by  converting  these  into  alums  or 
into  Al2(S04)3Aq.  by  any  of  the  well-known 
methods  of  alum-makers,  and  then  the  alumina 
made  by  calcining  this  salt,  as  given  on  p.  144. 


PART  VIII. 

MANUFACTURE   OP  THE  DOUBLE   CHLORIDE   OF 
ALUMINIUM  AND  SODIUM. 

SINCE  the  cost  of  the  aluminium  chloride  is 
equal  to  the  cost  of  the  sodium  used,  in  making 
aluminium,  many  attempts  have  been  made  to 
cheapen  its  manufacture  from  alumina,  but  with- 
out much  success.  Mr.  Frishmuth,  of  Philadel- 
phia, claims  that  he  has  lowered  the  cost  of  alum- 
inium principally  by  making  the  APCl6  much 
cheaper  than  before.  Mr.  Webster's  process, 
which  has  been  applied  on  such  a  large  scale,  is 
altogether  concerned  with  producing  the  APCl6 
cheaply,  not  a  word  being  said  about  improve- 
ments in  making  the  sodium.  However,  with 
these  exceptions,  and  possibly  one  or  two  others 
which  will  be  found  further  on,  the  making  of 
these  chlorides  has  remained  much  as  Deville 
left  it.  The  description  of  their  manufacture  as 
conducted  at  Salindres  is  the  only  account  given 
by  Mierzinski,  and  so  that  may  be  taken  as  the 
process  now  in  general  use,  especially  in  Europe. 
It  will  be  found  on  p.  166.  I  add  here  just  a  few 
words  to  Fremy's  description  of  the  process,  which 
may  serve  to  render  his  description  more  exact : — 


CHLORIDE   OF  ALUMINIUM   AND   SODIUM.         155 

Mierzinski  says  that  when  the  double  chloride 
is  to  be  made,  special  importance  is  to  be  attached 
to  using  materials  free  from  iron  in  preparing  the 
alumina,  as  iron  cannot  be  removed  from  A12C16.- 
2XaCl  as  easily  as  from  A12C16.  Mierzinski  also 
devotes  some  space  to  descriptions  of  chlorine 
generators,  but  that  is  a  separate  subject,  full  de- 
scriptions of  which  can  be  found  in  any  good  work 
on  practical  chemistry. 

There  have  been  a  few  attempts  to  make  these 
chlorides  in  different  ways  from  that  used  in 
Deville's  process.  I  find  two  such  processes, 
which,  however,  cannot  have  been  much  of  an 
improvement  on  Deville's,  or  else  they  would  have 
supplanted  it. 

M.  Dullo  makes  the  following  observations  on 
the  production  of  APC16  direct  from  clay: — * 

"Up  to  the  present  time  the  A12C1*  necessary  to 
the  production  of  aluminium  has  been  prepared  by 
treating  cryolite  or  beauxite,  calcining  them  with 
carbonate  of  soda,  and  neutralizing  directly  with 
HOI  or  CO2  the  alu initiate  of  soda  formed.  This 
process  may  be  simplified,  and  the  APC16  obtained 
much  more  easily,  by  direct  treatment  of  clay. 
For  this  purpose  a  good  clay,  free  from  iron  and 
sand,  is  mixed  with  enough  water  to  make  a  thick 
pulp,  to  which  is  added  !N~aCl  and  pulverized 
carbon.  For  every  100  parts  of  dry  clay  there  are 

*  Bull,  de  la  Soc.  Chem.  1860,  vol.  T.  p.  472. 


156  ALUMINIUM. 

taken  120  parts  XaCl  and  30  of  carbon.  The  mix- 
ture is  dried  and  broken  up  into  small  fragments, 
which  are  then  introduced  into  a  red-hot  retort 
traversed  by  a  current  of  chlorine.  Carbonic 
oxide  is  disengaged,  while  at  the  same  time  APC16 
and  a  little  SiCl4  are  formed.  It  is  not  necessary 
that  the  chlorine  should  be  absolutely  dry,  it  may 
be  employed  just  as  it  comes  from  the  generator. 
The  gas  is  absorbed  very  rapidly,  because  between 
the  aluminium  and  silicon  there  are  reciprocal 
actions  under  the  influence  of  which  the  chemical 
actions  are  more  prompt  and  energetic.  The 
aluminium  having  for  chlorine  a  greater  affinity 
than  silicon  has,  A12C16  is  first  formed,  and  it  is 
only  when  all  the  aluminium  is  thus  transformed 
that  any  SiCl4  is  formed.  When  SiCl4  begins  to 
form  the  operation  is  stopped,  the  incandescent 
mixture  is  taken  out  of  the  retort  and  treated 
with  water.  The  solution  is  evaporated  to  dryness 
to  separate  out  a  small  quantity  of  silica,  SiO2, 
which  is  in  it,  the-residue  is  taken  up  with  water, 
and  the  Al2ClV2NaCl  remains  when  the  filtered 
solution  is  evaporated  to  dryness.  These  succes- 
sive solutions  and  evaporations  might  probably  be 
suppressed,  especially  if  only  enough  chlorine  is 
passed  over  the  incandescent  clay  to  just  convert  all 
the  aluminium  into  APC16,  in  which  case  no  SiCl4 
will  be  formed,  and  therefore  no  soluble  silica  can 
exist  in  the  solution  to  contaminate  the  APC16  or 


CHLORIDE   OF  ALUMINIUM   AND  SODIUM.        157 

impede  its  reduction.     M.  Dullo  recommends  re- 
ducing the  AlfClV2]$raCl  by  zinc.     See  Part  X. 

'  Chemical  News/  1878,  p.  307,  contains  a  short 
account  of  an  improved  method  of  producing 
A1*C16,  which  consists  essentially  in  passing  vapors 
of  hydrochloric  acid,  HC1,  and  carbon  disulphide, 
CS*,  simultaneously  over  heated  alumina  or  clay* 
The  CS2  changes  it  into  aluminium,  sulphide, 
A12S8,  and  the  HC1  converts  this  into  Al'Cl6, 
which  distils. 


14 


PART  IX. 

MANUFACTURE  OF  ALUMINIUM  AT  SALINDRES  (GARD). 

We  will  now  give  the  actual  preparation  at  Salin- 
dres,*  with  the  latest  improvements  which  it  has 
received  in  practice.  Aluminium  is  there  regularly 
prepared  at  the  works  of  the  Chemical  Manufac- 
turing Company  of  Alais  and  Camargue,  the  old 
firm  of  Henry  Merle  &  Co.,  new  firm  A.  R.  Pechi- 
ney  &  Co. 

The  principal  chemical  reactions  on  which  this 
process  rests  are  the  following  :  — 

Formation  of  aluminate  of  soda  by  calcining 
beauxite  with  Na2C03  — 

(AlFe)203.2H20  +  3¥a2C03=  Al203.33Ta20  +  Fe203 


Formation  of  alumina  by  precipitating  the  alu- 
minate of  soda  with  a  current  of  carbon  dioxide  — 

Al203.3ISra20  +  SCO2  +  3II20  =  A1203.3H20  -h 


Formation  of  Al2Cl6.2^sTaCl  by  the  action   of 
*  Fremy's  Ency.  Chem.,  M.  Margottet. 


REDUCTION   OF   THE   ALUMINIUM.  159 

chlorine  on  a  mixture  of  alumina,  carbon,  and  sodi- 
um chloride — 

APO3  +  30  +  2NaCl  +  601= Al2CK2NaCl + SCO. 

Reduction  of  this  double  chloride  by  sodium. 
Al2CR2XaCl  +  6¥a = 2  Al  +  SXaCl. 

The  primary  material  then  to  furnish  the  alumin- 
ium is  beauxite.  It  will  be  seen  that  to  obtain 
the  metal  it  is  necessary  to  proceed  successively 
through  the  following  operations: — 

I.  Preparation  of  the  aluminate  of  soda  and  so- 
lution of  this  salt  to  separate   it  from  the  ferric 
oxide  contained  in  the  beauxite. 

II.  Precipitation  of  hyd rated  alumina  from  the 
aluminate  of  soda  by  a  current  of  carbon  dioxide; 
washing  the  precipitate. 

III.  Preparation  of  a  mixture  of  alumina,  car- 
bon, and  salt,  drying  it,  and  then  treating  with 
gaseous  chlorine  to  obtain  the  double  chloride  of 
aluminium  and  sodium. 

IV.  Lastly,  treatment  of  this  chloride  by  sodium 
to  obtain  aluminium. 

We  will  now  review  these  operations  as  practi- 
cally carried  out  in  detail.  We  will  not  consider 
the  preparation  of  the  crude  materials  as  chlorine, 
sodium,  etc.,  which  is  spoken  of  elsewhere. 

I.    Preparation  of  the  Aluminate  of  Soda. 

The  aluminate  to  serve  for  the  preparation  of 
Al2Cl6.2XaCl  was  first  obtained  by  the  calcination 


160  ALUMINIUM. 

of  ammonia  alum.  At  Salindres  this  was  with- 
drawn and  beauxite  used,  a  material  consisting  of 
sesqui-oxide  of  iron  aad  aluminium  in  varying  pro- 
portions, with  two  molecules  of  water  and  a  little 
silica.  It  is  redder  the  more  iron  it  contains. 
Beauxite  is  plentiful  enough  in  the  south  of  France, 
principally  in  the  departments  of  Herault,  Bouches- 
du-Rhone,  and  Yar.  That  used  at  Salindres  comes 
from  Yar.  It  contains  at  least  seventy-five  per 
cent,  alumina.  To  separate  the  alumina  from  Fe203, 
it  is  treated  with  carbonate  of  soda,  under  the  in- 
fluence of  a  sufficiently  high  temperature,  the  A1203 
displacing  the  CO2  and  forming  alurninate  of  soda, 
Al203.3N"a20,  while  the  Fe203  remains  unattacked. 
A  simple  washing  with  water  then  permits  the 
separation  of  the  Al203.31^a20  from  the  insoluble 
Fe203.  The  beauxite  is  first  finely  pulverized  by 
means  of  a  vertical  mill-stone,  then  intimately 
mixed  with  some  Na2C03.  The  mixture  is  made 
for  one  operation,  of — 

480  kilos  beauxite. 

300     "    Na2CO3  of  90  alkali  degrees. 

This  mixture  is  introduced  into  a  reverberatory 
furnace,  resembling  in  form  a  soda  furnace,  and 
which  will  'bear  heating  strongly.  The  mass  is 
stirred  from  time  to  time,  and  it  is  kept  heated 
until  all  the  carbonate  has  been  attacked,  which  is 
recognized  by  a  test  being  taken  which  does  not 
effervesce  with  acids.  The  operation  lasts  from 
five  to  six  hours. 


REDUCTION   OF  THE   ALUMINIUM.  161 

The  aluminate  thus  obtained  is  separated  from 
Fe203  by  a  washing  with  warm  wrater.  This  wash- 
ing is  made  at  first  with  a  feeble  solution  which  has 
served  for  the  complete  exhaustion  of  the  preceding 
charge,  which  was  last  washed  with  pure  water, 
forming  thus  this  feeble  solution.  This  gives,  on 
the  first  leaching,  solutions  of  aluminate  concen- 
trated enough  to  be  called  strong  liquor,  which  are 
next  treated  by  the  current  of  CO2  to  precipitate 
the  hyd rated  alumina.  The  charge  is  next  washed 
with  pure  water,  wrhich  completely  removes  the 
aluminate  ;  this  solution  is  the  weak  liquor,  which 
is  put  aside  in  a  special  tank,  and  used  as  the  first 
leaching  liquor  on  the  next  charge  treated.  This 
treatment  takes  place  in  the  following  apparatus 
(see  Fig.  8) :  B  is  a  sheet-iron  vessel,  in  the  middle 
of  which  is  a  metallic  grating>,F,  on  which  is  held 
all  round  its  edges,  by  pins^  a  cloth,  serving  as  a 
filter.  The  upper  part  of  this  vessel  is  called  sim- 
ply the  filter.  A  ought  to  be  closed  by  a  metallic 
lid  held  on  firmly  by  bolts.  To  work  the  apparatus, 
about  500  kilos  of  the  charge  to  be  washed  is 
placed  on  the  filter  cloth,  the  lid  is  closed,  then  the 
steam-cock  /  of  the  reservoir  A  is  opened.  In  A 
is  the  weak  solution  from  the  last  washing  of  the 
preceding  charge.  The  pressure  of  the  steam 
makes  it  rise  by  the  tube  Tinto  the  filter;  another 
jet  of  steam,  admitted  by  the  cock  6,  rapidly 
warms  the  feeble  liquor  as  it  soaks  into  the  charge. 
After  filtering  through,  the  strong  liquor  is  drawn 

14* 


162 


ALUMINIUM. 


off  by  turning  the  stopcock  Cr.     The  weak  solu- 
tion of  the  reservoir  A  is  put  into  the  filter  in 


Fig.  8. 
B 


t.£VYTYf>£  (Ji 

successive  portions,  and  not  all  at  once  ;  and  after 
each  addition  of  solution  has  filtered  through,  its 
strength  in  B.°  is  taken,  before  any  more  solution 
is  run  in ;  then,  when  the  solution  marks  3  to  4°, 
it  is  placed  in  the  special  tank  for  weak  liquor, 
with  all  that  comes  through  afterwards.  Just 


REDUCTION   OF   THE   ALUMINIUM.  163 

about  this  time,  the  weak  liquor  of  the  reservoir 
A  is  generally  all  used  up,  and  is  replaced  by  pure 
water  introduced  by  the  tube  d.  All  the  solutions 
which  filtered  through,  marking  over  3  to  4°  B., 
are  put  together,  and  form  the  strong  liquor  which 
marks  about  12°  B.  This  extraction  of  the  alu- 
minate  being  completed  by  the  pure  wrater,  the 
residue  on  the  filter  is  taken  out,  and  a  new  opera- 
tion may  be  commenced. 

II.  Preparation  of  the  Alumina. 

The  strong  liquor  is  introduced  into  a  vessel 
having  an  agitator,  wThere  a  strong  current  of  CO2 
may  precipitate  the  A1203  from  it.  The  gas  is 
produced  by  small  streams  of  hydrochloric  acid 
continuously  falling  on  some  limestone  contained 
in  a  series  of  earthenware  jars.  The  precipitation 
vessel  is  called  a  baratte.  The  CO2  after  having 
passed  through  a  washing  flask,  is  directed  to  a 
battery  of  three  barattes,  where  the  precipitation 
is  worked  methodically,  so  as  to  precipitate  com- 
pletely the  alumina  of  each  baratte,  and  utilize  at 
the  same  time  all  the  carbon  dioxide  produced. 
In  order  to  do  this,  the  gas  always  enters  first  into 
a  baratte  in  which  the  precipitation  is  nearest  com- 
pletion, and  arrives  at  last  to  that  in  which  the 
solution  is  freshest.  When  the  gas  is  not  all  ab- 
sorbed in  the  last  baratte,  the  first  is  emptied,  for 
the  precipitation  in  it  is  then  completed,  and  it  is 


164 


ALUMINIUM. 


made  the  last  of  the  series,  the  current  being  now 
directed  first  into  the  baratte  which  was  previously 
second,  while  the  newly  charged  one  is  made  the 
last  of  the  series.  The  process  is  thus  kept  on 

Fig.  9. 


a.  Charging  pipe. 
Z>.  Steam  pipe. 

c.  Steam  drip. 

d.  CO2  enters. 

/.  Discharge  pipe. 

A.  Agitator,  made  of  iron  rods. 

C.  Tank  in  which  the  precipitate  settles. 

B.  Baratte  body. 

D.  Steam  jacket. 


REDUCTION   OF   THE  ALUMINIUM.  165 

continuously.     The  apparatus   used   is  shown   in 
Fig.  9. 

Each  baratte  holds  about  1200  litres  of  solution, 
and  the  complete  precipitation  of  all  the  alumina 
in  it  takes  five  to  six  hours.  A  mechanical  agi- 
tator stirs  the  contents  continually,  and  a  current 
of  steam  is  let  into  the  double  bottom  so  as  to 
keep  the  temperature  of  the  solution  about  70°. 
The  precipitated  alumina  and  the  solution  of 
Ka2C03  which  remains  are  received  in  a  vat 
placed  beneath  each  baratte.  The  solution  is  de- 
canted off*  clear,  after  standing,  and  then  evapo- 
rated down  to  dry  ness,  regenerating  the  Na*C03 
used  in  treating  the  beauxite  to  make  the  alumi- 
nate,  less  the  inevitable  losses  inseparable  from  all 
industrial  operations.  The  deposit  of  alumina  is 
put  into  a  conical  strainer  to  drain,  or  else  into  a 
centrifugal  drying  machine,  which  rapidly  drives 
out  of  the  hydrated  alumina  the  solution  of  Ka2C03 
which  impregnates  it ;  a  washing  with  pure  wrater 
in  the  drier  itself  terminates  the  preparation  of  the 
alumina.  At  the  works  at  Salindres,  a  part  of  this 
alumina  is  converted  into  sulphate  of  alumina, 
which  is  sold,  the  remainder  being  used  for  the 
aluminium  manufacture.  After  washing  in  the 
dryer,  the  alumina  presents  this  composition:— 

APO3 47.5 

H*0 50.0 

2.5 


166  ALUMINIUM. 

III.  Preparation  of  the  APCP.ZNaCl. 

When  a  current  of  chlorine  is  passed  through  a 
mixture  of  anhydrous  alumina  and  carbon,  APC16 
is  obtained.  This  simple  chloride  may  be  em- 
ployed for  obtaining  aluminium  ;  it  was  first  so 
employed  by  Deville  ;  but  it  is  deliquescent,  its 
preservation  is  difficult,  and  its  employment  very 
inconvenient.  Industrially,  as  indicated  by  De- 
ville, the  double  chloride  is  always  used,  as  it  does 
not  present  these  inconveniences  to  so  large  a 
degree.  The  double  chloride  may  be  obtained  in 
the  same  manner  as  the  simple  chloride ;  it  is  suf- 
ficient to  put  some  common  salt,  NaCl,  into  a 
mixture  of  alumina  and  carbon,  and,  on  heating 
this  mixture  strongly,  there  is  formed,  by  the 
action  of  the  chlorine,  Al2Cl6.2NaCl,  which  distils 
at  a  red  heat  and  condenses  in  a  crystalline  mass  at 
about  200°.  The  Irydrated  alumina  obtained  in 
the  preceding  operation  is  mixed  with  salt  and 
finely  pulverized  charcoal,  in  proper  proportions, 
the  whole  is  sifted,  and  a  mixture  produced  as 
homogeneous  as  possible ;  then  it  is  agglomerated 
with  water  and  made  into  balls  the  size  of  the  fist. 
These  balls  are  first  dried  in  a  drying  stove,  at 
about  150°,  then  calcined  at  redness  in  retorts, 
where  the  double  chloride  should  commence  to  be 
produced  just  as  the  balls  are  completely  dried. 
These  retorts  are  vertical  cylinders  of  refractory 
earth,  each  one  is  furnished  with  a  tube  in  its  lower 


REDUCTION  OF   THE   ALUMINIUM. 


167 


part  for  the  introduction  of  chlorine,  and  with 
another  towards  its  upper  end  for  the  exit  of  the 
vapor  of  double  chloride.  (See  Fig.  10.)  A  lid 

Fig.  10. 


carefully  luted  during  the  operation  with  a  mix- 
ture of  fine  clay  and- horse  dung  serves  for  the 
charging  and  discharging  of  the  retort.  The 
double  chloride  is  condensed  in  earthen  pots  like 
flower  pots,  made  of  ordinary  clay,  and  closed  by  a 
well-luted  cover,  into  which  passes  a  pipe  of  clay 
to  conduct  the  gas  resulting  from  the  operation 
into  flues  connected  with  the  main  chimney.  Each 
retort  is  heated  by  a  fire,  the  flame  of  which  circu- 
lates all  round  it,  and  permits  keeping  it  at  a  bright 
red  heat.  An  operation  is  conducted  as  follows : 


168  ALUMINIUM. 

The  retort  is  filled  with  stove-dried  balls,  the  lid- 
is  carefully  luted,  and  the  retort  is  heated  gently 
till  all  the  moisture  is  driven  off.  This  complete 
desiccation  is  of  great  importance,  and  requires 
much  time.  Then  chlorine,  furnished  by  a  battery 
of  three  generating  vessels,  is  passed  in.  During 
the  first  hours,  the  gas  is  totally  absorbed  by  the 
balls,  and  the  double  chloride  distils  regularly  for 
about  three  hours,  and  runs  into  the  earthen  pots 
where  it  solidifies.  Toward  the  end,  the  distilla- 
tion is  more  difficult  and  less  regular,  and  the 
chlorine  is  then  only  incompletely  absorbed.  After 
each  operation  there  remains  a  little  residue  in  the 
retort,  which  accumulates  and  is  removed  every 
two  days,  when  two  operations  are  made  per  day. 
One  operation  lasts  at  least  twelve  hours,  and  a 
retort  lasts  sometimes  a  month.  The  double 
chloride  is  kept  in  the  pots  in  which  it  was  con- 
densed until  the  time  it  is  to  be  used  in  the  next 
operation ;  it  is  almost  chemically  pure,  save  traces 
of  iron,  and  is  easy  to  keep  and  handle. 

IV.  Reduction  of  the  Double  Chloride  by  Sodium. 

The  difficulty  of  this  operation,  at  least  from  an 
industrial  point  of  view,  is  to  get  a  slag  fusible 
enough  and  light  enough  to  let  the  reduced  metal 
easily  sink  through  it  and  unite.  This  result  has 
been  reached  by  using  cryolite,  a  white  or  grayish 
mineral  originally  from  Greenland,  very  easy  to 


REDUCTION  OF  THE  ALUMINIUM. 


169 


melt,  formula  Al2F6.6XaF.  This  material  forms 
with  the  XaCl  resulting  from  the  reaction  a  very 
fusible  slag,  in  the  midst  of  which  the  aluminium 
collects  well,  and  falls  to  the  bottom.  In  one  ope- 


ration the  charge  is — 


100  kilos 
45     " 
35     u 


APF^GNaF. 

Na. 


The  double  chloride  and  cryolite  are  pulverized, 
the  sodium,  cut  into  small  pieces  a  little  larger  than 
the  thumb,  is  divided  into  three  equal  parts,  each 
part  being  put  into  a  sheet-iron  basket.  The  mixture 
of  double  chloride  and  cryolite,  being  pulverized,  is 
divided  into  four  equal  parts,  three  of  these  are 
respectively  put  in  each  basket  with  the  sodium, 

Fig.  11. 


the  fourth  being  placed  in  a  basket  by  itself.     The 
reduction  furnace  (see  Fig.  11)  is  a  little  furnace  of 

15 


170  ALUMINIUM. 

refractory  brick,  with  an  inclined  hearth  and  a 
vaulted  roof.  This  furnace  is  strongly  braced  by 
iron  tie-rods,  because  of  the  concussions  caused  by 
the  reaction.  The  flame  may  at  any  given  moment 
be  directed  into  a  flue  outside  of  the  hearth.  At 
the  back  part  of  the  furnace,  that  is  to  say,  on  that 
side  towards  which  the  bed  slopes,  is  a  little  brick 
wall  which  is  built  up  for  each  reduction  and  is 
taken  away  in  operating  the  running  out  of  the 
metal  and  slag.  A  gutter  of  cast  iron  is  placed 
immediately  in  front  of  the  wall  to  facilitate  run- 
ning out  the  materials.  All  this  side  of  the  furnace 

O 

ought  to  be  opened  or  closed  at  pleasure  by  means 
of  a  damper.  Lastly,  there  is  an  opening  for  charg- 
ing in  the  roof,  closed  by  a  lid.  At  the  time  of  an 
operation  the  furnace  should  be  heated  to  low  red- 
ness, then  are  introduced  in  rapid  succession  the 
contents  of  the  three  baske'ts  containing  sodium, 
etc.,  and  lastly  the  fourth  containing  only  double 
chloride  and  no  sodium.  Then  all  the  openings  of 
the  furnace  are  closed,  and  a  very  vivid  reaction 
accompanied  b3Tdull  concussions  immediately  takes 
place.  At  the  end  of  fifteen  minutes,  the  reaction 
subsides,  the  dampers  are  opened,  and  the  heat  con- 
tinued, meanwhile  stirring  the  mass  from  time  to 
time  with  an  iron  poker.  At  the  end  of  three 
hours  the  reduction  is  ended,  and  the  metal  collects 
at  the  bottom  of  the  liquid  bath.  Then  the  run- 
ning out  is  proceeded  with  in  three  phases  :  First. 
Running  off  the  upper  part  of  the  bath,  which 


REDUCTION   OF   THE   ALUMINIUM.  171 

consists  of  a  fluid  material  completely  free  from  re- 
duced aluminium  and  constituting  the  white  slag. 
To  run  this  out  a  brick  is  taken  away  from  the 
upper  course  of  the  little  wall  which  terminates 
the  hearth.  These  slags  are  received  in  an  iron 
wagon.  Second.  Running  out  the  aluminium. 
This  is  done  by  opening  a  small  orifice  left  in  the 
bottom  of  the  brick  wall,  which  was  temporarily 
plugged  up.  The  liquid  metal  is  received  in  a  cast- 
iron  melting  pot,  the  bottom  of  which  has  been 
previously  heated  to  redness.  This  aluminium  is 
immediately  cast  in  a  series  of  small  rectangular 
cast-iron  moulds.  Third.  Running  out  of  the  rest 
of  the  bath,  which  constitutes  the  gray  slags. 
These  were,  like  the  white  slags,  formed  by  the 
XaCl  and  cryolite,  but  they  contain  in  addition, 
isolated  globules  of  aluminium.  To  run  these  out 
all  the  bricks  of  the  little  wall  are  taken  away. 
This  slag  is  received  in  the  same  melting-pot  into 
which  the  aluminium  was  run,  the  latter  having 
been  already  moulded  Here  it  cools  gradually, 
and  after  cooling  there  are  always  found  at  the 
bottom  of  the  pot  several  grains  of  metal.  In  a 
good  operation  there  are  taken  from  one  casting 
10.5  kilos  of  aluminium,  which  is  sold  directly  as 
commercial  metal. 

The  foregoing  description  from  Fremy  sets  forth 
in  its  perfection  the  production  of  aluminium  by 
means  of  sodium,  and  until  very  recently  this  was 
the  only  successful  commercial  process.  A  large 


172  ALUMINIUM. 

amount  of  aluminium  is  now  produced  by  this 
process,  and  it,  therefore,  does  not  lack  interest. 
The  following  data  as  to  the  expense  of  this  pro- 
cess may  he  very  appropriately  inserted  here,  giving 
the  cost  at  Salindres  in  1872. 

In  1872,  3600  kilos  of  Al  were  made  at  Salindres 
at  the  following  average  cost: — 

a.  Manufacture  of  one  kilo  of  N"a. 

Soda  .     .     .     9.35  kilos  (a)  32  fr.  per  100  kilos  =  3  fr.    9  cent. 

Coal  ...  74.32  "  "1.40"  "  "  "  =  1"  4  " 

Wages  ...  1  "  73  " 
Expenses  .  .  3  "  46  " 


Total  .     .     .     .  11  "  32  " 

p.  Manufacture  of  one  kilo  of  Al2Cl6.2NaCl. 

Anhydrous  A12O3 

0.59  kilos  @  86  fr.  per  100  kilos  =  0  fr.  50.7  cent. 

MnO2      .      3.74     "      "  14  "     "      "      "     =0  "  52.3  " 

HC1    .     .    15.72     "      "    3  "     "      "      "     =0  "47.1  " 

Coal    .     .    25.78     "      "1.40      "      "      "     =0   "36.1  " 

Wages     .     .     .    0  "  23.8  " 

Expenses    .     .    0  "  38.0  " 


Total  ....    2   "  48.0  ' 

y.  Manufacture  of  one  kilo  of  Al. 
Na     .     .3.44  kilos  @  11.32  fr.  per  kilo          =  38  fr.  90  cent. 
Al2Cl6.2NaCl 

10.04    "     "      2.48"     "      "  =24  "  90  " 

Cryolite     3  87     "     "    61.0    "     "    100  kilos  =   2  "  36  " 

Coal        29.17     "     "      1.4.0  "     "      "       "    =   0  "  41  " 

Wages    ...    1  "  80  " 

Costs  .    0  "  88  " 


Total  .  69  "  25 


*  A.  Wurtz,  Wagner's  Jaresb.,  1874,  vol.  xxi. 


REDUCTION   OF   THE   ALUMINIUM.  173 

This  must  be  increased  ten  per  cent,  for  losses 
and  other  expenses,  making  the  cost  of  aluminium 
80  fr.  per  kilo,  and  it  is  sold  for  100. 

According  to  a  statement  in  the  '  Bull,  de  la  Soc. 
de  I'lndustrie  Minerale,'  ii.,  451,  made  in  1882. 
Salindres  was  then  the  only  place  in  which  alu- 
minium was  manufactured. 


LATER  IMPROVEMENTS  IN  DEVILLE'S  PROCESSES. 

The  later  improvements  in  this  process  have  been 
made  principally  by  Mr.  J.  Webster,  of  Birming- 
ham, England,  and  some  are  claimed  by  Frishmuth 
of  Philadelphia.  We  will  examine  the  reports  of 
Webster's  processes  and  the  claims  of  Frishmuth. 

WEBSTER'S  PROCESS. 

Recently  the  statement*  has  been  current  in  a 
number  of  journals  that  material  improvements 
have  been  made  in  the  manufacture  of  aluminium  at 
the  Aluminium  Crown  Metal  Works  at  Hollywood, 
near  Birmingham,  England,  under  the  direction  of 
Mr.  Webster.  Mr.  Webster  describes  one  of  his 
improvements,  which  is  patented,f  as  follows  : 
Three  parts  of  alum  are  mixed  with  one  part  of 
coal  pitch,  and  the  mixture  heated  to  200°  or  260°. 

*  Dingier,  1883,  cclix.  86. 
f  Austrian  Pat.  Sept.  28,  1882. 
15* 


174  ALUMINIUM. 

In  about  three  hours  the  pasty  mass  is  spread  upon 
a  stone  floor,  and  after  becoming  cool  is  broken  in 
pieces.  Hydrochloric  acid  of  twenty  to  twenty- 
five  per  cent,  is  poured  upon  these  pieces  placed  in 
piles  which  are  turned  over  from  time  to  time. 
When  the  evolution  of  sulphuretted  hydrogen, 
IPS,  has  stopped,  about  five  per  cent,  of  charcoal 
powder  or  lampblack,  with  enough  water  to  make 
a  thick  paste,  is  added.  The  mass  is  thoroughly 
broken  up  and  mixed  in  a  mill,  and  then  worked 
into  balls  of  about  a  pound  each.  These  are  bored 
through  to  facilitate  drying,  and  heated  in  a  dry- 
ing chamber  at  first  to  40°,  then  in  a  furnace  from 
95  up  to  150°.  The  balls  are  then  kept  for  three 
hours  at  a  low  red  heat  in  retorts  while  a  mixture 
of  two  parts  steam  and  one  part  air  is  passed 
through,  so  that  the  sulphur  and  carbon  are  con- 
verted into  SO2  and  CO2,  and  thus  escape.  The 
current  of  gas  carries  over  some  K2S04,  FeSO4,  and 
A1203,  and  is  therefore  passed  through  clay  con- 
densers. After  these  have  been  driven  off  the  dry 
residue  is  removed  from  the  retort,  again  ground 
in  a  mill  to  fine  powder,  which  now  consists  of 
A12C3  and  K2304.  This  powder  is  treated  with 
about  seven  times  its  weight  of  water,  then  boiled 
in  a  pan  or  boiler  by  means  of  steam  for  about  one 
hour,  then  allowed  to  stand  till  cool.  The  solution 
containing  the  K2S04  is  run  off  and  evaporated  to 
dryness,  the  alumina  is  washed  out  and  dried. 


REDUCTION   OF  THE  ALUMINIUM.  175 

The  product  thus  obtained  contains  84.1  per  cent. 
A1203. 

The  ahove  patent  is  seen  to  cover  only  the  man- 
ufacture of  pure  alumina.  A  later  account  thus 
describes  Mr.  Webster's  plant  and  processes.  It 
is  taken  from  the  Birmingham,  England, '  Gazette,' 
and  was  copied  into  an  American  journal*  as  fol- 
lows : — 

"  There  has  been  recently  patented  in  most  of 
the  leading  countries  of  the  world  an  invention  of 
great  importance.  The  Aluminium  Crown  Metal 
Co.,  at  Hollywood,  near  Birmingham,  now  claim  to 
have  perfected  an  improved  process  by  which  they 
produce  pure  alumina  from  alum,  convert  it  into 
APC16,  and  reduce  this  by  sodium.  By  this  pro- 
cess the  two  common  impurities  of  aluminium, 
silicon  and  iron,  are  avoided.  The  inventor  is  Mr. 
James  Webster,  the  founder  and  principal  of  the 
company.  Their  works  having  been  erected  within 
the  last  five  years,  the  plant  is  of  the  most  recent 
date,  comprising  all  the  modern  improvements  in 
calcining  furnaces  and  retorts,  sheet-rolling  and 
wire-drawing  mills,  together  with  the  requisite 
casting,  fitting,  and  other  shops. 

"  On  retiring  from  business  some  years  ago  as  a 
metal  manufacturer,  Mr.  Webster  took  up  his  resi- 
dence at  Hollywood,  and  while  nominally  engaged 

*  Bulletin  of  the  Iron  and  Steel  Association,  Philadelphia, 
January  3,  1883. 


176  ALUMINIUM. 

in  farming  carried  on  the  experiments  which  he 
had  commenced  as  far  back  as  1851  for  the  inven- 
tion of  an  expeditious  and  inexpensive  mode  of 
producing  aluminium.  He  designed  all  the  vari- 
ous buildings,  appliances,  and  apparatus  necessary 
for  the  carrying  on  of  experiments,  upon  which  he 
expended  upwards  of  £3000,  besides  £2000  or 
£3000  in  procuring  patent  rights  at  home  and 
abroad.  A  French  syndicate  has  just  oifered  him 
£25,000  for  the  patent  for  France  alone,  while 
parties  in  the  United  States,  Belgium,  and  Ger- 
many are  arranging  to  purchase  rights. 

u  The  invention  has  only  been  perfected  about 
eighteen  months,  and  the  firm  have  but  recently 
begun  to  place  the  product  on  the  market,  yet  such 
is  the  demand,  that  though  they  are  now  working 
day  and  night,  they  cannot  execute  one-quarter  of 
the  orders  accumulating  on  their  books.  By  the 
ordinary  method  of  precipitation,  12  tons  of  alum 
and  6  tons  of  K2C03  or  Na2C03  are  required  to  pro- 
duce one  ton  of  alumina,  and  the  whole  process 
occupies  nine  weeks ;  whereas,  in  Mr.  Webster's 
plan,  no  precipitant  is  used,  and  a  ton  can  be  manu- 
factured in  a  week  with  the  existing  plant.  The 
cost  of  one  ton  of  alumina  by  the  ordinary  method 
is  upwards  of  £1000,  while  it  is  less  than  £100  by 
Mr.  Webster's  process. 

"  Mr.  Webster's  process  consists  in  taking  a  given 
quantity  of  alum  and  pitch,  which  are  finely  ground, 
mixed  together,  and  placed  in  a  calcining  furnace, 


REDUCTION   OF   THE   ALUMINIUM.  177 

by  which  means  38  per  cent,  of  water  is  driven  off, 
leaving  the  sulphur,  potash,  and  alumina,  with 
some  ferric  oxide.  The  calcined  mixture  is  then 
put  in  vertical  retorts,  and  steam  and  air  are  forced 
through,  which  leaves  a  residue  of  K20  and  A1203 
only.  This  is  then  placed  in  a  vat  of  warm  water 
heated  by  steam.  The  caustic  potash  liquor  is  then 
run  oft'  and  boiled  down,  while  the  residual  APO3 
is  collected  in  sacks  and  dried.  This  deposit  con- 
tains about  84  per  cent.  APO3,  while  that  obtained 
by  the  old  process  of  precipitation  has  only  65  per 
cent.  Thus  a  saving  is  effected  of  nine-tenths  in 
cost  and  19  per  cent,  more  alumina  is  obtained. 
In  addition  to  this,  the  whole  of  the  bye  products 
are  recovered,  consisting  of  KOH,S  (which  is  used 
in  making  H2S04),  and  aluminate  of  iron.  From 
these  bye  products  is  made  a  blue  dye,  which  is 
sold  for  six  shillings  a  pound,  and  is  used  in  place 
of  indigo  for  dyeing  calico  and  other  materials. 
The  APC16  is  reduced  by  sodium. 

" '  The  English  Ironmonger'  for  April,  1886,  con- 
tains a  long  article  describing  the  extensions  which 
this  company  have  made,  their  works  having  now 
attained  a  large  size,  wThile  the  number  and  variety 
of  their  products,  in  aluminium  and  its  alloys,  as 
ingots,  wire,  sheet,  or  worked  up  in  "hundreds  ot 
different  ways,  is  truly  surprising.  They  have 
monopolized  this  business  in  England,  and  are  very 
enterprising  in  introducing  their  manufactures  else- 
where." 


178  ALUMINIUM. 

FRISHMUTH'S  PROCESS. 

In  the  United  States  the  only  improvement  in 
the  sodium  process  of  reducing  aluminium  is 
contained  in  the  following  patent: — * 

Win.  Frishmuth,  of  Philadelphia,  in  his  patent 
makes  the  following  claims  : — 

1.  The  simultaneous  generation  of  sodium  vapor 
and  a  volatile   compound  of  aluminium   in  two 
separate    vessels    or    retorts,   and    mingling    the 
vapors  thus  obtained  in  a  nascent  (?)  state  in  a  third 
vessel,  wherein  they  react  on  each  other. 

2.  The  sodium  vapor  is  produced  from  a  mixture 
of  a  sodium  compound  and  carbon,  or  some  other 
reducing  agent ;  and  the  aluminous   vapor  from 
aluminous  material. 

3.  The  simultaneous  generation  of  sodium  vapor 
and  vapor  of  A12C16  or  A12F6 ;  or  of  sodium  vapor 
and  Al2Cl6.2NaCl. 

4.  Converting  the  aluminous  material  to  a  vapor 
by  heating  it  in  a  retort  with  NaCl,and  subjecting 
it  at  the  same  time  to  chlorine  gas;  mingling  the 
vapor  of  Al2Cl6.2Nad  thus  obtained   with  vapor 
simultaneously  generated  from  Na2C03  and  carbon. 

*  U.  S.  Pat.,  308,152.    Nov.  18, 1884. 


REDUCTION  OF  THE  ALUMINIUM.  179 

OTHER  PROCESSES. 

H.  Niewerth,  of  Hanover,  has  patented  in  the 
United  States  and  other  countries  the  following 
process  :*  A  compound  of  aluminium,  with  chlorine 
or  fluorine,  is  hrought  by  any  means  into  the  form 
of  vapor,  and  conducted,  strongly  heated,  into 
contact  with  a  mixture  of  62  parts  Xa2C03,  28  coal 
and  10  chalk,  which  is  also  in  a  highly  heated  con- 
dition. This  mixture  disengages  sodium,  which 

O      O  ' 

reduces  the  gaseous  chloride  or  fluoride  of  alumin- 
ium, the  nascent  sodium  being  the  reducing  agent. 
In  place  of  the  above  mixture  other  suitable  mix- 
tures which  generate  sodium  may  be  employed,  or 
mixtures  may  also  advantageously  be  used  from 
which  potassium  is  generated. 

Hector  von  Grousilliers,  Springe,  Hanover,  pat- 
ents the  following  improvement  :f  In  order  to 
avoid  the  difficulties  ordinarily  met  with  in  the 
use  of  Al2Cl6.2XaCl  to  obtain  aluminium,  the 
patentee  raises  the  volatilizing  point  of  APCl6  by 
performing  its  reduction,  either  chemically  or 
electrolytically,  under  pressure  in  a  strong,  her- 
metically-closed vessel  lined  with  clay  or  magnesia 
and  provided  with  a  safety  valve. 

*  Sci.  Am.  Suppl.,  Nov.  17,  1883. 
t  Eng.  Pat.,  June  29,  1885,  No.  7858. 


PART  X. 

REDUCTION  OF  ALUMINIUM  BY   OTHER   REDUC- 
ING AGENTS  THAN  SODIUM. 

REDUCTION  BY  CYANOGEN. 

ACCORDING  to  Knowles's  patent,*  aluminium 
chloride,  APC16,  is  reduced  by  means  of  potassium 
or  sodium  cyanide,  the  APC16,  either  fused  or  in 
the  form  of  vapor,  being  brought  in  contact  with 
either  the  melted  cyanide  or  its  vapor.  The 
patent  further  states  the  strange  fact  that  pure 
alumina  may  be  added  to  increase  the  product. 

Corbelli,  of  Florence,f  patented  the  following 
method  in  England :  Common  clay  is  freed  from 
all  foreign  particles  by  washing,  then  well  dried. 
One  hundred  grammes  of  it  are  mixed  with  six 
times  its  weight  of  concentrated  sulphuric  or 
hydrochloric  acid ;  then  the  mixture  is  put  in  a 
crucible  and  heated  to  400  or  500°.  The  mass  re- 
sulting is  mixed  with  200  grammes  of  dry  yellow 
prussiate  of  potash  and  150  grammes  of  N"aCl,  and 
this  mixture  heated  in  a  crucible  to  whiteness. 

*  Sir  Francis  C.  Knowles,  Eng.  Pat.  1857,  No.  1742. 
f  Wagner's  Jaliresb.,  1858. 


REDUCTION   BY   OTHER  AGENTS   THAN   SODIUM.      181 

After  cooling,  the  reduced  aluminium  is  found  in 
the  bottom  of  the  crucible  as  a  button. 

According  to  Deville's  experiments,  this  process 
will  not  give  any  results.  Watts  remarks  that 
any  metal  thus  obtained  must  be  very  impure, 
consisting  chiefly  of  iron.  The  patent  is  dated 
1858,  No"  142. 

REDUCTION  BY  HYDROGEN. 

F.  W.  Gerhard*  decomposes  aluminium  fluor- 
ide, APF6,  or  Al2F6.6NaF — cryolite— by  subjecting 
it  to  hydrogen  at  a  red  heat.  The  aluminium 
compound  is  placed  in  a  number  of  shallow  dishes 
of  glazed  earthen  ware,  each  of  which  is  surrounded 
by  a  number  of  other  dishes  containing  iron 
tilings.  These  dishes  are  placed  in  an  oven  pre- 
viously heated  to  redness,  hydrogen  gas  is  then 
admitted,  and  the  heat  increased.  Aluminium 
then  separates,  hydrofluoric  acid,  HF,  being 
formed,  but  immediately  taken  up  by  the  iron 
filings  and  thereby  prevented  from  reacting  on  the 
aluminium.  To  prevent  the  pressure  of  the  gas 
from  becoming  too  great,  an  exit  tube  is  provided, 
which  may  be  opened  or  closed  at  pleasure.  This 
process,  patented  in  England  in  1856,  No.  2980,  is 
ingenious  and  was  said  to  yield  good  results.  The 
inventor  has,  however,  returned  to  the  use  of  the 


*  Watts's  Dictionary. 
16 


182  ALUMINIUM. 

more  costly  reducing  agent,  sodium,  which  would 
seem  to  imply  that  the  hydrogen  method  has  not 
yet  quite  fulfilled  his  expectations. 

REDUCTION  BY  CARBURETTED  HYDROGEN. 

Mr.  A.  L.  Fleury,*  of  Boston,  mixes  pure 
alumina  with  gas  tar,  resin,  petroleum,  or  some 
such  substance,  making  it  into  a  stiff  paste  which 
may  be  divided  into  pellets  and  dried  in  an  oven. 
They  are  then  placed  in  a  strong  retort  or  tube 
which  is  lined  with  a  coating  of  plumbago.  In 
this  they  are  exposed  to  a  cherry-red  heat.  The 
retort  must  be  sufficiently  strong  to  stand  a  press- 
ure of  from  25  to  30  pounds  per  square  inch,  and 
be  so  arranged  that  by  means  of  a  safety  valve  the 
necessary  amount  of  some  hydro-carbon  may  be 
introduced  into  the  retort  among  the  heated  mix- 
ture, and  a  pressure  of  20  to  30  pounds  must  be 
maintained.  The  gas  is  forced  in  by  a  force  pump, 
By  this  process  the  APO3  is  reduced,  while  the 
metal  remains  as  a  spongy  mass  mixed^vith  car- 
bon. This  mixture  is  re-melted  with  metallic 
zinc,  and  when  the  latter  has  collected  the  alumin- 
ium, it  is  driven  off  by  heat.  The  hydrocarbon 
gas  under  pressure  is  the  reducing  agent.  The 
time  required  for  reducing  100  pounds  of  alumina, 
earth,  cryolite,  or  other  compound  of  aluminium, 

*  Chemical  News,  June,  1869,  p.  332. 


REDUCTION    BY   OTHER    AGENTS   THAN   SODIUM.      183 

should  not  be  more  than  four  hours.  When  the 
gas  can  be  applied  in  a  previously  heated  condition 
as  well  as  being  strongly  compressed,  the  reduction 
takes  place  in  a  still  shorter  period. 

Xothing  is  now  heard  of  this  process,  and  it  has 
been  presumably  a  failure.  It  is  said  that  several 
thousand  dollars  were  expended  by  Mr.  Fleury 
and  his  associates  without  making  a  practical 
success  of  it.  We  should  be  glad  to  hear  in  the 
future  that  their  sacrifices  have  not  been  in  vain, 
and  that  the  process  still  has  possibilities  in  it 
which  will  some  time  be  realized. 

Petitjean*  makes  aluminium  sulphide,  APS3,  by 
one  of  Fremy's  methods,f  or  makes  a  double  sul- 
phide of  aluminium  with  potassium  or  sodium  by 
mixing  alumina  with  a  little  tar  or  turpentine  in 
a  carbon  lined  crucible,  heating  strongly,  and  then 
mixing  with  a  powder  composed  of  Ka2C03,  or 
K2C03,  and  sulphur ;  again  heating  a  long  time  at 
bright  redness.  The  sulphide  or  double  sulphide 
thus  made  is  put  in  a  crucible  or  retort  through 
the  bottom  of  which  can  be  led  a  stream  of  carbu- 
retted  hydrogen,  which  separates  the  aluminium 
from  its  combination  with  the  sulphur.  Alumin- 
ium J  can  also  be  reduced  from  APS3  by  mixing  it 
with  iron  filings  or  a  pulverized  rnetal  having 

*  Kerl  and  Stohman,  Poly.  Central  Blatt.  1858,  888. 
f  See  Appendix. 
J  See  Appendix. 


184  ALUMINIUM. 

similar  qualities,  and  melting  the  mixture.  A 
metallic  mixture  may  be  used  instead  of  carbu- 
retted  hydrogen  in  the  above  operation. 

REDUCTION  BY  DOUBLE  REACTION. 

M.  Comenge,*  of  Paris,  obtains  aluminium  from 
its  sulphide  either  by  heating  it  in  an  atmosphere 
of  hydrogen,  or  by  heating  it  with  A1203  or 
A12(S04/  in  such  proportions  that  sulphur  dioxide, 
SO2,  and  aluminium  may  be  the  sole  products;  or 
the  sulphide  may  be  decomposed  by  iron,  copper, 
or  zinc.  The  reactions  involved  would  be — • 

A12S3  +  3H-H=  2  Al  +  3H2S. 

A12S3  +  2  A1203= 6  Al  -f  3S02. 

A12S3  +  Al2(S04/= 4A1  +  6S02. 

A21S3  +  3(Fe.Cu.Zn.)=  2A1  +  3(Fe.Cu.Zn.)S. 
Johnsonf  patented  the  following  process:  Alu- 
minium sulphide  is  mixed  with  quite  dry  A12(S04)3 
in  such  proportions  that  the  sulphur  and  oxygen 
present  may  evolve  as  SO2.  The  mixture  is  heated 
to  redness  in  an  unoxidizing  atmosphere,  when 
SO2  evolves  and  the  metal  remains.  The  reaction 
is  furthered  by  agitation.  The  aluminium  in  the 
resulting  mass  can  be  treated  in  the  way  commonly 
used  in  puddling  spongy  iron,  and  then  either 
pressed  or  hammered  together.  Or,  the  aluminium 

*  Eng.  Pat.  1858,  No.  461. 

Kerl  and  S tollman's  Handbucb. 


REDUCTION   BY  OTHER   AGENTS  THAN  SODIUM.      185 

sulphide  may  be  heated  to  redness  in  an  unoxidiz- 
ing  atmosphere  and  dry  hydrogen  or  water  gas 
conducted  over  it,  and  the  metal  separated  from 
the  resulting  mass  by  dressing. 

Mr.  Niewerth's*  process  may  be  operated  in  his 
newly  invented  furnace,  but  it  may  also  be  carried 
on  in  a  crucible  or  another  form  of  furnace.  The 
furnace  alluded  to  consists  of  three  shaft  furnaces, 
the  outer  ones  well  closed  on  top  by  iron  covers, 
and  connected  beneath  by  tubes  with  the  bottom 
of  the  middle  one :  the  tubes  being  provided  with 
closing  valves.  These  side  shafts  are  simply  water- 
gas  furnaces,  delivering  hot  water-gas  to  the 
central  shaft,  and  by  working  the  two  alternately 
supplying  it  with  a  continuous  blast.  The  two  pro- 
ducers are  first  blown  very  hot  by  running  a  blast 
of  air  through  them  with  their  tops  open,  then  the 
cover  of  one  is  closed,  the  blast  shut  oft',  steam 
turned  on  just  under  the  cover,  and  water  gas 
immediately  passes  from  the  tube  at  the  bottom  of 
the  furnace  into  the  central  shaft.  The  middle 
shaft  has  meanwhile  been  filled  with  these  three 
mixtures  in  their  proper  order: — 

First.  A  mixture  of  sodium  carbonate,  carbon, 
sulphur,  and  alumina. 

Second.  Aluminium  sulphate. 

Third.  A  flux,  preferably  a  mixture  of  XaCl  and 
KOL 


*  Sci.  Am.  Suppl.,  Nov.  17,  1885. 
16* 


186  ALUMINIUM. 

• 

This  central  shaft  must  be  already  strongly 
heated  to  commence  the  operation,  it  is  best  to  fill 
it  with  coke  before  charging,  and  as  soon  as  that 
is  hot  to  put  the  charges  in  on  the  coke.  Coke 
may  also  be  mixed  with  the  charges,  but  it  is  not 
necessary.  The  process  then  continues  as  follows: 
The  water-gas  enters  the  bottom  of  the  shaft  at  a 
very  high  temperature.  These  highly  heated 
gases,  carbonic  oxide  and  hydrogen,  act  upon  the 
charges  so  that  the  first  breaks  up  into  a  combina- 
tion of  sodium  sulphide  and  aluminium  sulphide, 
from  which,  by  means  of  the  second  charge  of 
A12(SG4)3,  free  aluminium  is  reduced.  As  the  latter 
passes  down  the  shaft,  it  is  melted  and  the  flux 
assists  in  collecting  it,  but  is  not  absolutely  neces- 
sary. Instead,  of  producing  this  double  sulphide, 
pure  aluminium  sulphide  might  be  used  for  the 
first  charge,  or  a  mixture  which  would  generate 
APS3 ;  or,  again,  pure  iui2S,  K2S,  CuS,  or  any 
other  metallic  sulphide  which  will  produce  the 
effect  alone,  in  which  case  aluminium  is  obtained 
alloyed  with  the  metal  of  the  sulphide.  Instead 
of  the  first  charge  a  mixture  of  alumina,  sulphur, 
and  carbon  might  be  introduced.  Or,  the  A12(S04)3 
of  the  second  charge  might  be  replaced  by  alumina. 
So,  one  charge  may  be  Na2S,  K2S,  or  any  other 
metallic  sulphide,  and  the  second  charge  may  be 
either  A1203  or  A12(S04)3. 


REDUCTION   BY  OTHER   AGENTS   THAN   SODIUM.      187 

REDUCTION  BY  CARBON  AND  CARBON  DIOXIDE. 

J.  Morris'55'  of  Uddington  claims  to  obtain  alumin- 
ium by  treating  an  intimate  mixture  of  alumina 
and  charcoal  with  carbon  dioxide.  For  this  pur- 
pose, a  solution  of  A12C16  is  mixed  with  powdered 
wood-charcoal  or  lampblack,  then  evaporated  till 
it  forms  a  viscous  mass  which  is  shaped  into  balls. 
During  the  evaporation  hydrochloric  acid  is  given 
off.  The  residue  consists  of  alumina  intimately 
mixed  with  carbon.  The  balls  are  dried,  then 
treated  with  steam  in  appropriate  vessels  for  the 
purpose  of  driving  off  all  the  chlorine,  care  being 
taken  to  keep  the  temperature  so  high  that  the 
steam  is  not  condensed.  The  temperature  is  then 
raised  so  that  the  tubes  are  at  a  low  red  heat,  and  dry 
carbon  dioxide,C02,is  then  passed  through.  This  CO2 
is  said  to  be  reduced  by  the  carbon  to  carbonic  oxide, 
CO,  which  now,  as  affirmed  by  Mr.  Morris,  reduces 
the  alumina.  Although  the  quantity  of  carbonic 
oxide  escaping  is  in  general  a  good  indication  of  the 
progress  of  the  reduction,  it  is,  nevertheless,  not 
advisable  to  continue  heating  the  tubes  or  vessels 
until  the  evolution  of  this  gas  has  ceased,  as  in  con- 
sequence of  slight  differences  in  the  consistency  of 
the  balls  some  of  them  give  up  all  their  carbon 
sooner  than  others.  The  treatment  with  carbon 

*  Dingier,  1883,  vol.  259,  p.  86.     German  Pat.  No.  221oO, 
Aug.  30,  1882. 


188  ALUMINIUM. 

dioxide  lasts  about  thirty  hours  when  the  substances 
are  mixed  in  the  proportion  of  five  parts  carbon 
to  four  parts  alumina.  Morris  states  further  that 
the  metal  appears  as  a  porous  spongy  mass,  and  is 
freed  from  the  residual  alumina  and  particles  of 
charcoal  either  by  smelting  it,  technically  "  burn- 
ing it  out,"  with  cryolite  as  a  flux  or  by  mechani- 
cal treatment. 

* 

REDUCTION  BY  CARBON. 

About  the  first  attempt  of  this  nature  we  can 
find  record  of  is  the  following  article  by  M.  Cha- 
pelle : — * 

"  When  I  heard  of  the  experiments  of  Deville, 
I  desired  to  repeat  them,  but  having  neither  alu- 
minium chloride  nor  sodium  to  use,  I  operated  as 
follows :  I  put  natural  clay,  pulverized  and  mixed 
with  ground  Nad  and  charcoal,  into  an  ordinary 
earthen  crucible  and  heated  it  in  a  reverberatory 
furnace,  with  coke  for  fuel.  I  was  not  able  to  get 
a  white  heat.  After  cooling,  the  crucible  was 
broken,  and  gave  a  dry  pulverulent  scoria  in  which 
were  disseminated  a  considerable  quantity  of  small 
globules  about  one^half  a  millimetre  in  diameter, 
and  as  white  as  silver,  They  were  malleable,  in- 
soluble in  nitric  or  cold  hydrochloric  acids,  but  at 
60°  dissolved  rapidly  in  the  latter  with  evolution 
of  hydrogen ;  the  solution  was  colorless  and  gave 

*  Compt.  Bendus,  1854,  yol,  xxxyiij.  p.  358. 


REDUCTION   BY   OTHER   AGENTS    THAN   SODIUM.      189 

with  ammonia  a  gelatinous  precipitate  of  hydrated 
alumina.  My  numerous  occupations  do  not  permit 
me  to  assure  myself  of  the  purity  of  the  metal. 
Moreover,  the  experiment  was  made  under  condi- 
tions which  leave  much  to  be  desired,  but  my  in- 
tention is  to  continue  my  experiments  and  especially 
to  operate  at  a  higher  temperature.  In  addressing 
this  note  to  the  Academy  I  but  desire  to  call  the 
attention  of  chemists  to  a  process  which  is  very 
simple  and  susceptible  of  being  improved.  I  hope 
before  many  days  to  be  able  to  exhibit  larger  glob- 
ules than  those  which  my  first  experiment  fur- 
nished." 

M.  Chapelle  never  did  address  any  further  com- 
munications to  the  Academy  on  this  subject,  and 
•we  must  presume  that  further  experiments  did  not 
confirm  these  first  ones. 

G.  W.  Keinar*  states  that  the  pyrophorous  mass 
which  results  from  igniting  potash  or  soda  alum 
with  carbon,  contains  a  carboniferous  alloy  of  alu- 
minium with  potassium  or  sodium,  from  which  the 
alkaline  metal  can  be  removed  by  weak  nitric  acid. 

COWLES  BROS.'  PROCESS. 

This  process,  which  reduces  alumina  by  carbon 
in  the  presence  of  another  metal  to  take  up  the 
aluminium,  using  the  electric  furnace,  is  the  nov- 

*  Wagner's  Jaliresb.  1859,  p.  4. 


190  ALUMINIUM. 

elty  which  is  attracting  widespread  attention  to  the 
metallurgy  of  aluminium.  Its  history  has  already 
been  sketched,  and  will  be  still  further  developed 
in  the  following  pages.  It  properly  comes  under 
the  heading  of  "  Reduction  by  Carbon." 

"  Early  in  the  present  century,  Sir  H.  Davy, 
Berzelius,  and  Oerstedt,  all  famous  chemists,  at- 
tempted unsuccessfully  to  reduce  alumina  by  elec- 
tricity. Likewise,  many  learned  scientists  have 
striven  to  decompose  it  by  carbon,  as  other  metals 
are  smelted  from  their  ores,  but  without  success, 
and  the  opinion  has  become  profound  and  wide- 
spread among  chemists  that  alumina  could  not  be 
reduced  by  carbon  and  heat.  But  this  is  exactly 
what  the  Cowles  process  accomplishes,  and  by  its 
means  the  Cowles  Electric  Smelting  and  Alumin- 
ium Company  is  enabled  to  supply  the  alloys  of 
aluminium  with  other  metals  at  one-quarter  to  one- 
third  their  former  price.  *  As  to  the  details  of  the 
process,  we  refer  to  the  papers  of  Professor  Hunt 
and  the  one  read  by  Mr.  Mabery."* 

The  following  is  the  patent  claim  of  Messrs. 
Cowles :  U.  S.  Pat.  324,658  and  324,659,  August 
18,  1885.  Electric  smelting  of  aluminium.  To 
Cowles  Bros.,  Cleveland,  Ohio.  Claim:  Reducing 
the  aluminium  compound  in  company  with  a  metal 
in  a  furnace  heated  by  electricity  in  presence  of 

*  Cowles  Bros. '  Pamphlet. 


REDUCTION   BY   OTHER  AGENTS  THAN  SODIUM.       191 

carbon.  The  alloy  of  aluminium  and  the  metal 
formed  is  treated  to  separate  the  aluminium. 

The  following  paper  is  the  first  official  and  sci- 
entific account  of  Cowles  Bros/  process,  and  was 
read  before  the  American  Association  for  the  Ad- 
vancement of  Science  by  Professor  Charles  F.  Ma- 
bery  of  the  Case  School  of  Applied  Science,  Cleve- 
land.* 

"  The  application  of  electricity  to  metallurgical 
processes  has  hitherto  been  confined  to  the  reduc- 
tion of  metals  from  solution,  while  few  attempts 
have  been  made  to  effect  dry  reductions  by  means 
of  an  electric  current.  Some  time  since  Eugene  H. 
Cowles  and  Alfred  H.  Cowles,  of  Cleveland,  con- 
ceived the  idea  of  obtaining  a  continuous  high 
temperature  on  an  extended  scale  by  introducing 
into  the  path  of  an  electric  current  some  material 
that  would  afford  the  requisite  resistance,  thereby 
producing  a  corresponding  increase  in  the  tempera- 
ture. After  numerous  experiments,  coarsely  pul- 
verized carbon  was  selected  as  the  best  means  for 
maintaining  an  invariable  resistance,  and  at  the 
same  time  as  the  most  available  substance  for  the 
reduction  of  oxides.  When  this  material  mixed 
with  the  oxide  to  be  reduced  was  made  a  part  of 
the  electric  circuit,  enclosed  in  a  fire-clay  retort, 
and  subjected  to  the  action  of  a  current  from  a 
powerful  dynamo,  not  only  was  the  oxide  reduced, 

*  Ann  Arbor  Meeting,  August  28, 1885. 


192  ALUMINIUM. 

but  the  temperature  increased  to  such  an  extent 
that  the  whole  interior  of  the  retort  fused  com- 
pletely. In  "other  experiments  lumps  of  lime, 
sand,  and  corundum  were  fused,  with  a  reduction 
of  the  corresponding  metal ;  on  cooling,  the  lime 
formed  large,  well-defined  crystals,  the  corundum 
beautiful  red-green  and  blue  octahedral  crystals. 
Following  up  these  results  with  the  assistance  of 
Prof.  Mabery,  who  became  interested  at  this  stage, 
it  was  soon  found  that  the  intense  heat  thus  pro- 
duced could  be  utilized  for  the  reduction  of  oxides 
in  large  quantities,,  and  experiments  were  next 
tried  on  a  large  scale  with  the  current  from  a  fifty 
horse-power  dynamo.  For  the  protection  of  the 
walls  of  the  furnace,  which  were  of  fire-brick,  a 
mixture  of  ore  and  coarsely  pulverized  gas  carbon 
was  made  a  central  core,  and  was  surrounded  on 
the  side  and  bottom  by  fine  charcoal,  the  current 
following  the  lesser  resistance  of  the  core  from 
carbon  electrodes  inserted  in  the  ends  of  the  fur- 
nace in  contact  with  the  core.  The  furnace  was 
charged  by  first  filling  it  with  charcoal,  making  a 
trough  in  the  centre,  and  filling  this  with  the  ore 
mixture,  the  whole  being  covered  with  a  layer  of 
coarse  charcoal.  The  furnace  was  closed  on  top 
with  fire-brick  slabs  containing  two  or  three  holes 
for  the  escape  of  the  gaseous  products  of  the  reduc- 
tion, and  the  whole  furnace  was  made  air  tight  by 
luting  with  fire  clay.  Within  a  few  minutes  after 
starting  the  dynamo,  a  stream  of  carbonic  oxide 


REDUCTION   BY   OTHER    AGENTS    THAN   SODIUM.      193 

issued  through  the  openings,  burning  usually  with 
a  flame  eighteen  inches  high.  The  time  required 
for  complete  reduction  was  ordinarily  about  an 
hour.  Experience  has  already  shown  that  alu- 
minium, silicon,  boron,  manganese,  sodium,  and 
potassium  can  be  reduced  from  their  oxides  with 
ease.  In  fact,  there  is  no  oxide  that  can  withstand 
the  temperature  attainable. in  this  furnace.  Char- 
coal is  changed  to  graphite ;  does  this  indicate 
fusion  ?  As  to  wrhat  can  be  accomplished  by  con- 
verting enormous  electrical  energy  into  heat  within 
narrow  limits  it  can  only  be  said  that  it  opens  the 
way  into  an  extensive  field  of  pure  and  applied 
chemistry.  It'  is  not  difficult  to  conceive  of 
temperature  limited  only  by  the  power  of  carbon 
to  resist  fusion. 

"  Since  the  motive  power  is  the  chief  expense  in 
accomplishing  reductions  by  this  method,  its 
commercial  success  is  closely  connected  with  ob- 
taining power  cheaply.  Realizing  the  importance 
of  this  point,  Messrs.  Cowles  have  purchased  at 
Lockport,  !N".  Y.,  a  water-power  where  they  can 
utilize  1200  horse-power.  An  important  feature 
in  the  use  of  these  furnaces  from  a  commercial 
standpoint  is  the  slight  technical  skill  required  in 
their  manipulation.  The  four  furnaces  operated 
in  the  experimental  laboratory  at  Cleveland  are  in 
charge  of  two  young  men,  who  six  months  ago 
knew  absolutely  nothing  of  electricity.  The  pro- 
ducts at  present  manufactured  are  the  various 

17 


194  ALUMINIUM. 

grades  of  aluminium  bronze^  made  from  a  rich 
furnace  product  obtained  by  adding  copper  to  the 
charge  of  ore.  Aluminium  silver  is  also  made ; 
and  a  boron  bronze  may  be  prepared  by  the  re- 
duction of  boracic  acid  in  contact  with  copper, 
while  silicon  bronze  is  made  by  reducing  silica  in 
contact  with  copper.  As  commercial  results  may 
be  mentioned  the  production  in  the  experimental 
laboratory,  which  averages  50  pounds  of  10  per 
cent,  aluminium  bronze  daily,  which  can  be  sup- 
plied to  the  trade  in  large  quantities  on  the  basis 
of  $5  per  pound  for  the  aluminium  contained,  the 
lowest  market  quotation  of  aluminium  being  now 
$15  per  pound." 

Dr.  T.  Sterry  Hunt  has  written  and  read  several 
papers  on  this  furnace  and  process,  and  we  extract 
from  them  anything  not  mentioned  in  Prof.  Ma- 
be  ry's  paper. 

The  following  paper  was  read  before  the  Am. 
Ins.  of  Mining  Engineers  by  Dr.  T.  Sterry  Hunt, 
of  Montreal : — * 

"  The  application  of  electricity  in  the  extraction 
of  metals  has  hitherto  been  chiefly  confined  to  the 
electrolysis  of  dissolved  or  fused  compounds  by 
various  methods.  The  power  of  electric  currents 
to  generate  intense  heat  in  their  passage  through 
a  resisting  medium  has  long  been  known,  and  the 
late  Sir  Wm.  Siemens  thereby  succeeded  in  melting 

*  Halifax  Meeting,  Sept,  1C,  1885. 


REDUCTION    BY   OTHER    AGENTS   THAN   SODIUM.      195 

considerable  quantities  of  steel.  Messrs.  Cowles  took 
a  new  step  in  the  metallurgic  art  by  making  the 
heat  thus  produced  a  means  of  reducing,  in  presence 
of  carbon,  the  oxides  not  only  of  the  alkali  metals, 
but  of  calcium,  magnesium,  manganese,  aluminium, 
silicon,  and  boron,  with  an  ease  which  permits  the 
production  of  these  elements  and  their  alloys  with 
copper  and  other  metals  on  a  commercial  scale. 

"  If  alumina,  in  the  form  of  granular  corundum, 
is  mixed  with  the  carbon  in  the  electric  path, 
aluminium  is  rapidly  liberated,  being  in  part  car- 
ried off  with  the  escaping  gas  and  in  part  con- 
densed in  the  upper  layer  of  charcoal.  In  this  way 
are  obtained  considerable  masses  of  nearly  pure 
aluminium,  and  others  of  a  crystalline  compound 
of  the  metal  with  carbon.  When,  however,  some 
granular  copper  is  placed  with  the  corundum,  an 
alloy  of  aluminium  and  copper  is  obtained,  which 
is  probably  formed  in  the  overlying  stratum,  but 
at  the  close  of  the  operation  is  found  in  fused 
masses  below.  In  this  way  there  is  obtained,  after 
the  current  has  passed  an  hour  and  a  half  through 
the  furnace,  four  or  tive  pounds  of  an  alloy  con- 
taining 15  to  20  per  cent,  of  aluminium  and  free 
from  iron.  On  substituting  this  alloy  for  the 
copper  in  a  second  operation,  an  alloy  with  over 
30  per  cent,  aluminium  is  obtained.  The  diffi- 
culties in  the  way  of  gathering  together  the  reduced 
metal  without  the  aid  of  copper  promise  to  be 
overcome  at  an  early  day,  so  that  we  may  expect 


196  ALUMINIUM. 

a  cheap  production  of  such  alloys  and  of  the  pure 
metal.  The  present  plant  at  Cleveland  is  but  an 
experimental  one,  and  has  been  in  operation  only 
a  few  months.  The  company  will  soon  put  in 
operation  at  Loekport  a  125  horse-power  dynamo, 
and  nine  more  of  equal  power  will  be  added,  per- 
mitting the  establishment  of  the  electric  furnace 
on  a  large  scale," 

Paper  read  before  the  National  Academy  of 
Science  by  Dr.  Hunt: — * 

uDr.  Hunt  showed  some  alloys  of  aluminium 
with  carbon  and  silicon,  and  a  peculiar  alloy  be- 
lieved to  consist  entirely  of  aluminium  and  nitro- 
gen. As  yet,  the  pure  metal  has  only  been 
produced  direct  from  the  furnace  in  small  lumps, 
but  it  may  be  obtained  by  melting  an  alloy  of 
aluminium  and  tin  with  lead,  when  the  latter 
takes  up  the  tin  and  separates  from  the  aluminium, 
sinking  beneath  it.  Or,  we  get  aluminium  by  sub- 
liming either  its  alloy  with  carbon  or  with  copper, 
when  the  pure  aluminium  is  carried  over.  The 
maximum  amount  of  aluminium  which  copper  can 
tolerate  is  10  per  cent.,  until  we  approach  the 
other  end  of  the  scale,  when  alloys  with  70  to  80 
per  cent,  of  aluminium,  or  more,  give  valuable  work- 
able alloys.  In  the  early  experiments  with  the 
Cowles  furnace,  an  engine  of  30  horse-power  running 
a  dynamo  yielded  a  daily  output  of  50  pounds  of 

*  Washington  Meeting,  April  30,  1886. 


REDUCTION    BY   OTHER    AGENTS   THAN   SODIUM.      197 

10  per  cent,  aluminium  bronze.  Brush  has  now 
constructed  an  engine  running  900  revolutions  per 
minute,  which  for  every  35  horse-power  developed 
reduces  one  pound  of  the  alloy  per  hour.  The 
expense  of  working  is  now  covered  by  one-half 
cent  per  horse-power  per  hour;  thus  the  cost  of 
the  alloy  is  about  17  cents  per  pound.  Within  the 
past  week,  the  gases  given  off  by  the  furnace  have 
been  analyzed.  In  the  first  part  of  the  process  it 
is  found  that  a  large  amount  of  nitrogen  is  given 
off,  showing  that  air  leaks  into  the  furnace.  After 
an  hour  and  a  half  this  gas  is  much  diminished. 
The  Cowles  at  first  used  moist  carbon  for  packing, 
but  have  now  overcome  the  necessity  of  dampen- 
ing it,  thereby  saving  the  waste  of  heat  in  driving 
out  the  water." 

The  latest  and  most  complete  description  of  the 
process  is  a  paper  read  by  Mr.  W.  P.  Thompson 
before  the  Liverpool  Section  of  the  Society  of 
Chemical  Industry.*  Mr.  Thompson  has  been 
Cowles  Bros.'  agent  in  taking  out  their  patents  in 
England.  The  paper  is  as  follows  : — 

"  That  this  invention  is  a  new  departure  will  be 
acknowledged  by  every  one  when  they  learn  that 
chromium,  titanium,  silicon,  aluminium,  calcium, 
and  the  other  alkaline  earth  metals  are  obtained 
by  direct  reduction  of  their  oxides  by  carbon — till 

*  Jrnl.  of  the  Soc.  of  Chcm.  Industry,  April  29,  1886. 


198  ALUMINIUM. 

a  year  ago  almost  universally  considered  a  prac- 
tical impossibility. 

"Conduction  of  the  current  of  the  large  dynamo 
to  the  furnace  and  hack  is  accomplished  by  a  com- 
plete metallic  circuit,  except  where  it  is  broken  by 
the  interposition  of  the  carbon  electrodes  and  the 
mass  of  pulverized  carbon  in  which  the  reduction 
takes  place.  The  circuit  is  of  13  copper  wires, 
each  0.3  inch  in  diameter.  There  is  likewise  in 
the  circuit  an  ampere  meter,  or  ammeter,  through 
whose  helix  the  whole  current  flows,  indicating 
the  total  strength  of  the  current  heing  used^Cfhis 
is  an  important  element  in  the  management  of  the 
furnace,  for,  hy  the  position  of  the  finger  on  the 
dial,  the  furnace  attendant  can  tell  to  a  nicety 
what  is  being  done  hy  the  current  in  the  furnace. 
Between  the  ammeter  and  the  furnace  is  a  resist- 
ance coil  of  German  silver  kept  in  water,  throwing 
-more  or  less  resistance  into  the  circuit  as  desired. 
This  is  a  safety  appliance  used  in  changing  the 
current  from  one  furnace  to  another,  or  to  choke 
off  the  current  before  breaking  it  by  a  switch. 

"The  furnace  (see  Figs.  12,  13,  14)  is  simply  a 
rectangular  box,  A,  one  foot  wide,  five  feet  long 
inside,  and  fifteen  inches  deep,  made  of  firebrick. 
From  the  opposite  ends  through  the  pipes  BB  the 
two  electrodes  CC  pass.  The  electrodes  are  im- 
mense electric-light  carbons  three  inches  in  diam- 
eter and  thirty  inches  long.  If  larger  electrodes 
are  required,  a  series  this  size  must  be  used 


REDUCTION  BY  OTHER  AGENTS  THAN 

Fig  12.  [(  UNIVERSITY 


Longitudinal  section. 
Fig.  14. 


Transverse  section. 


instead,  as  so  far  all  attempts  to  make  larger  car- 
bons   that    will    not    disintegrate    on    becoming 


200  ALUMINIUM. 

incandescent  have  failed.  The  ends  of  the  carbons 
are  placed  within  a  few  inches  of  each  other  in  the 
middle  of  the  furnace,  and  the  resistance  coil  and 
ammeter  are  placed  in  the  circuit.  The  ammeter 
registers  50  to  2000  amperes.  These  connections 
made,  the  furnace  is  ready  for  charging. 

•"The  walls  of  the  furnace  must  first  be  pro- 
tected, or  the  intense  heat  would  melt  the  fire 
brick.  The  question  arose,  what  would  be  the 
best  substance  to  line  thewalls?  Finely  powdered 
charcoal  is  a  poor  conductor  of  electricity,  is  con- 
sidered infusible  and  the  best  non-conductor  of 
heat  of  all  solids.  From  these  properties  it  would 
seem  the  best  material.  As  long  as  air  is  excluded 
it  will  not  burn.  But  it  is  found  that  after 
usin^  pure  charcoal  a  few  times  it  becomes  value- 
less ;  it  retains  its  woody  structure,  as  is  shown  in 
larger  pieces,  but  is  changed  to  graphite,  a  good 
conductor  of  electricity,  and  thereby  tends  to 
diffuse  the  current  through  the  lining,  heating  it 
and  the  walls.  The  fine  charcoal  is  therefore 
washed  in  a  solution  of  lime-water,  and  after  dry- 
ing, each  particle  is  insulated  by  a  fine  coating  of 
lime.  The  bottom  of  the  furnace  is  now  filled 
with  this  lining  about  two  or  three  inches  deep. 
A  sheet-iron  gauge  is  then  placed  along  the  sides 
of  the  electrodes,  leaving  about  two  inches  between 
them  and  the  side  walls,  in  which  space  more  of 
the  charcoal  is  placed*.  The  charge  J5/,  consisting 
of  about  25  pounds  of  alumina,  in  its  native  form  as 


REDUCTION    BY    OTHER    AGENTS    THAN   SODIUM.      201 

corundum,  12  pounds  of  charcoal  and  carbon,  and 
50  pounds  of  granulated  copper,  is  now  placed 
within  the  gauge  and  spread  around  the  electrodes 
to  within  a  foot  of  each  end  of  the  furnace.  In 
place  of  granulated  copper,  a  series  of  short  copper 
wires  or  bars  can  be  placed  parallel  to  each  other 
and  transverse  to  the  furnace,  among  the  alumina 
and  carbon,  it  being  found  that  where  grains  are 
used  they  sometimes  fuse  together  in  such  a  way 
as  to  short-circuit  the  current.  After  this,  a  bed 
of  charcoal,  -F,  the  granules  of  which  vary  in  size 
from  a  chestnut  to  a  hickory,  is  spread  over  all, 
and  the  gauge  drawn  out.  This  coarse  bed  of 
charcoal  above  the  charge  allows  free  escape  of  the 
carbonic  oxide  generated  in  the  reduction.  The 
charge  being  in  place,  an  iron  top,  6r,  lined  with 
h're-brick,  is  placed  over  the  whole  furnace  and 
the  crevices  luted  to  prevent  access  of  air.  The 
brick  of  the  walls  insulate  the  cover  from  the 
current. 

"  Xow  that  the  furnace  is  charged  and  the  cover 
luted  down,  it  is  started.  The  ends  of  the  electrodes 
were  in  the  beginning  placed  close  together,  as 
shown  in  the  longitudinal  section,  and  for  this 
cause  the  internal  resistance  of  the  furnace  may  be 
too  low  for  the  dynamo,  and  cause  a  short  circuit. 
The  operator,  therefore,  puts  sufficient  resistance 
into  the  circuit,  and  by  watching  the  ammeter  and 
now  and  then  moving  one  of  tfie  electrodes  out  a  trifle, 
he  can  prevent  undue  short  circuiting  in  the  begin- 


202  ALUMINIUM. 

ning  of  the  operation.  In  about  ten  minutes,  the 
copper  between  the  electrodes  has  been  melted  and 
the  latter  are  moved  far  enough  apart  so  that  the 
current  becomes  steady.  The  current  is  now  in- 
creased till  1300  amperes  are  going  through, 
driven  by  50  volts.  Carbonic  oxide  has  already 
commenced  to  escape  through  the  two  orifices  in 
the  top,  where  it  burns  with  a  white  flame.  By 
slight  movements  outwards  of  the  electrodes  during 
the  coming  five  hours,  the  internal  resistance  in 
the  furnace  is  kept  constant,  and  at  the  same  time 
all  the  different  parts  of  the  charge  are  brought  in 
turn  into  the  zone  of  reduction.  At  the  close  of 
the  run  the  electrodes  are  in  the  position  shown  in 
the  plan,  the  furnace  is  shut  down  by  placing  a 
resistance  in  the  circuit  and  then  the  current  is 
switched  into  another  furnace  charged  in  a  similar 
manner.  It  is  found  that  the  product  is  larger  if 
the  carbons  are  inclined  at  angles  of  30°  to  the 
horizontal  plane. 

"  This  regulating  of  the  furnace  by  hand  is  rather 
costly  and  unsatisfactory.  Several  experiments 
have  therefore  been  tried  to  make  it  self-regulating, 

O  O ' 

and  on  January  26,  1886,  a  British  patent  was 
applied  for  by  Cowles  Bros.,  covering  an  arrange- 
ment for  operating  the  electrodes  by  means  of  a 
shunt  circuit,  electro-magnet,  and  vibrating  arma- 
ture. Moreover,  if  the  electrodes  were  drawn  back 
and  exposed  to  the  air  in  their  highly  heated  state, 
they  would  be  rapidly  wasted  away.  To  obviate 


REDUCTION   BY   OTHER   AGENTS   THAN   SODIUM.      203 

this,  Messrs.  Cowles  place  what  may  be  called  a 
stuffing  box  around  them,  consisting  of  a  copper 
box  tilled  with  copper  shot.  The  wires  are  attached 
to  the  boxes  instead  of  the  electrodes.  The  hot 
electrodes  as  they  emerge  from  the  furnace  first 
encounter  the  shot,  which  rapidly  carry  off  the 
heat,  and  by  the  time  they  emerge  from  the  box 
they  are  too  cool  to  be  oxidized  by  contact  with 
the  air. 

uXinety  horse-power  have  been  pumped  into 
the  furnace  for  five  hours.  At  the  beginning  of 
the  operation  the  copper  first  melted  in  the  centre 
of  the  furnace.  There  was  no  escape  for  the  heat 
continually  generated,  and  the  temperature  in- 
creased until  the  refractory  corundum  melted,  and 
being  surrounded  on  all  sides  by  carbon  gave  up  its 
oxygen.  This  oxygen,  uniting  with  the  carbon  to 
form  carbonic  oxide,  has  generated  heat  which 
certainly  aids  in  the  process.  The  copper  has  had 
nothing  to  do  with  the  reaction,  as  it  will  take 
place  in  its  absence.  Whether  the  reaction  is  due 
to  the  intense  heat  or  to  electric  action  it  is  difficult 
to  say.  If  it  be  electric,  it  is  Messrs.  Cowles's  im- 
pression that  we  have  here  a  case  where  electrolysis 
can  be  accomplished  by  an  alternating  current, 
although  it  has  not  been  tried  as  yet.  Were  the 
copper  absent,  the  aluminium  set  free  would  now 
absorb  carbon  and  become  a  yellow,  crystalline 
carbide  of  aluminium  ;  but,  instead  of  that,  the 
copper  has  become  a  boiling,  seething  mass,  and 


204  ALUMINIUM. 

the  bubblings  of  its  vapors  may  distinctly  be  heard. 
The  vapors  probably  rise  an  inch  or  two,  condense 
and  fall  back,  carrying  with  them  the  freed  alumin- 
ium. This  continues  till  the  current  is  taken  otf 
the  furnace,  when  we  have  the  copper  charged 
with  15  to  30  per  cent.,  and  in  some  cases  as  high 
as  40  per  cent,  of  its  weight  of  aluminium,  and  a 
little  silicon.  After  cooling  the  furnace  this  rich 
alloy  is  removed.  A  valuable  property  of  the  fine 
charcoal  is  that  the  metal  does  not  spread  and  run 
through  its  interstices,  but  remains  as  a  liquid  mass 
surrounded  below  arid  on  the  sides  by  fine  charcoal 
which  sustains  it  just  as  flour  or  other  fine  dust 
will  sustain  drops  of  water  for  considerable  periods, 
without  allowing  them  to  sink  in.  The  alloy  is 
white  and  brittle.  This  metal  is  then  melted  in 
an  ordinary  crucible  furnace,  poured  into  large 
ingots,  the  amount  of  aluminium  in  it  determined 
by  analysis,  again  melted,  and  the  requisite  amount  of 
copper  added  to  make  the  bronze  desired. 

"Two  runs  produce  in  ten  hours'  average  work 
100  pounds  of  white  metal,  from  which  it  is  esti- 
mated that  Cowles  Bros.,  at  Lockport,  are  producing 
aluminium  in  its  alloys  at  a  cost  of  about  forty  cents 
per  pound.  The  Cowles  Co.  will  shortly  have  1200 
horse-power  furnaces.  With  a  larger  furnace  there 
is  no  reason  why  it  should  not  be  made  to  run  con- 
tinuously like  the  ordinary  blast  furnace. 

"  In  place  of  the  copper  any  non-volatile  metal 
may  be  used  as  a  condenser  to  unite  with  any 


REDUCTION    BY    OTHER    AGENTS    THAN    SODIUM.       205 

metal  it  may  be  desired  »to  reduce,  provided,  of 
course,  that  the  two  metals  are  of  such  a  nature 
that  they  will  unite  at  this  high  temperature.  In 
this  way  aluminium  may  be  alloyed  with  iron, 
nickel-silver,  tin,  or  cobalt.  Messrs.  Cowles  have 
made  alloys  containing  50  Al  and  50  Fe,  30  Al, 
and  70  Cu,  25  Al  and  75  ]^i.  Silicon  or  boron 
or  other  rare  metals  may  be  combined  in  the  same 
way,  or  tertiary  alloys  may  be  produced ;  as,  for 
instance,  where  tire  clay  is  reduced  in  presence  of 
copper  we  obtain  an  alloy  of  aluminium,  silicon, 
and  copper.  This  alloy  is  white  and  brittle  if  it 
contains  over  ten  per  cent,  of  aluminium  and  sili- 
con together.  With  from  two  to  six  per  cent,  of 
these  two,  in  equal  proportions,  the  alloy  is  stronger 
than  gun-metal,  has  great  toughness,  does  not 
oxidize  when  heated  in  the  air,  and  has  a  fine  gold 
color.  I  hear  to-day  that  an  aluminium-silicon 
bronze  wire  made  by  Cowles  has  shown  a  tensile 
strength  of  200,000  pounds,  hitherto  unprecedented 
in  any  metal. 

"As  to  the  ores  of  aluminium.  For  Mitis  cats- 
ings,  where  iron  and  silicon  are  not  prejudicial, 
beauxite  or  various  clays  may  be  used  to  advantage. 
For  bronze  making,  alumina  containing  silica  in 
considerable  quantities  is  as  available  as  the  pure 
earth  and  is  indeed  superior  to  it."  To  manufacture 
pure  aluminium,  pure  alumina  is  necessary. 
Cowles  Bros,  use  corundum  obtained  from  Xorthern 
Georgia.  (See  p.  49.) 

18 


206  ALUMINIUM. 

REDUCTION  BY  IRON. 

The  statement  has  been  made*  that  aluminium 
sulphide,  APS3,  is  to  be  obtained  from  powdered 
cryolite  by  treating  it  with  water,  which  dissolves 
out  sodium  fluoride,  NaF,  and  the  residual  A12F6 
being  calcined  with  sulphide  of  lime,  CaS,  there 
results  A12S3  and  CaF2.  The  A12S3  is  then  decom- 
posed by  heating  to  redness  with  iron  turnings. 

According  to  a  patent  given  to  F.  Lauterborn,f 
Germany,  Aug.  14,  1880,  if  pulverized  cryolite  is 
boiled  with  water,  NaF  is  set  free  and  A12F6 
remains.  Likewise,  calcium  fluoride,  CaF2,  boiled 
with  APC16  gives  CaCP  and  APF6.  The  aluminium 
fluoride  by  heating  with  sulphide  of  lime  will  be 
converted  into  APS3.  Finally,  the  APS3,  by  heat- 
ing red  hot  with  iron  gives,  it  is  claimed,  metallic 
aluminium. 

The  above  are  all  the  details  of  this  process  to 
be  found.  See  in  the  Appendix  an  experiment  on 
thus  decomposing  cryolite. 

H.  Niewerthij:  has  patented  the  following  pro- 
cess: "Ferro-silicumis  mixed  with  APF6  in  proper 
proportions  and  the  mixture  submitted  to  a  suit- 
able red  or  melting  heat  by  which  the  charge  is 
decomposed  into  volatile  silicon  fluoride,  SiF4,  iron, 
and  aluminium,  the  two  latter  forming  an  alloy. 

*  Chemical  News,  1860. 

t  Dingier,  242,  p.  70. 

•\.  Sci.  Am.  Suppl.  Nov.  17,  1883. 


REDUCTION    BY  OTHER   AGENTS   THAN    SODIUM.       207 

In  order  to  obtain  the  valuable  alloy  of  aluminium 
and  copper  from  this  iron-aluminium  alloy,  the 
latter  is  melted  with  metallic  copper,  which  will 
then  by  reason  of  greater  affinity  unite  with  the 
aluminium,  while  the  iron  will  retain  but  an 
insignificant  amount  of  it.  On  cooling  the  bath, 
the  bronze  and  iron  separate  in  such  a  manner  that 
they  can  readily  be  kept  apart.  In  place  of  pure 
APF6,  cryolite  may  advantageously  be  employed, 
or  A12C16  may  also  be  used,  in  which  case  silicon 
chloride  volatilizes  instead  of  the  fluoride.  Or, 
again,  pure  silicon  may  be  used  with  APF6,  cryo- 
lite, or  APC16,  in  which  case  pure  aluminium  is 
obtained." 

Preparation  of  Aluminium  and  Sodium  im  the 
Bessemer  Converter. 

According  to  the  experiments  of  Mr.  W.  P. 
Thompson,*  sodium  and  aluminium  may  be  advan- 
tageously prepared  by  means  of  a  Bessemer  con- 
verter. The  same  process  it  seems  should  serve 
equally  well  for  the  preparation  of  the  other 
difficultly  reducible  metals,  such  as  calcium,  stron- 
tium, barium,  magnesium,  etc. 

Mr.  "W.  P.  Thompsonf  has  taken  out  a  patent  in 
England^  for  the  manufacture  of  aluminium  and 
similar  metals,  which  is  carried  out  as  follows: 
The  inventor  employs  as  a  reducing  agent  iron, 

*  Bull,  de  la  Soc.  Chcm.  de  Paris,  1880,  xxiv.  128. 
f  Idem.  p.  719.  \  Mar.  27,  1879.  No.  2101. 


208  ALUMINIUM. 

either  alone  or  conjointly  with  carbon  or  hydrogen. 
The  operation  is  effected  in  an  apparatus  similar  to 
a  Bessemer  converter,  divided  into  two  compart- 
ments. In  one  of  these  compartments  is  placed 
melted  iron,  "or  an  alloy  of  iron,  which  is  made  to 
run  into  the  second  by  turning  the  converter. 
This  last  compartment  has  two  tuyeres,  one  of 
which  serves  to  introduce  hydrogen,  while  by  the 
other  is  introduced  either  A12C16,  APF6,  APC16.- 
2NaCl,  or  Al2F6.6NaF,  in  liquid  or  gaseous  state. 
In  presence  of  the  hydrogen  the  iron  takes  up 
chlorine  or  fluorine,  chloride  or  fluoride  of  iron  is 
diseno-ao-ed,  and  aluminium  mixed  with  carbon 

£D      O  ' 

remains  as  a  residue.  Then  this  mixture  of  iron, 
aluminium,  and  carbon  is  returned  to  the  other 
compartment  where  the  carbon  is  burnt  out  by 
means  of  a  current  of  air.  The  mass  being  then 
returned  to  the  chamber  of  reduction,  the  operation 
described  is  repeated.  When  almost  all  the  iron 
has  been  consumed,  the  reduction  is  terminated  by 
hydrogen  alone.  There  is  thus  obtained  an  alloy 
of  iron  and  aluminium.  (The  preparation  of  sodium 
does  not  require  the  intervention  of  hydrogen.  A 
mixture  of  iron  with  an  excess  of  carbon  and 
caustic  soda,  N"aOH,  is  heated  in  the  converter, 
when  the  sodium  distils  off.*  "When  all  the 
carbon  has  been  burnt,  the  iron  remaining  as  a 
residue  may  be  converted  into  Bessemer  steel.  As 
iron  forms  an  alloy  with  potassium,  the  method 

*  Compare  with  p.  141. 


REDUCTION   BY   OTHER   AGENTS   THAN   SODIUM.      209 

would  scarcely  serve  for  the  production  of  that 
metal.)  To  obtain  the  pure  aluminium,  sodium  is 
first  prepared  by  the  process  indicated,  the  chlo- 
ride or  fluoride  of  aluminium  is  introduced  into 
the  apparatus  in  the  other  chamber,  when  the 
metal  is  reduced  by  the  vapor  of  sodium.  The 
chambers  ought  to  be  slightly  inclined,  and  an 
agitator  favors  the  reaction.  The  inventor  intends 
to  apply  his  process  to  the  manufacture  of  mag- 
nesium, strontium,  calcium,  and  barium. 

Calvert  and  Johnson*  made  experiments  on  the 
reduction  of  aluminium  by  iron,  and  the  produc- 
tion thereby  of  iron-aluminium  alloys.  We  give 
the  report  in  their  own  words : — 

"We  shall  not  describe  all  the  fruitless  efforts 
we  made,  but  confine  ourselves  only  to  those  which 
gave  satisfactory  results.  The  first  alloy  we  ob- 
tained was  by  heating  to  a  white  heat  for  two 
hours  the  following  mixture  :— 

8  equivalents  of  A12C16    .        .        .     1076  parts. 
40          "  "  iron  filings     .         .     1120      *' 

8          u  "  lime        .        .        .224      " 

"The  lime  was  added  to  the  mixture  with  the 
view  of  removing  the  chlorine  from  the  APC16,  so 
as  to  liberate  the  metal  and  form  fusible  calcium 
chloride,  CaCl2.  Subtracting  the  lime  from  the 
above  proportion,  we  ought  to  have  obtained  an 
alloy  having  the  composition  of  1  Equivalent  Al 

*  Phil.  Mag.,  1855,  x.  240. 
18* 


210  ALUMINIUM. 

to  5  Equivalents  of  Fe,  or  with  9.09  per  cent, 
aluminium.  The  alloy  we  obtained  contained  12 
per  cent.,  which  leads  to  the  formula  AlFe4.  This 
alloy,  it  will  be  noticed,  has  an  analogous  com- 
position to  the  one  we  made  of  iron  and  potas- 
sium, and  like  it  was  extremely  hard,  and  rusted 
when  exposed  to  a  clamp  atmosphere.  Still  it 
could  be  forged  and  welded.  We  obtained  a 
similar  alloy  by  adding  to  the  above  mixture  some 
very  finely  pulverized  charcoal  and  subjecting  it 
to  a  high  heat  in  a  forge  furnace  for  two  hours. 
This  alloy  gave  on  analysis  12.09  per  cent.*  But,  in 
the  mass  of  CaCl2  and  carbon  remaining  in  the  cruci- 
ble there  was  a  large  amount  of  globules  varying 
in  size  from  a  pin  head  to  a  pea,  as  white  as  silver 
and  extremely  hard,  which  did  not  rust  in  the  air 
or  in  hyponitric  fumes.  Its  analysis  gave  24.55 
per  cent,  aluminium  ;  the  formula  APFe3  would 
give  25  per  cent.  Therefore  this  alloy  has  the 
same  composition  as  A1203,  iron  replacing  oxygen. 
"We  treated  these  globules  with  weak  sulphuric 
acid,  which  removed  the  iron  and  left  the  alumin- 
ium, the  globules  retaining  their  form,  and  the 
metal  thus  obtained  had  all  the  properties  of  the 
pure  aluminium. 

"We  have  made  trials  with  the  following  mix- 
ture, but,  although  they  have  yielded  results,  still 
they  are  not  sufficiently  satisfactory  to  describe  in 

*  In  the  original  paper  it  is  given  as  12.09  per  cent.  iron. 
The  inference  is  unavoidable  that  this  was  a  misprint,  but  it 
is  not  corrected  in  the  Errata  at  the  end  of  the  volume. 


REDUCTION   BY   OTHER   AGENTS  THAN   SODIUM.      211 

this  paper,  which  is  the  first  of  a  series  we  intend 
publishing  on  alloys.     This  mixture  was  : — 

Kaolin 1750  parts. 

NaCl 12CO      " 

Fc 875      " 

"  From  this  we  obtained  a  metallic  mass  and  a 
few  globules  which  we  have  not  yet  analyzed." 

Fremy:  Alloys  of  aluminium  and  iron  have 
been  prepared  by  Benzon  by  calcining  a  mixture 
of  alumina,  carbon,  and  iron  or  Fe203.  (See  p.  214.) 

Watts :  E.  L.  Benzon*  reduces  aluminium  by 
heating  alumina  with  the  oxide  of  another  metal, 
as  of  copper,  iron,  zinc,  or  a  mixture  of  alumina 
with  carbon  and  the  other  metal  in  a  free  state, 
the  materials  being  all  finely  divided  and  mixed 
in  atomic  proportions,  or  rather  with  the  carbon 
slightly  in  excess. 

M.  Evrard,f  in  order  to  make  aluminium 
bronze,  makes  use  of  an  aluminous  pig  iron.  (It 
is  not  stated  how  this  aluminous  pig  iron  is  made.) 
This  is  slowly  heated  to  fusion,  and  copper  is 
added  to  the  melted  mass.  Aluminium,  having 
more  affinity  for  copper  than  for  iron,  abandons 
the  latter  and  combines  with  the  copper.  After 
the  entire  mass  has  been  well  stirred,  it  is  allowed 
to  cool  slowly  so  as  to  permit  the  bronze,  which 
is  heavier  than  iron,  to  find  its  way  to  the  bottom 

*  Eng.  Pat.,  1858,  No.  2753. 

t  Annalesdu  Genie  Civil,  Mars,  1867,  p.  189. 


212  ALUMINIUM. 

of  the  crucible.     M.  Evrard  makes  silicon  bronze 
in  the  same  way  by  using  siliceous  iron. 

<  Eng.  and  Mining  Journal,'  May  15, 1886  :  "  The 
iron-aluminium  alloy  used  in  the  Mitis  process,  we 
are  informed  by  Mr.  Ostberg,  is  made  in  Sweden 
by  the  addition  of  clays  in  iron  smelting,  a  patented 
process  producing  alloys  with  7  to  8  per  cent, 
aluminium  very  cheaply.  Mr.  Ostberg  adds  that 
he  purchased  a  small  quantity  of  Cowles  Bros.' 
alloy,  which  gave  rise  to  our  previous  unqualified 
statement  that  he  used  Cowles'  alloys."  (See 
'Mitis  Castings,' Part  XL). 

REDUCTION  WITH  COPPER. 

Calvert  and  Johnson*  obtained  copper  alloyed 
with  aluminium  by  recourse  to  a  similar  chemical 
reaction  to  that  employed  to  get  their  iron-alu- 
minium alloy.  Their  mixture  was  composed  of— 

20  equivalents  of  Cu         .        .         .        .     640  parts. 

8          "  "  A12C16   ....  1076      " 

10          "  "  CaO      .         .        .        .     280      " 

"  We  mixed  these  substances  intimately  together, 
and  after  having  subjected  them  to  a  high  heat  for 
one  hour  we  found  at  the  bottom  of  the  crucible  a 
melted  mass  covered  with  cuprous  chloride,  Cu2Cl2, 
and  in  this  mass  small  globules,  which  on  analysis 
contained  8.47  per  cent,  aluminium,  corresponding 
to  the  formula — 

*  Phil.  Mag.  1855,  x.  242. 


REDUCTION   BY   OTHER   AGENTS    THAN   SODIUM.       213 

5  equivalents  of  Cu     .     .  160    .     .     91.96  per  cent. 
1  "  "  Al      .     .     14    .     .      8.04       " 

174  100.00 

"  We  made  another  mixture  of  A12C16  and  copper 
in  the  same  proportions  as  above,  but  left  out  the 
lime.  We  obtained  an  alloy  in  this  case  also, 
which  contained  12.82  per  cent,  aluminium,  corres- 
ponding to  the  formula — 

3  equivalents  of  Cu      .     .    96    .     .     87.27  per  cent. 
1  "  "  Al      .     .     14    .     .     12.73       " 

110  100.00 

Kerl  and  Stohman  give  the  following  account  of 
Benzon's  process:  "Benzon*  has  patented  the 
reduction  of  aluminium  with  copper,  forming  an 
aluminium-copper  alloy.  He  mixes  copper,  or 
oxidized  copper,  or  cupric  oxide,  in  the  finest 
possible  state,  with  fine,  powdered,  pure  alumina 
and  charcoal,  preferably  animal  charcoal.  The 
alumina  arid  copper  or  copper  oxide  are  mixed  in 
equivalent  proportions,  but  an  excess  of  charcoal 
is  used.  The  mixture  is  put  in  a  crucible  such  as 
is  used  for  melting  cast  steel,  which  is  lined  inside 
with  charcoal.  The  charge  is  covered  with  char- 
coal, and  the  crucible  subjected  first  to  a  tempera- 
ture near  the  melting  point  of  copper,  until  the 
alumina  is  reduced,  and  then  the  heat  is  raised 
high  enough  to  molt  down  the  alloy.  In  this  way 
can  be  obtained  a  succession  of  alloys,  whose  hard- 

*  Eng.  Pat,  1858,  No.  27C3. 


214  ALUMINIUM. 

ness  and  other  qualities  depend  on  the  percentage 
of  aluminium  in  them.  In  order  to  obtain  alloys 
of  a  certain  composition,  it  is  best  to  produce  first 
an  alloy  of  the  highest  attainable  content  of  alu- 
minium, to  analyze  it,  and  then  melt  it  with  the 
required  quantity  of  copper.  The  same  process 
can  be  used  for  the  reduction  of  alumina  with  iron 
or  Fe203,  only  the  carbon  must  in  this  case  be  in 
greater  excess,  and  a  stronger  heat  kept  up  longer 
must  be  used  than  when  producing  the  copper- 
aluminium  alloy.  In  contact  with  Fe203  the 
alumina  is  more  easily  reduced  than  with  metallic 
iron." 

Kerl  and  Stohman  remark  that  were  these 
methods  practicable,  then  at  once  there  is  the 
possibility  of  producing  copper-aluminium  alloys 
at  a  low  price,  and,  on  the  other  hand,  of  easily 
producing  pure  aluminium  from  the  iron  alloy. 
According  to  researches  conducted  in  the  labora- 
tories at  Zurich  and  Augsburg,  it  was  found  that 
the  melted-down  copper  contained  either  no  alu- 
minium or  at  most  a  trace.  (See  Appendix.) 

Aluminium-bronze  is  also  made  by  Mr.  Evrard's 
process  given  on  p.  211. 

REDUCTION  BY  ZINC. 

M.  Dullo*  observes  that  the  double  chloride  of 
aluminium  and  sodium,  which  he  makes  directly 

*  Bull,  dc  la  Soc.  Chem.  1860,  v.  472. 


REDUCTION   BY   OTHER   AGENTS   THAN   SODIUM.      215 

from  clay,  may  be  reduced  by  zinc.  He  says, 
"  The  reduction  by  zinc  presents  no  difficulties, 
but  it  is  less  easy  tban  with  sodium.  An  excess 
of  zinc  should  be  employed,  which  may  be  got  rid 
of  afterwards  by  distillation.  The  metal  thus  pre- 
pared possesses  all  the  characteristics  and  all  the 
properties  of  that  obtained  from  beauxite  with 
sodium." 

M.  IS".  Basset,*  a  chemist  in  Paris,  has  recently 
patented  a  new  process  for  obtaining  aluminium. 
If  the  statements  are  correct  they  are  of  great  value. 
The  paper  is  as  follows:  All  the  metalloids  and 
the  metals  which  form  by  double  decomposition 
proto-chlorides  or  sesqui-chlorides  more  fusible  or 
more  soluble  than  A12C16  may  reduce  A12C16  or 
even  Al'Cr^NaCl.  Thus,  As,  Bi,  Cu,  Zn,  Sb,  Hg, 
or  even  Sn,  or  amalgam  of  Zn,  Sb,  or  Sn  may  be 
employed  to  reduce  the  single  or  double  chloride. 
The  author  employs  zinc  in  preference  to  the  others 
in  consequence  of  its  low  price,  the  facility  of  its 
employment,  its  volatility,  and  the  property  which 
it  has  of  metallizing  easily  the  aluminium  as  it  is 
set  free.  When  metallic  zinc  is  put  in  the  presence 
of  Al2Cl6.2XaCl  at  250  to  300°,  zinc  chloride, 
ZnCl2,  is  formed  and  aluminium  is  set  free.  This 
dissolves  in  the  zinc  present  in  excess,  the  ZnCl2 
combines  with  the  I^aCl,  and  the  mass  becomes 
little  by  little  pasty,  then  solid,  while  the  alloy 

*  Le  Genie  Industrie],  1862,  p.  152. 


216  ALUMINIUM. 

remains  fluid.  If  the  heat  is  now  raised,  the  mass 
melts  anew,  the  zinc  reduces  a  new  portion  of  the 
double  chloride,  and  the  excess  of  zinc  enriches 
itself  in  aluminium  proportionately.  These  facts 
constitute  the  basis  of  the  following  general  pro- 
cess :  One  equivalent  of  A12C16  is  melted,  two  of 
KaCl  added,  and  when  the  vapors  of  hydrochloric 
acid  are  dissipated,  four  equivalents  of  zinc,  in 
powder  or  grain,  is  introduced.  The  zinc  melts 
rapidly,  and  by  agitation  the  mass  of  chloride 
thickens  and  solidifies.  The  mass  is  now  composed 
of  A12C16,  NaCl,  and  ZnCl2,  and  remains  in  a  pasty 
condition  on  top  of  the  fluid  zinc  containing  alu- 
minium. This  pasty  mass  is  removed,  piled  up  in 
a  crucible  or  in  a  furnace,  and  bars  of  the  fluid 
alloy  of  zinc  and  aluminium  obtained  from  a  pre- 
vious operation  are  placed  on  top  of  it.  This  is 
gradually  heated  to  bright  redness,  and  kept  there 
for  an  hour.  The  melted  mass  is  then  stirred  with 
a  rake  and  poured  out.  It  is  an  alloy  of  the  two 
metals  in  pretty  nearly  equal  proportions.  This 
alloy,  melted  with  some  chloride  from  the  first 
operation  furnishes  aluminium  containing  only  a 
small  per  cent,  of  zinc,  which  disappears  by  a  new 
fusion  under  chloride  mixed  with  a  little  A12F6, 
providing  the  temperature  is  raised  to  a  white 
heat  and  maintained  till  the  cessation  of  the  vapors 
of  zinc,  air  being  excluded. 

The  metal  is  pure  if  the  zinc  employed  contained 
no  foreign  materials  or  metals.     It  is  melted  and 


REDUCTION    BY   OTHER    AGENTS   THAN   SODIUM.      217 

cast  into  ingots.  In  case  the  zinc  contains  iron,  or 
even  if  the  A1*C16  contains  some,  the  metallic  pro- 
duct of  the  second  operation  may  be  treated  with 
dilute  sulphuric  acid  to  remove  it.  The  insoluble 
residue  is  washed  and  melted  layer  by  layer  with 
fluorspar  or  cryolite  and  a  small  quantity  of  APC16.- 
2$"aCl,  intended  solely  to  help  the  fusion." 

Mr.  Wedding*  makes  the  following  remarks  on 
this  process : — 

"  It  is  some  time  since  Mr.  Basset  established  the 
possibility  of  replacing  sodium  by  zinc  in  the 
manufacture  of  aluminium.  Operating  on  A12C16.- 
2XaCl  with  granulated  zinc,  the  reduction  takes 
place  towards  300°.  The  reduced  aluminium  dis- 
solves in  the  excess  of  zinc,  while  the  ZnCl2  formed 
combines  with  the  ]S"aCl,  forming  a  pasty  mass  if 
the  heat  is  not  raised.  Under  the  action  of  heat 
the  alloy  enriches  itself  in  aluminium,  because  the 
zinc  volatilizes.  The  zinc  retained  by  this  alloy  is 
completely  eliminated  by  fusion  with  Al2Cl6.2KaCl 
and  a  little  fluorspar.  The  temperature  ought  to 
be  pushed  at  last  to  a  white  heat,  and  maintained 
till  no  vapor  of  zinc  escapes,  air  being  excluded 
during  the  operation.  These  results  I  have  con- 
firmed, having  submitted  the  experiments  of  Mr, 
Basset  to  an  attentive  examination,  and  I  recom- 
mend its  use.  However,  the  process  demands  very 
much  precaution  because  of  the  high  temperature 

*  Journal  de  Pharm.  L4]  iii.  p.  loo  (1866). 
19 


218  ALUMINIUM, 

which  it  necessitates.  Another  chemist,  Mr. 
Spccht,  even  in  1860  decomposed  APC16  by  zinc, 
and  has  the  same  report  to  make — that  he  thinks 
the  process  will  be  some  time  advantageously  prac- 
tised on  a  large  scale." 

However,  this  method  has  not  succeeded  in  being 
established  in  practice,  probably  on  account  of  the 
high  temperature  which  is  necessary  to  drive  off 
the  zinc,  in  which  operation  some  aluminium  is 
lost. 

Kagensbusch,*  in  Leeds,  makes  the  singular 
proposition  to  melt  clay  with  fluxes ;  then,  by  add- 
ing zinc  or  lead,  to  decompose  it  by  an  electrical 
current  and  isolate  an  aluminium-zinc  or  alu- 
minium-lead alloy,  from  which  the  zinc  may  be 
volatilized  or  the  lead  cupelled. 

Mr.  Fred.  J.  Seymourf  patents  the  reduction  of 
aluminium  by  zinc,  and  makes  the  following  claim  : 
An  improvement  in  extracting  aluminium  from 
aluminous  earths  and  ores  by  mixing  them  with 
an  ore  of  zinc,  carboniferous  material  and  a  flux, 
and  subjecting  the  mixture  to  heat  in  a  closed 
retort,  whereby  the  zinc  is  liberated,  is  caused  to 
assist  in  bringing  or  casting  down  the  aluminium 
in  a  metallic  state,  and  an  alloy  of  aluminium  and 
zinc  is  obtained. 

The  only  information  outside  of  the  patent  claims 

*  Eng.  Pat.,  1872,  No.  4811. 

t  U.  S.  Pat.,  No.  291,631,  Jan.  8,  1884. 


REDUCTION    BY  OTHER   AGENTS    THAN    SODIUM.       219 

which  I  could  find  in  regard  to  this  process  is  con- 
tained in  the  following  newspaper  article,  which, 
although  wordy  and  indefinite,  will  have  to  be 
taken  in  the  absence  of  a  more  precise  account. 

"Mr.  F.  J.  Seymour,*  a  well-known  practical 
metallurgist,  late  of  Bridgeport,  Conn.,  has,  as  the 
result  of  several  years'  study,  succeeded  in  producing 
aluminium  at  a  low  cost,  and  by  the  novel  furnace 
just  designed  asserts  that  he  can  extract  the  metal 
on  a  commercial  basis  in  large  quantities.  Not  to 
go  into  all  the  technical  details,  which  are  ex- 
tremely interesting  to  metallurgists,  it  is  sufficient 
to  say  that  Mr.  Seymour  has  discovered  that  the 
close  affinity  existing  between  aluminium  and  zinc 
can  be  utilized  in  vaporizing,  capturing,  and  deposit- 
ing the  aluminium,  the  separation  being  effected 
by  the  aid  of  heat  in  a  furnace,  or  rather  a  series  of 
furnaces,  of  peculiar  construction.  The  charge  for 
each  furnace  is  zinc  ore  100  parts,  koalin  50,  carbon 
(either  anthracite  coal  or  its  equivalent  in  hydro- 
carbon gas)  125,  pearl  ash  or  its  equivalent  15, 
XaCl  10  ;  all  intimately  mixed.  The  retorts  are  of 
steel,  36  inches  long,  12  inches  diameter,  sides  J 
inch  thick.  The  heat  necessary  to  produce  the 
result  is  about  2500°  F.,  or  1400°  C.  Properly 
handled,  one  furnace  should  make  two  charges  in 
24  to  30  hours.  Four  men  can  operate  50  retorts. 

*  Cleveland  Letter  to  the  '  New  York  Times,'  April  14, 

1884. 


220  ALUMINIUM. 

The  number  of  retorts  can  be  increased  to  several 
hundred  in  a  single  system.  Capitalists  are  already 
interested  in  this  new  process,  and  the  prospects  are 
that  operations  on  an  extensive  scale  will  soon 
follow.  Independent  investigations  in  the  same 
line  in  this  city  have  resulted  in  the  recent  incor- 
poration of  a  company  for  the  extraction  of  alu- 
minium by  electricity.  Thus  far  the  secret  of  the 
process  has  been  strictly  guarded,  and  no  details 
can  be  given." 

Mr.  Seymour  has  quite  recently  taken  out  another 
patent,  the  claims  of  which  are  hardly  reconcilable 
with  those  of  the  former  patent.  The  claim  is  as 
follows : — 

Patent  to  Fred.  J.  Seymour,*  Wolcottville,  Conn., 
assignor  of  one-half  to  Mr.  Henry  Brown,  New 
York.  The  following  is  the  claim  :  u  The  process 
of  extracting  aluminium  from  aluminous  earths, 
consisting  in  subjecting  such  ore  or  earth  with  an 
ore  of  zinc,  carbonaceous  matter,  and  a  flux,  to 
heat, in  a  retort;  wherein  the  oxides  of  aluminium 
and  zinc  are  vaporized  ;  collecting  and  condensing 
the  vapors  in  a  condenser,  and  afterwards  subject- 
ing the  condensed  product  to  heat  with  carbo- 
naceous matter,  substantially  as  herein  described." 

If  Mr.  Seymour  can  make  a  process  work  accord- 
ing to  the  details  of  the  above  extraordinary  claim, 

*  U.  S.  Pat.  No.  337,996,  filed  March,  1885,  granted  March 
16,  1886. 


REDUCTION    BY   OTHER   AGENTS   THAN    SODIUM.      221 

he  will  certainly  have  a  claim  on  the  admiration 
of  all  scientific  men.  The  idea  of  vaporizing  the 
oxides  of  zinc  and  aluminium  is  certainly  unique. 
I  wrote  to  Mr.  Seymour,  asking  for  further  details 
of  his  process,  and  if  he  was  making  any  alu- 
minium, but  have  received  no  further  informa- 
tion than  has  already  been  given. 

4  The  American  Machinist,'  August,  1886,  con- 
tains the  statement  that  the  American  Aluminium 
Company  has  been  organized  at  Detroit  with  a 
capital  stock  of  §2,500,000 ;  to  use  the  patents  of 
Dr.  Smith  for  the  United  States,  Great  Britain  and 
France.  I  was  informed-  by  a  gentleman  in  the 
aluminium  industry  that  this  company  were  to 
operate  Mr.  Seymour's  zinc  process. 

REDUCTION  BY  LEAD. 

Accord  ing  to  the  invention  of  Mr.  A.  E.Wilde,*  of 
Xotting  Hill,  lead  or  sulphide  of  lead,  or  a  mixture 
of  the  two,  is  melted  and  in  a  molten  state  poured 
upon  dried  or  burnt  alum.  The  crucible  in  which 
the  mass  is  contained  is  then  placed  in  a  furnace 
and  heated,  with  suitable  fluxes.  The  metal,  when 
poured  out  of  the  crucible,  will  be  found  to  contain 
aluminium.  The  aluminium  and  lead  can  be  sub- 
sequently separated  from  each  other  by  any  known 
means,  or  the  alloy  or  mixture  of  the  two  metals 

*  Sci.  Am.  Suppl.,  Aug.  11,  1877. 
19* 


222  ALUMINIUM. 

can  be  employed  for  the  various  useful  purposes  for 
which  lead  is  more  or  less  unsuited. 

Kagensbusch's  process,  using  lead,  is  described 
on  p.  218  under  the  reduction  by  zinc. 

REDUCTION  BY  MANGANESE. 

"W.  Weldon,*  of  Burstow,  Eng.,  claims  to  melt 
together  cryolite  with  CaCl2  or  another  non-metal- 
lic chloride  or  sulphide,  and  then  to  reduce  the 
APC16  or  APS3  produced  with  manganese,  which 
he  claims  is  even  powerful  enough  to  reduce 
sodium. 


REDUCTION  BY  ELECTRICITY. 

The  reduction  of  A12C16  or  APCl6.2^aCl  by 
sodium  is  the  only  process  by  which  the  pure 
metal  is  now  made.  However,  many  attempts 
have  been  made  to  isolate  it  by  means  of  the  elec- 
tric current.  The  reduction  may  take  place  in 
either  the  dry  or  wet  way.  The  reduction  of 
fused  APCl6.2XaCl  by  the  battery  was  accidentally 
discovered  simultaneously  by  Deville  in  France 
and  Bunsen  in  Germany,  in  1854,  and  is  nothing 
else  but  an  application  of  the  process  already  an- 
nounced by  Bunsen  of  decomposing  magnesium 

*  Eng.  Pat.,  1883,  No.  97.    Wagner's  Jahresb.,  1884. 


REDUCTION   BY  OTHER   AGENTS   THAN   SODIUM.      223 

chloride,  MgCl2,  by  the  battery.     Deville's  account 
of  the  process  is  as  follows: — * 

"It  appears  to  me  impossible  to  obtain  alumin- 
ium by  the  battery  in  aqueous  solutions.  I  should 
believe  this  to  be  an  impossibility  if  the  brilliant 
experiments  of  Mr.  Bunsen  in  the  preparation 
of  barium  did  not  shake  my  convictions.  Still 
I  must  say  that  all  the  processes  of  this  de- 
scription which  have  recently  been  published  for 
the  preparation  of  aluminium  have  failed  to  give 
me  good  results.  To  prepare  the  bath  for  decom- 
position in  the  dry  way,  I  heated  a  mixture  of  2 
parts  APC16  and  1  part  NaCl,  dry  and  pulverized, 
to  about  200°  in  a  porcelain  capsule.  They  com- 
bine with  disengagement  of  heat,  and  the  resulting 
bath  is  very  fluid.  The  apparatus  which  I  use  for 
the  decomposition  comprises  a  glazed  porcelain 
crucible,  which  as  a  precaution  is  placed  inside  a 
larger  one  of  clay.  The  wrhole  is  covered  by  a 
porcelain  cover  pierced  by  a  slit  to  give. passage  to 
a  large,  thick  leaf  of  platinum,  w7hich  serves  as  the 
negative  electrode ;  the  lid  has  also  a  hole  through 
which  is  introduced,  fitting  closely,  a  well-dried 
porous  cylinder,  the  bottom  of  which  is  kept  at 
some  distance  from  the  inside  of  the  porcelain 
crucible.  This  porous  vessel  incloses  a  pencil  of 
retort  carbon,  which  serves  as  the  positive  electrode. 
Melted  Al2Cl6.22s"aCl  is  poured  into  the  porous  jar 
and  into  the  crucible  so  as  to  stand  at  the  same 

*  Ann.  de  CUem.  et  de  Phys.  [3J.  46,  452. 


224 


ALUMINIUM. 


height  iu  both  vessels;  the  whole  is  heated  just 
enough  to  keep  the  bath  in  fusion,  and  there  is 
passed  through  it  the  current  from  several  Bunsen 
cells,  two  cells  being  strictly  sufficient.  The  an- 
nexed diagram  shows  the  crucibles  in  section. 

Fig.  15. 


"  The  aluminium  deposits  with  some  JS"aCl  on 
the  platinum  leaf;  the  chlorine,  with  a  little 
APC16,  is  disengaged  in  the  porous  jar,  and  forms 
white  fumes,  which  are  prevented  from  rising  by 
throwing  into  the  jar  from  time  to  time  some  dry, 


DEDUCTION   BY  OTHER   AGENTS   THAN   SODIUM.      225 

pulverized  XaCl.  To  collect  the  aluminium,  the 
platinum  leaf  is  removed  when  sufficiently  charged 
with  the  saline  and  metallic  deposit;  after  letting 
it  cool  the  deposit  is  rubbed  off  and  the  leaf  placed 
in  its  former  position.  The  material  thus  detached, 
melted  in  a  porcelain  crucible,  and  after  cooling 
washed  with  water,  yields  a  gray,  metallic  powder, 
which  is  melted  under  a  layer  of  Al2Cl6.22>TaCl  and 
reunited  into  a  button." 

Bunsen*  adopted  a  similar  arrangement.  The 
porcelain  crucible  containing  the  bath  of  A12C16. 
2XaCl  kept  in  fusion  was  divided  into  two  com- 
partments in  its  upper  part  by  a  partition,  in  order 
to  separate  the  chlorine  liberated  from  the  alumin- 
ium reduced.  He  made  the  two  electrodes  of 
retort  carbon.  To  reunite  the  pulverulent  alumin- 
ium, Bunsen  melted  it  in  a  bath  of  Al2Cl6.2XaCl, 
continually  throwing  in  enough  XaCl  to  keep  the 
temperature  of  the  bath  about  the  fusing  point  of 
silver. 

Deville,f  without  being  acquainted  with  Bun- 
sen's  investigations,  employed  the  same  arrange- 
ment, but  he  abandoned  it  because  the  retort 
carbon  slowly  disintegrated  in  the  bath,  and  a 
considerable  quantity  of  Al2Cl'.2^"aCl  was  lost  by 
the  higher  heat  necessary  to  reunite  the  globules 
of  aluminium  after  the  electrolysis.  Deville  also 

*    Pogg,  97,   648. 

t  Ann.  de  Phys.  et  de  Chem.  [3],  43,  27. 


226  ALUMINIUM. 

observed  that  by  working  at  a  higher  tempera- 
ture, as  Bunsen  has  done,  he  obtained  purer  metal, 
but  in  less  quantity.  The  effect  of  the  high  heat 
is  that  silicon  chloride  is  formed  and  volatilizes,  and 
the  iron  which  would  have  been  reduced  with  the 
aluminium  is  transformed  to  FeCl2  by  the  A12C16, 
and  thus  the  aluminium  is  purified  of  silicon  and 
iron. 

Mierzinski  makes  the  following  practical  remarks 
on  the  use  of  electricity  in  producing  aluminium  :— 

"An  important  factor  which  we  must  notice  in 
the  present  production  of  aluminium  is  the  appli- 
cation of  electricity.  On  all  sides  the  greatest 
efforts  are  being  made  to  apply  electricity  to 
chemical  technology ;  in  the  future  the  importance 
of  electricity  will  centre  on  its  application  to  reduc- 
ing metals.  Even  in  the  year  1807  Davy  succeeded 
in  decomposing  caustic  potash  by  means  of  a  current 
from  a  400  element  Wollaston  battery.  But  we 
now  have  magneto-electric  and  dynamo-electric 
machines  which  are  much  lighter  and  cheaper  than 
they  were  in  Davy's  time.  The  application  of 
electricity  for  producing  metals  also  possesses  the 
advantage  not  to  be  ignored,  that  a  degree  of  heat 
may  be  attained  with  it  such  as  cannot  be  reached 
by  a  blowpipe  or  regenerative  gas  furnace.  The 
highest  furnace  temperature  attainable  is  2500  to 
2800°  C.,  but  long  before  this  point  is  reached  the 
combustion  becomes  so  languid  that  the  loss  of 
heat  by  radiation  almost  equals  the  production  of 


REDUCTION   BY  OTHER   AGENTS   THAN   SODIUM.      227 

heat  by  combustion,  and  hinders  a  further  elevation 
of  temperature.  But  in  applying  electricity,  the 
degree  of  heat  attainable  is  theoretically  unlimited. 
A  further  advantage  is  that  the  smelting  takes 
place  in  a  perfectly  neutral  atmosphere,  the  whole 
operation  goes  on  without  much  preparation  and 
under  the  eyes  of  the  operator.  Finally,  in  ordi- 
nary furnaces  the  refractory  material  of  the  vessel 
must  stand  a  higher  heat  than  the  substance  in  it, 
whereas  by  smelting  in  an  electrical  furnace  the 
material  to  be  fused  has  a  higher  temperature  than 
the  crucible  itself. 

"  The  manufacture  of  aluminium  is  effected  now 
either  by  separating  out  the  metal  itself  directly 
from  the  solutions  of  its  salts  or  by  reducing  it 
with  sodium.  However,  in  spite  of  numerous 
attempts,  sodium  has  not  been  replaced  as  a  reduc- 
ing agent.  In  the  production  of  aluminium,  the 
making  of  A1203  from  beauxite  costs  9.7  per  cent., 
making  the  Al2Cl6.2XaCi  33.4  per  cent,,  and  de- 
composing by  sodium  56.9  per  cent,  of  the  whole 
cost.  The  attempt  to  reduce  alumina  directly  by 
carbon  Mr.  W.  Weldon  considers  as  impossible 
because  he  could  not  produce  the  temperature 
required  for  the  reaction  to  take  place.  Hence 
appears  the  great  importance  of  utilizing  the 
temperature  attainable  by  the  electric  current. 
The  separation  of  aluminium  by  electrolysis  is  now 
done  only  by  the  use  of  anhydrous  Al2Cl8.2!N"aCl, 
melting  at  200°  C.  The  anodes  are  made  of  plates 


228  ALUMINIUM. 

of  alumina  and  carbon  pressed  together,  having  the 
conducting  wire  leading  through  their  whole 
length  in  order  to  lessen  the  resistance  as  much  as 
possible.  The  metal  is  obtained  as  a  granular 
powder  mixed  with  Js"aCl.  Where  possible,  vessels 
of  chalk  or  magnesia  should  be  used,  since  alu- 
minium takes  up  silicon  from  siliceous  crucibles 
and  becomes  brittle." 

There  have  been  some  improvements  made  in  the 
form  of  apparatus  over  those  used  by  Bunsen  and 
Deville,  designed  to  produce  the  metal  on  a  com- 
mercial scale.  The  best  one  is  that  patented  in 
Germany  by  Richard  Gratzel.*  He  uses  melting- 
pots  of  porcelain,  alumina,  or  aluminium,  which 
serve  also  as  negative  electrodes.  A  number  of 
these  are  placed  in  one  furnace.  The  following 
section  shows  the  arrangement  (Fig.  16).  The 
positive  electrode  K  can  be  made  of  a  mixture  of 
anhydrous  alumina  and  carbon  pressed  into  shape 
and  ignited.  A  mixture  of  alumina  and  gas-tar 
answers  very  well ;  or  it  can  even  be  made  of  gas- 
tar  and  gas-retort  carbon.  During  the  operation 
little  pieces  of  carbon  fall  from  it  and  would  con- 
taminate the  bath,  but  are  kept  from  doing  so  by 
the  mantle  (7.  This  isolating  vessel  G  is  perforated 
around  the  lower  part  at  #,  so  that  the  chlorine  gas 
liberated  at  K  may  escape  through  the  tube  0', 
while  reducing  gases  can  be  brought  into  the  cruci- 

*  D.  R.  Pat.  No.  26,962. 


REDUCTION   BY  OTHER  AGENTS   THAN   SODIUM.      229 

ble  by  the  tube  O2.     To  lessen  the  electrical  resist- 
ance and  to  renew  the  bath  of  chloride  or  fluoride, 

Fig.  16. 


bars  of  carbon,  alumina,  or  magnesia  are  placed 
inside  the  isolating  mantle  G. 

This  process  is  now  being  worked  on  a  large 
scale  in  Germany,  being  also  used  for  producing 
magnesium.  There  are  works  at  Bremen  and 
Hamburg. 

M.  Duvivier*  states  that  by  passing  an  electric 


20 


*  The  Chemist,  Aug.  1854. 


230  ALUMINIUM. 

current  from  eighty  Bunsen  cells  through  a  small 
piece  of  laminated  disthene  between  two  carbon 
points,  the  disthene  melted  entirely  in  two  or  three 
minutes,  the  elements  which  composed  it  were 
partly  disunited  by  the  power  of  the  electric  cur- 
rent, and  some  aluminium  freed  from  its  oxygen. 
Several  globules  of  the  metal  separated,  one  of 
which  was  as  white  and  as  hard  as  silver. 

Kagensbusch,*  of  Leeds,  makes  the  singular 
proposition  to  melt  clay  with  fluxes,  then  add  zinc 
or  a  like  metal,  pass  an  electric  current  through 
the  fused  mass,  isolating  an  alloy  of  aluminium  and 
the  metal,  from  which  the  foreign  metal  may  be 
removed  by  distillation,  sublimation,  or  cupella- 
tion. 

Gaudinf  reduces  aluminium  by  a  process  to 
which  he  applies  the  somewhat  doubtful  title  of 
economic.  He  melts  together  equal  parts  of  cryo- 
lite and  NaCl,  and  traverses  the  fused  mass  by  an 
electric  current.  Fluorine  is  evolved  at  the  positive 
pole,  while  aluminium  accumulates  at  the  negative. 

Thus  far  we  have  given  the  methods  based  on 
elect rolyzing  fused  salts.  These  seem  to  be  the 
operations  best  suited  to  throwing  down  aluminium 
in  mass.  The  electrolysis  of  aqueous  solutions 
seems  so  far  to  have  succeeded  only  in  depositing 
very  thin  films  of  metal.  We  will  now  give  the 

*  Eng.  Pat.  1872,  No.  4811. 
f  Moniteur  Scieutifique,  xi.  62. 


REDUCTION   BY   OTHER   AGENTS   THAN   SODIUM.      231 

various  methods   proposed  for  electrolyzing  alu- 
minium in  the  wet  way. 

Messrs.  Thomas  and  Tilly*  coat  metals  with 
aluminium  and  its  alloys  by  using,  for  depositing 
the  pure  metal,  a  solution  of  freshly  precipitated 
alumina  dissolved  in  boiling  water  containing 
potassium  cyanide,  or  a  solution  of  freshly  calcined 
alum  in  aqueous  potassium  cyanide ;  also  from 
several  other  liquids.  Their  patent  covers  the 
deposition  of  the  alloys  of  aluminium  with  silver, 
tin,  copper,  iron,  silver  and  copper,  silver  and  tin, 
etc.  etc. 

M.  Corbelli,  of  Florence,f  deposits  aluminium 
by  electrolyzing  a  mixture  of  rock  alum  or  sulphate 
of  alumina  with  CaCl2  or  UaCl,  in  aqueous  solu- 
tion, the  anode  being  mercury  placed  at  the  bottom 
of  the  solution  and  connected  to  the  battery  by  an 
iron  wire  coated  with  insulating  material  and 
dipping  its  uncovered  end  into  the  mercury.  The 
zinc  cathode  is  immersed  in  the  solution.  Alu- 
minium is  deposited  on  the  zinc,  and  the  chlorine 
which  is  liberated  at  the  anode  unites  with  the 
mercury,  forming  calomel. 

J.  B.  Thompson^  reports  that  he  has  for  over 
two  years  been  depositing  aluminium  on  iron,  steel, 
and  other  metals,  and  also  depositing  aluminium 

*  Eng.  Pat.,  1855,  No.  2756. 
f  Eng.  Pat.,  1858,  No.  507. 
J  Chem.  News,  xxiv.  194. 


232  ALUMINIUM. 

bronze  of  various  tints,  but  declines  to  state  his 
process. 

J.  A.  Jeancon*  has  patented  a  process  for  de- 
positing aluminium  from  an  aqueous  solution  of  a 
double  salt  of  aluminium  and  potassium  of  specific 
gravity  1.161 ;  or  from  any  solution  of  an  alumin- 
ium salt,  such  as  sulphate,  nitrate,  cyanide,  etc., 
concentrated  to  20°  B.  at  50°  F.  He  uses  a  battery 
of  four  pairs  of  Smee's  or  three  Bunsen's  cells, 
with  elements  arranged  for  intensity,  and  electro- 
lyses the  solutions  at  140°  F.  The  first  solution 
will  decompose  without  an  aluminium  anode,  but 
the  others  require  such  an  anode  on  the  negative 
pole.  The  solution  must  be  acidulated  slightly 
with  acid  corresponding  to  the  salt  used,  the  tem- 
perature being  kept  at  140°  F.  constantly. 

M.  A.  Bertrandf  states  that  he  deposited  alu- 
minium on  a  plate  of  copper  from  a  solution  of 
double  chloride  of  aluminium  and  ammonia,  by 
using  a  strong  current,  and  the  deposit  was  capable 
of  receiving  a  brilliant  polish. 

C.  W  inkier  J  states  that  he  has  spent  much  time 
and  tried  all  methods  so  far  proposed,  and  comes 
to  the  conclusion  that  aluminium  cannot  be  de- 
posited by  electro-deposition  in  the  wet  way. 

*  Annual  Record  of  Science  and  Industry,  1875. 

t  Chera.  News,  xxxiv.  227. 

t  Journal  of  the  Chem.  Soc.,  x.  1134. 


REDUCTION   BY  OTHER  AGENTS   THAN   SODIUM.      233 

Sprague*  also  states  his  inability  to  deposit  alumin- 
ium electrically  from  solution. 

M.  L.  Senetf  electrolyzes  a  saturated  solution  of 
AP(S04)3,  separated  by  a  porous  septum  from  a 
solution  of  NaCl.  A  current  is  used  of  four 
amperes.  The  double  chloride,  Al2Cl6.2NaCl,  is 
formed,  then  decomposed,  and  the  aluminium 
liberated  deposited  on  the  negative  electrode. 

Gerhard  and  Smith:):  patented  a  process  for  de- 
positing electrically  aluminium  and  its  alloys. 

John  Braun§  decomposes  a  solution  of  alum,  of 
specific  gravity  1.03  to  1.07,  at  the  usual  tempera- 
ture, using  an  insoluble  anode.  In  the  course  of 
the  operation,  the  sulphuric  acid  set  free  is  neu- 
tralized by  the  continual  addition  of  alkali ;  and, 
afterwards,  to  avoid  the  precipitation  of  alumina, 
a  non-volatile  organic  acid  is  added  to  the  solution. 

Moses  Gr.  Fanner)  has  patented  an  apparatus  for 
obtaining  aluminium  electrically  consisting  of  a 
series  of  conducting  cells  in  the  form  of  ladles, 
each  ladle  having  a  handle  of  conducting  material 
extending  upwards  above  the  bowl  of  the  next 
succeeding  ladle ;  each  ladle  can  be  heated  sepa- 
rately from  the  rest ;  the  anodes  are  hung  in  the 
ladles,  being  suspended  from  the  handles  of  the 

*  Sprague's  Electricity,  p.  309. 
f  Cosmos  les  Mondes,  Aug.  10,  1885. 
\  Eng.  Pat.,  1884,  No.  16,653. 
§  German  Pat.,  No.  28,760. 
II  U.  S.  Pat.,  No.  315,266,  Apr.  1885. 
20* 


234  ALUMINIUM. 

preceding  ladles,  the  ladles  themselves  being  the 
cathodes. 

Mierzinski  says  that  the  deposition  of  aluminium 
from  an  aqueous  solution  of  its  salt  has  not  yet 
been  accomplished,  and  declares  Gore  to  have  been 
in  error  when  he  stated  that  he  had  covered  copper 
with  a  film  of  aluminium  by  using  a  feeble  current 
and  a  solution  of  APC16  in  water. 

Several  years  ago,  the  writer  was  in  Mr.  Frish- 
muth's  works,  in  Philadelphia,  and  observed  that 
he  was  then  doing  a  large  amount  of  plating,  de- 
positing an  alloy  of  aluminium  and  nickel.  Nickel 
plating  is  known  to  be  very  hard  and  lasting,  but 
it  has  a  dark-bluish  color,  not  agreeable  to  many. 
The  presence  of  aluminium  with  it  whitens  it  so 
that  the  plating  is  a  very  close  imitation  of  silver, 
and  wears  much  better  than  silver  plating.  He 
was  depositing  with  a  twenty  horse-power  dynamo. 
The  articles  were  previously  cleaned  in  a  hot  pot- 
ash solution,  and  then  hung  in  the  plating  bath. 
I  do  not  know  the  composition  of  his  solution,  he 
keeps  that  secret,  but  it  was  green  and  strongly 
arnmoniacal. 


PART  XL 

WORKING  IN  ALUMINIUM. 

MELTING  ALUMINIUM. 

DEVILLE  :  To  melt  aluminium  it  is  necessary  to 
use  an  ordinary  earthen  crucible  and  no  flux. 
Fluxes  are  always  useless  and  almost  always  harm- 
ful. The  extraordinary  chemical  properties  of  the 
metal  are  the  cause  of  this ;  it  attacks  very  actively 
borax  or  glass  with  which  one  might  cover  it  to 
prevent  its  oxidation.  Fortunately  this  oxidation 
does  not  take  place  even  at  a  high  temperature. 
When  its  surface  has  been  skimmed  of  all  impuri- 
ties it  does  not  tarnish.  Aluminium  is  very  slow 
to  melt,  not  only  because  its  specific  heat  is  consid- 
erable, but  its  latent  heat  appears  very  large.  It 
is  best  to  make  a  small  fire  and  then  wait  patiently 
till  it  melts.  One  can  very  well  work  with  an  un- 
covered crucible.  When  it  is  desired  to  melt 
pieces  together,  they  can  be  united  by  agitating  the 
crucible  or  compressing  the  mass  with  a  well-cleaned, 
cylindrical  bar  of  iron.  Clippings,  filings,  etc.,  are 
melted  thus  :  Separate  out  first,  as  far  as  possible, 
foreign  metals,  and  to  avoid  their  combining  with 


236  ALUMINIUM. 

the  aluminium  heat  the  divided  metal  to  as  low 
a  heat  as  possible,  just  sufficient  to  melt  it.  The 
oil  and  organic  matters  will  burn,  leaving  a  cinder, 
which  hinders  the  reunion  of  the  metal  if  one  does 
not  press  firmly  with  the  iron  bar.  The  metal  may 
then  be  cast  very  easily,  and  there  is  found  at  the 
bottom  of  the  crucible  a  little  cinder  which  still 
contains  a  quantity  of  aluminium  in  globules. 
These  may  be  easily  separated  by  rubbing  in  a 
mortar  and  then  passing  through  a  sieve,  which 
retains  the  flattened  globules. 

Kerl  &  Stohman :  To  be  able  to  melt  well  and 
pour  aluminium,  the  whole  quantity  of  metal  which 
is  to  be  melted  at  one  time  must  not  be  put  into 
the  crucible  at  once,  but  little  by  little,  so  increas- 
ing the  mass  from  time  to  time  as  the  contents 
become  fully  melted.  The  necessary  knack  for 
attaining  a  good  clean  melt  consists  in  dipping  the 
pieces  which  are  to  be  melted  together  in  benzine 
before  putting  in  the  crucible.  Mourey  even  pours 
a  small  quantity  of  benzine  into  the  crucible  after 
the  full  melting  of  the  metal,  and  he  recommends 
the  employment  of  benzine  in  the  melting  of  all 
the  noble  metals.  Turning  to  the  cases  arising  in 
the  employment  of  aluminium  in  the  different  in- 
dustrial arts,  one  must  as  far  as  possible  separate 
out  first  the  pieces  which  have  been  soldered,  in 
order  that  the  newly  melted  aluminium  may  riot 
be  contaminated  by  the  solder.  The  solder  adher- 
ing to  these  pieces  can  be  removed  by  treating  them 


WORKING   IN   ALUMINIUM. 


with,  nitric  acid,  by  which  the  aluminium  is  not 
attacked. 

Mierzinski :  To  melt  aluminium  one  cannot  heat 
it  in  common  clay  crucibles,  because  it  reduces  sil- 
icon from  them,  by  which  the  metal  becomes  gray 
and  brittle.  This  difficulty  can  be  removed  by 
lining  the  crucible  with  carbon,  or  better,  with  well- 
burnt  cryolite-clay.  Moreover,  in  practice,  it  is 
only  in  the  rarest  cases  that  pure  aluminium  is 
obtained  to  be  melted  up,  but,  as  a  rule,  it  is  al- 
loyed with  four  to  eight  per  cent,  of  silver. 

CASTING  ALUMINIUM. 

Deville :  Aluminium  can  be  cast  very  easily  in 
metallic  moulds,  but  better  in  sand  for  complicated 
objects.  The  mould  ought  to  be  very  dry,  made  of 
a  porous  sand,  and  should  allow  free  exit  to  the  air 
expelled  by  the  metal,  which  is  viscous  when 
melted.  The  number  of  vents  ought  to  be  very 
large,  and  a  long,  perfectly  round  git  should  be 
provided.  The  aluminium,  heated  to  redness, 
ought  to  be  poured  rather  quickly,  letting  a  little 
melted  metal  remain  in  the  git  till  it  is  full,  to  pro- 
vide for  the  contraction  of  the  metal  as  it  solidifies. 
In  general,  this  precaution  ought  to  be  taken  even 
when  aluminium  is  cast  in  iron  ingot  moulds  or 
moulds  of  any  other  metal.  The  closed  ingot 
moulds  give  the  best  metal  for  rolling  or  hammer- 
ing. By  following  these  precautions,  castings  of 


238  ALUMINIUM. 

great  beauty  may  be  obtained,  but  it  is  not  advisa- 
ble to  conceal  tbe  fact  that  to  be  able  to  succeed 
completely  in  all  these  various  operations  requires 
for  aluminium,  as  for  all  other  metals,  a  special 
familiarity  with  the  material  which  practice  alone 
is  able  to  give. 

In  the  fusion  of  impure  aluminium,  very  different 
phenomena  are  observed  according  to  the  nature  of 
the  foreign  metal  which  contaminates  it.  Ferru- 
ginous material  often  leaves  a  skeleton  less  fusible 
and  pretty  rich  in  iron ;  a  liquation  has  taken 
place,  increasing  the  purity  of  the  melted  material. 
When  the  aluminium  contains  silicon  this  liquation 
is  no  longer  possible,  or  at  least  it  is  very  difficult, 
and  I  have  sometimes  seen  some  commercial  alu- 
minium so  siliceous  that  the  workmen  were  unable 
to  remelt  it.  But  the  aluminium  which  is  made 
at  present  is  much  purer  than  that. 

PURIFICATION  OF  ALUMINIUM. 

Freeing  from  Slag. — Deville  gives  the  following 
information  on  this  important  subject: — 

"It  is  of  great  importance  not  to  sell  any 
aluminium  except  that  which  is  entirely  free  from 
the  slag  with  which  it  was  produced  and  with 
which  its  whole  mass  may  become  impregnated. 
We  have  tried  all  sorts  of  ways  of  attaining  this 
end,  so  as  to  obtain  a  metal  which  would  not  give 
any  fluorides  or  chlorides  upon  boiling  with  water, 


WORKING   IN   ALUMINIUM.  239 

or  give  a  solution  which  would  be  precipitated  by 
silver  nitrate.  At  Glaciere,  we  granulated  the 
metal  by  pouring  it  while  in  good  fusion  into 
water  acidulated  with  H2S04 ;  this  method  par- 
tially succeeded.  But  the  process  which  M.  Paul 
Morin  uses  at  present,  and  which  seems  to  give 
the  best  results,  is  yet  simpler.  Three  or  four 
kilos  of  aluminium  are  melted  in  a  plumbago  cru- 
cible without  a  lid,  and  kept  a  long  time  red  hot 
in  contact  with  the  air.  Almost  always  acid 
fumes  exhale  from  the  surface,  indicating  the 
decomposition  by  air  or  moisture  of  the  saline 
matter  impregnating  the  metal.  The  crucible 
being  withdrawn  from  the  fire,  a  skimmer  is  put 
into  the  metal.  This  skimmer  is  of  cast  iron  ;  its 
surface  ought  not  to  be  rough  and  it  will  not  be 
wetted  by  the  aluminium  in  the  least  during  the 
skimming.  The  white  and  slaggy  matters  are 
then  removed,  carrying  away  also  a  little  metal, 
and  are  put  aside  to  be  remelted.  So,  in  this 
purification,  there  is  really  no  loss  of  metal.  After 
having  thus  been  skimmed,  the  aluminium  is  cast 
into  ingots.  This  operation  is  repeated  three  or 
four  times  until  the  metal  is  perfectly  clean,  which 
is,  however,  not  easily  told  by  its  appearance,  for, 
after  the  first  fusion,  the  crude  aluminium  when 
cast  into  ingots  has  a  brilliancy  and  color  such  as 
one  would  judge  quite  irreproachable,  but  the 
metal  would  not  be  clean  when  it  was  worked, 
and  especially  when  polished  would  present  a  mul- 


240  ALUMINIUM. 

titude  of  little  points  called  technically  'piqures,' 
which  give  to  its  surface,  especially  with  time,  a 
disagreeable  look.  Aluminium,  pure  and  free 
from  slag,  improves  in  color  on  using.  It  is  the 
contrary  with  the  impure  metal  or  with  alumin- 
ium not  freed  from  slag.  When  aluminium  is 
submitted  to  a  slow,  corroding  action,  its  surface 
will  cover  itself  uniformly  with  a  white,  thin 
coating  of  alumina.  However,  any  time  that  this 
layer  is  black  or  the  aluminium  tarnishes,  we  may 
be  sure  that  it  contains  a  foreign  metal  and  that 
the  alteration  is  due  to  this  impurity." 

Watts  suggests  that  the  iron  skimmer  be  oxi- 
dized on  its  surface. 

Freeing  from  Impurities. — Again  Deville  is  the 
authority,  and  we  quote  his  advice  on  the  sub- 
ject :— 

"  A  particular  characteristic  of  the  metallurgy 
of  aluminium  is  that  it  is  necessary,  in  order  to  get 
pure  metal,  to  obtain  it  so  at  the  first  attempt. 
When  it  contains  silicon,  I  know  of  no  way  to 
eliminate  it,  all  the  experiments  which  I  have 
made  on  the  subject  have  had  a  negative  result ; 
simple  fusion  of  the  metal  in  a  crucible,  permitting 
the  separation  by  liquation  of  metals  more  dense, 
seems  rather  to  increase  the  amount  of  silicon  than 
to  decrease  it.  When  the  aluminium  contains  iron 
or  copper,  each  fusion  purifies  it  up  to  a  certain 
limit,  and  if  the  operation  is  done  at  a  low  heat 
there  is  found  at  the  bottom  of  the  crucible  a 


WORKING   IN   ALUMINIUM.  241 

metallic  skeleton  containing  much  more  iron  and 
copper  than  the  primitive  alloy.  At  first  I  made 
this  liquation  in  the  muffle  of  a  cupel  furnace,  in 
which  process  the  access  of  air  permitted  the  par- 
tial oxidation  of  these  two  metals.  The  little  lead 
which  aluminium  may  sometimes  take  up  may 
thus  be  easily  separated.  Unfortunately,  the  pro- 
cess does  not  give  completely  satisfactory  results. 
It  is  the  same  in  fusing  impure  aluminium  under 
a  layer  of  potassium  sulphide,  K3S3;  there  is  a 
partial  separation  of  the  lead,  copper,  and  iron. 
That  which  has  succeeded  best  with  us  is  the  pro- 
cess which  we  have  employed  for  a  long  time  at 
Glaciere,  and  which  consists  in  melting  the  alu- 
minium under  nitre  in  an  iron  crucible.  We  have 
in  this  way  improved  the  quality  of  large  quanti- 
ties of  aluminium.  The  operation  is  conducted  as 
follows:  Aluminium  has  generally  been  melted 
with  nitre  in  order  to  purify  it  by  means  of  the 
strong  disengagement  of  oxygen  at  a  red  heat,  no 
doubts  being  entertained  as  to  the  certainty  of  the 
result.  But  it  is  necessary  to  take  great  care 
when  doing  this  in  an  earthen  crucible.  The 
silica  of  the  crucible  is  dissolved  by  the  nitre,  the 
glass  thus  formed  is  decomposed  by  the  aluminium, 
and  the  siliceous  aluminium  thus  formed  is,  as  we 
know,  very  oxidizable,  and  especially  in  the  pres- 
ence of  alkalies.  So,  the  purification  of  aluminium 
by  nitre  ought  to  be  done  in  a  cast-iron  crucible 
well  oxidized  itself  by  nitre  on  the  inside. 
21 


242  ALUMINIUM. 

"  On  melting  aluminium  containing  zinc  in  con- 
tact with  the  air  and  at  a  temperature  which  will 
volatilize  the  zinc,  the  largest  part  of  the  latter 
burns  and  disappears  as  flaky  oxide.  To  obtain  a 
complete  separation  of  the  two  metals  it  is  neces- 
sary to  heat  the  alloy  to  a  high  temperature  in  a 
brasqued  crucible.  This  experiment  succeeds  very 
W7ell,but  it  is  here  shown  that  the  aluminium  must 
oxidize  slightly  on  its  surface,  for  some  carbon  is 
reduced  by  the  aluminium  from  the  carbonic 
oxide  with  w?hich  the  crucible  is  filled.  This 
carbon  thus  separated  is  quite  amorphous." 

This  phenomenon  may  not  appear  so  extraor- 
dinary if  we  consider  the  case  in  this  way :  The 
aluminium  is  dissolved  in  the  fluid  zinc  in  a  man- 
ner strictly  analogous  to  the  aluminium  dissolved 
in  mercury.  Kow,  it  will  be  seen  that  alumin- 
ium-amalgam decomposes  easily,  the  mercury  ap- 
pearing to  impart  to  the  aluminium  the  ability  to 
combine  easily  with  oxygen,  so  that  .in  the 
amalgam  aluminium  is  said  to  play  the  part  of  an 
alkali  metal,  with  which  it  is  so  closely  related  in 
its  compounds.  Considering  the  case  of  the  alu- 
minium dissolved  in  melted  zinc  instead  of  in 
mercury,  it  appears  probable  that  the  zinc  imparts 
in  the  same  manner  as  the  mercury,  though  not 
necessarily  in  the  same  degree,  the  alkali  charac- 
teristics to  the  metal,  causing  it  to  oxidize  even  at 
the  expense  of  carbonic  oxide. 

Mierzinski   recommends   the   purification  with 


WORKING   IN   ALUMINIUM.  243 

nitre  to  be  made  in  a  crucible  made  of  alumina  or 
aluminate  of  soda. 

Gr.  Bucbner*  states  that  commercial  aluminium 
contains  considerable  quantities  of  silicon,  which 
by  treatment,  when  melted,  with  hydrogen,  evolves 
hydrogen  silicide.  This  does  not  result  if  arsenic 
is  present. 

Mallet  made  chemically  pure  aluminium  by  treat- 
ing the  commercial  metal  with  bromine,  purifying 
the  resulting  APBr6  by  fractional  distillation,  and 
then  reducing  it  with  pure  sodium.  By  repeatedly 
melting  the  metal  upon  aluminium  leaf,  he  obtained 
it  chemically  pure.  Although  this  method  is  quite 
applicable  when  studying  the  properties  of  the 
pure  metal,  yet  it  cannot  serve  on  an  industrial 
scale. 

USES  OF  ALUMINIUM. 

"  Since  aluminium  was  prepared  by  Devillef  on  a 
large  scale  it  has  received  numerous  applications. 
Its  beautiful  color,  its  lightness,  its  unoxidizability 
in  contact  with  air  or  sulphuric  acid,  its  harmless- 
ness  to  the  health,  the  ease  with  which  it  may  be 
worked,  are  some  of  the  properties  which  assure  for 
it  a  place  among  the  useful  metals.  On  account  of 
its  very  high  price  the  first  articles  made  of  it  were 
those  of  ornament  and  luxury.  The  very  first  article 

*  Wagner's  Jahresb.,  1884. 
t  Fremy's  Ency.,  1883. 


244  ALUMINIUM. 

made  of  it  was  a  baby  rattle,  intended  for  the  young 
Prince  Imperial  in  1856.  Afterwards  there  were 
made  of  it  jewelry,  medals,  inlaid  work,  and  carved 
mouldings  for  inlaid  work  and  rich  furniture.  It  is 
very  well  suited  for  fine  jewelry  by  reason  of  its 
adaptability  to  being  cast  and  carved,  the  beautiful 
reflections  from  a  chased  surface,  its  color,  which 
matches  well  with  gold,  and  its  absence  of  all  odor. 
Later  on,  the  lightness  of  aluminium  leads  to  its 
use  for  telescope  tubes,  marine  glasses,  eye-glasses, 
and  especially  sextants.  In  delicate  physical  ap- 
paratus, where  it  is  necessary  to  avoid  the  inertia 
of  large  masses,  aluminium  replaces  the  other 
metals  with  advantage.  It  is  used  for  beams 
for  delicate  balances  and  for  very  small  weights. 
There  have  been  made  of  it  sabre  sheaths,  sword 
handles,  and  the  imperial  eagles  for  the  French 
army.  Finally,  made  into  fine  wire,  it  is  worked 
into  lace,  embroidery,  etc.  For  all  these  purposes 
aluminium  answers  better  than  silver,  for  the 
objects  are  much  lighter  and  do  not  tarnish.  The 
resistance  of  aluminium  to  most  of  the  agents 
which  attack  the  useful  metals  has  led  to  its  em- 
ployment for  culinary  articles ;  a  large  number  of 
which  were  seen  at  the  London  Exhibition  in  1862. 
But  the  advantages  of  aluminium  vessels  have  not 
yet  been  sufficiently  comprehended,  and  this  use 
of  it  has  at  present  been  entirely  discontinued. 
Likewise,  aluminium  jewelry  is  not  seen  any 
more;  so  that  the  metal  seems  reserved  for  little 


WORKING    IN   ALUMINIUM.  245 

more  than  optical  and  surgical  instruments.  But 
the  aluminium  industry  is  nevertheless  established 
on  a  permanent  basis  and  will  continue,  because  of 
the  numerous  applications  of  its  alloys." 

M.  Dumas  made  a  helmet  of  aluminium,  gilded 

'   o 

and  ornamented,  which  weighed  complete  only  one 
and  one-fifth  pounds. 

Aluminium  leaf,  beaten  very  thin,  may  be  used 
anywhere  in  place  of  silver  leaf.  It  is  applied  in 
the  same  manner,  and  is  more  durable. 

Aluminium  wire  has  been  proposed  for  telegraph 
lines.  The  conductivity  of  aluminium  is  double 
that  of  iron,  and  as  it  is  so  much  lighter,  thinner 
wire  can  be  used.  As  its  high  price  is  a  practical 
difficulty,  an  alloy  of  iron  and  aluminium  has  been 
suggested. 

"  One  of  the  most  likely  applications  of  alu- 
minium is  probably  as  a  material  for  statuettes  and 
small  works  of  art  of  this  description,  especially  if 
the  means  could  be  found  of  giving  to  it  a  richer 
color  and  appearance  either  by  a  kind  of  bronzing 
or  some  alloy. 

"  Aluminium  makes  very  bright  reflectors,  not 
tarnished  by  the  products  of  combustion,  while  the 
slight  bluish  tinge  of  the  metal  corrects  the  yel- 
lowish tinge  of  the  flame.  For  culinary  uses  it  is 
well  adapted,  because  of  its  lightness  and  the  little 
tendency  it  has  to  become  corroded  by  any  of  the 
liquids  likely  to  come  in  contact  with  it.  It  is 
necessary  to  observe,  however,  that  this  power  of 

21* 


246  ALUMINIUM. 

resisting  the  action  of  corroding  agencies,  and 
more  especially  the  atmosphere  of  large  towns,  is 
exhibited  only  by  the  pure  metal.  Most  of  the 
metal  of  commerce  is  very  impure  with  iron  and 
silicon,  not  having  been  properly  freed  from  slag. 
Aluminium  thus  contaminated  soon  becomes  tar- 
nished, and  much  disappointment  has  been  experi- 
enced from  this  cause  by  those  who  have  used  it 
for  ornamental  purposes.  According  to  Deville,  the 
impurities  just  mentioned  are  found  to  the  greatest 
amount  in  the  metal  obtained  from  cryolite." 

In  the  '  Scientific  American/  vol.  xii.  pp.  31  and 
51,  is  a  long  article  on  plating  with  a  luminium, 
giving  complete  directions  for  preparing  articles, 
solutions,  etc. 

A  large  collection  of  articles  of  aluminium  was 
shipped  from  England  to  Calcutta  in  Oct.  1883, 
intended  for  exhibition  there.  The  exhibit  con- 
sisted of  wire,  pens,  pencil-cases,  railway-carriage 
fittings,  locks  and  bolts,  harness  furniture  in  great 
variety,  chandeliers,  cutlery,  and  ships'  fittings, 
and  illustrated  very  well  the  various  uses  to  which 
the  metal  can  be  put.  It  is  being  used  for  the 
lighter  parts  of  such  instruments  as  galvanometers, 
etc.,  for  suture  wire,  and  perhaps  its  most  promis- 
ing field  is  for  engineering,  astronomical,  and 
optical  instruments. 

"  Aluminium  is  sold  as  leaf  in  books,  like  gold 
leaf,  for  decorations,  at  from  40  to  50  cents  per 
book,  and  is  being  experimented  with  by  manu- 


WORKING   IN   ALUMINIUM.  247 

facturers  of  jewelry.  In  Germany,  experiments 
have  been  made  with  it  as  a  coating  for  iron,  to  be 
applied  for  ornamental  purposes,  and  as  an  improve- 
ment on  tin  plate.  Its  use  is  extending  slowly  but 
surely,  its  cost  being  at  present  the  principal 
obstacle  to  its  wider  employment."* 

Experiments  were  made  in  the  U.  S.  Mint  in 
1865,  on  alloys  of  aluminium  for  coins.  The 
results  wrere  not  sufficiently  successful  to  induce 
the  Government  to  adopt  the  metal  for  that  purpose. 

SOLDERING  ALUMINIUM. 

At  the  time  Deville  wrote  his  book,  the  difficulty 
of  soldering  aluminium  properly  was  one  of  the 
greatest,  if  not  the  greatest,  obstacle  to  the  employ- 
ment of  the  metal.  His  views  on  the  question  may 
be,  therefore,  very  interesting ;  they  are  as  follows : — 

"Aluminium  may  be  soldered,  but  in  a  very 
imperfect  manner,  either  by  means  of  zinc  or 
cadmium,  or  alloys  of  aluminium  with  these 
metals.  But  a  very  peculiar  difficulty  arises  here, 
wre  know  no  flux  to  clean  the  aluminium  which 
does  not  attack  the  solder,  or  which,  protecting  the 
solder,  does  not  attack  the  aluminium.  There  is  also 
an  obstacle  in  the  particular  resistance  of  aluminium 
to  being  wetted  by  the  more  fusible  rnetals,  and 
on  this  account  the  solder  does  not  run  between 

*  Mineral  Resources  of  the  U.  S.  1883-4. 


248  ALUMINIUM. 

and  attach  itself  to  the  surfaces  to  be  united.  .M- 
Christofle  and  M.  Charriere  made,  in  1855,  during 
the  Exposition,  solderings  with  zinc  or  tin.  But 
this  is  a  weak  solder  and  does  not  make  a  firm 
seam.  MM.  Tissier,  after  some  experiments  made 
in  my  laboratory,  proposed  alloys  of  aluminium 
and  zinc,  which  did  not  succeed  any  better.  How- 
ever, M.  Denis,  of  Nancy,  has  remarked  that  when- 
ever the  aluminium  and  the  solder  melted  on  its 
surface  are  touched  by  a  piece  of  zinc,  the  adhesion 
becomes  manifest  very  rapidly,  as  if  a  particular 
electrical  state  was  determined  at  the  moment  of 
contact.  But  even  this  produces  only  weak  solder- 
ings,  insufficient  in  most  cases. 

"  A  long  time  ago,  M.  Hulot  proposed  to  avoid 
the  difficulty  by  previously  covering  the  piece 
with  copper,  then  soldering  the  copper  surfaces. 
To  effect  this,  plunge  the  article,  or  at  least  the 
part  to  be  soldered,  into  a  bath  of  acid  sulphate  of 
copper.  Put  the  positive  pole  of  a  battery  in  com- 
munication with  the  bath,  and  with  the  negative 
pole  touch  the  places  to  be  covered,  and  the  copper 
is  deposited  very  regularly.  M.  Mourey  has  suc- 
ceeded in  soldering  aluminium  by  processes  yet 
unknown  to  me ;  samples  which  I  have  seen  looked 
excellent.  I  hope,  then,  that  this  problem  has 
found,  thanks  to  his  ingenuity,  a  solution  ;  a  very 
important  step  in  enlarging  the  employment  of 
aluminium." 


WORKING   IN  ALUMINIUM.  249 

Mierzinski  gives  the  following  statements  about 
M.  Mourey's  solder: — 

"  Mourey,  who  first  made  a  practicable  solder 
for  aluminium,  used  two  kinds  of  solder,  soft  and 
hard.  The  first  was  used  for  the  usual  soldering 
up  of  flasks  or  pieces  of  metal.  He  made  solders 
of  five  different  alloys,  the  composition  of  which 
were  as  given  in  the  table  below : — 

I.         II.        III.       TV.        V. 
Al          ...     20        15        12          8          6 

Zn         ...     80        85        88        92        94 

These  solders  have  varying  melting  points,  and 
thus  there  results  the  hard  and  soft  solders.  One 
can  take  a  soft  solder,  as  IV.,  for  brazing,  and  one 
like  II.  for  ordinary  soldering."* 

Schwarzf  improved  these  solders  by  adding 
copper  to  the  alloy.  His  solders  have  the  follow- 
ing composition : — 

I.  II.  III.  IV.  V. 

Al         ...    12  9         7  6  4 

Cu         ...      8  6          5  4  2 

Zn         ...     80  85  88  90  94 

MoureyJ  recommends  improved  solders  of  some- 
what similar  composition.  They  are : — 


I. 

II. 

III. 

IV. 

V. 

VI. 

VII. 

Al  .     .     . 

30 

20 

12 

9 

7 

6 

4 

Cu       .     . 

20 

15 

8 

... 

... 

... 

2 

Brass  . 

... 

... 

... 

6 

5 

4 

... 

Zn  .     .     . 

50 

65 

80 

85 

88 

90 

94 

*  It  is  usual  to  employ  hard  solder  for  brazing,  and  No.  II. 
would  be  harder  than  No.  IV.— J.  W.  R. 

t  Dingier,  157,  445.  \  Dingier,  166,  205. 


250  ALUMINIUM. 

Col.  "Wm.  Frishmuth*  recommends  a  solder  con- 
taining : — 

Al    .        .        .        .        .        .        .        .20 

Cu 10 

Zn 30 

Sn 60 

Ag 10 

Col.  Frishmuthf  states  that  the  solder  just  given 
is  used  for  fine  ornamental  work ,  while  for  lower- 
grade  work  he  uses  the  following : — 

I.       n.        in. 

Sn          ....     95        97        98-99 
Bi  ....       5          3          2-1 

Frishmuth  recommends  for  a  flux,  in  all  cases, 
either  paraffin,  stearin,  vaseHn,  copaiva  balsam,  or 
benzine.  In  the  solder  for  fine  work,  if  aluminium 
is  used  in  larger  quantity  than  recommended,  the 
solder  becomes  brittle. 

Kerl  and  Stohman  give  the  following  practical 
observations  on  this  subject:— 

"  At  first,  the  soldering  of  aluminium  appeared 
impossible.  But  Ph.  Mourey,  a  gold  and  silver 
worker  in  Paris,  invented  a  new  method  by  which 
he  could  solder  any  kind  of  object  of  this  metal. 
The  following  are  his  receipts:— 

"  There  are  needed,  according  to  the  objects  to  be 
soldered,  five  different  solders,  which  are  composed 
of  aluminium,  copper,  and  zinc,  in  different  propor- 
tions : — 

*  Teclmiker,  vi.  249.  f  Wagner's  Jahresb.,  1884. 


WORKING   IN   ALUMINIUM.  251 

I.  II.  III.  IV.  V. 

Al.         .         .     12  9          7          6  4 

Cu.        .        .      8  6          5          4  2 

Zn  .        .        .     80  85  88  90  94 

"To  make  the  solder,  first  pat  the  copper  in  the 
crucible.  When  it  is  melted,  then  add  the  alu- 
minium in  three  or  four  portions,  thereby  some- 
what cooling  the  melted  mass.  When  both  metals 
are  melted,  the  mass  is  stirred  with  a  small  iron 
rod,  and  then  the  required  quantity  of  zinc  added, 
free  from  iron,  and  as  clean  as  possible.  It  melts 
very  rapidly.  The  alloy  is  then  stirred  briskly 
with  an  iron  rod  for  a  time,  some  fat  or  benzine 
being  meanwhile  put  in  the  crucible  to  prevent 
contact  of  the  metal  with  air  and  oxidation  of  the 
zinc.  Finally  the  whole  is  poured  out  into  an  in- 
got mould  previously  rubbed  with  benzine.  After 
the  addition  of  zinc,  the  operation  must  be  finished 
very  rapidly,  because  the  latter  will  volatilize  and 
hum  out.  As  soon  as  the  zinc  is  melted,  the  cru- 
cible is  taken  out  of  the  fire. 

"The  separate  pieces  of  metal  to  be  soldered 
together  are  first  well  cleaned,  then  made  some- 
what rough  with  a  file  at  the  place  of  juncture, 
and  the  appropriate  solder  put  on  it  in  pieces  about 
the  size  of  millet  grains.  The  objects  are  laid  on 
some  hot  charcoal,  and  the  melting  of  the  solder 
effected  by  a  blast  lamp  or  a  Rochemont  turpentine- 
oil  lamp.  During  the  melting  of  the  solder,  it  is 
rubbed  with  a  little  soldering  iron  of  pure  alumin- 


252  ALUMINIUM. 

ium.  The  soldering  iron  of  pure  aluminium  is 
essentially  a  necessity  for  the  success  of  the  opera- 
tion, since  an  iron  of  any  other  metal  will  allo}7 
with  the  metals  composing  the  solder,  while  the 
melted  solder  does  not  stick  to  the  iron  made  of 
aluminium. 

"  The  method  just  described  differs  from  the  one 
described  by  Mourey  in  so  far  that  he  used,  at  first, 
alloys  of  aluminium  and  zinc  only,  with  no  copper. 
He  used  one  of  the  more  fusible  alloys  to  first  unite 
the  pieces,  and  then  used  a  less  fusible  one  to  finish 
with.  In  order  to  avoid  the  oxidation  of  the  sol- 
der he  added  while  using  the  hard  solder,  which 
must  be  worked  with  a  hotter  iron,  a  quantity  of 
copaiva  balsam  and  turpentine,  which  acts  just  as 
borax  in  working  silver.  With  these  new  solders 
of  aluminium,  copper,  and  zinc  the  process  is  much 
simpler,  the  work  is  done  wTith  one  solder  and  the 
moistening  with  balsam  is  unnecessary.  The  sol- 
derings  may  be  done  so  perfectly  that  plates  soldered 
together  never  break  at  the  joint  when  bent  back 
and  forth,  but  always  give  way  in  other  places ; 
which  is  a  result  not  always  possible  in  the  best 
soldering  of  plates  of  silver." 

Bell  Bros,  used  to  operate  the  works  at  N"ewcas- 
tle-on-Tyne,  and  their  description  may  contain  a 
few  points  not  yet  brought  forward  : — * 

"In  order  to  unite  pieces  of  aluminium,  small 

*  Chem.  News,  iv.  81. 


WORKING   IN   ALUMINIUM.  .       253 

tools  of  the  same  metal  are  used,  which  facilitate 
at  the  same  time  the  fusion  of  the  solder  and  its 
adhesion  to  the  previously  prepared  surfaces.  Tools 
of  copper  or  brass  must  be  strictly  avoided,  as  they 
would  form  colored  alloys  with  the  aluminium  and 
the  solder.  The  use  of  the  little  tools  of  alumin- 
ium is  an  art  which  the  workman  must  acquire  by 
practice.  At  the  moment  of  fusion  the  work  needs 
the  application  of  friction,  as  the  solder  suddenly 
melts  very  completely.  In  soldering  it  is  well  to 
have  both  hands  free  and  to  use  only  the  foot  for 
the  blowing  apparatus.  The  solders  used  are  of 
aluminium,  copper,  and  zinc.  (See  the  ones  given 
by  Kerl  &  Stohman,  p.  250.)  No.  IY.  is  the  one 
generally  preferred,  particularly  for  small  objects. 
In  order  to  make  the  solder,  the  copper  is  first 
melted,  the  aluminium  added,  and  the  whole 
stirred  with  an  unpolished  iron  rod,  just  as  it 
comes  from  the  forge,  adding  also  a  little  tallow. 
The  zinc  is  then  added,  avoiding  too  much  heat, 
which  would  drive  it  off.  In  soldering,  also,  too 
high  a  heat  should  be  avoided  for  the  same  reason. 

VENEERING  WITH  ALUMINIUM. 

Deville  is  the  first  writer  to  make  mention  of 
this  art : — 

"  M.  Sevrard  succeeded  in  1854  in  plating  alumin- 
ium on  copper  and  brass  with  great  perfection. 
The  two  metallic  surfaces  being  prepared  in  the 
22 


254  ALUMINIUM. 

ordinary  manner  and  well  scoured  with  sand,  they 
are  placed  one  on  the  other  and  held  tightly  be- 
tween two  iron  plates.  The  packet  is  then  heated 
to  dark  redness,  at  which  temperature  it  is  strongly 
compressed.  The  veneer  becomes  very  firmly  at- 
tached, and  sheets  of  it  may  be  beaten  out.  I  have 
a  specimen  of  such  work  perfectly  preserved.  The 
delicate  point  of  the  operation  is  to  just  heat  the 
packet  to  that  point  that  the  adherence  may  be 
produced  without  fusing  the  aluminium,  for  when 
it  is  not  heated  quite  near  to  this  fusing  point,  the 
adherence  is  incomplete.  Experiments  of  this 
kind  with  copper  and  aluminium  foil  did  not  suc- 
ceed, for  as  soon  as  any  adherence  manifested  itself 
the  two  metals  combined  and  the  foil  disappeared 
into  the  copper.  In  an  operation  made  at  too  low  a 
temperature,  the  two  metals,  as  they  do  not  behave 
similarly  on  rolling,  become  detached  after  a  few 
passes  through  the  rolls.  Since  then,  the  experi- 
ments in  veneering  aluminium  on  copper,  with  or 
without  the  intervention  of  silver,  have  succeeded 
very  well." 

The  only  other  article  to  be  found  on  this  subject 
is  Dr.  Clemens  Winckler's  paper,  from  which  we 
extract  the  following  : — * 

uThe  question  demands  attention  whether  it  is 
not  possible  to  coat  certain  metals  and  alloys  writh 
aluminium,  and  thereby  impart  to  them,  superfi- 

*  Industrie  Blatter,  1873. 


WORKING   IN   ALUMINIUM.  255 

cially  at  least,  the  advantageous  properties  of  that 
metal.  The  present  high  price  of  the  metal  does 
not  stand  in  its  way  for  this  purpose ;  and  it  only 
remains  now  to  decide  whether  it  is  practicable  to 
coat  our  common  metals,  iron,  copper,  etc.,  with  it. 
The  question  must  at  present  be  answered  in  the 
negative.  Two  methods  can  be  used  for  covering 
one  metal  with  another,  galvanoplasty  and  plating 
or  veneering.  The  separation  of  aluminium  by 
the  galvanic  current  succeeds  only  by  the  use  of  a 
bath  of  molten  anhydrous  Al2Cl6.2^N"aCl,  melting 
at  165°  C.  (329°  F.),  but  the  metal  is  deposited  as  a 
non-coherent  powder,  mixed  with  ISTaCl,  and  there- 
fore the  object  of  plating  is  not  attained  in  this  way. 
Ko  one  has  yet  been  able  to  throw  down  aluminium 
in  a  metallic  state  from  aqueous  solution,  and  it  was 
an  error  when  Grore  stated  that  he  had  coated  cop- 
per with  aluminium  by  means  of  a  solution  of  A12C16 
in  water  and  a  weak  galvanic  current.  Concerning 
the  coating  of  metals  by  the  so-called  plating 
method,  it  is  indeed,  according  to  my  own  experi- 
ence, possible  to  a  certain  degree,  but  the  product . 
is  entirely  useless,  every  plating  requiring  an  incip- 
ient fusing  of  both  metals  and  their  final  intimate 
union  by  rolling.  The  ductility  of  aluminium  is, 
however,  greatly  injured  by  even  a  slight  admixture 
with  other  metals ;  iron  makes  it  brittle  and  copper, 
in  small  per  cent,  makes  it  fragile  as  glass.  If  now 
it  were  possible  in  any  way  to  fuse  a  coating  of 
aluminium  upon  another  metal,  there  would  be 


256  ALUMINIUM. 

formed  an  intermediate  alloy  between  the  two 
metals  from  which  all  ductility  would  be  gone  and 
which  would  crumble  to  powder  under  the  pressure 
of  the  rolls,  thus  separating  the  aluminium  surface 
from  the  metal  beneath.  But  even  if  it  were  pos- 
sible in  this  way  to  coat  a  metal  with  a  thin  plate, 
it  is  still  doubtful  if  anything  would  be  attained 
thereby.  For,  while  compact  aluminium  resists 
oxidizing  and  sulphurizing  agencies,  the  divided 
metal  does  not.  In  powder  or  leaves  aluminium  is 
readily  oxidized,  as  is  shown  by  its  amalgam  be- 
coming heated  in  the  air  and  quickly  forming  alu- 
mina. In  the  form  of  a  coating  upon  other  metals 
it  must  necessarily  be  in  a  somewhat  finely  divided 
state,  and  hence  would  probably  lose  its  durability." 

GILDING  AND  SILVERING  ALUMINIUM. 

Deville  says:  "The  gilding  and  silvering  of 
aluminium  by  electricity  is  very  difficult  to  do 
satisfactorily  and  obtain  the  desirable  solidity.  M. 
Paul  Morin  and  I  have  often  tried  it  by  using  a 
bath  of  acid  sulphide  of  gold  or  of  nitrate  of  silver 
with  an  excess  of  sulphurous  acid.  Our  success 
has  only  been  partial.  However,  M.  Mourey,  who 
has  already  rendered  great  services  in  galvano- 
plasty,  gilds  and  silvers  the  aluminium  of  com- 
merce with  a  surprising  perfection  considering  the 
little  time  he  has  had  to  study  the  question.  I 
also  know  that  Mr.  Christofle  has  gilded  it,  but  I 


WORKING   IN   ALUMINIUM.  257 

am  entirely  ignorant  of  the  methods  employed  by 
these  gentlemen." 

Watts's  Dictionary :  "  Eight  grammes  of  gold  are 
dissolved  in  aqua  regia,  the  solution  diluted  with 
water  and  left  to  digest  twenty-four  hours  with  an 
excess  of  lime.  The  precipitate,  with  the  lime,  is 
well  washed,  and  then  treated  with  a  solution  ot 
twenty  grammes  of  hyposulphate  of  soda.  The 
liquid  resulting  serves  for  the  gilding  of  aluminium 
without  the  aid  of  heat  or  electricity,  the  metal 
being  simply  immersed  in  it  after  being  previously 
well  cleaned  by  the  successive  use  of  caustic  potash, 
nitric  acid,  and  pure  water." 

Kerl  and  8 tohmau :  "  Gilding  and  silvering 
aluminium  galvanically  does  not  offer  the  least 
difficulty.  One  can,  by  using  a  proper  ground, 
coat  it  with  silver  and  gold  in  six  different  colors, 
by  employing  the  correct  combination,  such  as 
shining  or  matt  gold  and  silver  or  lead  gray." 


22* 


PART  XII. 

ALLOYS  OF  ALUMINIUM. 

General  Remark. — Mierzinski : — 

"Aluminium  unites  easily  with  most  metals,  the 
combination  being  usually  accompanied  by  a  lively 
disengagement  of  heat.  Quite  homogeneous  alloys 
can  be  made,  which  for  the  most  part  are  easily 
worked  and  have  important  applications.  The 
alloys  in  general  become  harder  the  greater  the 
proportion  of  aluminium,  and  become  brittle  if  this 
proportion  passes  a  certain  limit,  which  with  gold 
and  copper  is  very  low.  On  addition  of  a  larger 
amount  of  aluminium  than  this  limit  allows,  gold 
and  copper  become  whiter,  and  at  last  entirely  lose 
their  color.  The  addition  of  other  metals  to  alu- 
minium imparts  to  it  the  same  new  properties.  It 
becomes  brighter  and  somewhat  harder,  but,  united 
with  small  quantities  of  zinc,  tin,  gold,  or  silver, 
remains  malleable.  Iron  and  copper  impart  to  it 
no  specially  prejudicial  qualities,  if  they  are  not 
present  in  too  large  quantities.  The  alloys  most 
frequently  used  are  those  of  copper,  silver,  and  tin. 
These  owe  their  numerous  uses  to  their  fine  color, 
their  resistance  to  most  chemical  agents,  and  the 
facility  with  which  they  may  be  worked." 


ALLOYS  OF  ALUMINIUM.  259 

ALUMINIUM  AND  SILICON. 

Tissier:  "As  Deville  has  observed,  silicon  is  far 
from  injurious  to  the  malleability  of  aluminium, 
the  latter  bearing  it  much  as  iron  and  copper  do. 
We  have  had  occasion  to  analyze  a  specimen  of 
aluminium,  which,  although  it  worked  with  diffi- 
culty, was  yet  employed  to  make  various  objects, 
and  yet,  attacked  by  HC1,  it  left  an  insoluble  resi- 
due of  no  less  than  15.67  per  cent.  But,  even 
admitting  that  this  residue  still  retained  some  alu- 

o 

minium  with  the  silicon,  we  think  that  there  was 
at  least  10  per  cent,  of  the  latter  in  this  specimen." 
Deville :  "  Any  siliceous  material  whatever,  put 
in  contact  with  aluminium  at  a  high  temperature, 
is  always  decomposed ;  and  if  the  metal  is  in  excess 
there  is  formed  an  alloy  or  a  combination  of  silicon 
and  aluminium  in  which  the  two  bodies  may  be 
united  in  almost  any  proportions.  Glass,  clay,  and 
the  earth  of  crucibles  act  in  this  way.  However, 
aluminium  may  be  melted  in  glassware  or  earthen 
crucibles  without  the  least  contamination  of  the 
metal  if  there  is  no  contact  between  the  metal  and 
the  material ;  the  aluminium  will  not  wet  the 
crucible  if  put  into  it  alone.  But,  the  moment  that 
any  flux  whatever  facilitates  immediate  contact, 
even  sodium  chloride  does  this,  the  reaction  begins 
to  take  place,  and  the  metal  obtained  is  always 
more  or  less  siliceous.  It  is  for  this  reason  that  I 
have  prescribed  in  melting  aluminium  not  to  add 


260  ALUMINIUM. 

any  kind  of  flux,  even  when  the  flux  would  not  be 
attacked  by  the  metal.  Among  the  fusible  ma- 
terials which  facilitate  the  me] ting  of  aluminium, 
it  is  necessary  to  remark  of  the  fluorides  that  they 
attack  the  siliceous  materials  of  the  crucible,  dis- 
solving them  with*  great  energy,  and  then  the 
siliceous  materials  thus  brought  into  solution  are 
decomposed  by  the  aluminium  with  quite  remark- 
able facility.  Aluminium  charged  with  silicon 
presents  quite  different  qualities  according  to  the 
proportion  of  the  alloy.  When  the  aluminium  is 
in  large  excess,  there  is  obtained  what  I  have  called 
the '  cast-iron'  state  of  aluminium,  by  means  of  which 
I  discovered  crystallized  silicon  in  1854.  This 
4  cast' aluminium,  gray  and  brittle,  contains  accord- 
ing to  my  analysis  10.3  per  cent,  of  silicon  and 
traces  of  iron.  When  siliceous  aluminium  is  at- 
tacked by  hydrochloric  acid,  the  hydrogen  which 
it  disengages  has  an  infected  odor,  which  I  formerly 
attributed  to  the  presence  of  a  hydrocarbon,  but 
which  we  now  know  is  due  to  hydrogen  silicide,  Sill4, 
thanks  to  the  fine  experiments  of  MM.  Wohler 
and  Buff.  It  is  by  the  production  of  this  gas  that 
may  be  explained  the  iron  smell  which  is  given 
out  by  aluminium  more  or  less  contaminated  with 
silicon.  But  aluminium  may  absorb  much  larger 
proportions  of  silicon,  for,  on  treating  fluo-silicate 
of  potash  with  aluminium,  M.  Wohler  obtained  a 
material  still  metallic  containing  about  70  per  cent, 
of  silicon,  sometimes  occurring  as  easily  separable 


ALLOYS   OF   ALUMINIUM.  261 

crystals.  Since  I  had  the  occasion  in  a  work  which 
I  published  on  silicon  to  examine  a  large  number 
of  these  combinations,  I  found  that  they  were  much 
more  alterable  than  pure  aluminium  or  silicon, 
without  doubt  because  of  the  affinity  which  exists 
between  silica  and  alumina.  I  have,  therefore, 
dwelt  on  and  tried  to  explain  the  importance 
of  this  point  in  obtaining  perfectly  pure  alumin- 
ium. I  should  say,  in  addition,  that  the  metal 
now  sold  in  commerce  may  contain  either  iron  or 
silicon,  according  to  the  method  of  preparation. 
These  two  impurities  are  hurtful  to  most  of  the 
qualities  of  the  aluminium,  and  everything  ought 
to  be  done  to  avoid  their  presence." 

ALUMINIUM  AND  MERCURY. 

Deville :  "  Mercury  is  not  able  to  unite  with 
aluminium.  Experiments  of  this  nature  which  I 
have  made  myself,  and  which  Mr.  Wollaston  has 
confirmed,  prove  it  most  clearly." 

Watts :  "  According  to  Caillet,  aluminium  may 
be  amalgamated  by  the  action  of  ammonium  or 
sodium  amalgam,  with  water;  also  when  it  is  con- 
nected with  the  negative  pole  of  a  voltaic  battery 
and  dipped  into  the  mercury  moistened  with  acid- 
ulated water,  or  into  a  solution  of  mercuric  nitrate. 
Tipsier*  confirms  this  statement  respecting  the 

*  Compt.  Rend.,  xlix.  56. 


262  ALUMINIUM. 

battery  method,  and  adds  that  if  the  aluminium 
foil  is  not  very  thick  it  becomes  amalgamated 
throughout  and  very  brittle."  Tissier  also  finds 
that  aluminium  may  be  made  to  unite  with  mer- 
cury merely  by  the  intervention  of  a  solution  of 
caustic  potash  or  soda,  without  the  intervention  of 
the  battery.  If  the  surface  of  the  metal  be  well 
cleaned,  or  moistened  with  the  alkaline  solution,  it 
is  immediately  melted  by  the  mercury,  and  a  shin- 
ing amalgam  forms  on  its  surface.  The  amalgam 
of  aluminium  instantly  loses  its  lustre  when  ex- 
posed to  the  air,  becoming  heated  and  rapidly 
converted  into  alumina  and  mercury.  It  decom- 
poses water  with  evolution  of  hydrogen  and  forma- 
tion of  alumina  and  mercury.  Nitric  acid  attacks 
it  with  violence. 

Watts  (First  Supplement)  states  that  aluminium 
amalgam  may  be  formed  either  by  bringing  the 
aluminium  in  contact  with  mercury  containing  a 
small  quantity  of  sodium,  or  by  Joules's  method  of 
electrolyzing  the  solution  of  an  aluminium  salt, 
with  mercury  for  the  negative  pole  ;*  but  the  best 
method  is  to  heat  the  two  metals  together  in  a  gas 
which  does  not  act  on  either  of  them.  To  do  this, 
a  piece  of  aluminium  foil  is  placed  at  the  bottom 
of  a  thick-walled  test-tube,  and  well-dried  mercury 
is  poured  on  it,  the  tube  having  been  previously 
drawn  out  at  the  middle  to  prevent  the  foil  rising 

*  Chem.  Gazette,  1850,  p.  339. 


ALLOYS   OF  ALUMINIUM.  263 

to  the  surface.  The  air  is  then  expelled  by  a 
stream  of  carbonic  acid  gas  and  the  tube  is  heated, 
without  interrupting  the  current  of  gas,  till  the 
metal  is  all  dissolved. 

Aluminium  amalgam  decomposes  in  contact 
with  air  or  water  more  quickly  than  sodium  amal- 
gam. When  a  few  drops  of  an  amalgam  contain- 
ing but  a  small  proportion  of  aluminium  are  left 
in  contact  with  moist  air,  gelatinous,  opalescent 
excrescences  of  pure  hydrated  alumina  are  seen  to 
form  on  their  surfaces,  exhibiting  both  in  their 
form  and  mode  of  growth  considerable  resemblance 
to  the  so-called  Pharoah's  serpents.  This  hydrated 
alumina  is  perfectly  soluble  in  acids  and  alkalies. 
Water  has  the  same  effect  as  moist  air.  Watts,  in 
vol.  viii.,  states  that  aluminium  oxidizes  when 
its  surface  is  rubbed  with  a  piece  of  soft  leather 
impregnated  with  mercury.  The  rubbed  surface 
becomes  warm,  and  in  a  few  seconds  whitish  ex- 
crescences appear,  consisting  of  pure  alumina. 
The  presence  of  mercury  appears  necessary  to 
produce  the  result. 

Fremy  says  that  Tissier  has  proven  that  alumin- 
ium previously  contaminated  with  caustic  potash 
or  soda  combines  easily  with  mercury.  The  alloy 
which  results  is  very  brittle,  the  aluminium  in  it 
decomposes  water,  oxidizes  easily  in  the  air,  and 
behaves  as  a  metal  of  the  alkaline  earths. 

Gmelin*  states  that  potassium  amalgam  intro- 

*  Hand  Book,  vi.  3. 


264  ALUMINIUM. 

duced  into  a  hole  bored  in  a  crystal  of  alum 
immediately  acquires  a  rotary  motion,  which  lasts 
sometimes  half  an  hour.  At  the  same  time,  it 
takes  up  a  considerable  quantity  of  aluminium  and 
becomes  more  viscid. 

ALUMINIUM  AND  COPPER. 

Tissier  Bros.,  1858  :  "  Just  as  copper  increases 
the  hardness  of  aluminium,  so  aluminiu'm  in  small 
proportions  increases  the  hardness  of  copper.  How- 
ever, aluminium  does  not  injure  its  malleability, 
but  makes  it  susceptible  of  taking  a  beautiful 
polish,  and,  according  to  the  proportions,  varies  its 
color  from  red  gold  to  pale  yellow.  These  facts 
were  announced  some  time  back  by  Dr.  Percy,  in 
England,  who  made  the  alloy  by  introducing 
copper  into  the  mixture  of  cryolite  and  sodium 
which  he  was  reducing.  We  have  made  large 
quantities  of  these  alloys,  and  we  may  say  that 
they  leave  nothing  to  be  desired  in  regard  to  lustre 
or  color  to  make  them  perfect  imitations  of  gold. 
They  alter  much  less  by  successive  fusions  than 
the  alloys  of  copper  with  zinc  and  tin  employed 
for  the  same  object.  A  ten  per  cent  aluminium 
alloy  was  harder  than  our  gold  coin,  took  a  fine 
polish  by  burnishing,  and  had  the  color  of  pale 
jeweller's  gold ;  it  could  be  forged  and  worked  the 
same  as  copper.  The  five  per  cent,  aluminium 
alloy  was  less  hard  than  the  preceding,  but,  like 


ALLOYS    OF    ALUMINIUM.  265 

it,  takes  a  fine  polish,  and  in  tint  approaches 
nearly  to  pure  gold.  The  twenty  per  cent,  alumin- 
ium alloy  much  resembles  bismuth,  having  a 
whitish-yellow  tint.  This  alloy  crystallizes  in 
large  leaves  and  pulverizes  in  the  mortar  like  bis- 
muth or  antimony.  Alloys  with  five  to  ten  per 
cent,  of  aluminium  may  have  their  color  changed 
at  will,  either  by  leaving  in  nitric  acid,  which 
takes  away  the  copper  and  leaves  the  aluminium, 
or  in  hydrochloric,  which  leaves  the  copper.  The 
resistance,  hardness,  and  elasticity,  which  are 
communicated  to  copper  by  introducing  small 
quantities  of  aluminium,  will  certainly  make  these 
important  industrial  alloys." 

Deville,  1859:  "The  aluminium  and  copper 
alloys  with  two  to  three  per  cent,  aluminium  are 
used  by  M.  Christofle,  who  employs  them  for  large 
castings  of  objects  of  art.  They  are  harder  than 
aluminium,  and  work  well  under  the  burin  and 
chisel.  The  alloy  with  ten  per  cent,  aluminium 
had  its  useful  properties  first  described  by  M. 
Debray.  It  is  very  hard,  can  be  beaten  out  cold, 
but  with  remarkable  perfection  when  hot,  and  may 
be  well  compared  to  iron,  which  it  resembles  in  all 
these  physical  properties.  It  is  also  very  ductile. 
This  ten  per  cent,  aluminium  alloy  is  usually 
known  as  aluminium  bronze.  It  behaves  as  a  true 
alloy,  and,  in  consequence,  will  not  liquate  into 
different  combinations.  It  is  formed  of — 

23 


266  ALUMINIUM. 

9  equivalents  of  Cu     .         .         .     275          9 

1  "  "  Al     .         .         .       28          1 

303        10 

This  is  proven  by  the  fact  that,  when  in  making 
the  alloy  the  pure  copper  is  in  the  crucible  and  a 
bar  of  aluminium  is  added,  the  combination  takes 
place  with  such  disengagement  of  heat  that  if  the 
crucible  is  not  of  good  quality  it  will  be  fused,  for 
the  whole  becomes  white  hot. 

"  The  color  of  the  ingot  of  bronze  is  exactly  that 
of  c  green  gold,'  an  alloy  of  gold  and  silver.  The 
bronze  receives  a  beautiful  polish,  being  comparable 
in  this  regard  only  to  steel.  Its  chemical  proper- 
ties do  not  differ  much  from  those  of  most  of  the 
allo3rs  of  copper.  However,  in  numerous  experi- 
ments, we  have  noticed  that  it  resists  most  chemical 
agents  much  better  than  these,  especially  sea-water 
and  sulphuretted  hydrogen.  Its  tenacity  is  equal 
to  that  of  steel.  M.  Lechatelier  made  the  follow- 
ing determinations  on  the  metal  cast  into  cylinders: 


Per  cent,  of           Diarn.  of 
aluminium.          cylinder. 

10           -10.0m.  m. 

Breaking  strain. 

4627  kilos. 

Strength  per 
sq.  m.  m. 

58.36  kilos. 

10 

10.1      " 

4432     " 

55.35     " 

8 

10.1      " 

2657     " 

33.18     " 

5 

10.1      " 

2582     " 

32.20     " 

5 

10.1      u 

2517     " 

31.43     " 

French  wrought  iron         .         .     35.00     " 

"  A.  Gordon  made  some  experiments  recently,  in 
which  the  strength  of  the  aluminium  bronze  which 


ALLOYS   OF   ALUMINIUM.  267 

he  tested  was  84.00  kilos  per  square  millimetre. 
I  made  the  test  on  some  wire,  and  the  result  I 
reached  was  85.00  kilos ;  under  the  same  condi- 
tions iron  gave  60.00  and  best  steel  90.00  kilos. 
According  to  experiments  as  to  its  wear  as  journal 
boxes,  it  is  found  to  wear  away  less  than  any  other 
journal  metal  yet  tried. 

"  Its  malleability  is  almost  perfect,  as  is  seen  by 
the  following  report  of  M.  Boudaret,  a  practical 
engineer:  First,  aluminium  bronze  is  malleable  at 
all  temperatures,  from  bright  red  to  cold  ;  second, 
it  is  perfectly  malleable  at  red  heat,  breaking  less 
and  elongating  more  than  pure  copper ;  third,  it  is 
hard  to  roll  in  the  cold,  after  several  passes  it 
ceases  to  elongate  and  must  then  be  annealed  very 
often  or  it  will  break  quickly;  fourth,  it  results 
from  the  foregoing  that  it  is  best  to  roll  it  at  as 
high  a  heat  as  possible  below  fusion  ;  fifth,  anneal- 
ing and  tempering  render  it  softer  than  simple 
annealing.  If  after  having  annealed  at  bright  red 
heat  it  is  let  cool  in  still  air  to  redness  arid  then 
plunged  into  cold  water,  it  is  ductile  and  malleable 
enough  in  the  cold  to  stand  all  industrial  working." 

Mierzinski,  1885:  "Two  points  are  to  be  at- 
tended to  in  making  aluminium  bronze.  First,  a 
very  pure  copper  must  be  used,  the  best  is  that 
electrically  deposited,  but  it  generally  costs  too 
much.  The  next  best  is  the  Lake  Superior  brand. 
The  usual  commercial  copper  gives  all  sorts  of  poor 
results,  owing  to  the  antimony,  arsenic,  tin,  zinc, 


268  ALUMINIUM. 

or  iron  contaminating  it.  The  bronze  loses  by  being 
alloyed  with  zinc  or  tin.  Second,  the  alloy  must 
be  remelted  two  or  three  times  to  remove  its  brittle- 
ness.  In  all  probability,  the  percentage  of  alu- 
minium increases  by  remelting.  The  usual  alloys 
are  those  with  1,  2,  5,  and  10  per  cent,  aluminium. 
The  5  per  cent  bronze  is  golden  in  color,  polishes 
well,  casts  beautifully,  is  very  malleable  cold  or 
hot,  and  has  great  strength,  especially  after  ham- 
mering ;  its  defect  is  that  it  easily  oxidizes  or 
tarnishes.  The  7.5  per  cent,  bronze  is  to  be  recom- 
mended as  superior  to  the  5  per  cent. ;  it  has  a 
peculiar  greenish-gold  color,  which  makes  it  very 
suitable  for  decoration.  All  these  good  qualities 
are  possessed  by  the  10  per  cent,  bronze.  It  is 
bright  golden,  keeps  its  polish  in  the  air,  may  be 
easily  engraved,  shows  an  elasticity  much  greater 
than  steel,  and  can  be  soldered  with  hard  solder. 
It  gives  good  castings  of  all  sizes  and  runs  in  sand 
moulds  very  uniformly.  Thin  castings  come  out 
very  sharp,  but  if  a  casting  is  thin  and  suddenly 
thickens,  small  offshoots  must  be  made  at  the 
thick  place  into  which  the  rnetal  can  run  and  then 
soak  back  into  the  casting  as  it  cools  and  shrinks, 
thus  avoiding  cavities  by  shrinkage  at  the  thick 
part.  Its  sp.  gr.  is  7.689,  that  of  soft  iron.  Its 
strength,  when  cast,  is  between  that  of  iron  and 
steel ;  but  when  hammered  it  is  equal  to  best  steel. 
It  may  be  forged  at  about  the  same  heat  as  cast 
steel,  and  then  hammered  until  it  is  almost  cold 


ALLOYS   OF    ALUMINIUM.  269 

without  breaking  or  ripping.  Tempering  makes 
it  soft  and  malleable.  It  does  not  foul  a  file,  and 
may  be  easily  drawn  into  wire.  Any  part  of  a 
machine  which  is  usually  made  of  steel  can  be  re- 
placed by  this  bronze.  As  a  solder  for  it,  Hulot  uses 
an  alloy  of  the  usual  half-and-half  lead-tin  solder 
with  12.5,  25,  or  50  per  cent  of  zinc  amalgam." 

Fremy  :  "  By  the  addition  of  a  small  amount  of 
copper,  aluminium  becomes  hard,  brittle,  and  takes 
a  bluish-white  color.  The  alloy  with  5  per  cent, 
aluminium  is  very  malleable,  but  if  over  10  per 
cent.  Al  is  present  the  alloy  cannot  be  used. 
The  10  per  cent,  bronze  is  now  replacing  ordinary 
bronze  in  the  manufacture  of  articles  which  are  to 
stand  great  resistance,  such  as  axle  bearings, 
weavers'  shuttles,  etc.  Reflectors  are  also  made  of  it, 
for  the  smoke  of  oil,  like  illuminating  gas,  does  not 
tarnish  it.  By  whatever  method  these  bronzes  are 
made,  they  are  at  first  very  brittle,  but  by  a  series 
of  successive  fusions  and  solidifications  they  may  be 
made  to  acquire  the  necessary  solidity  and  tenacity." 

Kerl  and  Stohman :  "Most  of  the  copper-alu- 
minium alloys  are  very  brittle  and  easily  oxidized. 
Only  the  5  to  10  per  cent,  aluminium  alloys  are 
fixed,  forgeable,  tenacious,  and  of  fine  color. 
Alloys  with  much  aluminium  and  little  copper  are 
not  forgeable,  and  are  bluish  or  grayish-white. 
AVith  60  to  70  per  cent,  aluminium  they  are  very 
brittle,  glass  hard,  and  beautifully  crystalline. 

23* 


270  ALUMINIUM. 

With  50  per  cent,  the  alloy  is  quite  soft,  but  under 
30  per  cent,  of  aluminium  the  hardness  returns." 

4  Chemical  News,'  vii.  p.  220,  contains  a  long 
paper  on  testing  aluminium  bronze  (10  per  cent.) 
as  to  its  suitability  for  the  construction  of  astro- 
nomical and  philosophical  instruments,  the  work 
of  an  English  Royal  Engineer.  He  concludes  his 
observations  with  these  words  :  "  It  appears  from 
these  experiments  that  the  10  per  cent,  bronze  is 
far  superior,  not  in  one  or  in  some  but  in  every 
respect,  to  any  metal  hitherto  used  for  these  instru- 
ments. Its  sp.  gr.  is  7.689,  strength  73,185  pounds 
per  square  inch,  to  that  of  gun  metal  35,000  ;  it  is 
malleable  almost  to  its  melting  point,  and  can  be 
soldered  with  either  brass  or  silver  solder.'7 

'  Chemical  News,'  v.  p.  138,  contains  a  number 
of  experiments  on  the  relative  strengths  of  these 
alloys.  The  results  are  as  follows,  the  numbers 
expressing  the  results  being  merely  relative  :— 

Strength. 
Ordinary  gun  metal,  11  per  cent   tin  and 

89  per  cent,  copper    .         .         .         .         .        .10 

Copper,  with  10  per  cent,  aluminium  .        .         .19 
Drawn  copper- wire       ......       7 

Drawn  brass-wire         .         .         .         .         .         .8 

(  Cu      Sn      Al 

I  96        4        0    .         .        .         .4 
Tertiary  alloys  <|  96        4        l  ^        _  w 

(  96        4        2    .        .        .        .16 

Bell  Bros.,  Newcastle,  give  the  specific  gravity 
of  the  aluminium  bronzes  as  being — • 


ALLOYS  OF   ALUMINIUM.  271 

3  per  cent,  aluminium        .        .         .     8.091 

4  "  "  ...     8.621 

5  "  "  ...     8.369 
10       "                 "          ,      .  7.689 

'  Wagner's  Jahresb.'  vol.  x.,  contains  a  long  article 
on  aluminium  bronze,  ten  per  cent.,  most  of  the 
facts  in  which  have  been  already  given.  We  may 
note  that  the  melting-point  of  this  alloy  is  there 
stated  as  about  650°. 

Bernard  S.  Procter,*  after  describing  thirty-one 
experiments  comparing  aluminium  bronze  and 
brass,  sums  up  the  conclusions  as  follows : — 

"  From  the  above  experiments  it  appears  that 
aluminium  bronze  has  a  little  advantage  over  ordi- 
nary brass  in  power  to  withstand  corrosion,  and  its 
surface,  when  tarnished,  is  more  easily  cleaned. 
This  should  give  it  general  preference  where  cost 
of  material  is  not  an  important  consideration,  es- 
pecially if  strength,  lightness,  and  durability  are 
at  the  same  time  desirable.  It  is  out  of  my  power 
to  say  anything  about  its  fitness  for  delicate  ma- 
chinery, except  that  its  chemical  examination  has 
revealed  nothing  which  can  detract  from  the  pre- 
ference its  mechanical  superiority  should  give  it. 
Being  so  much  less  acted  on  by  ammonia  and  coal- 
gas  suggests  its  suitability  for  chemical  scales, 
weights,  scoops,  etc.  Its  resistance  to  the  action  of 
the  weather  and  the  ease  with  which  tarnish  is. 
removed  render  it  especially  applicable  for  door- 

*  Chem.  News,  1861,  vol.  iv.  p.  59. 


272  ALUMINIUM. 

plates,  bell-handles,  etc.  Its  mechanical  strength 
and  chemical  inactivity  together  recommend  it  for 
hinges  exposed  to  the  weather.  In  experiments  18, 
22,  etc.,  the  tendency  of  brass  to  corrode  on  the 
edges  and  at  any  roughness  on  its  surface  will  be 
observed,  while  the  bronze  is  free  from  this  defect. 
In  several  cases  the  bronze  seemed  to  be  more 
quickly  covered  with  a  slight  tarnish  which  did 
not  increase  perceptibly,  probably  the  tarnish  act- 
ing as  a  protection  to  the  metal ;  but  the  brass, 
though  less  rapidly  discolored,  continued  to  be 
corroded  and  apparently  with  increased  speed  as 
the  action  was  continued.  The  bronze  is  more 
easily  cleaned.  For  culinary  vessels  its  superiority 
to  metals  now  in  use  appears  questionable.  Vari- 
ous philosophical  instruments  are  among  the  pur- 
poses for  which  the  use  of  the  bronze  appears 
advantageous.  Undoubtedly,  the  great  obstacle  to 
its  extensive  application  is  its  high  price,  resulting 
partly  from  the  difficulty  of  getting  sufficiently 
pure  copper,  the  presence  of  a  small  amount  of  iron 
being  very  prejudicial."  The  author  states  that  he 
wrote  the  article  with  a  home-made  pen  of  alumin- 
ium bronze,  and  suggests  that  it  is  well  worthy  of 
the  attention  of  pen-makers. 

Thurston*  says:  "The  ten  per  cent,  bronze  has 
a  tenacity  of  about  100,000  pounds,  compressive 
strength  130,000  pounds,  and  its  ductility  and 

*  Materials  for  Engineering. 


ALLOYS   OF    ALUMINIUM.  273 

toughness  are  such  that  it  does  not  even  crack 
when  distorted  by  this  load.  It  is  so  ductile  and 
malleable  that  it  can  be  drawn  down  under  a  ham- 
mer to  the  fineness  of  a  cambric  needle.  It  works 
well,  casts  well,  holds  a  fine  surface  under  the  tool, 
and  when  exposed  to  the  weather  it  is  in  every 
respect  considered  the  best  bronze  yet  known.  Its 
high  cost  alone  has  prevented  its  extensive  use  in 
the  arts.  The  alloys  are  very  uniform  in  character. 
Even  one  per  cent,  of  aluminium  added  to  copper 
causes  a  considerable  increase  in  ductility,  increases 
its  fusibility,  and  enables  it  to  cast  well ;  two  per 
cent,  gives  a  mixture  used  for  castings  which  are 
to  be  worked  with  a  chisel.  It  is  softened  by  sud- 
den cooling  from  a  red  heat.  Its  coefficient  of  ex- 
pansion is  small  at  ordinary  temperatures.  It  has 
great  elasticity  when  made  into  springs." 
Guettier  makes  the  following  remarks : — * 
"  Mr.  Strange's  experiments  in  regard  to  the 
relative  rigidity  of  brass,  ordinary  bronze,  and  alu- 
minium bronze  showed  that  the  latter  was  about 
forty  times  as  rigid  as  soft  brass  and  three  times 
as  rigid  as  ordinary  bronze.  Under  the  tool,  alumin- 
ium bronze  produces  long  and  resisting  chips,  and 
although  not  entirely  unoxidizable,  it  is  not  so 
easily  tarnished  by  air  as  brass,  bronze,  or  steel." 
Knight  :f  "Aluminium  bronze  is  more  difficult 

*  Metallic  Alloys,  by  Guettier. 

f  American  Mechanical  Dictionary. 


274  ALUMINIUM. 

to  cut  than  brass,  but  cuts  very  smooth  and  clean. 
If  less  costly  it  would  replace  red  and  yellow  brass. 
In  contact  with  fatty  matters  or  juice  of  fruit,  no 
soluble  metallic  salt  is  formed,  which  highly  recom- 
mends it  for  various  articles  of  table  use." 

Cowles  Bros.*  thus  describe  the  alloys  of  alumin- 
ium and  copper  which  they  make  :— 

"  In  England  the  Aluminium  Crown  Metal  Co. 
has  for  the  past  three  or  four  years  been  turning 
out  large  quantities  of  aluminium  alloys  based  on 
the  price  of  $14.60  per  pound  for  the  aluminium 
in  them.  Even  at  the  high  prices  charged,  these 
Webster  alloys  have  attained  a  great  popularity, 
and  are  replacing  German  silver,  brass,  bronze,  etc. 
Aluminium  added  to  any  of  the  common  alloys, 
such  as  brass,  German  silver,  or  Britannia  metal, 
adds  greatly  to  all  their  desirable  qualities.  Alu- 
minium bronze  cannot  only  be  used  in  all  places 
where  brass  or  bronze  are  now  used,  but  it  will 
likewise  soon  supersede  iron  and  steel  in  many 
places;  as  for  artillery.  The  maximum  standard 
of  strength  demanded  by  the  British  and  German 
governments  in  their  wrought-steel  guns,  which 
cost  from  50  cents  to  $1  per  pound,  is  at  present 
70,000  pounds  tensile  strength  and  15  per  cent, 
elongation.  These  guns  could  be  cast  of  aluminium 
bronze,  giving  a  greater  strength  and  elongation, 
at  far  less  cost,  being  made  in  one-quarter  of  the 

*  Cowles'  Pamphlet,  April,  1886. 


ALLOYS  OF   ALUMINIUM.  275 

time  and  with  a  comparatively  inexpensive  plant. 
The  melting-point  of  the  bronze  is  somewhat  below 
that  of  copper  and  its  specific  gravity  is  7.23.  It 
is  without  rival  as  an  anti-friction  metal,  besides 
having  the  hardness,  tenacity,  and  wearing  quali- 
ties of  the  best  steel.  It  has  also  the  peculiar 
uiictuousness  of  copper  and  lead,  being  so  strong 
and  tough  that  very  small  quantities  of  the  rolled 
bronze  may  be  used  to  bush  boxes  of  cast  or 
wrought  iron,  so  that  its  first  cost  is  less  than  that 
of  the  thick  masses  of  brass  or  phosphor-bronze 
now  used.  The  five  per  cent,  bronze  makes  beauti- 
ful wearing  plumbers'  goods,  and  can  be  used  also  for 
table  articles,  being  free  from  the  offensive  smell 
and  taste  peculiar  to  brass.  Aluminium  in  almost 
all  proportions  up  to  eight  per  cent,  improves  all 
brasses.  Some  it  makes  more  ductile,  in  others  it 
improves  the  color,  and  all  are  greatly  increased  in 
strength  and  power  to  resist  corrosion.  The  alloy 
copper  67,  zinc  26,  aluminium  7  has  a  strength  of 
96,000  pounds,  while  that  of  copper  67,  zinc  30, 
aluminium  3  has  a  strength  of  65,000  pounds  with 
12  per  cent,  elongation.  When  we  understand 
that  ordinary  brass  rarely  has  a  tensile  strength 
over  30,000  pounds,  the  extraordinary  value  of  the 
aluminium  can  be  appreciated.  The  strength  of 
these  alloys  on  the  testing  machine  is  as  follows  : — 


276  ALUMINIUM. 

Alloy,  Tensile  strength  per     Elongation, 

Al  brass  castings.  sq.  in.,  pounds.  per  cent. 

Al  Cu  Zn 

5.8  67.4  26.8  95,712  1 

3.3  63.3  33.3  85,867  7.6 

3.0  67.0  80.0  67,341  12.5 

1.5  77.5  21.0  32,356  41.7 

1.5  71.0  27.5  41,952  27.0 

1.25  70.0  28.0  35,059  25.0 

2.5  70.0  27.5  40,982  28.0 

1.0  57.0  42.0  68,218  2.0 

1.15  55.8  43.0  69,520  4.0 


Average  commercial  cast  brass     23,000  Less  than  10.0 

"  The  second  alloy  is  made  by  mixing  two  parts 
five  per  cent,  aluminium  bronze  with  one  part  zinc. 

"  The  aluminium  bronzes  gave  the  following 
results : — 

Al  Cu  Tensile  strength,       Elongation  in 

pounds.  per  cent. 

2.5  97.5  42,770  53 
5.0  95.0  68,480  7.8 

6.6  93.4  55,038  80 
7.5  92.5  54,636  16 
7.5  92.5  60,520  22 

91                9  87,783  5 

90  10  108,966 

90  10  99,931  1.5 

90  10  97,103  3.0 

90  10  105,336  7.8 

90  10  110,657  5.4 

16.8  83.2  29,369           (Sp.  gr.  3.23) 

"  The  two  10  per  cent,  bronzes  last  given  were 
plunged  while  red  hot  into  water.  Cowles  Bros. 


ALLOYS   OF   ALUMINIUM.  277 

are  now  selling  10  per  cent,  bronze  at  forty  cents 
per  pound." 

In  regard  to  some  alloys  of  aluminium  and 
copper  in  which  other  metals  are  present,  we  Would 
notice  the  following  alloys  which  have  been  made  in 
addition  to  those  already  incidentally  mentioned. 

Aluminium  can  be  melted  with  brass,  argentan, 
etc.,  by  which  new  bronzes  are  made  of  beautiful 
color,  great  hardness,  and  polish,  unalterable  in  the 
air,  easily  cast,  etc.  One  per  cent,  of  aluminium 
is  sufficient  to  modify  the  qualities  of  brass  or  tin 
bronze,  while  2  per  cent,  shows  a  decided  change. 
By  taking  ordinary  bronze  with  1  to  2  per  cent,  of 
zinc  or  tin,  and  adding  1  to  2  per  cent,  of  alu- 
minium, alloys  are  obtained  possessing  additional 
qualities  to  those  of  aluminium  bronze,  and  which 
can  replace  it  in  places  and  for  purposes  where  the 
latter's  qualities  are  not  so  well  suited. 

Besides  these  simple  alloys  we  have  those  of 
copper  with  nickel,  tin,  zinc,  bismuth,  and  alu- 
minium, in  such  quantities  as  to  make  any  desired 
color  or  degree  of  hardness.  The  following  has  a 
beautiful  white  polish,  which  is  a  close  imitation 
of  silver : — 

Copper .     100 

Nickel 23 

Aluminium 7 

F.  H.  Sauvage  makes  a  metal  resembling  pure 
silver,  which  he  calls  Neogen.     It  contains — 
24 


278  ALUMINIUM. 

Cu  .         .         .         .         .         .         .  58 

Zn  .......  27 

Ni  .......  12 

Sn  .......  2 

Al  ....... 


"  Minargent"  is  a  similar  alloy,  containing  — 

Cu  .......     100 

Ni  .......      70 

Sb  .......        5 

Al  ......         .2 

To  make  this  last  alloy,  the  directions  are  first  to 
melt  together  the  copper,  nickel,  and  antimony, 
and  then  granulate  the  resulting  alloy  in  water. 
The  dried  granules  are  mixed  with  the  aluminium 
and  with  1.5  per  cent,  of  a  flux  consisting  of  2  parts 
horax  and  1  part  fluorspar,  and  then  remelted. 

P.  Baudrin  makes  an  alloy  very  much  resembling 
silver  in  color,  malleability,  ring,  and  even  sp.  gr., 
of  the  following  composition  :  — 

Cu  .......  75 

Ni  .......  16 

Zn  .......  2.25 

Sn  .......  2.75 

Co  .......  2 

Fe  ....  1.5 

Al  .......  0.5 

Jas.  Webster*  patents  the  following  bronze: 
copper  is  melted,  and  aluminium  added  so  as  to 

*  German  Pat.,  11,577. 


ALLOYS   OF   ALUMINIUM.  279 

make  a  10  per  cent,  bronze,  which  is  then  mixed 
with  1  to  6  per  cent,  of  an  alloy  of — 

Cu 20 

Ni 20 

Sn 30 

Al 7 

Thos.  Shaw,  of  Newark,  N.  J.,*  pa  tents  a  phosphor 
aluminium  bronze,  making  the  following  claims: 
First,  an  alloy  of  copper,  aluminium,  and  phos- 
phorus containing  0.83  to  5  per  cent,  of  aluminium, 
0.05  to  1  per  cent,  of  phosphorus,  and  the  remainder 
copper.  Second,  its  manufacture  by  melting  a  bath 
of  copper,  adding  to  it  aluminium  in  the  proportion 
stated,  the  bath  being  covered  with  a  layer  of  palm 
oil  to  prevent  oxidation,  and  then  adding  a  small 
proportion  of  phosphorus. 

Cowles  Bros,  in  their  pamphlet  give  the  follow- 
ing tests  of  the  strength  of  aluminium-silver  cast- 


Tensile  strength,  Elongation, 

pounds.  per  cent. 

5  p.  ct.  Al  broiize,  1  part ;  Ni  2  parts      79,163  33.0 

"          4  parts ;  Ni  1  part    118,000 

German  silver  without  aluminium        44,242  24.0 

"          "      with             "                92,849  1.0 

Solders  for  Al  Bronze. — Cowles  give  the  follow- 
ing jeweller's  solder  for  aluminium  bronze:— 

*  U.  8.  Pat.,  303,236.     Aug.  1884. 


280  ALUMINIUM. 

Hard  solder  for  10  per  cent,  bronze— 

Au      .......     88.88 

Ag      .......      4.68 

Cu       .......       6.44 

Middling  hard  solder  for  10  per  cent,  bronze— 

Au      .......     54.40 

Ag      .......    27.00 

Cu  .     .  .....     18.00 

Soft  solder  for  Al  bronze  — 


Au  ....  14.30 
Ag  ....  57.10 
Cu  ....  14.30 

Silicon  and  Aluminium  Bronze.  —  Cowles  Bros. 
have,  by  reducing  fire  clay  in  presence  of  copper, 
obtained  alloys  of  aluminium,  silicon,  and  copper. 
This  alloy  is  white  and  brittle  if  it  contains  over 
10  per  cent,  of  aluminium  and  silicon  together. 
With  from  2  to  6  per  cent,  of  these  in  equal  pro- 
portions, the  alloy  is  stronger  than  gun  metal,  is 
very  tough,  does  not  oxidize  when  heated  in  the 
air,  and  has  a  fine  color.  Cowles  report  that  a 
silicon-aluminium  bronze  wire  has  shown  a  tensile 
strength  of  200,000  pounds,  a  strength  hitherto 
unprecedented  in  any  metal. 

ALUMINIUM  AND  IRON. 

Tissier  Bros.,  1858  :  "  An  alloy  of  aluminium 
and  iron  with  5  per  cent,  iron  was  made  by 


ALLOYS   OF  ALUMINIUM.  281 

placing  very  fine  iron  wire  with  fragments  of  alu- 
minium in  a  crucible  containing  melted  XaCl. 
Under  these  circumstances  the  iron  could  not  oxi- 
dize, and  the  alloy  was  easily  formed.  We  have 
in  this  way  been  able  to  discover  that  small  quan- 
tities of  iron  give  to  aluminium  the  property  of 
crystallizing,  and  much  impair  its  malleability. 
When  aluminium  has  become  low  in  price,  it  will 
be  interesting  to  see  what  qualities  it  can  com- 
municate to  iron  as  cast  iron  or  steel,  introduced 
in  large  or  small  quantities.  Iron  raises  the  fusing 
point  of  the  aluminium,  for  we  have  melted  alu- 
minium free  from  iron  on  a  plate  of  aluminium 
containing  4  to  5  per  cent.  iron. 

Deville,  1859 :  .  "  Iron  and  aluminium  combine 
in  all  proportions.  These  alloys  are  hard,  brittle, 
and  crystallize  in  long  needles,  when  the  propor- 
tion of  iron  reaches  7  or  8  per  cent.  The  alloy 
containing  10  per  cent,  iron  much  resembles  sul- 
phide of  antimony.  It  liquates,  however,  with 
some  facility,  leaving  a  less  fusible  skeleton,  while 
less  ferruginous  aluminium  runs  down.  But  this 
method  of  purifying  aluminium  is  not  exact.  The 
presence  of  a  large  quantity  of  iron  in  aluminium 
alters  both  its  chemical  and  physical  properties." 

Rogers  :*  "  By  melting  a  steel  high  in  carbon 
with  aluminium,  alloys  of  steel  and  aluminium 
may  be  obtained.  I  have  one  containing  6.4  per 

*  Moniteur  Industrie!,  1859,  No.  2379. 

24* 


282  ALUMINIUM. 

cent,  of  the  latter.  I  melted  67  parts  of  this  alloy 
with  500  of  steel,  so  that  the  resulting  steel  con- 
tained 0.8  per  cent,  aluminium.  This  metal  had 
the  qualities  of  the  best  Bombay  wootz.  A  small 
per  cent,  of  aluminium  makes  steel  hard,  strong, 
and  brittle,  a  larger  quantity  makes  it  very  dense, 
without  impairing  its  peculiar  polish  or  detracting 
from  its  qualities." 

Fremy,  1883:  "Aluminium  unites  with  iron 
with  the  greatest  facility.  To  form  an  alloy  it  is 
sufficient  to  stir  a  rod  of  iron  in  melted  aluminium, 
when  it  covers  itself  with  a  layer  of  aluminium 
and  takes  on  the  aspect  of  being  amalgamated. 
The  alloy  with  5  per  cent,  iron  is  hard,  brittle, 
and  more  difficult  to  fuse  than  aluminium.  The 
7  per  cent,  iron  alloy  possesses  the  same  proper- 
ties, with  a  crystalline  structure.  The  10  per 
cent,  iron  alloy,  according  to  Deville,  resembles 
sulphide  of  antimony,  Sb2S3.  On  the  other  hand, 
M.  Debray  affirms  that  7  to  9  per  cent,  of 
iron  in  aluminium  causes  no  appreciable  change  in 
its  properties.  By  melting  ten  parts  aluminium, 
five  parts  ferric  chloride,  and  twenty  parts  KC1 
and  !NaCl,  Michel  obtained  on  cooling  a  mass 
which,  treated  with  very  dilute  sulphuric  acid, 
left  six-sided  prisms  having  the  color  of  iron  and 
the  formula  Al2Fe,  containing  51  per  cent.  Fe.* 
Calvert  and  Johnson  obtained  the  alloy  Al2Fe3, 

*  Ann.  Cheni.  und  Pharm.  115,  102. 


ALLOYS    OF    ALUMINIUM.  283 

containing  twenty-four  per  cent,  aluminium  and 
seventy-six  per  cent,  iron,  which  was  unalterable 
in  moist  air  (see  p.  210).  The  alloy  AlFe4,  con- 
taining 10.8  per  cent,  aluminium,  has  been  pre- 
pared by  melting  two  parts  aluminium,  five  parts 
sheet  iron,  and  one  part  of  chalk.  It  is  easily 
worked  and  rolled,  but  rusts  on  contact  with  the 
air." 

Mierzinski :  "  A  few  per  cent,  of  aluminium  is 
useful  in  making  cast  steel,  to  which  it  imparts 
greater  hardness  and  a  bright  silver-like  polish ; 
0.8  per  cent,  aluminium  gives  steel  all  the  qualities 
of  best  Bombay  wootz,  and  objects  made  of  it, 
treated  with  dilute  sulphuric  acid,  give  the  undu- 
lating markings  generally  found  only  on  Damascus 
steel.  Stoddart  and  Faraday  found  in  wootz 
steel  0.013  to  0.690  per  cent,  of  aluminium.  An 
alloy  of  24.5  per  cent,  aluminium  is  silver  white, 
extraordinarily  hard,  and  does  not  rust  in  the  air. 

Mitis  castings  :*  "  The  subject  of  the  use  of  alu- 
minium in  wrought-iron  castings  was  discussed  at 
the  meeting  of  the  American  Society  of  Mining 
Engineers,  Pittsburgh  meeting,  on  Feb.  16.  It 
was  described  by  the  inventor,  Mr.  Peter  Ostberg, 
of  Stockholm,  and  as  his  paper  has  not  yet  appeared 
we  give  a  few  particulars  which  may  be  of  interest. 

u  Wrought-iron  scrap  is  melted  in  plumbago 
crucibles  in  a  special  reverberatory  furnace  fired 

*  Eng.  and  Mining  Journal,  Feb.  27,  1886. 


284  ALUMINIUM. 

with  petroleum.  The  crucible  is  covered,  while  a 
'hole  in  a  cover  corresponds  with  and  is  directly 
under  a  hole  in  the  roof  of  the  furnace.  Wrought 
iron  fuses  at  about  4000°  F.,  and  it  would  be  neces- 
sary to  heat  it  far  beyond  its  point  of  fusion  before 
it  would  be  fluid  enough  to  cast  into  line  moulds 
and  to  make  it  possible  to  handle  it  before  it  would 
solidify.  Now  it  is  in  this  superheating  that  the 
iron  absorbs  gases,  and  consequently  it  is  impossible 
to  make  solid  castings  in  this  way.  In  order  to 
obviate  this  difficulty,  Mr.  Ostberg  has  made  use 
of  the  well-known  fact  that  certain  alloys  of  metals 
possess  a  fusing  point  much  less  than  that  of  the 
metals  composing  them,  among  which  aluminium 
alloys  are  very  noticeable.  In  making  w  rough  t- 
iron  or  mitis  castings  a  very  small  quantity  of  alu- 
minium, about  0.05  per  cent.,  is  added  to  the  charge 
in  the  crucible  the  moment  it  has  been  melted. 
The  charge  is  about  sixty  pounds.  The  aluminium 
is  added  in  the  form  of  an  iron-aluminium  alloy 
containing  7  to  8  per  cent,  of  aluminium.  The 
fusing  point  of  the  whole  is  at  once  lowered 
some  500  degrees,  and  the  charge  being  then 
nearly  500  degrees  above  its  new  .fusing  point  be- 
comes extremely  fluid  and  can  be  cast  into  the 
finest  moulds ;  while  the  great  difference  between 
its  temperature  and  its  reduced  fusing  point  gives 
all  the  time  necessary  for  manipulating  it  without 
danger  of  solidifying.  This  extreme  fluidity 
allows  the  ready  escape  of  gases  which  would 


ALLOYS   OF    ALUMINIUM.  285 

otherwise  make  the  casting  porous,  and  the  result 
appears  to  be  a  remarkably  fine,  solid,  and  tough 
casting  of  wrought  iron. 

"  These  mitis  castings  are  said  to  be  30  to 
50  per  cent,  stronger  than  the  iron  from  which 
they  are  made;  but,  although  aluminium  undoubt- 
edly increases  the  strength  of  most  metals  with 
which  it  alloys,  it  is  not  credited  with  the  increase 
of  strength  in  this  case  ;  for  it  is  said  that  after 
hammering,  the  mitis  metal  loses  its  increase  in 
strength  and  returns  to  the  fibrous  appearance  and 
strength  of  the  original  iron. 

"  The  alloys  of  iron  and  steel  with  aluminium 
have  long  been  known,  and  reference  is  made  to 
the  addition  of  such  an  alloy  to  steel  by  Faraday, 
only  a  few  years  after  the  discovery  of  aluminium  ; 
but  this  application  to  wrought  iron  castings 
appears  to  be  new  and  is  certainly  very  interest- 
ing. 

"  The  alloy  used  by  Mr.  Ostberg  at  his  works  in 
"Worcester,  Mass.,  is  made  by  the  Cowles  Electric 
Smelting  Co.,  and  contains  6  to  8  per  cent, 
aluminium  and  1  to  1.25  per  cent,  of  silicon.  It 
costs  about  fort}T  cents  per  pound,  but  as  only  0.05 
per  cent,  aluminium  is  required  in  the  iron, 
the  addition  to  its  cost  is  very  slight.  This  utili- 
zation of  the  well-known  property  of  aluminium 
to  lower  the  fusing  point  of  the  iron  is  a  very  neat 
and  clever  application  of  a  curious  phenomenon, 
and  it  is  said  to  succeed  very  well.  Whether  it. 


286  ALUMINIUM. 

will  also  facilitate  the  making  of  small  steel  cast- 
ings is  not  stated,  but  it  would  probably  in  this 
case  make  the  metal  more  fluid  and  obviate  the 
necessity  of  using  those  extremely  high  heats 
which  are  necessary  to  cause  the  steel  to  melt  and 
run  well  into  the  moulds." 

Mr.  Ostberg  sent  a  note  to  the  '  Engineering  and 
Mining  Journal/  stating  that  he  used  only  a  small 
sample  of  Cowles'  alloys,  but  that  he  uses  almost 
altogether  a  7  to  8  per  cent,  aluminium  alloy, 
made  in  Sweden  by  a  very  simple  and  cheap 
patented  process,  which  consists  in  adding  clays  in 
iron  smelting. 

The  following  note,  bearing  on  this  subject,  is 
from  Watts:  "The  'London  Mining  Journal' 
states  that  if  common  kaolin  is  added  to  iron  when 
being  smelted  in  a  crucible  to  convert  it  into  steel, 
an  improved  product  is  the  result."  Aside  from 
this  note,  the  author  has  been  unable  to  find  any 
reference  to  the  process  suggested  by  Mr.  Ostberg. 

Mr.  Sellers,  of  Philadelphia,  remarked  after  the 
reading  of  Dr.  Hunt's  paper  on  the  Cowles  furnace 
at  the  Washington  meeting  of  the  National  Acad- 
emy of  Sciences,  April,  1886  (see  p.  196),  that  he 
had  made  a  series  of  experiments  on  the  use  of 
aluminium  with  iron  in  casting,  and  obtained 
what  is  technically  called  a  "  dead  melt"  in  two  or 
three  minutes,  instead  of  an  hour  as  required  by 
previous  methods.  The  result  is  very  fine  castings, 


ALLOYS   OF  ALUMINIUM.  287 

and  without  the  flaws  which   so   often  vex  the 
founder. 

A  company  has  been  incorporated  in  New  Jersey 
within  the  last  month  to  regulate  the  use  and  sell 
rights  to  use  Mr.  Ostberg's  patents.  Mr.  Fritz,  of 
the  Bethlehem  Iron  Works,  is  one  of  the  heads  of 
the  company,  which  includes  other  prominent 
Bethlehem  capitalists. 

ALUMINIUM  AND  ZINC. 

Tissier  Bros.,  1858:  "An  alloy  with  10  per 
cent,  aluminium  is  brittle,  has  the  appearance  of 
zinc,  is  more  fusible  than  aluminium,  and  less 
so  than  zinc.  An  alloy  with  25  per  cent, 
aluminium  has  a  tine  even  grain,  and  is  still  more 
fusible  than  aluminium  and  less  so  than  zinc.  An 
alloy  with  50  per  cent,  did  not  appear  to  be 
homogeneous ;  heated  on  an  aluminium  plate  it 
separated  into  a  fusible  portion  and  a  part  which 
did  not  melt  till  the  plate  did.  These  alloys  have 
been  tried  as  solders  for  aluminium,  and  so  far 
have  succeeded  better  than  any  other  alloys,  but, 
unfortunately,  when,  melted  they  are  thick  and 
cast  with  difficulty,  so  much  so  that  it  is  necessary 
to  spread  them  over  the  joint  as  a  plumber  does 
when  he  wipes  the  joints  of  lead  pipes.  Joints 
thus  made  stand  hammer  blows  or  rough  usage 
very  poorly."  • 

Deville,  1859 :     "  The  alloys  of  aluminium  and 


288  ALUMINIUM. 

zinc  are  brittle,  at  least  unless  the  zinc  is  in  small 
proportion.  Several  specimens  of  zinciferous  alu- 
minium were  put  into  commerce  by  a  singular 
accident ;  the  retorts  used  for  making  the  alumin- 
ium were  made  at  the  Vielle  Montague  Zinc  Works, 
and  having  in  their  mixture  some  ground-up  old 
zinc  retorts,  the  new  retorts  contained  zinc,  which 
got  into  the  aluminium  and  altered  its  properties 
in  a  very  evident  manner.  Some  analyses  of  this 
metal  having  been  made  in  England,  some  asserted 
that  French  aluminium  was  only  an  alloy  to  which 
zinc  gave  a  fusibility  which  might  be  wanting  in 
pure  aluminium.  The  alloys  of  zinc  and  alumin- 
ium have  been  used  in  experiments  to  solder  alu- 
minium solidly,  but  so  far  with  little  success. 
Zinc  unites  easily  with  the  aluminium,  altering  its 
properties  when  exceeding  a  few  per  cent." 

Kerl  and  Stohman,  1874  :  "  Zinc  and  alumin- 
ium melted  together  in  atomic  proportions  under 
a  cover  of  Nad  and  KC1  unite  with  incandescence, 
forming  a  silver-white,  very  brittle,  crystalline  alloy, 
with  a  specific  gravity  of  4.532." 

Fremy,  1883:  "The  alloys  of  zinc  and  alu- 
minium are  employed  to  solder  aluminium.  They 
will  take  a  very  fine  polish.  The  alloy  with  three 
per  cent,  zinc  is  yet  malleable,  but  that  with  thirty 
per  cent,  aluminium  is  white,  crystalline,  and  very 
brittle." 


ALLOYS  OF  ALUMINIUM.  289 

ALUMINIUM  AND  TIN. 

Tissier  Bros.,  1858  :  An  alloy  with  3  per  cent, 
tin  is  very  brittle,  a  little  more  fusible  than 
aluminium.  It  was  made  by  combining  the  metals 
under  a  cover  of  NaCl,  then  remelted  alone,  and 
cast.  Its  grain  is  very  fine  and  crossed,  and  it 
breaks  at  the  first  blow  of  the  hammer.  If  tin, 
even  in  small  quantities,  injures  the  qualities  of 
aluminium,  the  latter,  on  the  contrary,  gives  to  tin 
hardness  and  tenacity,  if  it  is  not  present  in  too 
large  an  amount.  The  alloy  with  5  per  cent, 
aluminium  possesses  these  desirable  qualities.  The 
alloy  with  10  per  cent,  is  not  homogeneous,  for  it 
arranges  itself  in  the  ingot  in  two  layers,  an  upper 
brittle  one,  a  little  more  fusible  than  aluminium, 
another  lower  one  containing  nearly  all  the  tin  but 
rendered  harder  and  less  fusible  by  a  small  quan- 
tity of  aluminium.  These  alloj^s  have  been  used 
to  solder  aluminium  because  of  their  fusibility  and 
the  ease  with  which  they  adhere  to  a  clean  surface, 
but  they  have  the  same  inconveniences  as  the  zinc 
solders,  tney  run  thick  and  are  fragile. 

Deville :  Tin  unites  easily  with  aluminium, 
altering  its  properties  as  soon  as  the  proportion 
has  passed  a  few  per  cent.  These  alloys  may  be 
used  to  solder  aluminium,  but  they  answer  imper- 
fectly. 

Kerl  and  Stohman :  The  aluminium-tin  alloys 
with  over  30  per  cent,  of  the  former  are  silver- 

25 


290  ALUMINIUM. 

white,  but  porous  and  brittle.  The  19  per  cent. 
and  especially  the  7  per  cent,  aluminium  alloys 
are,  on  the  contrary,  malleable  and  workable  at  a 
red  heat. 

Fremy :  A  small  quantity  of  tin  renders  alu- 
minium brittle,  but  a  small  percent,  of  aluminium 
alloyed  with  tin  renders  it  harder  and  more  elastic. 
Such  an  alloy,  besides  being  easy  to  work,  may 
advantageously  replace  tin  in  many  of  its  uses. 
The  alloys  most  recommended  are  those  with  5,  7, 
and  19  per  cent,  of  aluminium. 

Mierzinski:  Aluminium  and  tin  unite  in  cer- 
tain proportions,  but  the  tin  will  not  combine  with 
more  than  7  per  cent,  of  aluminium,  for  the  10 
per  cent,  aluminium  alloy  is  no  longer  homogeneous 
but  on  cooling  liquates  away  a  more  fusible  and 
leaves  a  less  fusible  alloy,  the  latter  being  richer 
in  tin.  An  alloy  with  3  per  cent,  aluminium  is 
harder  than  tin  and  less  acted  on  by  acids.  The 
7  per  cent,  aluminium  alloy  is  especially  recom- 
mended as  being  easy  to  work,  capable  of  being 
polished,  but  possessing  the  drawback  that  it  can- 
not be  melted  without  a  part  of  the  tin  separating 
from  the  aluminium. 

M.  Bourbouze,*  a  French  physicist,  employs  an 
alloy  of  aluminium  and  tin  for  the  interior  parts 
of  optical  instruments,  in  place  of  brass.  The 
alloy  contains  9  per  cent,  of  tin.  It  is  white,  like 

*  Iron  Age,  July  29,  1886. 


ALLOYS   OF   ALUMINIUM.  291 

aluminium,  and  has  a  density  of  2.85.  This  light- 
ness is  of  great  advantage.  It  can  be  soldered  as 
easily  as  brass,  without  special  apparatus,  and  is 
more  resistant  to  reagents  than  aluminium.  It 
would  be  very  useful  for  electrical  instruments, 
especially  those  of  a  portable  character. 

ALUMINIUM  AND  LEAD. 

Tissier:  As  Deville  has  remarked,  these  two 
metals  have  such  little  tendency  to  combine  that 
there  may  be  recovered  intact  in  the  bottom  of  an 
ingot  of  aluminium  any  small  pieces  of  lead  which 
may  accidentally  have  got  into  the  metal. 

Deville:  Lead  unites  only  imperfectly  with 
aluminium.  However,  an  alloy  may  exist  in  cer- 
tain proportions,  especially  at  the  temperature 
necessary  to  the  cupellatiou  of  aluminium.  The 
cupellation  of  aluminium  with  lead  is  quite  pos- 
sible. 

Kerl  and  Stohman  :  Aluminium  does  not  unite 
with  lead. 

Mierzinski :  Aluminium  and  lead  do  not  unite. 
By  melting  the  metals  together  and  cooling  down, 
they  are  found  separated  from  each  other,  the 
aluminium  above  and  the  lead  beneath.  This 
property  suggests  the  possibility  of  using  it  to 
separate  silver  from  work  lead,  as  soon  as  its  price 
allows. 


;292  ALUMINIUM. 

ALUMINIUM  AND  ANTIMONY. 

Tissier:  Aluminium  also  appears  to  have  as 
little  tendency  to  unite  with  antimony  as  with 
lead ;  we  did  not  succeed  in  getting  a  homoge- 
neous alloy  of  the  two  metals. 

Kerl  and  Stohman :  Aluminium  does  not  unite 
with  antimony. 

ALUMINIUM  AND  BISMUTH. 

Tissier :  The  combination  of  these  two  metals 
takes  place  easily  and  gives  rise  to  very  fusible 
alloys,  which  oxidize  very  rapidly  when  melted. 
They  are  also  very  alterable  in  the  air  at  ordinary 
temperatures  when  the  bismuth  is  in  large  per 
cent.  However,  these  metals  do  not  appear  able 
to  unite  in  all  proportions,  as  the  following  experi- 
ment seems  to  prove.  We  melted  together  10 
grms.  aluminium  and  20  grms.  bismuth.  The 
combination  took  place  under  NaCl,  and  although 
it  was  stirred  carefully  the  button  appeared  to  be 
of  two  layers,  the  lower  one  composed  of  almost 
pure  bismuth,  and  the  upper  one  more  malleable, 
detachable  from  the  lower  by  a  blow  of  the 
hammer,  and  weighing  13.45  grms.  Supposing 
that  this  latter  contained  all  the  aluminium  (there 
appeared  to  be  none  in  the  other  layer),  then  the 
alloy  was  composed  of  nearly  75  per  cent,  alumin- 
ium and  25  per  cent,  bismuth.  Thus  the  aluminium 
did  not  appear  able  to  take  up  over  25  per  cent,  of 


ALLOYS   OF   ALUMINIUM.  293 

bismuth.  The  alloy  containing  10  per  cent,  bis- 
muth is  hard,  malleable,  takes  a  fine  polish,  is 
unattaoked  by  nitric  acid,  and  not  blackened  by 
sulphuretted  hydrogren.  We  say  it  was  malleable 
because  it  could  be  worked  to  a  certain  extent  under 
the  hammer,  and  we  thought  it  could  be  easily 
drawn  out,  but  in  spite  of  frequent  annealings  it 
split  in  all  directions  and  we  had  to  stop  working 
it.  We  tried,  by  diminishing  the  per  cent,  of 
bismuth,  to  take  away  this  bad  quality,  and  to 
this  end  prepared  alloys  with  5,  3,  2.5,  and  0.5  per 
cent,  of  the  latter,  but  without  obtaining  satisfac- 
tory results. 

Watts  :  One-tenth  of  one  per  cent,  of  bismuth 
renders  aluminium  so  brittle  that  it  cracks  under 
the  hammer  after  being  repeatedly  annealed. 

ALUMINIUM  AND  NICKEL. 

Tissier:  The  alloy  with  50  per  cent,  nickel  was 
made  by  melting  together  the  metals  in  equal  pro- 
portions under  XuCl ;  the  heat  evolved  was  suffi- 
cient to  raise  the  mass  to  incandescence.  This  alloy 
remained  pasty  at  the  temperature  of  melting 
copper.  It  is  so  brittle  that  it  pulverizes  under 
the  hammer.  By  melting  proper  proportions  of 
this  alloy  with  more  aluminium,  an  alloy  with  25 
per  cent,  nickel  was  produced.  This  is  less  fusible 
than  aluminium,  and  as  brittle  as  the  50  per  cent, 
alloy.  By  melting  some  25  per  cent,  nickel  alloy 

25* 


294  ALUMINIUM. 

with  aluminium,  a  5  per  cent,  nickel  alloy  was 
obtained.  This  is  much  less  brittle  than  the  pre- 
ceding, but  is  still  very  far  from  being  easy  to 
work.  From  the  5  per  cent,  alloy  one  with  3  per 
cent,  was  made.  With  this  amount  of  nickel  the 
aluminium  acquired  much  hardness  and  rigidity, 
and  was  easy  to  work.  A  curious  fact  with  this 
alloy  is  that  it  may  be  melted  on  a  plate  of  alu- 
minium, showing  its  fusion  point  to  be  less  than 
that  of  pure  aluminium,  the  reverse  effect  to  what 
iron  produces,  which  if  present  in  the  same  pro- 
portion would  diminish  the  fusibility  of  the 
aluminium.  To  sum  up,  the  action  of  nickel  on 
aluminium  is  much  analogous  to  that  of  iron,  for 
nickel,  like  iron,  produces  crystalline  alloys  with 
aluminium,  and  if  employed  with  care  gives  to  it 
certain  desirable  qualities  such  as  hardness,  elas- 
ticity, etc. 

Mierzinski :  To  alloy  aluminium  with  nickel  a 
certain  limiting  quantity  of  nickel  must  not  be 
exceeded.  When  the  latter  is  present  less  than  3 
per  cent.,  it  behaves  similarly  to  iron  in  improving 
the  qualities  of  the  aluminium  in  many  ways, 
especially  in  hardness  and  elasticity.  More  than 
3  per  cent,  makes  the  aluminium  brittle  and  un- 
workable. 

Argentan  has  a  beautiful  color,  and  takes  a  high 
polish,  it  contains — 

Cu 70 

Ni 23 

Al    .  7 


ALLOYS    OF    ALUMINIUM. 


Minargent  contains — 

Cu  . 

Ni   . 

Sb    .        . 

Al   . 


100 

70 

5 

2 


ALUMINIUM  AND  SILVER. 

Tissier:  Silver  is  the  metal  which  seems  most 
useful  in  improving  aluminium.  Five  per  cent, 
silver  gives  to  aluminium  elasticity  which  is  want- 
ing in  pure  aluminium,  increases  its  hardness  and 
its  capability  of  being  polished,  and  does  not  injure 
its  malleability.  We  have  sold  a  quantity  of  these 
alloys,  the  properties  of  which  we  will  describe. 
All  the  alloys  up  to  50  per.  cent  of  silver  are  more 
fusible  than  aluminium,  the  fusibility  increasing 
with  the  amount  of  silver.  The  alloy  with  33  per 
cent,  silver  is  fusible  enough  to  serve  for  a  solder ; 
but,  like  the  alloys  of  aluminium  with  zinc  and 
tin,  it  casts  with  difficulty  and  makes  a  brittle 
joint.  With  10  per  cent,  silver  the  aluminium 
will  not  stand  under  the  hammer.  The  50  per 
cent,  alloy  breaks  like  those  of  copper.  The  pres- 
ence of  silver  in  aluminium  can  always  be  recog- 
nized by  the  action  of  the  alloy  on  a  moderately 
concentrated  solution  of  caustic  potash.  Alumin- 
ium whitens  in  this  solution,  but,  if  it  contains 
silver,  this  being  exposed  by  the  dissolving  away 
of  the  aluminium  gives  the  surface  a  black  color. 
By  introducing  5  per  cent,  of  aluminium  into  silver 


296  ALUMINIUM. 

the  latter  acquires  the  hardness  of  silver  coin,  the 
alloy  takes  a  beautiful  polish,  does  not  contain  as 
alterable  a  metal  as  copper,  and  contains  95  per 
cent,  of  silver  instead  of  90.  This  alloy  is  easily 
distinguished  from  the  alloy  into  which  copper 
enters  by  the  test  with  nitric  acid,  which  whitens 
instead  of  blackening  it. 

Deville:  A  few  per  cent,  of  silver  will  take 
away  from  aluminium  all  its  malleability.  How- 
ever, the  alloy  with  3  per  cent,  is  used  by  M. 
Christofle  for  casting  objects  of  art ;  and  the  alloy 
with  5  per  cent,  to  make  knife  blades,  and  it  may 
be  worked  like  pure  aluminium.  It  has,  moreover, 
the  color  and  lustre  of  silver,  and  is  not  tarnished 
by  sulphuretted  hydrogen. 

Kerl  and  Stohman :  According  to  Hirzel,  the 
alloy  containing  20  per  cent,  aluminium  is  very 
porous,  silver-white,  tarnishing  in  the  air,  sp.  gr. 
6.733.  AlAg2,  containing  11.11  per  cent,  alumin- 
ium is  also  silver-white,  a  little  porous,  tarnishes 
in  the  air,  sp.  gr.  8.744.  AlAg4,  containing  5.9  per 
cent,  aluminium  is  pure  silver-white,  very  malle- 
able, forgeable,  tarnishing  in  the  air,  sp.  gr.  9.376. 

Fremy  :  The  alloys  of  aluminium  and  silver  are 
easy  to  form  by  direct  fusion  of  the  two  metals ; 
their  hardness  is  generally  superior  to  that  of 
aluminium,  but,  nevertheless,  they  are  quite  as  easy 
to  work,  and  in  some  cases  more  fusible  than  it. 
Debray  states  that  the  50  per  cent,  alloy  is  as  hard 
as  bronze. 


ALLOYS   OF   ALUMINIUM.  297 

Mierzinski  :  Five  per  cent,  of  silver  makes  alu- 
minium elastic  and  as  hard  as  coin  silver,  but  not 
brittle.  Tbis  alloy  is  workable  like  pure  alumin- 
ium, takes  a  fine  polisb,  is  light,  not  magnetic, 
does  not  rust,  and  has  the  color  of  pure  silver, 
whose  place  it  can  take  for  many  purposes.  How- 
ever, the  assertion  that  this  or  any  other  alloy  of 
silver  and  aluminium  is  not  attacked  by  hydrogen 
sulphide  is  incorrect  and  untenable,  since,  according 
to  careful  experiments,  these  alloys  are  attacked 
quicker  and  more  actively  by  it  than  pure  silver. 
This  alloy  is  used  for  watch-springs,  dessert-spoons, 
etc.,  on  account  of  its  hardness  and  elasticity.  The 
alloy  with  3  per  cent,  silver  has  a  very  fine  silver 
color.  The  50  per  cent,  alloy  is  as  hard  as  bronze, 
but  so  brittle  that  it  cannot  be  pressed ;  all  the 
alloys  with  over  10  per  cent,  silver  up  to  the  50  per 
cent,  alloy  are  brittle  and  cannot  be  worked  with  a 
hammer. 

"  Tiers  Argent"  is  an  alloy  of  two-thirds  alumin- 
ium and  one-third  silver,  which  was  made  homo- 
geneous at  first  with  some  difficulty  but  is  now 
easily  made.  Spoons,  forks,  and  salvers  of  this 
alloy  leave  nothing  to  be  desired.  It  possesses  a 
hardness  superior  to  silver,  and  can  be  easily  en- 
graved.* 

Cowles  Bros,  state  that  what  is  generally  known 
and  sold  as  aluminium  silver  is  an  alloy  of  alu- 

*  Cbem.  News,  xvi.  289. 


298  ALUMINIUM. 

minium,  nickel,  and  copper;  or,  in  effect,  it  is  alu- 
minium added  to  German  silver.  The  great 
advantage  of  this  metal  is  that  it  will  keep  its 
beautiful  white  lustre  for  all  time,  and  permits  of 
objects  being  made  from  it  in  an  enduring  and  sub- 
stantial manner.  It  requires  no  plating  of  any  kind. 

ALUMINIUM  AND  GOLD. 

Tissier  :  Aluminium  endures  a  large  quantity  of 
gold  without  its  ductility  being  impaired.  We  have 
prepared  an  alloy  with  10  per  cent,  of  gold  which 
works  at  a  red  heat  as  well  as  aluminium,  is  a  little 
harder  but  scarcely  polishes  any  better  than  it.  Its 
color,  for  some  cause,  is  darkish  brown,  like  that 
of  tin  lightly  sulphurized.  The  alloy  containing 
15  per  cent,  gold  can  no  longer  be  forged.  As  to 
the  effect  of  small  quantities  of  aluminium  on  gold, 
5  per  cent,  of  it  gives  to  the  latter  a  white  color 
and  makes  it  brittle  as  glass. 

Fremy  :  The  alloy  with  one  percent,  aluminium 
possesses  the  color  of  "  green  gold  ;"  it  is  very  hard 
but  yet  malleable.  The  alloy  with  10  per  cent, 
aluminium  is  white,  crystalline,  and  brittle;  the 
alloy  with  5  per  cent,  is  brittle  as  glass. 

Mierzinski :  Aluminium  can  take  up  as  much  as 
10  per  cent,  of  gold  without  its  malleability  de- 
creasing. This  alloy  can  be  forged,  but  not  well 
polished.  The  color  of  the  gold  has  entirely  dis- 
appeared, seeming  to  have  no  effect  on  the  alumin- 
ium. 


ALLOYS  OF  ALUMINIUM.  299 

ALUMINIUM  AND  PLATINUM. 

Tissier :  Aluminium  unites  with  platinum  with 
great  ease,  forming  with  it  alloys  more  or  less  fusi- 
ble according  to  the  proportions  of  aluminium. 
Five  per  cent,  of  platinum  makes  an  alloy  not  mal- 
leable enough  to  be  worked  ;  it  is  probable  that  by 
diminishing  the  amount  of  platinum  a  suitable 
alloy  might  be  produced.  In  color  it  approaches 
that  of  gold  containing  5  per  cent  of  silver. 

ALUMINIUM  AND  CADMIUM. 

Deville :  Cadmium  unites  easily  with  alumin- 
ium. The  alloys  are  all  malleable  and  fusible,  and 
may  be  used  to  solder  aluminium,  though  imper- 
fectly. 

ALUMINIUM  AND  BORON. 

Deville:  "By  melting  aluminium  with  borax, 
boracic  acid,  or  fluo-borate  of  potassa,  an  alloy 
very  rich  in  boron  was  obtained.  This  alloy,  like 
siliceous  aluminium,  possesses  the  singular  prop- 
erty that  the  boron  diminishes  all  its  useful  qualities. 
The  alloy  is  very  white,  only  able  to  bear  slight 
bending,  and  tears  under  the  rolls.  It  exhales  a 
very  strong  odor  of  hydrogen  silicide,  SiH4,  with- 
out doubt  due  to  the  silica  of  the  vessel  which  was 
attacked  at  the  same  time  as  the  borax.  M. 


300  ALUMINIUM. 

Wohler  and  I  have  shown  that  the  boron  may  be 
extracted  from  this  alloy  in  two  different  forms, 
the  graphitoidal  and  the  diamantine  boron."  De- 
ville  gives  at  the  end  of  his  volume  on  aluminium 
the  mode  of  preparation  of  this  diamantine  boron. 

ALUMINIUM  AND  CARBON. 

Deville :  I  was  not  able,  by  any  effort  I  made, 
to  combine  carbon  with  aluminium.  On  decom- 
posing carbon  tetrachloride,  CC14,  by  aluminium, 
there  is  formed  ordinary  carbon,  while  the  alumin- 
ium which  remains  has  undergone  no  change. 

Cowles:  Specimens  of  alloys  of  aluminium  and 
carbon,  yellow  and  crystalline,  have  been  exhibited, 
which  were  made  in  the  Cowles  furnace.  (See 
p.  195.) 

ALUMINIUM  AND  GALLIUM. 

Watts :  Lecoq  de  Boisbaudran  makes  the  fol- 
lowing remarks :  "  If  the  proportion  of  aluminium 
is  to  be  considerable,  the  two  metals  are  melted 
together  at  dull  redness.  The  alloys  thus  obtained 
remain  brilliant,  arid  do  not  sensibly  absorb  the 
oxygen  of  the  air  in  their  preparation.  After 
cooling  they  are  solid  but  brittle,  even  when  the 
excess  of  aluminium  has  raised  the  melting  point 
to  incipient  redness.  They  decompose  water  iu 
the  cold,  but  better  at  40°,  with  rise  of  tempera- 


ALLOYS   OF   ALUMINIUM.  301 

ture,  evolution  of  hydrogen,  and  formation  of  a 
chocolate-brown  powder,  which  is  ultimately  re- 
solved into  white  flakes  of  alumina." 


ALUMINIUM  AND  TITANIUM. 

"Wohler*  fused  in  a  clay  crucible  10  grms.  of 
titanic  acid,  30  grms.  cryolite,  15  grms.  each  of 
Nad  and  KC1,  and  5  grms.  of  aluminium.  This 
was  kept  at  the  melting  point  of  silver  for  one 
hour  and  then  opened.  The  aluminium  had 
become  lammelar,  and  when  dissolved  in  caustic 
soda  left  a  quantity  of  brilliant,  crystalline  plates, 
found  to  be  a  compound  of  aluminium,  titanium, 
and  silicon.  The  elements  of  the  compound  appear 
to  be  able  to  unite  in  various  proportions.  Its 
density  was  3.3.  It  was  infusible  before  the  blow- 
pipe, but  heated  to  redness  in  chlorine  it  burnt, 
giving  chlorides  of  the  three  metals  present. 
Another  experiment,  heated  only  to  the  melting 
point  of  nickel,  gave  a  white  compound  richer  in 
silicon,  sp.  gr.  2.7. 

Alloysf  of  aluminium  with  wolfram,  molybde- 
num, and  manganese  were  made  by  Michel  in 
Wohler's  laboratory,  on  which  the  following  report 
is  made : — 

*  Chcm.  News,  1860,  p.  310. 
t  Ibid. 
26 


302  ALUMINIUM. 

ALUMINIUM  AND  TUNGSTEN. 

A14W  was  made  by  fusing  together  15  grms. 
tungstic  acid,  30  grms.  cryolite,  15  grms.  each  of 
KC1  and  ]N"aCl,  and  15  grms.  aluminium,  at  a  strong 
red  heat.  The  excess  of  aluminium  was  removed 
from  the  regulus  by  HC1.  The  alloy  is  an  iron- 
gray  powder,  crystalline,  single  crystals  were 
several  millimetres  long,  brittle  and  hard  rhombic 
prisms.  Sp.  gr.  5.58.  Hot  caustic  soda  extracts 
all  the  aluminium  from  these  crystals,  leaving 
behind  pure  tungsten. 

ALUMINIUM  AND  MOLYBDENUM. 

Molybdic  acetate  is  dissolved  in  hydrofluoric 
acid,  the  solution  evaporated  to  dry  ness,  and  the 
.residue  mixed  with  cryolite,  flux,  and  alumin- 
ium, in  the  same  proportions  as  given  for  tungsten. 
Excess  of  aluminium  is  dissolved  from  the  product 
with  caustic  soda,  and  there  remains  a  black, 
crystalline  powder  consisting  of  iron-gray  rhombic 
prisms,  soluble  in  hot  nitric  or  hydrochloric  acid, 
and  consisting  entirely  of  aluminium  and  molyb- 
denum. 

ALUMINIUM  AND  MANGANESE. 

We  fused  together  10  grms.  anhydrous  manganese 
chloride,  15  grms.  each  of  KC1  and  NaCl,  and  15 


ALLOYS   OF   ALUMINIUM.  303 

grms.  aluminium.  The  excess  of  aluminium  was 
removed  by  HC1.  There  remained  a  dark-gray, 
crystalline  powder  consisting  of  square  prisms,  spe- 
cific gravity  3.4.  Dilute  caustic  soda  extracts  all 
the  aluminium  from  these,  leaving  the  manganese. 

ALUMINIUM  AND  SODIUM. 

Deville :  Aluminium  unites  easily  with  sodium, 
especially  in  small  proportions.  From  this  it  fol- 
lows that  the  properties  of  the  metal  made  care- 
lessly by  using  sodium  are  completely  altered. 
The  last  traces  of  sodium  can  be  removed  only  with 
great  trouble,  especially  when  the  aluminium  has 
been  produced  in  presence  of  fluorides,  because  of 
the  marked  affinity  of  aluminium  for  fluorine  at 
the  temperature  at  which  aluminium  fluoride, 
A12F6,  commences  to  volatilize. 

Fremy:  Aluminium  easily  combines  with  so- 
dium. If  the  combination  contains  2  per  cent,  of 
sodium,  it  easily  decomposes  water,  which  circum- 
stance gave  cause  to  the  notable  loss  of  aluminium 
when  it  was  first  being  manufactured. 

ALUMINIUM  AND  NITROGEN. 

Dr.  Hunt,*  in  reading  a  paper  on  the  Cowles 
furnace  (see  p.  196),  showed  a  specimen  of  a  pecu- 
liar alloy  believed  to  consist  entirely  of  aluminium 
and  nitrogen. 

*  Washington  Meeting,  Nat.  Acad.  Sciences,  April,  1886. 


APPENDIX. 


NATIVE  SULPHATE  OF  ALUMINA. 

IN  the  summer  of  1884,  a  large  deposit  of  rock  called 
"  native  alum"  was  discovered  on  the  Gila  River,  Sorocco 
Co.,  New  Mexico,  about  two  miles  below  the  fork  of  the 
Little  Gila  and  four  miles  below  the  Gila  Hot  Springs. 
The  deposit  is  said  to  extend  over  an  area  one  mile  square 
and  to  be  very  thick  in  places.  The  greater  part  of  the 
mineral  is  impure,  as  is  usual  with  native  occurrences,  but 
it  is  thought  that  large  quantities  are  available.  A  com- 
pany formed  in  Sorocco  has  taken  up  the  alum-bearing 
ground.  Through  the  kindness  of  Mr.  W.  B.  Spear,  of 
Philadelphia,  I  was  enabled  to  get  a  specimen  of  it. 

It  is  white,  with  a  yellowish  tinge.  On  examining 
closely  it  is  seen  to  consist  of  layers  of  white,  pure-looking 
material  arranged  with  a  fibrous  appearance  at  right 
angles  to  the  lamination.  These  layers  are  about  one- 
quarter  of  an  inch  thick.  Separating  them  are  thin  layers 
of  a  material  which  is  deeper  yellow,  harder  and  more 
compact.  The  whole  lump  breaks  easily  and  has  a  strong 
alum  taste.  On  investigation,  the  fibrous  material  was 
found  to  be  hydrated  sulphate  of  alumina,  the  harder 
material  sulphate  of  lime. 

It  is  probable  that  this  deposit  was  the  bed  of  a  shallow 
26* 


306  APPENDIX. 

lake  in  which  the  alum-bearing  water  from  the  hot  springs 
concentrated  and  deposited  the  sulphate  of  alumina. 
Periodically,  or  during  freshets,  the  Little  Gila,  flowing 
through  a  limestone  country,  bore  into  this  lake  water 
containing  lime,  which,  meeting  the  A12(S04)3  solution, 
immediately  caused  a  deposit  of  CaSO*.  When  the  dry 
season  came,  the  Little  Gila  dried  up,  the  deposit  of  alum 
was  made,  and  thus  were  formed  the  succession  of  layers 
through  the  deposit. 

Analysis  showed  7  to  8  per  cent,  insoluble  material, 
and  the  remainder  A12(SO4)3.18H2O.  A  small  amount  of 
iron  was  present. 

DECOMPOSITION  OF  CRYOLITE. 

According  to  a  patent  given  to  F.  Lauterborn  (see  p. 
206),  cryolite  can  be  decomposed  by  boiling  with  water  ; 
sodium  fluoride  going  into  solution  arid  aluminium  fluor- 
ide remaining  as  residue. 

To  test  the  accuracy  of  this  statement,  I  boiled  250 
grms.  of  the  mineral  in  5  litres  of  water  for  3  hours.  The 
solution  was  filtered  hot  and  evaporated  to  dryness. 
There  was  no  residue.  The  material  on  the  filter  ap- 
peared to  be  undecomposed  cryolite. 

The  experiment  does  not  prove  that  the  decomposition 
is  impossible,  but  makes  it  appear  extremely  improbable. 


AMERICAN  ALUMINIUM. 

I  bought  some  of  Mr.  Frishmuth's  aluminium  from 
Bullock  &  Crenshaw,  Philadelphia.  The  surface  was 
slightly  whitened  by  oxidation,  resembling,  though  not 


GRAVITY   OF   ALUMINIUM.  307 

to  such  a  degree,  the  oxidation  which  takes  place  on  slabs 
of  zinc  when  exposed  to  the  air.  The  wire  was  not  per- 
fectly smooth,  being  at  places  slightly  rough  and  scaly. 
It  was  quite  soft  and  malleable.  Its  color  was  nearly  white, 
but  with  a  slight  blue  tinge,  which,  if  intensified,  would 
have  made  it  resemble  zinc  more  than  any  other  metal. 
Duplicate  analyses  of  it  gave  me  the  following  results : — 

Si 0.65  0.56 

Fe 1.94  1.87 

Al  (by  diff.)   .        .        .     97.41  97.57 

After  making  these  analyses,  I  came  across  the  analysis 
of  Mr.  Frishmuth's  metal  given  on  p.  53. 

SPECIFIC  GRAVITY  OF  ALUMINIUM. 

The  sp.  gr.  of  the  metal  whose  analysis  was  just  given 
I  determined  very  accurately  on  a  Becker  balance.  Com- 
pared with  water  at  4°  C.,  it  was  2.735.  I  wished  to  see 
if  this  would  correspond  to  the  sp.  gr.  calculated  from  the 
analysis.  The  data  were  as  follows  : — 


Si  . 
Fe  . 
Al  . 

Calculated  sp.  gr 2.757 

The  correspondence  being  so  close  has  suggested  that 
the  sp.  gr.  of  commercial  aluminium,  carefully  taken,  gives 
the  approximate  amount  of  iron  present ;  for  the  sp.  gr. 
of  silicon  is  so  near  to  that  of  aluminium,  that  10  per 
cent,  of  the  former,  an  amount  never  found  in  commercial 
aluminium  at  present,  would  only  affect  the  sp.  gr.  0.03. 


Average 
sp.  gr. 
2.34 

Average  per 
cent,  present. 
0.60 

Products. 
0.014 

7.7 

1.80 

0.138 

2.67 

97.60 

2.605 

308  APPENDIX. 

So  then,  within  the  limits  usually  found  in  commercial 
aluminium,  i.  e.,  silicon  less  than  5  per  cent,  and  iron 
anywhere  less  than  10  per  cent.,  a  careful  determination 
of  the  sp.  gr.  should,  hy  a  little  calculation,  give  the  amount 
of  iron  present  within  a  limit  of  error  of  0.5  per  cent,  at 
most,  thus  saving  a  wet  determination  of  iron. 

AMALGAMATION  OF  ALUMINIUM. 

Wishing  to  observe  the  effect  of  mercury  on  metallic 
aluminium,  I  took  a  clean,  bright  piece  of  aluminium  foil 
of  Mr.  Frishmuth's  make,  and  put  on  it  a  small  globule 
of  mercury,  which  I  rubbed  in  with  the  finger.  Almost 
immediately  a  white  powder  appeared  and  the  foil  felt 
warm  from  the  heat  generated.  On  brushing  away  this 
powder,  the  foil  underneath  appeared  white  and  unattacked. 
By  letting  the  mercury  remain  on  the  foil,  it  very  soon 
eat  a  hole  through  it.  Compare  with  p.  261. 

It  thus  appears  that  mercury  unites  with  a  clean  sur- 
face of  aluminium,  forming  an  amalgam,  and  the  alumin- 
ium in  the  amalgam  oxidizes  in  the  air  to  alumina.  The 
question  arises,  why  does  aluminium  oxidize  so  easily  ? 
We  know  how  the  properties  of  this  metal  depend  much 
on  its  state  of  division  ;  its  foil  will  burn  in  the  air,  where- 
as the  metal  in  bulk  will  not.  The  mercury  serves,  as  it 
amalgamates  the  aluminium,  to  draw  apart  even  the  mole- 
cules of  the  metal,  and  so  this  extremely  minute,  even 
molecular  division  of  the  aluminium  permits  it  to  exhibit 
in  an  intensified  degree  the  principle  just  stated,  which 
was  illustrated  by  the  burning  of  the  foil,  t.  e.,  the  finer  its 
state  of  division  the  more  easily  is  it  acted  on  by  oxidiz- 
ing agents.  Translating  this  into  the  language  of  chemi- 
cal affinities,  in  metallic  aluminium  the  atoms  are  united 


AbUMINIUM   SULPHIDE.  309 

two  by  two  by  a  mutual  exchange  of  affinities,  and  the 
oxygen  of  the  air  is  not  able  to  break  this  molecular  bond 
at  ordinary  temperatures.  But  by  the  intervention  of 
the  mercury  this  bond  is  broken,  and  the  atoms  of  alu- 
minium become  united  with  atoms  of  mercury,  which 
weakens  the  bond  holding  the  molecule  together.  The 
strong  affinity  which  oxygen  has  for  aluminium  is  now 
able  to  break  up  the  new  molecule,  the  metal  is  rapidly 
oxidized  and  the  mercury  set  free. 

REDUCTION  OF  ALUMINA. 

I  experimented  on  reducing  alumina  by  carbon  in  pres- 
ence of  copper.  (See  p.  213.)  I  took  for  a  charge — 

40  grms CuO  and  Cu. 

5     "  .        .        .        .     A12O3. 

5     "  .        .        .        .     Charcoal. 

These  were  intimately  mixed  and  finely  powdered,  put  in  a 
white-clay  crucible  and  covered  with  cryolite.  The  whole 
was  slowly  heated  to  bright  redness,  and  kept  there  for  two 
hours.  A  bright  button  was  found  at  the  bottom  of  the 
crucible.  This  button  was  of  the  same  sp.  gr.  as  pure 
copper,  and  a  qualitative  test  showed  no  trace  of  aluminium 
in  it. 

This  is  the  same  result  that  other  experimenters  have 
reached,  and  the  conclusion  seems  to  be  that  the  process 
gives  no  practical  results. 

PRODUCTION  AND  REDUCTION  OF  ALUMINIUM 
SULPHIDE,  AL2S3. 

Until  the  reseai  ches  of  M.  Fremy,  no  other  method  of 
producing  A12S3  was  known  save  by  acting  on  the  metal 


310  APPENDIX. 

with  sulphur  at  a  very  high  heat.  Fremy  was  the  first 
to  open  up  this  new  field,  and  it  may  be  that  his  discover- 
ies will  yet  be  the  basis  of  successful  industrial  processes. 
Fremy  is  often  quoted  in  connection  with  APS3,  and  in 
order  to  understand  just  how  much  he  discovered  we  here 
give  all  that  his  original  paper  contains  concerning  this 
sulphide.* 

"  We  know  that  sulphur  has  no  action  on  silica,  boric 
oxide,  magnesia,  or  alumina.  I  thought  that  it  might  be 
possible  to  replace  the  oxygen  by  sulphur  if  I  introduced 
or  intervened  a  second  affinity,  as  that  of  carbon  for 
oxygen.  These  decompositions  produced  by  two  affinities 
are  very  frequent  in  chemistry,  it  is  thus  that  carbon  and 
chlorine,  by  acting  simultaneously  on  silica  or  alumina, 
produce  silicon  or  aluminium  chloride,  while  either  alone 
could  not  decompose  it ;  a  similar  case  is  the  decomposi- 
tion of  chromic  oxide  by  carbon  bisulphide,  producing 
chromium  sesquisulphide.  Reflecting  on  these  relations, 
I  thought  that  carbon  bisulphide  ought  to  act  at  a  high 
heat  on  silica,  magnesia,  and  alumina,  producing  easily 
their  sulphides.  Experiment  has  confirmed  this  view.  I 
have  been  able  to  obtain  in  this  way  almost  all  the  sul- 
phides which  until  then  had  been  produced  only  by  the 
action  of  sulphur  on  the  metals. 

"  To  facilitate  the  reaction  and  to  protect  the  sulphide 
from  the  decomposing  action  of  the  alkalies  contained  in 
the  porcelain  tube  which  was  used,  I  found  it  sometimes 
useful  to  mix  the  oxides  with  carbon  and  to  form  the  mix- 
ture into  bullets  resembling  those  employed  in  the  prepa- 
ration of  APC16.  I  ordinarily  placed  the  bullets  in  little 

*  Ann.  de  Chem.  et  de  Phys.  [3]  xxxviii.  312. 


ALUMINIUM   SULPHIDE.  311 

carbon  boats,  and  heated  the  tube  to  whiteness  in  the 
current  of  vaporized  carbon  bisulphide.  The  presence  of 
divided  carbon  does  not  appear  useful  in  the  preparation 
)hide. 

.12S3  formed  is  not  volatile;  it  remains  in  the  car- 
bon boats  and  presents  the  appearance  of  a  melted  vitre- 
ous mass.  On  contact  with  water  it  is  immediately  de- 
composed. 

Al2S3-f3H2O=Al2O3+3H2S. 

"  The  alumina  is  precipitated,  no  part  of  it  going  into 
solution.  This  precipitated  AFO3  is  immediately  soluble 
in  weak  acids.  The  clear  solution,  evaporated  to  dryness, 
gives  no  trace  of  alumina.  It  is  on  this  phenomenon  that 
I  base  a  method  of  analysis  as  will  be  seen  below. 

"Analysis  of  the  product.  A12S3  being  non-volatile,  it 
is  always  mixed  with  some  undecomposed  alumina.  It  is, 
in  fact,  impossible  to  entirely  transform  all  the  alumina 
into  A12S3.  I  have  heated  less  than  a  gramme  of  alumina 
to  redness  five  or  six  hours  in  carbon  bisulphide  vapor, 
and  the  product  was  always  a  mixture  of  Al2O3and  A12S3. 
The  reason  is  that  the  sulphide  being  non-volatile  and  fusi- 
ble coats  over  the  alumina  and  prevents  its  further  decompo- 
sition. The  A12O3  thus  mixed  with  the  A12SS,  and  which 
has  been  exposed  to  a  red  heat  for  a  long  time,  is  very 
hard,  scratches  glass,  and  is  in  grains  which  are  entirely 
insoluble  in  acids.  By  reason  of  this  property  I  have 
been  able  to  analyze  the  product  exactly,  for  on  treating 
the  product  with  water  and  determining  on  the  one  hand 
the  sulphuretted  hydrogen  evolved,  and  on  the  other  the 
quantity  of  soluble  alumina  resulting,  I  have  determined 
the  two  elements  of  the  compound.  One  gramme  of  my 


312  APPENDIX. 

product  contained  0.365  grm.  of  A12S3,  or  36.5  per  cent., 
the  remainder  being  undecomposed  alumina."  The  com- 
position of  this  APS3  was — 

Al  0.137  grm.  =  37.5  per 

S  ...     0.228     "      =  62.5       " 

0.365      "         100.0       " 
The  formula  APS3  requires — 

Al 36.3  per  cent. 

8 63.7       " 

The  above  is  the  substance  of  Fremy's  remarks  on 
APS3.  The  next  investigation  in  this  field  was  made  by 
Reichel.  His  paper  is  on  the  sulphides  of  magnesium  and 
aluminium  and  he  proceeded  in  methods  so  similar  with 
both  metals  that  he  sometimes  describes  a  process  only  for 
magnesium  sulphide,  MgS,  with  details,  and  merely  states 
his  results  in  working  the  same  way  for  APS3,  which  will 
account  for  the  frequent  allusion  in  his  paper  to  MgS. 
The  paper  is  very  lengthy,  but  only  what  bears  directly  on 
the  subject  in  hand  is  extracted. 

"  I  wished*  to  obtain  more  definite  knowledge  of  MgS 
and  APS3,  and  I  also  had  a  practical  end  in  view  ;  for, 
depending  on  the  small  affinity  of  sulphur  for  magnesium 
and  aluminium,  I  hoped,  if  not  to  isolate  them  from  the 
sulphide,  at  least  to  try  the  possibilities  of  this  method." 
(As  preliminary,  Reichel  here  gives  extended  remarks  on 
the  behavior  of  aluminium  and  magnesium  towards  sul- 
phur, and  a  description  of  the  sulphides.) 

"  APS3  appears  yellow,  at  least  that  made  from  the 
metal  and  sulphur  with  exclusion  of  air  always  has  this 

*  Jrnl.  fr.  Prak.  Chem.  xi  .  55. 


ALUMINIUM   SULPHIDE.  313 

color.     It  is  only  by  heating  the  metal  with  sulphur  vapor 
with  admittance  of  air  that  the  product  is  of  a  darker 


experiments  to  determine  if  the  preparation 
MgS  was  not  possible  in  the  same  way  as 
K2S,  Na2S,  and  BaS  are  made.  For  example,  by  melting 
potassium  oxide  with  sulphur  some  K2S  is  formed.  How- 
ever, on  doing  this  with  alumina  and  magnesia,  it  became 
evident  that  magnesium  and  aluminium  have  less  affinity 
for  sulphur  than  for  oxygen,  and  the  experiment  failed* 
But,  matters  were  changed  when  a  reducing  agent  was 
introduced  with  the  sulphur.  If  a  mixture  of  carbon, 
magnesia,  and  sulphur  are  heated,  MgS  results,  which  by 
treating  the  product  with  water  goes  into  solution  un- 
changed. Alumina  under  similar  treatment  gave  no 
APS3.  In  place  of  carbon  as  a  reducing  agent  I  next 
used  hydrogen.  By  igniting  magnesia  in  a  stream  of 
hydrogen  and  sulphur  vapor  some  little  MgS  was  formed, 
but  the  mass  of  the  magnesia  was  unchanged.  The  next 
step  was  to  substitute  sulphuretted  hydrogen  for  hydrogen 
and  sulphur  separately,  but  only  a  little  MgS  was  formed 
in  this  way. 

"  Since  the  sulphates  of  calcium  and  barium  are  reduced 
to  sulphides  with  very  little  trouble,  it  appeared  probable 
that  magnesium  sulphate,  MgSO4,  should  be  convertible 
into  MgS  by  a  reducing  agent.  The  attempts  to  do  this 
were  unsuccessful.  I  heated  MgSO4  in  vapor  of  ammon- 
ium sulphide,  but  it  underwent  no  change.  Since  accord- 
ing to  Stammer*  K2SO,  CaSO4,  and  BaSO4  may  be  re- 
duced to  sulphides  by  carbonic  oxide,  CO,  I  tried  to 

*  Pogg.  Ixxxii.  135. 
27 


314  APPENDIX. 

reduce  MgSO4   by  this  means.     The  following  reaction 
apparently  took  place-  — 

MgSO4+  4CO=MgO+COS,  +  3CO2.^^^ 

"  I  then  took  pure  magnesia,  filled  a  porcelain  tube 
with  it,  and  passed  carbon  bisulphide  vapor  througnrt. 
The  apparatus  was  first  filled  with  hydrogen,  then  as  soon 
as  the  tube  was  bright  red  the  carbon  bisulphide  flask  was 
warmed,  and  sulphuretted  hydrogen  and  carbonic  oxide 
began  to  issue  from  the  tube.  The  heating  was  continued 
till  carbon  bisulphide  condensed  in  the  outlet  tube,  then 
the  fire  was  removed  and  hydrogen  passed  through  the 
tube  till  it  was  cold.  The  MgS  resulting  was  of  a  gray 
color,  not  melted,  but  as  a  crumbly  powder.  The  reaction 
which  took  place  was  probably 

MgO+  2CS2-f-6H=MgS  +  3H'S-|-CO+  C. 

"  The  carbon  was  left  with  the  MgS;  and,  to  get  rid  of 
it  I  heated  the  tube  up  as  before  but  passed  hydrogen  and 
carbonic  oxide  through,  when  the  hydrogen  took  up  the 
carbon  forming  probably  some  hydrocarbon. 

"  Than*  says  that  carbon  oxysulphide,  COS,  is  formed 
by  leading  carbonic  oxide  and  sulphur  vapor  through  a 
red-hot  tube.  The  reactions  made  to  take  place  are 


=3COS. 

"  The  product  obtained  thus  contained  58  per  cent. 
MgS  and  42  per  cent,  undecomposed  magnesia.  In  act- 
ing on  alumina  in  the  same  way,  the  product  obtained  is 
a  mixture  of  APS3  and  aluhiina." 

*  Jahresb.  der  Chein.,  1867,  155. 


ALUMINIUM  SULPHIDE.  315 

Reichel  next  tried  the  different  methods  which  have 
been  proposed  to  reduce  these  sulphides  to  metal,  and 
thus  records  his  results  (see  p.  183)  : — 

"  Petitjean*  patented  a  process  in  England  for  reducing 
APS3  by  hydrogen  acting  at  a  high  temperature,  or  by 
melting  it  with  iron  filings.  MgS,  heated  a  long  time 
in  a  current  of  hydrogen,  remained  unchanged.  I  mixed 
MgS  with  iron  filings,  put  it  in  a  porcelain  crucible, 
covered  with  fresh,  dry,  fine  NaCl,  and  filled  the  crucible 
to  the  rim  with  carbon.  To  keep  out  all  oxygen,  I  put 
the  crucible  inside  a  larger  Hessian  crucible,  filling  in 
between  with  pulverized  charcoal.  After  heating  several 
hours  in  a  wind  furnace,  I  found  a  half-sintered  mass 
under  the  NaCl.  This  material,  on  being  boiled  with 
water,  evolved  no  trace  of  hydrogen  sulphide  but  only 
pure  hydrogen.  This  showed  that  the  iron  had  taken  the 
sulphur  from  the  MgS.  Still,  I  did  not  succeed  in  ex- 
tracting the  free  magnesium  from  it  by  amalgamation. 
In  the  same  manner,  A12S3  appeared  to  be  decomposed  by 
iron  and  heat,  but  it  was  also  impossible  in  this  case  to 
separate  the  metallic  aluminium  out  of  the  mass.  Copper 
effects  the  reduction  as  well  as  iron,  forming  CuS. 

"  Since  magnesium  is  not  sulphurized  on  ignition  in  a 
current  of  hydrogen  sulphide,  it  appeared  probable  that 
MgS  might  be  reduced  by  ignition  in  a  stream  of  hydrogen. 
I  first  tried  a  current  of  illuminating  gas,  well  dried  and 
freed  from  hydrogen  sulphide  by  a  potash  tube.  In  spite 
of  long  ignition,  the  MgS  was  unaltered.  Then  I  tried 
hydrogen,  but  that  also  was  unsuccessful,  the  MgS  would 
not  give  up  its  sulphur  to  hydrogen  at  a  bright  red  heat. 
Since  hydrogen  alone  does  not  act  on  MgS,  it  is  hardly 

*  Dingier,  148,  371. 


316  APPENDIX. 

to  be  expected  that  a  hydrocarbon  can  remove  any  sulphur 
from  it. 

"  To  find  how  carbonic  oxide  acted  towards  MgS,  I  ig- 
nited the  latter  in  a  stream  of  this  gas.  The  magnesium 
sulphide  used  contained  56.5  per  cent,  sulphur  and  33.0 
per  cent,  magnesium,  or  12.47  per  cent,  more  sulphur 
than  the  formula  MgS  allows.  Under  these  circumstances 
COS  was  evolved,  recognized  by  forming  barium  sulphide 
and  sulphate,  when  led  into  baryta  water.  As  soon  as 
these  gases  ceased  coming  off,  I  cooled  the  tube  in  a  current 
of  carbonic  oxide.  The  material  had  retained  its  former 
color  and  still  readily  evolved  hydrogen  sulphide  in  moist 
air  or  water.  But  it  had  lost  12.23  per  cent,  of  its  weight. 
The  gas,  it  appears,  had  united  only  with  the  sulphur  in 
excess  of  that  required  to  form  MgS,  and  the  polysulphide 
was  thus  changed  to  the  monosulphide." 

Reichel  makes  the  following  summary: — 

"  The  above  researches  show  that  magnesium  and  alu- 
minium can  unite  with  sulphur  directly  at  a  high  temper- 
ature. Also,  that  MgS  and  Mg2OS  will  be  formed  when 
magnesia  is  similarly  treated.  Alumina  is  unattacked  by 
sulphur.  Alumina  and  magnesia  are  changed  by  ignition 
in  carbon  bisulphide  to  sulphides.  When  carbon  bisulphide 
and  oxide  act  on  magnesia,  Mg2OS  remains  ;  alumina  is  un- 
changed. Magnesia  is  changed  by  ignition  in  hydrogen 
sulphide  to  MgS,  but  the  operation  is  tedious  and  imper- 
fect. By  melting  the  oxides  with  sulphur  no  sulphides  can 
be  obtained  ;  with  alumina  the  contemporaneous  action  of 
a  reducing  agent  is  necessary,  while  magnesia  melted  with 
carbon  and  sulphur  or  heated  in  hydrogen  and  sulphur 
vapor  becomes  MgS. 

"  APS3  possesses  a  yellow  color,  is  with  difficulty  fusi- 


ALUMINIUM  SULPHIDE.  317 

ble,  but  fuses  to  a  hard  crystalline  mass.  Usually  it  is 
obtained  as  a  sintered  yellow  powder.  In  damp  air  or 
water  the  following  reaction  takes  place: — 

APS3+6H2O==A12(OH)6  +  3H2S. 

"  It  burns  in  the  air  to  alumina  and  sulphur  dioxide. 
MgS  forms  a  polysulphide,  as  we  have  seen,  but  APS3  does 
not. 

"  Also,  APS3  and  MgS  appear  to  be  reduced  at  a  high 
heat  by  metals  which  have  a  greater  affinity  for  sulphur, 
yet  it  remains  to  be  seen  whether  this  property  is  techni- 
cally valuable." 

Leaving  these  two  experimenters,  Fremy  and  Reichel, 
we  have  very  few  allusions  to  the  subject.  Those  who 
have  proposed  to  produce  aluminium  from  APS3  state 
merely  that  they  use  Fremy 's  process  for  preparing  the 
APS3. 

We  have  found  an  article*  in  which  it  is  proposed  to  pass 
vapor  of  carbon  bisulphide  and  hydrochloric  acid  together 
over  ignited  alumina,  APS3  being  formed  as  an  intermedi- 
ate product ,  and  APC16  ultimately  formed  by  the  action  of 
the  acid.  The  writer  states  that  by  passing  the  first  alone 
over  the  ignited  alumina  the  gas  evolved  is  mostly  COS, 
though  a  portion  of  it  is  decomposed  to  sulphur  and  car- 
bonic oxide.  He  further  states  that  APS3  is  only  slightly 
acted  on  by  sodium  chloride,  is  unaffected  by  calcium  or 
magnesium  chlorides,  slightly  acted  on  by  potassium  chlor- 
ide, but  readily  chloridized  by  hydrochloric  acid. 

F.  Lauterborn  (see  p.  206)  claims  in  a  patented  process 
that  by  calcining  aluminium  fluoride  with  calcium  sulphide 

*  Chem.  News,  Dec.  19,  1873. 
27* 


318  APPENDIX. 

APS3  results.  I  cannot  find  any  corroboration  of  this 
statement. 

Mr.  Niewerth's  process  for  reducing  aluminium,  in  which 
he  either  uses  APS3  or  else  makes  it  as  an  intermediate 
product,  will  be  found  in  full  on  p.  185,  it  being  too  long 
to  repeat  here.  I  cannot  find  any  outside  testimony  as  to 
the  possibility  of  his  schemes. 

Reichel  has  probably  proven  the  possibility  of  reducing 
APS3  by  a  metal  having  more  affinity  for  sulphur.  From 
a  chemical  standpoint  its  reduction  by  copper,  iron,  etc., 
should  be  under  the  proper  conditions  a  very  easy  opera- 
tion. These  conclusions  follow  from  the  relative  affinity 
of  sulphur  for  the  metals,  which  is  set  forth  in  the  follow- 
ing investigation  : — 

"  A.  Orlowsky*  has  studied  the  affinity  of  sulphur 
for  the  metals.  From  his  researches  it  was  found  that 
it  usually  possesses  the  greatest  affinity  for  the  alkaline 
metals,  with  which  it  forms  polysulphides.  Among  the 
other  metals,  copper  possesses  the  greatest  affinity  for  sul- 
phur, then  follow  in  order  mercury,  silver,  iron,  lead,  and 
after  these  platinum,  chromium,  aluminium,  and  magne- 
sium, whose  affinities  for  sulphur  are  quite  insignificant." 

EXPERIMENTS  ON  AL2S3. 

Taking  the  data  given  in  the  foregoing  papers,  I  made 
a  series  of  experiments  on  first  making  APS3  and  then 
on  reducing  it. 

Experiment  L 

Took  pure,  white  alumina,  made  by  calcining  pure  sul- 

*  Jahresb.  der  Chemie,  1881,  p.  24. 


ALUMINIUM   SULPHIDE.  319 

phate  of  alumina,  put  it  in  porcelain  boats  in  a  hard  glass 
tube,  and  passed  vapor  of  carbon  bisulphide,  CS2,  over  it 
at  bright  redness  for  forty-five  minutes.  The  product  was 
cooled  out  of  contact  with  the  air.  The  result  was  a  gray- 
ish-black powder,  not  sintered  together  in  the  least.  On 
analyzing  the  product  by  Fremy's  method,  it  showed  12.65 
per  cent,  of  A12S3. 

Experiment  II. 

Took  equal  parts  of  alumina,  sulphur,  and  charcoal, 
ground  intimately  together  in  a  mortar,  and  served  as  in 
Experiment  I,  prolonging  the  action  of  CS2  to  an  hour  and 
a  half.  The  product  was  a  grayish-black  powder,  similar 
in  appearance  to  the  former  product.  It  contained  38.51 
per  cent.  APS3. 

Experiment  III. 

Repeated  Experiment  I,  but  used  a  porcelain  tube,  thus 
allowing  a  higher  heat  than  the  glass  tube  would  stand. 
The  treatment  lasted  an  hour  and  a  half.  The  product 
was  of  similar  appearance  to  the  previous  ones,  and  con- 
tained 39.54  per  cent.  Ai2S3. 

Experiment  IV. 

I  placed  some  ordinary  aluminium  sulphate,  A12(SO4)3.- 
18H2O,  in  the  porcelain  tube,  and  heated  it  gradually  up 
to  bright  redness  with  the  tube  open  at  both  ends,  cal- 
cining it  thus  for  two  hours.  The  result  was  that  the  tube 
was  filled  with  very  porous  alumina.  CS2  was  then  passed 
over  it  for  two  hours,  the  whole  being  kept  at  redness. 
The  product  was  dirty-white,  but  lemon-yellow  in  places, 
and  at  the  yellow  parts  sintered  together,  Analyzing  an 


320  APPENDIX. 

average  specimen,  it  showed  31.16  per  cent,  APS3.  It  is 
probable  that  if  a  yellow  piece  had  been  singled  out  it 
would  have  shown  much 'more  APS3  than  this  average 
sample. 

Experiment  V. 

I  placed  some  pure  alumina  in  small  hollows  cut  in 
pieces  of  charcoal,  and  placed  these  in  the  tube  instead  of 
the  porcelain  boats.  The  tube  was  then  placed  in  an 
assay  furnace  and  heated  almost  to  whiteness  for  an  hour 
and  half,  CS2  being  passed  through.  The  product  was 
small,  black,  fused  buttons  melted  down  into  the  bottoms 
of  the  cavities  in  the  charcoal.  These  lumps  were  black 
outside,  brittle,  compact  fracture,  and  the  broken  surfaces 
mottled,  dirty-white,  and  yellow.  They  had  a  strong  smell 
of  hydrogen  sulphide,  and  when  dropped  into  water  this 
gas  was  evolved  so  actively  as  to  make  quite  a  buzz,  resem- 
bling the  action  of  a  piece  of  zinc  dropped  into  acid.  In 
one  or  two  minutes  the  button  was  resolved  into  a  black 
powrder.  This  product  contained  40.43  per  cent.  APS3. 

Experiment  VI. 

Repeated  Experiment  V,  but  used  porcelain  boats.  The 
product  was  still  dark,  and  contained  38.80  per  cent.  APS3. 

Experiment  VII. 

Wishing  to  make  a  quantity  of  the  substance,  I  filled 
the  tube  with  alumina,  put  it  in  a  hot  fire,  and  passed  CS2 
over  it  three  hours.  The  product  was  grayish-black,  with 
here  and  there  touches  of  yellow,  with  lumps  of  consider- 
able size  sintered  together.  An  average  sample  of  it  con- 
tained 32.32  per  cent.  APS3. 


ALUMINIUM   SULPHIDE.  321 

Tabulating  these  results  we  have — 

Experiment        I.          II.         III.        IV.         V.          VI.       VII. 
Al*S3(p.ct.)    12.65    38.51    39.54    31.16    40.43    33.80    32.32 

First  I  would  notice  that,  as  remarked  by  Fremy,  the 
APS3  formed  incloses  the  particles  of  alumina  and  prevents 
further  action.  It  seems  highly  probable  that  a  stirring 
apparatus  to  keep  the  alumina  agitated  would  greatly  im- 
prove the  product.  Experiment  I  gave  poor  results  because 
the  heat  was  not  sufficient ;  Experiment  II  was  done  at  a 
higher  heat,  with  addition  of  carbon,  and  Experiment  III 
at  a  still  higher  heat,  without  carbon.  It  appears  from 
this  that  the  presence  of  carbon  had  very  little  influence 
on  the  amount  of  A12S3  produced.  Experiment  V,  giving 
the  best  results,  was  worked,  I  think,  at  a  higher  heat  than 
any  of  the  others  ;  but  Experiment  VI  was  conducted 
under  as  nearly  as  possible  the  same  conditions  ;  however, 
we  may  consider  the  products  as  being  nearly  enough 
alike,  the  carbon  does  not  appear  to  have  made  a  marked 
difference  in  the  product. 

To  establish  such  a  process  on  a  practical  scale,  a 
wrought-iron  or  fire-clay  retort  would  be  necessary,  with 
arrangements  to  heat  it  almost  to  whiteness.  Boats  of 
charcoal,  holding  ample  charges  of  alumina,  are  made  to 
fit  in  the  retort.  Some  sort  of  stirring  apparatus  to  agi- 
tate the  alumina  from  time  to  time  should  be  provided. 
The  CS2  could  be  brought  in  superheated  by  waste  heat 
from  the  furnace  and  passed  out  into  a  condenser.  Or,  to 
economize  still  further,  the  retort  might  be  lengthened,  its 
forepart  made  a  producer  of  CS2,  by  passing  sulphur  vapor 
over  carbon,  and  the  rear  part  be  filled  with  the  alumina  to 
utilize  this  CS2.  Many  other  devices  will  occur  to  the 


322  APPENDIX. 

practical  chemist  in  running  such  a  process,  the  above 
being  mere  suggestions. 

REDUCING  THE  AL2S3. 

Experiment  VIII. 

I  took  about  half  a  gramme  of  product  of  VII,  and 
wrapping  it  tightly  in  lead-foil  placed  it  on  a  cupel  and 
heated  in  a  muffle.  Air  was  kept  from  the  metal  by  a 
close-fitting  porcelain  cover.  On  removing  the  lid  after  a 
few  minutes,  there  appeared  a  button  of  lead  with  some 
powder  on  its  surface.  I  then  cupelled  the  lead  at  as 
low  a  temperature  as  possible.  The  metal  cupelled  away 
entirely,  leaving  no  aluminium.  On  repeating  with  every 
precaution  the  result  was  the  same. 

Experiment  IX. 

About  one  gramme  of  product  VII  was  wrapped  in 
copper  foil,  put  in  a  porcelain  crucible,  and  covered  with 
NaCl  and  a  little  charcoal.  A  close  cover  was  put  on, 
the  whole  placed  in  the  middle  of  a  Hessian  crucible,  the 
latter  filled  up  with  fine  charcoal,  and  a  cover  luted  on. 
On  heating  this  an  hour  at  bright  redness,  hardly  white- 
ness, there  resulted  a  large  button  of  copper.  However,  its 
specific  gravity  was  that  of  pure  copper,  and  a  qualitative 
test  showed  no  trace  of  aluminium.  It  occurs  to  me  now 
that  probably  the  NaCl  reacted  on  the  APS3,  forming  alu- 
minium chloride  and  sodium  sulphide,  preventing  the 
action  of  the  copper. 

Experiment  X. 

Repeated  Experiment  IX  with  tinfoil,  and  heating  only 
twenty  minutes.  The  tin  resulting  showed  some  alumin- 


ALUMINIUM  SULPHIDE.  323 

him  on  a  qualitative  test,  and  on  analyzing  it  I  found  0.52 
per  cent.  Considering  the  small  amount  of  sulphide  and 
the  rather  large  amount  of  tin  used,  it  is  probable  that 
nearly  all  the  aluminium  present  as  APS3  was  reduced. 

Experiment  XL 

Repeated  the  same,  but  using  powdered  antimony  to 
mix  with  the  APS3.  The  resulting  button  was  pure  anti- 
mony with  no  aluminium  in  it. 

Experiment  XII. 

Repeated  the  experiment,  employing  fine  iron  filings  and 
using  a  high  heat  for  one  and  a  half  hours.  The  product 
was  a  loose  mass  in  which  were  small  buttons  of  metal. 
These  buttons  were  bright,  yellower  than  iron,  and  con- 
tained 9.66  per  cent,  aluminium. 

Lack  of  time  and  opportunity  prevented  my  extending 
these  experiments  on  reduction.  I  had  intended  trying 
copper  filings,  zinc  filings,  mercury — excluding  air  by 
using  a  vacuum  or  an  atmosphere  of  hydrogen — or  its  re- 
duction by  hydrogen  gas. 

On  reviewing  the  experiments  reported  above,  those  with 
tin  and  iron  succeeded  best.  Knowing  the  great  affinity 
of  copper  for  sulphur,  I  cannot  but  think  that  an  experi- 
ment with  very  fine  copper  filings  intimately  mixed  with 
the  APS3  would  give  satisfactory  results. 

In  closing  I  would  remark  that  a  process  such  as  sug- 
gested on  p.  321  could  be  easily  arranged  on  a  large  scale, 
the  undecomposed  CS2  being  caught  and  so  no  more  of  it 
used  than  is  necessary  to  supply  sulphur  for  the  A12S3. 
The  product  could  be  mixed  with  fine  metallic  filings, 'put 
into  a  crucible,  surrounded  by  charcoal,  and  the  alloy 


324  ADDENDA. 

made.  The  metal  changed  to  sulphide  could  be  recovered 
by  reducing  the  slags.  These  processes  have  been  covered 
by  patents,  but  have  never  been  made  successful.  It  ap- 
pears that  if  rightly  managed  they  will  give  good  results 
and  produce  aluminium  alloys  cheaply. 


ADDENDA. 

ADDITIONAL  DETAILS  OF  CASTNER'S  SODIUM 
PROCESS. 

"  In  the  ordinary  sodium  process,*  lime  is  added  to  the 
reducing  mixture  to  make  the  mass  refractory,  otherwise 
the  alkali  would  fuse  when  the  charge  is  highly  heated, 
and  separate  from  the  light,  infusible  carbon.  The  carbon 
must  be  in  the  proportion  to  the  sodium  carbonate  as  four 
is  to  nine,  as  is  found  needful  in  practice,  so  as  to  assure 
each  particle  of  soda  in  the  refractory  charge  having  an 
excess  of  carbon  directly  adjacent  or  in  actual  contact. 
Notwithstanding  the  well-known  fact  that  sodium  is 
reduced  from  its  oxides  at  a  degree  of  heat  but  slightly 
exceeding  the  reducing  point  of  zinc  oxide,  the  heat 
necessary  to  accomplish  reduction  by  this  process  and  to 
obtain  even  one-third  of  the  metal  in  the  charge,  closely 
approaches  the  melting  point  of  wrought  iron. 

**  In  my  process,  the  reducing  substance,  owing  to  its 
composition  and  gravity,  remains  below  the  surface  of  the 
molten  salt,  and  is,  therefore,  in  direct  contact  with  the 

*  Journal  of  the  Franklin  Institute,  Nov.  1886. 


325 

fused  alkali.  The  metallic  coke  of  iron  and  carbon  con- 
tains about  30  per  cent,  carbon  and  70  per  cent,  iron, 
equivalent  to  the  formula  FeC2.  I  prefer  to  use  caustic 
soda,  on  account  of  its  fusibility,  and  mix  with  it  such 
quantity  of  so-called  '  carbide'  that  the  carbon  contained 
in  the  mixture  shall  not  be  in  excess  of  the  amount  theo- 
retically required  by  the  following  reaction  : — 

SXaOH  +  FeC2  =  3Na  +  Fe  +  CO+  CO2  +  3H  ; 

or,  to  every  100  pounds  of  pure  caustic  soda,  seventy- 
five  pounds  of  *  carbide,'  containing  about  twenty-two 
pounds  of  carbon. 

"  The  necessary  cover  for  the  crucible  is  fixed  station- 
ary in  each  chamber,  and  from  this  cover  a  tube  projects 
into  the  condenser  outside  the  furnace.  The  edges  of  the 
cover  are  convex,  those  of  the  crucible  concave,  so  that 
when  the  crucible  is  raised  into  position  and  held  there 
the  tight  joint  thus  made  prevents  all  leaking  of  gas  or 
vapor.  Gas  is  used  as  fuel,  arid  the  reduction  begins 
towards  1000°  C.  As  the  charge  is  fused,  the  alkali  and 
reducing  material  are  in  direct  contact,  and  this  fact, 
together  with  the  aid  rendered  the  carbon  by  the  fine 
iron,  in  withdrawing  oxygen  from  the  soda,  explains  \vliy 
the  reduction  is  accomplished  at  a  moderate  temperature. 
Furthermore,  by  reducing  from  a  fused  mass,  in  which 
the  reducing  agent  remains  in  suspension,  the  operation 
can  be  carried  on  in  crucibles  of  large  diameter,  the 
reduction  taking  place  at  the  edges  of  the  mass,  where 
the  heat  is  greatest,  the  charge  flowing  thereto  from  the 
the  centre  to  take  the  place  of  that  reduced. 

"  I  am  enabled  to  obtain  fully  ninety  per  cent,  of  the 
metal  in  the  charge,  instead  of  thirty  per  cent,  as  formerly. 
28 


326  ADDENDA. 

The  crucibles,  after  treatment,  contain  a  little  carbonate 
of  soda,  and  all  the  iron  of  the  '  carbide'  still  in  a  fine 
state  of  division,  together  with  a  small  percentage  of.  car- 
bon. These  residues  are  treated  with  warm  water,  the 
solution  evaporated  to  recover  the  carbonate  of  soda,  while 
the  fine  iron  is  dried,  and  used"  over  again  for  '  carbide."' 

NEW  PROCESS  FOR  MAKING  ALUMINIUM  CHLORIDE. 

Mr.  Cha's.  F.  Mabery  has  patented  and  assigned  to 
Cowles  Bros,  a  new  process  for  making  anhydrous  alu- 
minium chloride.  The  patent  was  granted  Oct.  26,  1886. 
The  first  claim  is  for  producing  it  by  passing  chlorine  gas 
over  an  alloy  of  aluminium  and  some  other  metal  kept  in 
a  closed  vessel  at  a  temperature  sufficient  to  volatilize  the 
APC16  formed,  which  is  caught  in  a  condenser.  The 
second  claim  is  for  passing  hydrochloric  acid  gas  through 
the  electric  furnace  in  which  alumina  is  being  decomposed 
by  carbon,  a  condenser  being  attached  as  before. 

REMARKS  ON  THE  MITIS  CASTINGS. 

Mr.  W.  H.  Wahl,  Secretary  of  the  Franklin  Institute, 
Phila.,  makes  the  following  remark  on  this  subject: — * 

"  The  simplicity  of  this  process,  the  certainty  with 
which  it  can  be  operated,  the  uniformity  of  the  product, 
and  its  good  qualities  in  respect  to  strength  and  ductility, 
indicate  an  extended  field  of  usefulness  for  it.  The  mitis 
castings  threaten  to  seriously  incommode  the  manufac- 
turers of  malleable  castings,  for  which  they  not  only  offer 

*  Journal  of  the  Institute,  Nov.  1886. 


PRODUCTION   OF   ALUMINIUM.  327 

a  perfect  substitute,  but  one  which,  in  respect  to  strength 
and  ductility,  is  distinctly  superior,  while  for  many  pur- 
poses mitis  castings  can  be  employed  for  which  malleable 
castings  could  not  be  made.  The  mitis  process  has  also 
been  applied  to  the  production  of  steel  castings,  and  with 
promising  results.  In  one  of  the  methods  experimentally 
tested,  the  sheet  castings  were  from  wrought  iron  scrap 
as  raw  material,  with  the  addition  of  the  proper  propor- 
tion of  cast  iron  to  bring  the  percentage  of  carbon  to  the 
point  required  for  each  special  purpose." 

PRODUCTION  OF  ALUMINIUM. 

From  advance  proof-sheets  of  vol.  iii.  'Mineral  Re- 
sources of  the  United  States,'  we  learn*  that  the  produc- 
tion of  metallic  aluminium  in  the  United  States  increased 
from  1800  troy  ounces  in  1884  to  3400  ounces  in  1885, 
valued  at  $2550.  Aluminium  bronze,  ten  per  cent.,  was 
made  to  the  amount  of  about  4500  pounds,  valued  at 
$1800. 

In  October,  1886,  a  Philadelphia  instrument  maker 
accepted  the  offer,  from  the  maker,  of  a  large  amount  of 
European  aluminium  at  the  price  of  50  cents  per  ounce, 
the  lowest  at  which  aluminium  has  yet  been  sold. 

*  Sci.  Am.,  Nov.  13,  1886. 


INDEX. 


Academy,    Paris,   patronage    of,  i  Alloys  of  aluminium  and  mer- 


towardfi  Deville,  32 
Acetic  acid,  action  of,  on   alu- 
minium, 78 

Acid,  acetic,  action  of,  on  alu- 
minium, 78 
hydrochloric,  action   of,  on 

aluminium,  75 
muriatic,  action  of,  on  alu- 
minium. ?."> 

nitric,    action    of,    on    alu- 
minium, ~~) 

sulphuric,  action  of,  on  alu- 
minium, 74: 

tartaric,  action   of,  on   alu- 
minium, 78 

Acids,  organic,  action  of,  on  alu- 
minium, 78 
Air.   action   of,   on    aluminium, 

70 

Albite,  formula  of,  43 
Alkalies,  caustic,  action  of,  on 

aluminium,  77 
Alkaline  carbonates,  action   of, 

on  aluminium,  88 
Alloys,    aluminium,   made    by 

Cowh's  Bros.,  205 
of  aluminium,  258-303 
and  antimony.  21'2 
and  bismuth'  292 
and  boron,  1199 
and  cadmium,  299 
and  carbon.  Moo 
and  copjXT,  204: 
and  gallium,  300 
and  gold. 
and  iron,  280 
,       and  lead, -J'. > L 
and  mangan 


cury,  201 
and  molybdenum,  302 
and  nickel,  293 
and  nitrogen,  303 
and  platinum,  299 
and  silicon,  259 
and  silver,  295 
and  sodium,  303 
and  tin,  289 
and  titanum,  301 
and  tungsten,  302 
and  zinc,  287 
with  steel,  281 
of  brass  and  aluminium.  276 
of  German   silver  and  alu- 
minium, 277 

Alumina,   composition    of,   pre- 
cipitated, 105 

crucibles,  use  of,  for  obtain- 
ing aluminium,  228 
in  purifying  alumin- 
ium, 243 
extracted  from  alum  stone 

or  shale,  153 
manufacture  of,  144-153 
manufactured  from  cryolite, 


28* 


dry  way,  14/> 

wet  way,  152 

precipitation  of,  by  carbonic 

acid  gas,  149 
reduction  of,  by  carbon  in 

presence  of  copper,  309 
sulphate  of,  Tilghman's  pro- 
cess for  decomposing,  144 
Aluminate  of  soda  crucibles,  use 
of,   in    purifying  alu- 
minium. 24:?' 


330 


INDEX. 


Aluminate  of  soda  precipitation 

by  Lovvig,  151 
precipitation  of,  at  Sal- 

indres,  159,  103 
Aluminite,  formula  of,  44 
Aluminium,  alloys  of,  258-303 
amalgam,  properties  of,  263 
bronze,  solders  for,  279 
chemical  properties  of,   70- 

89 
Crown  Metal  Co.'s,  173 

makers  of  alumin- 
ium bronze,  274 
crucibles,  use  of,  for  obtain- 
ing aluminium,  228 
history  of,  25-42 
manufacture    at    Salindres 

(Gard),  158-171 
metallurgy  of,  90-257 
occurrence  in  nature,  43-50 
physical  properties  of,  51-70 
plate  as  a  substitute  for  tin 

plate,  247 
protoxide,  26 
reduction  of,  by  other  agents 

than  sodium,  180 
silver,  297 
sodium,   double  chloride, 

making  of,  154-157 
uses  of,  243-247 
working  in,  235-257 
Alum-shale,  use  of,  for  making 

alumina,  153 
Alum-stone,  use  of,  for  making 

alumina,  153 

Alums,  native,  impurities  in,  45 
Alunite,  formula  of,  44 
Amalgam,   potassium,    used    in 

isolating  aluminium,  25 
Amalgamation    of    aluminium, 

261,  308 

Wohler's  efforts,  25 
American  aluminium,  306 
Co.,  Detroit,  221     , 
price  of,  1883-84,  39 
cryolite,  48 

Amfreville-la-mi-Voie,     alumin- 
ium works  at,  29,  33 
process  used  at,  124 
Ammonia,   aqua,  action   of,   on 

aluminium,  78 
Analyses  of  beauxite,  46 


Analyses  of  commercial  alumi- 
nium, 51,  52 
of  Mr.   Frishmuth's   metal, 

307 
Analysis  of  aluminium  sulphide, 

311 

of  Bombay  Wootz  for  alu- 
minium, 283 
Animal   matters,   action  of,   on 

aluminium,  87 
Animals,  aluminium  never  found 

in,  44 

Annealing  of  aluminium,  58 
Anorthite,  formula  of,  43 
Antimony,  alloys  of  aluminium 

with,  292 

reduction  of  aluminium  sul- 
phide by,  323 

Argentan,  a  serviceable  alloy,  294 
Artistic  purposes,  use  of  alumin- 
ium for,  245 

Balance  beams,  special  value  of 

aluminium  for,  35 
Barattes  for    precipitating   alu- 
mina, 163 
Barium,  alloys  with  aluminium, 

87 
oxide,  action  on  aluminium, 

87 
Barlow,  W.  H.,  on  the   tensile 

strength  of  aluminium,  62 
Basset,  M.  N.,  reduction  of  alu- 
minium by  zinc,  by,  215 
Battersea,  London,  first  alumin- 
ium works  in  England,  33 
Battery,   use  of   aluminium    in 

the,  75 

to  deposit  aluminium,  80 
Baudrin,  P.,  on  a  new  aluminium 

alloy,  278 

Beating  of  aluminium,  57 
Beaux,  analysis  of  beauxite  from, 

47 

Beauxite,  45-47 
analyses  of,  46 
and  cryolite,  chief  source  of 

aluminium,  45 
stimulated     production 

of,  27 

deposits  in  Ireland,  France, 
etc.,  46 


INDEX. 


331 


Beauxite.  formula  of,  44 

treatment  of,   at  Saliudres, 

100 
where  principally  found  in 

France,  100 
Beketoff,  on  the  action  of  oxide 

of  barium  on  aluminium,  87 
Bell  Bros.,  directions  for  solder- 
ing aluminium,  252 
makers  of  aluminium  at 
Newcastle-on-Tyne,  33 
stoppage   of   their   alu- 
minium works,  35 
Bells,  aluminium,  63 
Benjamin,  Mr.,  additional  details 
of  Castner's  sodium   process, 

Benzine,  use  of,  in  melting  alu- 
minium, 230 

Benzon,  iron  process  of,  211 
Berlin,  aluminium  works  in,  35 
Bertrand,  M.   A.,  deposition   of 

aluminium  by  electricity,  232 
Berzelius,   investigation   on    the 

composition  of  cryolite,  104 
Bessemer  converter,  reduction  of 
aluminium  in  the,  207 
reduction  of  sodium  and 

potassium  in,  208 
Birmingham,  England, Webster's 

aluminium  works  at,  36 
Bismuth,   alloys    of    aluminium 

with. 

Blast  furnace,  reduction  of  alu- 
minium in  a,  185-204 
Books    on     aluminium,    Tissier 

Bros.,  28 
Deville's.  20 
Mierzinski's,  £9 
Borates,  action  of,  on  aluminium, 

84 
Boron,  alloys  of  aluminium  with, 

299 

Boudaret,  M.,  report  on  the  mal- 
leability of  aluminium  bronze, 

2or 

Bourbouze,  M.,  on  an  aluminium 

tin  alloy,  290 
Brass,  aluminium,  strength  of, 

276 

compared   with    aluminium 
bronze,  27 1 


Braun,  John,  deposition  of  alu- 
minium by  electricity,  2^53 
Bremen,   aluminium  works    at. 

229     ' 
Bromide  of  aluminium  used  for 

making  pure  aluminium,  243 
Bromine,  action  on  aluminium,  88 
Bronze,  aluminium,  264 
a  true  alloy,  265 
compared  with  brass,  271 
compressive  strength  of, 

•jr.' 

Cowles  Bros.,  274 

first  exhibited  at  Paris, 

1867,  34 
making  of,  267 
malleability  of,  267 
manufactured   by   M. 

Evrard,  211 
melting  point  of,  271 
phosphorized.  279 
price  in  1878,  by  the  So- 

ciete  Anonyme,  36 
production  in  the  United 

States  in  1885,  327 
specific  gravity  of,  271 
tenacity  of,  266, 267, 270, 

276 

silicon-aluminium,  205,280 
silicon,  manufactured  by  M. 

Evrard,  211 
B  runner,  reduction  of  sodium  by, 

131 

Buchner,  G.,  purification  of  alu- 
minium from  silicon,  by,  243 
Buff  and  Wbhler  on  the  solution 

siliceous  aluminium,  260 
Bunsen  and  Deville's  electrolytic 
method  of  separating  alumin- 
ium, 41 

Bunsen,  electrical  process  of,  for 
depositing  aluminium,  222,  225 
Burnishing  of  aluminium,  55 

Cadmium,  alloys  of  aluminium 

with,  299 
Caillet,  on  the  amalgamation  of 

aluminium,  261 
Calcination  furnace  for  sodium 

mixture,  133 
Thomson's,  for  cryolite, 
146 


332 


INDEX. 


Calcination    retorts    for    alumi- 
nium-sodium chloride   at  Sa- 
-  lindres,  166 

Calcutta,  aluminium  at  the  ex- 
hibition of,  in  1883,  246 
Calvert  and  Johnson,  making  of 
iron  aluminium  alloys, 
282 
reduction  of  aluminium 

by  iron,  209 
Camden,  N.  J.,  aluminium  made 

at,  31 

Carbon,  action  on  aluminium,  88 
alloys   of   aluminium   with, 

300 

and  aluminium,  alloy  of,  203 
and  carbon  dioxide,  reduc- 
tion of  aluminium  by,  187 
as  lining  for  earthen  cruci- 
bles, 36 

changed  to  graphite,  193 
dioxide  and  carbon,  reduc- 
tion of  aluminium  by,  187 
disulphide,  use  of,  for  making 
aluminium    chlo- 
ride, 317 

for  making  alumin- 
ium sulphide,  310 
reduction  of  aluminium  by, 

188-206 
Carbonates  of  alkalies,  action  on 

aluminium,  88 
Carbonic  acid  gas,  lime-kiln  for 

producing,  150 
used  for  precipitat- 
ing     aluminium, 
149, 163 
Carburetted  hydrogen,  reduction 

of  aluminium  by,  182 
Casting  of  aluminium,  237 

its  importance,  36 
the    largest    ever 

made,  39 
Castings,  Mitis,  alloy   used   for 

making,  212 

Castner,  claims  made  in  his  pat- 
ent, 141 
process  for  reducing  sodium 

by, 324 

reduction  of  sodium  by,  131 
Chalk,  object  of  using,  in  the 
reduction  of  sodium,  133 


Chanu,    aluminium    plant    at 

Rouen,  29 
Chapelle,  M.,  on  the  reduction 

of  aluminium  by  carbon,  188 
Charridre,  on  soldering  alumin- 
ium, 248 
use  of  an  aluminium  tube  in 

tracheotomy,  87 

Chemical    classification  of   alu- 
minium, 88 
properties  of  aluminium, 

70-89 

reactions  in  the  sodium  pro- 
cess, 158 

Chemically  pure  aluminium,  di- 
rections for  making,  243 
Chlorhydrate  of  aluminium,  85 
Chloride  of  aluminium,  a  new 
process  for  producing, 
326 

Dullo's  process  for  mak- 
ing, 155 
improved    method   for 

producing,  157 
Chlorides,   metallic,  action  on 

aluminium,  85 
Chlorine,  action  on  aluminium, 

88 
Christofle,   M.,  castings  of  alu- 

mipium  bronze,  265 
gilding  of  aluminium,  80 
on  soldering  aluminium,  248 
on   the   use   of    aluminium- 
silver  alloy,  296 

Classification,  chemical,  of  alu- 
minium, 88 
Clay,   cryolite,   as    lining    for 

earthen  crucibles,  36 
Clays,  alumina  the  base  of,  43 
Cleaning   of   tarnished    alumin- 
ium, 54 

Cleveland,  manufacture  of  alu- 
minium in,  41,  190 
Coating  of  metals  with  alumin- 
ium, 231 

iron  with  aluminium,  247 
Coins,  use  of    aluminium    for. 

247 

Color  of  aluminium,  53 
Combinations  of  aluminium,  43 
Combustion  of  aluminium  leaf, 
71 


INDEX. 


333 


Comenge,   M.,   double    reaction 

method  of, 
Commercial  aluminium,  analyses 

of,  51 
made  chiefly  by  Deville's 

process,  41 

Compressive    strength    of    alu- 
minium bronze,  2~2 
Condenser  for  sodium,  131 
Conductivity  of  aluminium  for 

heat,  67 

electric,  of  aluminium,  66 
Converter,  the  Bessemer,  reduc- 
tion of  aluminium  in, 
807 
reduction  of  sodium  and 

potassium  in,  208 
Cooking,  aluminium  utensils  for, 

245 
utensils,  valuable    property 

of  aluminium  for,  68 
Copper,    alloys    of   aluminium 

with,  264-280 
deposition  of,  by  aluminium, 

81 
freeing  of  aluminium  from, 

240- 
oxide,  action  on  aluminium, 

87 
reduction  of  aluminium  by, 

212 
of    aluminium-sulphide 

by,  322 

the  quality  suitable  for  alu- 
minium bronze,  267 
Coppering  of  aluminium,  80 
Corbelli,  of  Florence,  cyanogen 

process  of,  180 
process  of,  for  deposit- 
ins:    aluminium    elec- 
trolytically,  231 
Cornwall,  supposed  discovery  of 

native  aluminium  at,  43 
Corundum,  49,  50 

discovery  in  Georgia,  49 
from    Georgia,    used    by 

Cowles  Bros.,  205 
price  at  the  mim->.  40 
use  of,  for  making  alumin- 
ium, 37 

Cost  of  aluminium  at  Salindres 
in  is;:.',  172 


Cowles's  aluminium  process,  his- 
tory of,  41 
Cowles  Bros.'  agent  in  England, 

197 
aluminium  bronze  made 

by,  274 
aluminous  materials  used 

by,  205 

owners  of   a  patent  for 
producing    aluminium 
chloride,^326 
patent  claims,  190 
process  for  the  reduction 
of  aluminium  by  car- 
bon, 189-205 

Cross,  W.,  description  of  Ame- 
rican cryolite,  48 
Crucible  clay,  action  on  alumin- 
ium, 84 
Crucibles,  action  of  aluminium 

on  siliceous,  259 
alumina,  use  of,  for  obtain- 
ing aluminium,  228 
in  purifying  alumin- 
ium, 243 

aluminate  of  soda,  use  of, 
in  purifying  aluminium, 
243 

aluminium,  use  of,  for  ob- 
taining aluminium,  228 
earthen,  action  of  aluminium 

on,  35 
iron,  used  by  Rose,  106 

use  of,  in  purifying  alu- 
minium, 241 

lime,  for  melting  alumin- 
ium, 36 

lining  for,  35,  123 
porcelain,  use  of,  for  obtain- 
ing aluminium.  228 
used    in    electrolyzing    alu- 
minium, 224 

Cryolite,    Allen    Dick's    experi- 
ments on  reduction  of,  115 
and  Beauxite,  chief  source 

of  aluminium,  45 
stimulated     production 

of,  27 
Berzelius's  investigation  of 

its  composition,  104 
clay  as    lining  for   earthen 
crucibles,  36 


334 


INDEX. 


Cryolite,  composition  of,  119 
decomposition  of,  306 
by  electricity,  230 
Deville's  process  for  reduc- 
ing, 119-126 
Dr.  Percy's  experiments  on 

reducing,  115 
formula  of,  44 
general  use  as  a  flux,  48 
H.  Rose's  paper  on  reduction 

of,  103-1 15 

importation  of,  by  the  Penn- 
sylvania Salt  Co.,  48 
imports    into   the   United 

States,  49 

in  the  United  States,  48 
manufacture    of   alumina 

from,  146-153 
occurrence  of,  48,  49 
reduction  of,  103-129 
at  Nanterre,  126 
by  ferro-silicum,  207 
Watts's  summary  of  its  use, 

127 
Crystalline  form  of  aluminium, 

69 

Crystallization  of  aluminium ,  115 
Crystallized  silicon,  260 
Culinary  articles,  use  of  alumin- 
ium for,  68,  245 
Cupellation  of  aluminium,  71 

from  lead,  291 
Curaudau,  reduction  of  sodium 

by,  131 

Cyanite,  formula  of,  44 
Cyanogen,  reduction  of  alumin- 
ium by,  180 

Davy,  reduction  of  sodium  by, 

131 
unsuccessful  efforts  to  isolate 

aluminium,  25 
Debray,  H.,  aluminium  plant  at 

Glaciere,  28 

Debray,  M.,  statement  of,  in  re- 
gard to  iron  in  aluminium,  282 
Decomposition    furnace   for   so- 
dium mixture,  134 
of   aluminium   sulphide  by 

water,  311,  317 

Degousse,  first  successful  beater 
of  aluminum  leaf,  58 


De  la  Rive,  on  the  action  of  sul- 
phuric acid  on  aluminium,  74 
Denis,  M.,  of  Nancy,  remark  on 
the  soldering  of  aluminium, 
248 

Density  of  aluminium,  64 
Deposition  of  aluminium  by  elec- 
tricity, 255 
by  the  battery,  80 
electrolytically,  222-234 
Deville,  aluminium  plant  at  Gla- 

cidre,  28 

analysis  of  beauxite  by,  47 
book  on  aluminium,  1859,29 
charges  against  Tissier  Bros., 

28 

conclusion  of  his  book,  30 
description  of  the  reduction 

of  sodium,  132 
experiments  on  gilding  and 

silvering  aluminium,  256 
H.  St.  Claire,  first  to  isolate 

pure  aluminium,  26 
on  soldering  of  aluminium, 

247 
on  the  aluminium  obtained 

by  Wbhler,  95  . 
on  the  casting  of  aluminium, 

237 
on  the  electrolytic  reduction 

of  aluminium,  223,  225 
on  the  melting  of  alumin- 
ium, 235 

on   veneering  with   alumin- 
ium, 253 
purification    of    aluminium, 

238 

researches  of,  at  the  Normal 
School,  Paris,  and  at 
Javel,  28 

on  cryolite  by,  118 
review  of  Percy's  and  Rose's 
investigations  of  cryolite, 
118 

treatment   of   silicates    and 
borates  with  aluminium,  84 
Deville's  cryolite  process,  Wo  li- 
ter's improvement  on,  126 
improvements  in  1854  for  ob- 
taining pure  aluminium,  96 
processes,    later    improve- 
ments on,  173 


INDEX. 


335 


Deville's  sodium  vapor  process, 

100 
Diaspore,  formula  of,  44 

where  found,  50 
Dick,  Allan,  paper  on  reducing 

cryolite,  116 
Disthene,   reduction    of,   by    an 

electric  current,  229 
Donny  and  Mareska,  condenser 

for  making  sodium,  131 
Double    reaction,    reduction    of 

aluminium  by,  1*4 
Drawing  of  aluminium  into  wire, 

60 
Drecbsler,   analysis  of  beauxite 

by,  47 
Dublin,    analysis    of    beauxite 

from,  47 

Ductility  of  aluminium,  60 
Dullo,   M.,  process  for   making 

aluminium  chloride,  loo 
remark  on  the  reduction  of 

aluminium  by  zinc,  214 
Dumas,  on  gases  in  aluminium, 

52 
Duvivier.    M.,   on    reduction    of 

aluminium  by  electricity,  229 
Dynamo  used   in  Cowles  Bros.' 

process,  204 

Elastic  rangre  of  aluminium,  62 
Elasticity  of  aluminium,  (U 
Electric  conductivity  of  alumin- 
ium. »5H 

furnace,  Cowles  Bros.,  199 
suggested  by  Miefzinski, 

226 

use    of,    for    producing 
aluminium     chloride, 
326 
Electrical    furnace,  gases    from 

the,  197 

separation  of  aluminium,  255 
Electricity    applied    to    melting 
*  steel,  194 
to    the    extraction    of 

metals,  1J»4 
reduction  of  aluminium  by, 

222 

of  sodium  by,  131 
un.-uccessful  efforts  of  Davy 
to  i>olatc  aluminium  by.  '!•) 


Electrolytic  methods  of  separat- 
ing aluminium,  41 
Enamelling   mixture  to  protect 

sodium  retorts,  135 
England,  Cowles  Bros.'  agent  in. 

197 

failure  of  aluminium  manu- 
facture in,  35 

first  aluminium  wrorks  in,  33 
Webster    perhaps    the   only 
maker  of  aluminium  in,  42 
Engraving  of  aluminium,  61 
Evrard,  M.,  making  of  alumin- 
ium bronze  by,  211 

Falk  &  Co.,  makers  of  alumin- 
ium leaf,  60 

Faraday's    experiments   on    the 
sonorousness  of  aluminium,  64 
Farmer,  Moses  G..  patented  ap- 
paratus of,  for  electrolytically 
obtaining  aluminium,  233 
Favre,    M.,  on    solution  of  alu- 
minium in  hydrochloric  acid, 
75 
Feisstritz,   analysis  of  beauxite 

from,  47 

Ferro-silicum,  reduction  of  alu- 
minium by,  206 
Fixity  of  aluminium,  66 
Fleury,   A.   L.,  carbu retted  hy- 
drogen process  of,  182 
Fluoride    of    aluminium,    Ger- 
hard's process  of  re- 
ducing, 181 
Lauterborn's  process  of 

reducing,  206 
reduction    by  ferro-sili- 

cum,  206 
Fluorides  as  fluxes,  260 

use  of,  as  flux,  102-120 
Fluorine,  action  on  aluminium, 

88 
Fluorspar,  action  on  aluminium. 

84. 
Flux,  fluorspar  as,  84 

use  of  fluorides  as  a,  102-120 
Fluxes  for  aluminium,  259 
Formulae  of  aluminous  minerals, 

4:; 

France,  deposits  of  beauxite  in, 
46 


336 


INDEX. 


France,  production  of  aluminium 

in,  1882,  39 
successful    manufacture    of 

aluminium  in,  35 
Fremy,   original   paper  on   alu- 
minium sulphide,  310 
Frishmuth,  aluminium  works  in 

Philadelphia,  37 
analyses  of  the  metal  of,  306 
improvement  of,  in  making 
aluminium-sodium  double 
chloride,  154 

plating    with    aluminium- 
nickel,  234 
production  of  aluminium, 

1883,  1884,  40 
solders   for  aluminium    by, 

250 
Frishmuth's  first  assertions  not 

verified,  42 
patent  claims,  178 
owners  of,  37 
process  mentioned  in  Watts's 

Dictionary,  42 
works,    annual    production 

of,  39 

Fritz,  Mr.,  of  Bethlehem,  Pa., 
interest  of,  in  the  mitis  process, 
287 

Fusibility  of  aluminium,  65 
Furnace,  Thomson's,  146 

Gallium,    alloys   of   aluminium 

with,  300 

Garnet,  formula  of,  44 
Gases  in  aluminium,  52 

from  the  electrical  furnace, 

197 

Gaudin,  electric  process  of,  230 
Gay  Lussac,  reduction  of  sodium 

by,  131 

Gerhard  &  Smith,  patent  process 
of,  for  depositing  aluminium, 
233 

Gerhard,  W.  F.,  furnace  for  re- 
ducing aluminium,  127 
German  silver,  aluminium,  277 
Germany,  aluminium  works  in, 

33 

failure  of  aluminium  manu- 
facture in,  35 

reduction  of  aluminium  in, 
228 


Gila  River,   N.  M.,   native  sul- 
phate of  alumina  on  the,  305 
Gilding  of  aluminium,  80,  256 
Glaci£re,  process  for  making  alu- 
minium, as  used  at,  98 
purification    of    aluminium 

from  slag  at,  239 
Rousseau  Bros.,  aluminium 

works  at,  28 
Glass,  action  of,  on  aluminium, 

84 

Gmelin,  an  observation  on  alu- 
minium amalgam,  263 
Gold,  allo\'s  of  aluminium  with, 

298 

Gordon,    A.,    on    the    tensile 
strength  of  aluminium  bronze, 
266 
Gore,  deposition   of  aluminium 

on  copper,  234 
Granite,  composition  of,  43 
Graphite,    carbon    changed    to, 

193 

cylinders,  use  of,  to  protect 
retorts  in  sodium  reduc- 
tion, 135 

Gratzel,  Richard,  electrolytic  pro- 
-  cess  of,  228 
Gravity,  specific,  of  commercial 

aluminium,  307 
Greenland,  cryolite  in,  48 
Grousilliers's  improvement  of  re- 
ducing under  pressure,  179 
Guettier,  remarks  on  aluminium 

bronze,  273 

Guiana,  deposits  of  beauxite  in, 
46 

Hadamar,   analysis  of  beauxite 
from,  47 

Hamburg,  aluminium  works  at, 
229 

Hardness  of  aluminium,  61 

Harmlessness  of  aluminium  salts 
to  the  body,  79 

Havrez,  P.  J.,  washing  appara- 
tus of,  149 

Heat,  conduction  of,  by  alumin- 
ium, 07 
specific,  of  aluminium,  68 

Helmet,  an  aluminium,  245 

Herreshoff',  importer  of  beauxite 
into  the  United  States,  47 


INDEX. 


337 


Hesse,  analysis  of  beauxite  frora, 

47 

deposits  of  beauxite  in,  46 
Hillebrand,  description  of  Amer- 
ican cryolite,  48 
Hirzel,  on  alloys  of  aluminium 

and  silver,  296 

History  of  aluminium,  25-42 
Hodges,  F.,  analysis  of  beauxite 

by,  47 
Hulot,  coppering  of  aluminium, 

80 

method    of    soldering    alu- 
minium, 248 
on  the  use  of  aluminium  in 

the  battery,  75 

Hunt,   Dr.  T.  Sterry,  paper  on 
Cowles's  process,  194 
second  paper  on  Cowles's 

process,  196 
views  on  the  aluminium 

industry,  42 
Hydrochloric  acid,  action  of,  on 

aluminium,  75 
Hydrogen,  action  on  aluminium, 

88 
reduction  of  aluminium  -by, 

181 

sulphide,  action  of,  on  alu- 
minium, 73 

use  of,  to  purify  aluminium, 
243 

Imports  of  aluminium,  1870  to 

1884,  40 
Impurities,  freeing  of  aluminium 

from,  240 

Instruments,  mathematical,  etc., 

suitability   of   aluminium 

bronze  for,  268 

optical  and  portable  electric, 

a  suitable  alloy  for,  290   . 

Iodine,    action    on    aluminium, 

88 
Ireland,   analysis    of    beauxite 

from,  47 

deposits  of  beauxite  in,  46 
Iron,  alloys  of  aluminium  with, 

280 

with  aluminium,  209 
aluminium  alloy,  production 
of,  :;-j:] 
29 


Iron,  aluminium  alloy,  used  in 

the  mitis  process,  212 
coated  with  aluminium,  247 
crucibles,  use  of,  in  purify- 
ing aluminium,  241 
used  by  Rose,  106 
freeing  of  aluminium  from, 

240 
in   commercial    aluminium, 

estimation  of,  307 
oxide,  action  on  aluminium, 

86 
reduction  of  aluminium  by, 

206 

sulphide  by,  323 

Ivigtuk,  Greenland,  cryolite  beds 
at,  48 

Jablochoff,  reduction  of  sodium 

by,  131 
Javel,  chemical  works  at,  28 

process  for  making  alumin- 
ium as  used  at,  98 
Jeancon,  J.  A.,  patented  process 
for     depositing      aluminium, 
232 

Jewelry,  aluminium,  247 
Johnson,  double  reaction  method 

of,  184 
Jouet,  Mr.,  analysis  of  beauxite 

by,  47 

j  Joules,  on  the  amalgamation  of 
aluminium,  262 

_ 

Kagensbusch,  electric  process  of, 

230 
of  Leeds,   on    reduction  of 

aluminium  by  zinc,  218 
on  reduction  of  aluminium 

by  lead,  222 
Kamarsch,  on  the  tensile  strength 

of  aluminium,  63 
Kerl  and  Stoh man,  directions  for 
soldering    aluminium, 
by,  250 

historical  r6sum6  by,  32 
on  the  melting  of  alu- 
minium, 236 
Klein  Steinheim,    analysis    of 

beauxite  from,  47 
Knight,  remarks  on  aluminium 
bronze,  273 


338 


INDEX. 


Knowles,  Sir  F.  C.,  cyanogen 
process  of,  180 

Lang,  I.,  analysis  of  beauxite' 
by,  47 

Langsdorff,  analysis  of  beauxite 
from,  47 

Lauterborn,  iron  reduction,  pro- 
cess of,  206 

Lauterborn's  process  for  decom- 
posing cryolite  tested, 


remark  on,  317 

Lavoisier,   first    to   suggest    the 
existence  of  aluminium,  25 
Lazulite,  formula  of,  44 
Lead,  action  on  an  aluminium- 
tin  alloy,  196 
alloys   of   aluminium  with, 

291 
deposition  of,  by  aluminium, 

82 
freeing  of  aluminium  from, 

241 
oxide,  action  on  aluminium, 

86 
reduction  of  aluminium  by, 

221 

sulphide  by,  322 
Leaf  aluminium,  245 
beating  of,  57 
combustion  of,  71 
decomposition  of  water 

by,  73 

Lechatelier,  M.,  on  the  tensile 
strength  of  aluminium  bronze, 
266 

Lecoq  de  Boisbaudran,  on  alu- 
minium-gallium alloys,  300 
"Lessiveur  methodique,"  149 
Liebig,   experiments    to    reduce 

aluminium,  93 
Lime,  action  of,  on  aluminium, 

77 

crucibles    for    melting    alu- 
minium, 36 

kiln ,  use  of,  to  furnish  car- 
bonic acid  gas,  150 
phosphate  of,  action  on  alu- 
minium, 85 

Lining  for  crucibles,  123 
Liquation  of  aluminium,  238-240 


Lissajous,  M.,  aluminium  tuning 
fork  made  by,  63 

Litharge,  action  on  aluminium, 
86 

LIthia  mica,  formula  of,  43 

Lockport,  N.  Y.,  Cowles  Bros., 
plant  at,  193-196 

Lbwig,  experiments  of,  in  pre- 
cipitating alumina,  151 

Lustre  of  aluminium,  55 

Mabery,  Prof.  Chas.  F.,  official 
announcement  of  Cowles 
Bros.'  process,  191-194 
on  a  new  process  for  pro- 
ducing aluminium  chlo- 
ride, 326 
views  on   the  aluminium 

industry,  41 

Magnesia  mica,  formula  of,  43 
Magnesium  sulphide,  production 

and  reduction  of,  312-317 
Magnetism  of  aluminium,  69 
Mal^tra,    aluminium     plant    at 

Rouen,  29 
Malleability  of  aluminium,  57 

bronze,  267 

Mallet,  directions  for  making 
chemically  pure  alumin- 
ium, 243 

on  the  resistance  of  pure  alu- 
minium to  alkalies,  77 
on  the  specific  heat  of  pure 

aluminium,  68 
gravity  of  aluminium, 

65 

Manganese,  alloys  of,  with  alu- 
minium, 302 
oxide,  action  on  aluminium, 

86 
reduction  of  aluminium  by, 

222 
Manufacture    of    aluminium 

bronze,  267 
Martin,  Wm.,  aluminium  plant 

at  Rouen,  29 

Mat,  production  of,  on  alumin- 
ium, 54 
Mayer,  L.,  analysis  of  beauxite 

by,  47 

Mel  ting  of  aluminium  scraps,  235 
point  of  aluminium,  65 


INDEX. 


339 


Mercury,  action  on  aluminium, 

25 
alloys   of  aluminium   with, 

261 
deposition  of,  by  aluminium, 

81 
Merle  &  Co.,  aluminium  works  j 

at  Salindres,  28,  35 
Metallic   aluminium    not   found : 

native,  43 

chlorides,  action  on  alumin- 
ium, 85 
oxides,  action  on  aluminium, 

86 

Metallurgy  of  aluminium,  90,  257 
general  remarks  on  the, 

128 

of  sodium,  130-143 
Metals,  coating  of,  with  alumin- 
ium, 231 

comparative  density  of,  64. 
electric  conductivity  of,  ' 

67 
thermal  conductivity  of,  , 

67 
plating  on,  with  aluminium, 

255 

precipitation  of,  from  solu- 
tion by  aluminium,  79 
relative  affinity  of  sulphur 

for,  318 

Michel,  experiment  on  alumin- 
ium and  molybdenum,  302 
making   of   iron-aluminium 

allo\>  by,  383 

Mierzinski,  formulas  of  some  alu- 
minium minerals  as  given 
by.  43 
general    remarks  on   alloys 

of  aluminium,  258 
on     making     aluminium 

bronze,  207 

on  the  manufacture  of  alu- 
minium-sodium chloride, 
154 

on  the  melting  of  alumin- 
ium, 237 

on  the  reduction  of  alumin- 
ium by  electricity,  226 
remark  on  the  electrolysis  of 
aqueous  solutions  o"f  alu- 
minium salts,  2: 54 


Mierzinski,  report  on  the  present 
state  of  the  alumina  industry, 
144 
Minargent,  composition  of,  and 

method  of  making,  278 
Mineral  soda,  105 
Mitis  castings,  283 

ores  suitable  for,  205 
W.  H.  Wahl's   remarks 

on, 326 

process,  iron-aluminium  al- 
loy used  in  the,  212 
Molten  aluminium,  viscidity  of, 

237 

Molybdenum,  alloys  of,  with  alu- 
minium, 302 

Monnier,  Alfred,  maker  of 
aluminium  at  Camden,  N.  J., 
31 

Morin  and  Deville,  experiments 
in  gilding  and  silverjng  alu- 
minium, 80 
Morin,  P.,  aluminium  plant  at 

Glaciere,  28 
experiments  on  gilding  and 

silvering  aluminium,  256 
improvements    by,   at  Nan- 

terre,  28 

on  the  action  of  wine  on  alu- 
minium, 78 

on  the  specific  heat  of  alu- 
minium, 68 
Morris.   J..  carbon   and    carbon 

dioxide,  method  of,  187 
Mourey,  method  of  soldering  alu- 
minium, 248 
receipt  for  removing  tarnish 

from  aluminium,  54 
success  in  gilding  and  silver- 
ing aluminium,  80,  256 
Muriatic  acid,  action  of,  on  alu- 
minium, 75 

Nanterre,  aluminium  works  at, 

28,  35 
production  of  aluminium  at, 

1859,  33 

reduction  of  cryolite  at,  126* 
Napoleon  III.,  liberality  of,  28 
Native  aluminium,  43 

sulphate  of  alumina,  305 
Neogen,  composition  of,  277 


340 


INDEX. 


Newcastle-on-Tyne,   Bell    Bros., 

aluminium  works  at,  33 
New  York  City,  manufacture  of 

sodium  in,  139-141 
Nickel,  alloys  of  aluminium  with, 

293 
aluminium  plating  by  Frish- 

muth,  234 
experiment    on    aluminium 

aud  tungsten,  302 
Niewerth,    double    reaction, 

method  of,  185 
iron    reduction,   process   of, 

206 

Niewerth's  nascent  sodium  pro- 
cess, 179 

process,  remark  on,  318 
Nitre,  action  of,  on  aluminium, 

83 
purification    of    aluminium 

by,  241 

Nitric   acid,  action   of,   on  alu- 
minium, 75 
Nitrogen,  action  on  aluminium, 

88 
alloys  of,  with   aluminium, 

303 

Normal  School,  Paris,  experi- 
ments at  the,  28 

Occurrence    of    aluminium    in 

nature,  43-50 
Odor  of  aluminium,  56 
Oerstedt,  first   published  paper 

on  aluminium,  90 
isolation  of  aluminium  by,  25 
Oerstedt's    paper    reviewed    by 

Wohler,  91 
Ores    of    aluminium   used    by 

Cowles  Bros.,  205 
Organic  acids,  action  of,  on  alu- 
minium, 78 

Orlowsky,  A.,  on  the  relative 
affinity  of  sulphur  for  the 
metal,  318 

Orthoclase,  formula  of,  43 
Ostberg,  Peter,  inventor  of  mitis 

castings,  283 
remark  on  the  reduction  of 

aluminium  by  iron,  212 
Oxidation  of  aluminium,  71 
Oxide  of  barium,  action  on  alu- 
minium, 87 


Oxide  of  copper,  action  on  aln- 

minium,  87 

of  iron,  action  on   alumin- 
ium, 86 

of  lead,  action  on  alumin- 
ium, 86 

of  manganese,  action  on  alu- 
minium, 86 

of  zinc,  action   on  alumin- 
ium, 86 

sub,  of  aluminium,  26 
Oxides,  metallic,  action  on  alu- 
minium, 86 

Palais  de  ^Industrie,  Paris,  1855, 
aluminium  bar  exhibited  at, 
34 

Paraffin,  Wagner's  use  of,  to  pre- 
serve sodium,  138 

Paris  Exhibition  of  1855,  alumin- 
ium objects  presented  at,  28 

Passemeutere,  aluminium,  60 

Peligot,  on  cupelling  alumin- 
ium, 71 

Pennsylvania  Salt  Co.,  importers 
of  cryolite,  48 

Pens,  suitability  of  aluminium 
bronze  for,  272 

Percy,  Dr.,  experiments  in  mak- 
ing aluminium  bronze,  264 
reduction  of  cryolite  prior  to 
Rose,  115 

Petitjean,  carburetted  hydrogen, 
process  of,  183 

Petitjean's  process  tested  by  Rei- 
chel,315 

Philadelphia,  Col.  Wm.  Frish- 
inuth's  aluminium  works  in, 
37 

Phosphate  of  lime,  action  on 
aluminium,  85 

Phosphorized  aluminium  bronze, 

Phosphorus  in  aluminium,  126 

Photo-salts  of  aluminium,  efforts 
to  produce,  27 

Physical  properties  of  alumin- 
ium, 51-70 

Plants,  alumina  never  found  in, 
44 

Plating,  aluminium,  231 
aluminium-nickel,  234 
with  aluminium,  246 


INltKX. 


341 


Platinum,   alloys  of  aluminium 

with.  •-'.»'.' 
Poggendorff   and    Reiss   on   the 

nuiiriu'tisin  of  aluminium,  69 
Polish  of  aluminium,  55 
Porcelain  crucibles,  use  of,  for 
obtaining: aluminium,  22>< 
imitation  of,  made  with  cryo- 
lite, 48 
Potash,  action  of,  on  aluminium,  ! 


77 


Production  of  aluminium  bronze 
in  the  United  States  in 
1885, 
by  Col.  Frishmuth,1883- 

"lS8t,  40 

in  France,  18S2,  39 
in  the  United  States  in 

188"),  327 

Properties    of    aluminium    sul- 
phide, 311,  316 


mica,  formula  of,  43 
Potassium,  aluminium  first  iso- 
lated by  the  use  of,  26 
amalgam,  experiment  with. 

by  Gmelin.  26:} 
used    in    isolating    alu- 
minium, 'J5 

and  sodium,  reduction  to- 
gether of,  138 

carbonates,  action  on  alu- 
minium, 8S 

chloride,  action  on  alumin- 
ium, 85 
decomposition    of,    by 

electricity,  142 
cyanide  as  a  reducing  agent, 

180 
reduction   in   the    Bessemer 

converter,  208 
in  the  electric  furnace, 

193 
replaced  by  sodium  by  De- 

vill. 

sulphate,  action  on  alumin- 
.    ium,  88 

vapor  of,  Davy's  efforts  to 
isolate  aluminium  with, 
25 

Precious  stones,  formula}  of,  44 
Precipitation  of  alumina  at  Sal- 

indres.  UW 
of  metals  from  solution  by 

aluminium,  79 

Price  of  aluminium  in  1857,  29 
in  1878,  by  the   Socie.6 

Anonyme,  36 
in  1883-84,  39 
in  October,  1886,  327 
Proctor,  Bernard  S.,  comparison 
of  brass  with  aluminium  bronze 
by.  271 

29* 


Pure  aluminium,  chemically,  di- 
rections  for    making, 
243 
only  made  by  using  so- 

dium, 42 
requirement  for  making, 

205 
Purification    of  aluminium,   74, 

238 
by  nitre,  83 


Rammelsberg,  on  silicon  in  com- 

mericial  aluminium,  52 
Rammelsberg,    Prof.,    experi- 

ments in  reducing  cryolite,  103 
Rattle,  baby,  first  article  made 

of  aluminium,  244 
Reduction  furnace,  Deville's,  for 

sodium,  134 
for  reducing  aluminium 

by  sodium,  169 
Gerhard's,  127 
of    alumina    by   carbon    in 

presence  of  copper,  309 
of  aluminium  at  Salindres, 

168 
by  carbon,  188 

and  carbon  dioxide, 

187 
by    carburetted    hydro- 

gen, ISii 
by  copper,  212 
by  cyanogen.  180 
by  double  reaction,  184 
by  electricity. 
by  feiTo-silicum,  206 
by  hydrogen,  181 
by  iron,  206 
by  lead,  221 
by  manganese,  222 
by  other  agents  than  so- 
dium, 180 


342 


INDEX. 


Reduction  of  aluminium  by  sili-  ! 

con,  207 
by  zinc,  214 
sulphide,  315,  322 
of  sodium  by  Castner,  324 
under  pressure,  179 
Reflectors,   advantages    of    alu- 
minium for,  245 
Regnault,  M.,  on  the  specific  heat 

of  aluminium,  68 
Reichel,  paper  on   sulphides  of 
aluminium    and    magnesium,  j 
312-317 

Reinar,  G.  W.,  on  the  reduction  j 
of  aluminium  by  carbon,  189     ; 
Reiss  and  Poggendorff,   on  the 
magnetism  of  aluminium,  69     i 
Retorts    for    reducing    sodium, 

134 
Retzlaff,  analysis  of  beauxite  by,  i 

47 
Ricarde-Seaver,  Major,  views  on  j 

aluminium,  37 
Rollins:  of  aluminium,  57 
Rose,  H.,  paper  on  reduction  of  j 

cryolite,  103-115 
Rouen,  aluminium  works  near,  I 

29,  83 

process  used  at,  124 
Rousseau    Bros.,    aluminium 

works  at  Glaciere,  28 
Ruby,  formula  of,  44 

St.  Austel,  supposed  discovery  of  j 

native  aluminium  at,  43 
Salindres,  aluminium  works  at, 

28,  35 

cost  of  aluminium  at,  172 
manufacture  of  aluminium 

at,  158-174 
of   aluminium-sodium     j 

chloride  at,  154-166 
Salt,  common,  action  on  alumin- 
ium, 85 

Salts,  metallic,  action  of  solu- . 
tions  of,  on  aluminium,  79         | 
Sapphire,  formula  of,  44 
Sartorius   of    Gottingen,    first     j 
maker  of  aluminium  balance     I 
beams,  35 

Sauvage,  F.  H.,  inventor  of  neo- ' 
gen,  277 


Schank,  washing   apparatus  of. 

149 
Schnitzer,  analysis   of  beauxite 

by,  47 
Schwarz,  improvenent  on  Mou- 

rey's  solders  by,  249 
Scraps,  aluminium,  melting  of, 

235 
melting  of,  by  Col. 

Frishmuth,  39 

Sellers,  Mr.,  of  Philadelphia,  on 
the  use  of  aluminium  in  cast- 
ing iron,  284 

Senct,  M.  L.,  on  depositing  alu- 
minium by  electricity,  233 
Sevrard,  M.,  success  of,  in   ve 

neeriug  aluminium,  253 
Seymour,  Fred.  J.,  patent  for  the 
reduction  of  aluminium 
by  zinc,  218 
second  patent  of,  220 
Shaw,    T.,    patented     phosphor 

aluminium  bronze,  279 
Siemens's  furnace,  used  in  reduc- 
ing sodium,  135 
Siemens,   Sir  Wm.,   melting  of 

steel  with  electricity,  194 
Silicates,  action  of,  on  alumin- 
ium, 84 

of  aluminium,  formulae  of,  43 
Siliceous  aluminium,  238 

on    the    gases    evolved 

du ring  sol  ution  of,  260 

Silicon,    alloys     of     aluminium 

with,  259 
aluminium  bronze,  205 

extraordinary  strength 

of,  280 
bronze  manufactured  by  M. 

Evrard,  211 
crystallized,  260 
disengagement  of,  as  si  lieu- 
retted  hydrogen  in  dissolv- 
ing aluminium,  76 
facilitates  the  oxidation   of 

aluminium,  71 
freeing  of  aluminium  from, 

243     - 
its  state  of  combination  in 

aluminium,  52 
use  of,  to  reduce  aluminium, 
207 


INDEX. 


343 


Silieu rotted  hydrogen,  formation 
of,  011  dissolving  aluminium, 
260 
Silver,  allovs  of  aluminium  with, 

295  " 

aluminium,  297 
comparative  value  with  alu- 
minium, 65 
deposition  of,  by  aluminium. 

81 
from  clay,  exhibited  at  Paris, 

1855,  34 
sulphide,  decomposition  of. 

by  aluminium.  74 
Silvering1  of  aluminium,  256 

difficulty  in,  80 
Smith,  Dr.,  patents  on  reduction 

of  aluminium,  221 
Soci£:e   Anonyme   de    1'alumin- 

ium,  35 

prices  of  aluminium  and 

aluminium  bronze,  36 

Soda,  action  of,  on  aluminium, 

77 

mica,  formula  of,  43 
mineral,  105 

Sodium,  alloys  of,  with  alumin- 
ium, 303 
aluminate,  precipitation  of, 

by  Lowig,  151 

amount  necessary  to  reduce 
aluminium  from  cryolite, 
122 
and    potassium,    reduction 

together  of,  138 
calcination  furnace,  133 
carbonates,   action   on    alu- 
minium, 88 

chloride,  action  on  alumin- 
ium, 85 
decomposition    of,    by 

electricity,  142 
cvanide  as  a  reducing  agent, 
*180 
Gerhard's  furnace  to  prevent 

loss  of,  120 
great  reduction  of  its  price 

in  1859,  27 

its  manufacture,  130-143 
manufacture   in   New  York 

City,  1886,  139-141 
mixture  for  reduction,  132 


Sodium,  nascent,  as  a  reducing 

agent,  179 
preservation  of,  by  Wagner's 

method.  138 
reaction  for  the  reduction  of, 

137 

reduction  by  Briinner,  131 
by  Castner,  139 

additional    details 

of,  324 

by  Curaudau,  131 
by  Davy,  131 
by  electricity,  142 
by  Gay  Lussac,  131 
by  Jablochoff,  142 
by  Thenard,  131 
furnace  for,  134 
in  the  Bessemer  conver- 
ter, 208 
in  the  electric  furnace, 

193 
of  aluminium  by  other 

agents  than,  180 
of  the  double  chloride 

by,  168 
process,   the    perfection 

of  the,  171 
substituted  for  potassium  by 

Deville,  27 

sulphate,  action  on  alumin- 
ium, 88 
temperature  of  the  reduction 

of,  137 
use  of  chalk  in  the  reduction 

of,  133 
vapor  process    as   used    by 

Deville,  100 
of  Frishmuth,  178 
Weldon's  calculation  of  the 

cost  of,  139 

Soils,  alumina  the  base  of,  43 
Soldering  liquor  for  aluminium, 

250 

of  aluminium,  247-253 
Solders  for  aluminium,  248-251 

bronze,  279 

Sonorousness  of  aluminium,  63 
Spear,  Mr.  W.  B.,  in  connection 
with  native  sulphate  of  alu- 
mina, 305 

Specht,  on  the  reduction  of  alu- 
minium by  /inc,  218 


344 


INDEX. 


Specific  heat  of  aluminium,  68 
gravity  of  aluminium,  64 

bronze,  271 

of  commercial   alumin- 
ium, 307 
Sprague,  remarks  on  electrolysis 

of  aluminium  salts,  232 
Spruce,  Mr.,  analysis  of  beauxite 

by,  47 

Stamping  of  aluminium,  58 
Stearic  acid  used  for  burnishing 

aluminium,  55 
Steel,   alloys    with    aluminium, 

281 

Stocker,  on  native  aluminium,  43 
Stoddart  and  Faraday,  analysis 

of  Bombay  wootz,  283 
Stones,  precious,  formulae  of,  44 
Strange,  Mr.,  experiments  with 

aluminium  bronze,  273 
Strength,   compressive,   of   alu- 
minium, 62 

aluminium  bronze,  272 
tensile,  of  aluminium,  62,  63 
of    aluminium    bronze, 

266,  267,  270,  276 
of    aluminium-silicon 

bronze,  205 

transverse,  of  aluminium,  62 
Sulphate  of  alumina,  decomposi- 
tion of,  by  electricity, 
231,  233 
native,  305 
Tilghman's   process  for 

decomposing,  144 
of  potash,    action    on    alu- 
minium, 88 

of  soda,  action  on  alumin- 
ium, 88 
Sulphide  appearance,  properties 

and  analysis  of,  311 
a  practical   process  for 

producing,  321 
experiments  on  produc- 
ing, 318 

on  reducing,  322 
production    and   reduc- 
tion of,  309-324 
reduction    of,    by    Co- 
menge's  method, 
184 
by  manganese,  222 


Sulphide  appearance,  reduction 
of,  by  Petitjean's  me- 
thod, 183 

remark  by  Than  on,  314 
researches  of  Fremy  on, 

310 

of  Reichel,  312 
carbon  di-,  use  of,  for  making 
aluminium     chloride, 
317 

use  of,  for  making  alu- 
minium sulphide,  310 
Sulphides    of    aluminium    and 
magnesium,  Reichel's 
paper  on,  312-317 
Sulphur,  action  on  aluminium, 

73,  88 
its   relative  affinitv  for.  the 

metals,  318 
Sulphuretted    hydrogen,    action 

of,  on  aluminium,  73 
Sulphuric    acid,    action    of,    on 

aluminium,  74 

Surgery,  use  of  aluminium  in,  87 
Sweat,  action  on  aluminium,  87 
Syndicate,  an  English,  to  control 
patents  on  aluminium,  39 

Tanks,  precipitating,  152 
Tarnish,  Mourey's  receipt  for  re- 
moving, from  aluminium,  54 
Tarnishing  of  aluminium,  cause 

of,  240 

Tartaric  acid,  action  of,  on  alu- 
minium, 78 

Taste  of  aluminium,  57 
Taylor,  W.  J.,  calculated  cost  of 

aluminium,  32 

Telegraph  wire,  aluminium,  243 
Temperature  necessary  to  reduce 

sodium,  137 

Tempering  of  aluminium,  58 
Tenacity  of  aluminium,  61 
Tensile  strength  of  aluminium, 

62,  63 
of    aluminium    bronze, 

266,  267,  270,  276 
of    aluminium-silicon 

bronze,  205 

Than,  remark  by,  on  the  forma- 
tion of  aluminium  sulphide, 
314 


INDEX. 


345 


Thenard,   reduction    of   sodium 

by,  131 

Thermal,    conductivity   of   alu- 
minium, 67 
Thomas  and  Tilly,  process  for 

aluminium  plating,  231 
Thompson,  J.  B.,  deposition  of 
aluminium  from  solution,  231 
Thompson,  W.  P.,  paper  on  the 

Cowles's  process,  197-205 
Thompson,  W.  P.,  reduction  of 

aluminium  by,  207 
Thomson's    calcination    furnace 

for  cryolite,  146 

"  Tiers  Argent/'  an  alloy  of  alu- 
minium and  silver,  297 
Tilghman's  process  for  decom- 
posing   sulphate  of   alumina, 
144 

Tin,  alloy  of  aluminium  and,  196 
alloys   of   aluminium  with, 

289 
aluminium   alloy,  action  of 

lead  on,  196 
production  of.  322 
its  injurious  effects  in  food, 

79 
plate,    aluminium    plate    a 

substitute  for,  247 
reduction  of  aluminium  sul- 
phide by,  322 
Titanum,   alloys  of  aluminium 

with,  301 
Tissier   Bros.,  Deville's  charges 

against,  28 

experiments  on  solder- 
ing aluminium,  248 
history  of  their  works,  29 
process,  124 
"Recherches  sur  1'Alu- 

minium,"  1858,  28 
Tissier,  on  the  amalgamation  of 

aluminium,  262 
Topaz,  formula  of,  44 
Tracheotomy,    aluminium    tube 

used  in,  87 
Tungsten,  alloys  of  aluminium 

with,  302 

Tuning  forks,  aluminium,  63 
Turquois,  formula  of,  44 

Uses  of  aluminium,  243-247 


Usiglio,  manager  of  the  works  at 
Saliudres,  33 

Vanadium,  occurrence  in  beaux- 
ite,  46 

Vangeois,  first  maker  of  alumin- 
ium wire,  60 

Veneering  with  aluminium,  253 

Vielle  Mcntagne  Zinc  Works,  on 
the  use  of  retorts  from,  288 

Viscidity  of  molten  aluminium, 
237 

Volatilization  of  aluminium,  66 

Wagner,  0.,  analysis  of  beauxite 

by,  47 
Wahl,  W.  H.,  remarks  on  mitis 

castings,  326 
Wasellite,  formula  of,  44 
Washing  apparatus,  149 

used  at  Salindres,  161 
methodical,  149 

Washington    monument,    cast- 
aluminium  tip  of,  39 
composition  of  the  alu- 
minium in  the  tip  of, 
53 
description  of  the  apex 

of,  40 
Water,  action  of,  on  aluminium, 

72 

sulphide,  311,  317 
decomposition    of,    by    alu- 
minium leaf,  73 
Watts's  Dictionary,  Frishmuth's 

process  mentioned  in,  42 
Watts,  on  the  use  of  cryolite  for 

producing  aluminium,  127 
Webster,   aluminium  works   of, 

at  Birmingham,  36 
improvement  of,  in  making 
aluminium  sodium  double 
chloride,  154 

James,  patented  alloy  of,  278 
process  of,  only  one  used  in 

England,  42 
Webster's  patent,  175 
process,  173-177 

Wedding.  M.,  remarks  on  Bas- 
set's zinc  process,  217 
Weldon,  W.,  of  Burstow,  Eng- 
land, manganese  process  of,  222 


346 


INDEX. 


Wertheim,  on  the  elasticity  of 

aluminium,  61 

Wilde,  A.  E.,  on  reducing  alu- 
minium by  lead,  221 
Winckler,  Dr.  Clemens,  histori- 
cal retrospect  to  1879, 
33 
on  coating  metals  with 

aluminium,  254 
remarks  on  electrolysis 
of    aluminium    salts, 
232 

Wine,  acid  action  of,  on  alumin- 
ium, 78 
Wire,  aluminium,  drawing  of,  60 

strength  of,  63 
Wirz  &  Co.,  Berlin,  stoppage  of 

their  aluminium  works,  35 
Wochein,   analysis    of   beauxite 

from,  47 
Wocheinite,    local  .name    for 

beauxite,  46 

Wohler  and  Buff,  on  the  solution 
of  siliceous  aluminium, 
260 

and  Deville,  on  the  extrac- 
tion of  Boron,  300 
Deville's  opinion  of,  31 
discovery   of   aluminium, 

1827,  26,  91 

experiments   to  obtain  alu- 
minium amalgam,  25 
first  paper  of,  91 
improvement    on    Deville's 

cryolite  process,  126 
method  used  in  1845,  26 
observation  on  melting  alu- 
minium with  a  blowpipe, 
71 


Wohler  and  Buff    on  the   resist- 
ance of  aluminium  to  aqua 
ammonia,  78 
review  of  Oerstedt's  paper, 

91 

second  paper  of,  93 
Working  of  aluminium,  235-257 
Works,   aluminium,    at    Amfre- 
ville,    near    Rouen,   29, 

124, 128 

at  Battersea,  London,  33 
at  Berlin,  35 
at  Birmingham,  England,  36, 

173 

at  Camden,  N.  J.,  31 
at  Cleveland,  Ohio,  4.1,  189 
at  Glacidre,  28,  98 
at  Javel,  28,  98 
at  Nanterre,  28,  35,  126,  128 
at  Newcastle-on-Tyne,  33 
at  Philadelphia,  37,  178 
at  Salindres,  28,  33,  128,  168 
in  England,  33,  35,  42 
in  France,  35,  128 
in  Germany,  33,  35 

Zinc,  alloys  of  aluminium  with, 

287 
deposition  of,  by  aluminium, 

83 
expelling    from    aluminium 

by  heat,  218 
freeing  of  aluminium  from, 

242 
oxide,  action  on  aluminium, 

86 
reduction  of  aluminium  by, 

214 


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