Selective leaching of arsenic and antimony contained in the anode slimes from copper refining

Abstract

Selenium, tellurium, silver and gold are recovered from the anode slimes of copper electrorefining. Silver-copper selenide-telluride phases must be previously oxidized to obtain selectively leachable compounds. Arsenic and antimony, present in anode slimes as AsSb oxidized compounds, may be selectively and almost completely dissolved in 0.4 M KOH at 80δC. After this extraction, alkaline roasting of anode slimes in the presence of K 2CO 3 at 600°C solubilizes Se (99%) and less than 2% As and 0.1% of Sb. After Se leaching, Cu and Te can be dissolved in 1.2 M HCl at 25°C as well as in CuSO 4H 2SO 4 solution. The residue contains BaSO 4, PbSO 4, SiO 2, Au, Ag and small amounts of Se, Cu and Te and can be smelted in order to obtain a bullion for Ag and Au recovery by the conventional electrorefining process.