HYDROMETALLURGICAL PROCESS FOR TREATING ELECTROLYTIC COPPER REFINERY ANODE SLIMES

摘要

1. Hydrometallurgical process for the reprocessing of anode slime from copper electrolysis and similar raw materials which, apart from silver, can also contain lead, gold, platinum metals, Se, Te, Sb, Sn, As, Bi, Cu, Ni, Zn, Fe, sulphate, chloride, silicic acid, etc. and acid-soluble copper and nickel as well as lead can be removed from the anode slime by pretreatment, characterized in that the thus pretreated anode slime is suspended with hydrochloric acid, chlorinated in statu nascendi by feeding in a sodium hypochloride solution and the resulting chlorine, the Au and Pt metals as well as the Se and Te-containing filtrate is separated, whilst the Ag is converted into AgCl and remains in the slime, from which the silver is then extracted by extraction with ammonia and the Ag(NH3 )2 Cl-containing solution is mixed with Cu**+ compounds at room temperature or in the heat and accompanied by stirring, the Ag**+ is quantitatively precipitated to metallic silver and after filtering, washing and drying is melted to metallic silver, whilst the filtrate is mixed with calcium hydroxide, the ammonia recovered by distillation and the filter cake left behind after filtering is returned to the metallurgical process.