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‘BULLETIN OF THE

(Se USDEDARIMENT OFAGRICOLTURE
I ox aS

No. 197

Contribution from the Bureau of Entomology, L. O. Howard, Chief.:
March 31, 1915.

HOMEMADE LIME-SULPHUR CONCENTRATE.

By E. W. Scort,
Entomological Assistant, Deciduous-Fruat Insect Investigations.

During the past few years much attention has been given by
investigators to the home preparation of lime-sulphur concentrate
and also to an inquiry into the chemical reactions involved, as affect-
ing the conditions under which the work should be done. These
investigations have had for their purpose the encouragement of
orchardists in the preparation of concentrates for their own use, or

by the fact that many fruit growers now prepare their own lime-
sulphur concentrates, thus effecting a material saving over the cost
of the commercial article.

Orchardists, as a rule, are not able consistently to obtain a product
of uniform density, even though the same formula be employed and
the work be accomplished as nearly as possible in an identical manner
for the different batches. This defect, however, is really of little
importance, since it is easy to test the density of the concentrate and
'make dilutions in conformity with the purpose for which it is to be

used.

During the past few years the Bureau of Entomology has given
attention to the making of lime-sulphur concentrates in connection
with work in deciduous-fruit insect investigations. No particular
chemical study was planned in connection with these cooking tests,
as it was merely desired to know the degree of density and percentage
of the ‘“‘sludge” which would result by the employment of different
formulas. The cooking tests for the most part were made at lime-
sulphur plants operated by orchardists, or by individuals who sup-
plied the concentrate to orchardists in the immediate territory.

EXPERIMENTS AT BERRYVILLE, VA.

ee a ee ee

Six experiments were conducted at a small plant at Berryville,
Va. This plant consisted of a 12-horsepower boiler and two 150-
gallon cooking vessels. The cooking was done by steam which was

Note.—Describes experiments in making lime-sulphur concentrates and gives the most satisfactory
formulas. Of interest to all practicing spraying in insecticide work.

81647°—Bull. 197—15

for the use of the neighborhood. The success of these efforts is shown.

2 BULLETIN 197, U. S. DEPARTMENT OF AGRICULTURE.

ejected through perforated coils in the bottom of the tanks. There

was no mechanical agitator, the mixture being agitated by hand by
the use of a long wooden paddle. The mixture was allowed to cook
50 minutes, when, after taking samples for testing purposes, the |
remainder was drained into a storage tank. The results of these
tests are given in Table I.

TaBLE I.—Results of cooking different lots of lime and sulphur in preparation of lime- |
sulphur wash, Berryville, Va., 1912.

|
Formula. Percentage

eee in'volume | Bestees
Lime. Sulphur. Water. of sludge. ;
Pounds. Pounds Gallons

1 50 100 39.0 28.5

2 50 100 50 50.0 30.0

3 50 100 50 35. 0 29.5

4 50 100 50 41.5 30.5

5 45 100 50 41.0 29.0

6 55 100 50 44.0 28. 0

The 50-100-50 formula was used in the first four of these experi-
ments. The Baumé test of the cooked wash varied from 28.5° to
30.5°, and the percentage in volume of sludge, after standing 24 hours,
varied from 35 to 50. The preparation of the wash in experiments 1
and 3 was as nearly the same as was possible, the lime being added
first and the sulphur immediately afterwards. In experiment 2 the
sulphur was added first.

In experiment 4 the mixture was not stirred after the steam was
turned on, the steam being depended upon for agitation. Otherwise
the treatment was the same as in experiment 1.

In experiments 5 and 6 the quantity of lime was decreased and in-
creased 5 pounds, respectively, from the amount previously used.
This was done to determine, if possible, whether more or less of this
particular brand of lime should be used. In every other respect the
treatment was the same as in experiment 1. The only points con-
sidered in this experiment were the Baumé test and the percentage in
volume of sludge.

~

EXPERIMENTS AT WINCHESTER, VA.

A lime-sulphur cooking plant located at Winchester, Va., also was
visited. This plant, which has a capacity of 500 gallons per day,
consists of a 150-gallon rectangular sheet-iron tank embedded in a
brick furnace in which wood is burned to furnish the heat. This
plant supplies a number of the surrounding fruit growers with lime- -
sulphur solution. As soon as the cooking has been completed, the
solution is piped directly through a 20-mesh strainer into 50-gallon ~
barrels and is delivered to the growers without being filtered. The
strainer, of course, takes out only the coarser particles; therefore it is
necessary for the grower thoroughly to shake the barrel each time

:
)

a

HOMEMADE LIME-SULPHUR CONCENTRATE, 3

any of the solution is taken out in order to get an even distribution
of the sludge. The following data were obtained, which show the
variation in density of the different batches. Four batches in which
the 50-100-50 formula was used tested 25°, 26°, 28°, and 29° Baumé,
respectively. Seven batches in which the 55-110-50 formtila was acbd
tested 28°, 29°, 29°, 30°, 30°, 30°, and 31° Baumé, respectively. It
will be abtea that chers was conmderable variation in degrees Baumé
for the different batches, although each was cooked as nearly as possi-
ble in the same way.

Similar variations in density were observed at a steam-cooking
plant at Chewsville, Md.

EXPERIMENTS AT HAGERSTOWN, MD.

A new lime-sulphur cooking plant at Hagerstown, Md., was visited.
The cooking vessels, two in number, consisted of the hulls of two large
boilers standing on end. Lach held about 1,500 gallons. The cook-

_ ing is done by steam. A few experiments were conducted at this

plant to determine, if possible, what formula should be used under
these conditions of manufacture to obtain a highly concentrated
solution. The results of these trials are given in Table IT.

TasLE 11.—Results of cooking different lots of lime and eee in preparation of lime-
sulphur wash, Hagerstown, Md.,

| Formula. Percentage
Experi- in volume | Degrees
ment No. | of sludge Baumé,
Lime. Sulphur. Water. (estimate).
Pounds. Pounds. Gallons.
1 800 1,600 800 35. 0 25.5
2 800 1,600 800 35. 0 26.0
3 750 1,500 | 285 gallons sludge, 715 gallons water..... 40.0 23.0
Added to above 1,000 gallons of 23°
4 200 400 Batimetmatenialessee cae eee Sse eee a 45.0 27.0
5 1,000 2,000 | 280 gallons sludge, 620 gallons water...... 45.0 32.5

In Experiments 1 and 2 800 gallons of solution were cooked at a
time. The 50-100-50 formula was used in each of the two experi-
ments with a result of 25.5° and 26° Baumé test solution respec-
tively. In each case there was about 35 per cent in volume of sludge.
The solution in Experiment 1 was allowed to remain in the vessel
24 hours, then the clear solution was drawn off and 285 gallons of
sludge remained in the tank. In order to see what effect this sludge
would have on the solution by cooking it over with the next batch
(Experiment 3), 715 gallons of water were added to it, making 1,000
gallons in all; 750 pounds of lime and 1,500 pounds of sulphur were
added to this and the mixture was cooked for one hour. After
allowing the solution to settle 24 hours the clear liquid tested 23°.
Baumé and there was 40 per cent in volume of sludge. An attempt
was made to raise the test of this solution (Experiment 4) by adding

4 BULLETIN 197, U. S. DEPARTMENT OF AGRICULTURE.

to it 200 pounds of lime and 400 pounds of sulphur. After cooking |
this for an hour and allowing it to settle there was 45 per cent in |
volume of sludge and the clear solution tested 27° Baumé. In an }
attempt to make a high-test solution by using a reduced quantity |
of water mixed with sludge Experiment 5 was conducted. To the |
280 gallons of sludge remaining in the cooking vessel from Experiment |
2 there were added 620 gallons of water, making a total of 900 gallons. |
To this was added 1,000 pounds of lime and 2,000 pounds of sulphur, |
This was cooked for one hour, and after allowing it to settle for 24 |
hours there was 45 per cent in volume of sludge, and the clear solu- |
tion tested 32.5° Baumé. It will be seen that a high-test solution |
was obtained by reducing the quantity of water, but the percentage
of sludge was also considerably increased.

EXPERIMENTS AT VIENNA, VA.

A few lime-sulphur cooking experiments were conducted at
Vienna, Va., in the spring of 1911. A large iron pot placed over a
wood fire was used as a cooking vessel. In four of these experiments
the 50-100-50 formula was used. The time of cooking was from 45
minutes to one hour. The results, which show variation in Baumé
test and a high percentage in volume of sludge, are given in Table
He

Tape III.—Resulis of cooking different lots of lime and sulphur in preparation of lime-
sulphur wash, Vienna, Va., 1911.

Gast Percentage
Experi- in volute Degrees
ment No. Bpslidee Baumé.
Lime. Sulphur. Water. Be:
Pounds. Pounds. Gallons.
8 8 16 8 40.0 30.6
9 40 80 40 33.0 28.8
10 40 80 40 40.0 28.7
11 40 80 40 50.0 27.0

EXPERIMENTS AT BENTON HARBOR, MICH.

Some experiments were conducted at Benton Harbor, Mich., in the
fall of 1912 for the purpose of making high-test solutions. The cook-
ing plant consists of a 12-horsepower boiler from which steam is
conducted into two 50-gallon barrels. There are no coils in the bot-
tom of the barrels, the steam simply being emitted through the open
end of a straight pipe extending to within a few inches of the bottom
of the barrel.

Small batches amounting to 25 gallons of the finished product were
cooked at atime. About 20 gallons of water were put into the barrel,
then the steam was turned on and the water brought to boiling. The
lime was then put in and after it had begun to slake the sulphur was

HOMEMADE LIME-SULPHUR CONCENTRATE, D

added. The mixture was stirred thoroughly throughout the time of
cooking, which lasted 1 hour. It was allowed to settle about 12 hours,
and then the clear solution was siphoned off. The sludge was put into
a cider press and the clear solution pressed out, using 10-ounce canvas
cloth for filter. A good grade of stone lime was used in experiments
1 to 5. Hydrated lime was tried in experiments 6 and 7. Commer-
- cial ground sulphur was used in all the experiments. The results are

given in Table IV.

_ eee

— Taste IV.—Results of cooking different lots of lime and sulphur in preparation of lime-
sulphur wash, Benton Harbor, Mich., 1912.

Formula.

Experi- Degrees
ment No. Baumé.
Lime. Sulphur. Water. Sediment.
Pounds. Pounds. Gallons. Pounds.

1 25 50 25 32 27.0

2 25 50 25 36 27.0

3 40 80 25 80 34.0

4 40 80 25 90 35.5

5 40 80 25 85 32.5

6 160 80 25 110 30.0

7 160 £0 25 100 31.5

|
1 Hydrated.

In Experiments 1 and 2 the 50-100-50 formula was used, with a
result of 27° Baumé test solution in each case and 32 pounds of
sludge in Experiment 1 and 36 pounds in Experiment 2. In Experi-
ments 3, 4, and 5 the same proportion of lime and sulphur as above
stated was used, but the amount of water was reduced, the formula
being 40 pounds of lime and 80 pounds of sulphur and water to make
25 gallons of concentrate. The Baumé tests of these three batches
varied from 32.5° to 35.5°, and the amount of sludge varied from
80 to 90 pounds. The sludge, after it had been run through the
cider press, was in the form of a thick paste, so the number of pounds
given does not nearly represent the number of pounds of dry sediment.

The formula used in the last two experiments was 60 pounds of
hydrated lime and 80 pounds of sulphur with water to make 25 gal-
lons of concentrate. Where the hydrated lime was used the solution
did not test so high and there was considerably more sludge.

DIRECTIONS FOR PREPARATION OF LIME-SULPHUR CONCENTRATE,

The 50-—100-50 formula has been generally recommended for the
preparation of home-boiled concentrated lme-sulphur solution.
The method of preparation is to boil together for 50 minutes to 1
hour 50 pounds of lime, 100 pounds of sulphur, and water to make
50 gallons of the concentrated solution. A good grade of fresh
stone lime containing not less than 90 per cent of calcium oxid is
necessary for the best results. Hydrated lime is sometimes used,

fhe

6 BULLETIN 197, U. S. DEPARTMENT OF AGRICULTURE.

but it is necessary to use a good grade and at least 20 per cent more of |
this form of lime, as it contains a high percentage of moisture.

Place enough water in the cooking vessel to finish with 50 gallons
of the solution. Bring the water to the boiling point,.start the
agitator, if the plant is equipped with one, then put in the lime
and immediately add the sulphur. The mixture should be stirred
vigorously either mechanically or by hand until the lime is slaked.
Agitation should be continued throughout the time of cooking, which
should not exceed one hour. If the solution is to be barreled without
filtering, it should be drawn off immediately and allowed to run ©
through a 30-mesh strainer into the barrels. The agitation should.
continue until all the solution is drawn off, so that there will be an —
equal distribution of the sludge in the different barrels.

PREPARATION OF HIGHLY CONCENTRATED LIME-SULPHUR SOLUTION.

From the experiments above reported, it 1s evident that a highly
concentrated lime-sulphur solution may be made by using the lime
and sulphur at the ratio of 1 to 2 as is usually recommended, but
with reduced quantities of water. The formula used in the com-
mercial lime-sulphur manufacturing plants visited and also in the
foregoing experiments is as follows:

PECANS LONC MMC sod ce are cher aren, noi mn ote Se ee pounds.. 80
Commercralicround:sil pHur. 2222.52 ee ee eee ees dos 160
Water to make the finished product ...........--..-...--+-- gallons.. 50

While there is about 50 per cent in volume of sludge after allowing
this solution to settle for 24 hours, there is only about 5 to 10 per cent
in volume of insoluble materials. These consist of sulphites, free
lime, free sulphur, magnesium compounds, etc., varying with the
kind of lime used and other conditions.« Solutions prepared by this
formula should test on an average 33° to 34° Baumé.

RELATIVE COST.

Commercial ground sulphur can be bought in car lots for about
$1.50 per hundred pounds, and lime at about 60 cents per barrel. At
these prices the highly concentrated solution can be made at the
following cost per barrel:

80 pounds lime at 60.cents per barrel... 2.222522 22 2ee- 222242 $0. 20
160 pounds sulphur at $1.50 per hundredw eas Se aE A es See 2.40
Labor and. fuel, estimated 22 tc.1,5. 2o285> nea eee See eee .70

Total cost per barrel of 50 gallons.............---.------+- 3.30

This does not include interest and wear on outfit, and cost of
containers for storing. At the foregoing prices of ingredients the
high-test concentrate would cost about 98 cents more per barrel than
the lower-test concentrate made by the 50—100-50 formula.

WASHINGTON : GOVERNMENT PRINTING OFFICH : 1915

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