MIXING CASTS OF PIG IRON AT FURNACE, ETC. I4I
analysis that would be a very close estimate of the
silicon or other metalloids to be found in any such
body of iron in that special grade, brand, or pile of iron.
Very often the founder has not room to pile iron, or
is compelled to use it direct from cars or small piles already in his yard. In such cases the different casts, or parts of such, could, after being mixed in loading it on buggies as described, be conveyed to the cupola stage and stacked in distinct piles according to variations that exist in the percentages of silicon, etc. -When charging the iron that amount necessary to make a mixture would be taken from the different piles in an alternate manner; this would insure a good mixing of the grades as they lay in the cupola. For an example, if an average of 1.90 in silicon was desired in a mixture, and the only iron that could be obtained were casts or piles containing 1.60 and 2.20 silicon, with sulphur about uniform, then each pile would be piled separately on the cupola stage and a pig taken from each pile alternately when charging the cupola. This is a plan which works well, providing a trusty man is in control of the charging. If such is not in command, there are times when this practice leaves a chance for error. Such can be brought about by new men, or old ones, making errors in sorting or placing the iron on the staging or in charging it into the cupola.
A plan which avoids risks, wherever two or more grades must be used to obtain the average desired, as described in the last paragraph, is to have different brands or grades go to the stage at the same time on independent buggies, and then instead of piling each grade separately as is done in the above plan, they areter of the carbons orhe one analysis which may be given is simply an average of the whole, generally taken from the two ends andith the uncertainty of furnace workings when in urgent need of ten hundred jon of iron; and Sir........................ 2,720 "