Fluidized roasting-stage leaching of a silver and gold bearing polymetallic sulfide concentrate

摘要

The process of fluidized roasting-stage leaching has been developed in this paper to extract silver and gold and their associated metals including copper, zinc and antimony from a complex polymetallic sulfide concentrate. Sintering of the concentrate with high Pb content might be avoided during fluidized bed roasting under appropriate operating parameters, and the SO_2 concentration in flue gas was sufficiently high to produce sulfuric acid. After the roasting, Cu and Zn in the mixture of calcine and soot were effectively extracted by two-step coun-tercurrent sulfuric acid leaching, while the dissolutions of Pb, Sb, Ag and Au were all negligible. Non-oxidative and oxidative chloride leaching was carried out successively after the sulfuric acid leaching. Ag and Sb in sulfuric acid leaching residue were well extracted by the non-oxidative leaching, and Au was effectively extracted by the oxidative leaching. Pb was still hardly dissolved by these two chloride teachings and concentrated in final residue.