THE DETERMINATION OF NICKEL IN NICKEL ORES
Journal of the American Chemical Society
advantage of leaving the iron, lime, and alumina insoluble at the start and only a small quantity of alkali is introduced into the analysis. A s for the mineral constituents they are better determined on a separate portion. Their accurate determination is made all the more difficult by the presence of an excessive amount of alkali metals as in Peckham's method. Our practice has been to heat the asphalt at a low temperature in a platinum dish, s l o~l y driving off the volatile constituents in
... e constituents in such a way that the asphalt does not buin. At the end the temperature map be raised and the reniaining organic matter burned without danger of loss. T h e ash is extracted with hydrochloric acid and any insoluble residue fused with a small amount of the mixed carbonates. T h e solution of the fusion in hydrochloric acid is added to the other and the analysis proceeded with as usual. In this way the quantity of alkaline salts is reduced to a minimum. Time is actually lost by deterniining the metals and sulphur in one portion as the determination of the latter must wait until the metals have been separated. I n all but two of the asphalt analyses of Dr. Day, as quoted by Messrs. Peckham, the decimal point is misplaced, making the per cent. sulphur far less than it should be.