One ton of bismuth in the lead smelter and 60 years of Kroll-Betterton

CIM Bulletin, Vol. 89, No. 1003, 1996

Funsho K. Ojebuoboh Asarco Inc., Technical Services Center Salt Lake City, Utah, U.S.A.

With several “green” applications on the horizon, bismuth has become an even more important minor metal in the smelting and refining of lead. Smelters with a complex sulphide feed invariably deal with bismuth. Its behavior during the smelting of lead in conventional sinter-blast furnace operation is discussed. Because it readily deports to the lead phase during the refining of lead, its separation from refined lead remained unsatisfactory in early lead production. When commercial requirements of bismuth in lead became more stringent early this century, the procedure whereby calcium and magnesium is used to debismuthise lead was developed. The present conduct of this 1936 process, the Kroll-Betterton process, is discussed with emphasis on operational improvements.

Keywords: Metallurgy, Bismuth, Smelting of lead, Refining of lead, Kroll-Betterton process.