Leaching of Copper Sulphides and Copper Mattes in Oxygenated Chloride/Sulphate Leachants

Abstract

The leaching of chalcocite (Cu₂S) and copper-lead matte in oxygenated acidic chloride-sulphate leachants at 85°C has been studied. Copper leaches from both materials via a two stage process, the overall reactions being and The chloride ions are believed to promote the formation of a crystalline porous sulphur layer on the reacting particle so that essentially complete copper extraction is possible. The same mechanism is also believed to apply during the leaching of copper iron matte and white metal. During the leaching of the copper lead matte, the galena reacts first by galvanically protecting the chalcocite in the duplex structure forming lead sulphate and elemental sulphur. The overall reaction is: