Extn. of graphite from residues of calcium cyanamide hydrolysis - by multiple flotation and acid treatment

摘要

Prepn. of very fine-particle graphite from residues of calcium cyanamide hydrolysis by water and CO2, is carried out by multi-stage flotation to produce an enriched graphite concentrate, which is then treated with acid to remove CaCO3, and opt. finally treated with alkali. Used as reduction carbon for electrothermal mfr. of silicon and its alloys, for prodn. of moulded products, as carburising agent or as covering powder for metallurgical melts. Graphite of 90-98% purity is obtd. by an economical process with reduced consumption of acid. By use of HNO3 as acid, the sepd. soln. can be used in fertilisers.