POLLUTION-FREE PROCESS FOR TREATING COPPER SULFIDE FLOTATION CONCENTRATES AND RECOVERING COPPER

摘要

Copper is recovered from copper sulfide flotation concentrates or any copper sulfide ore without emitting significant amounts of sulfur dioxide (SO2). Balls or pellets of the copper sulfide and lime are formed and roasted to produce a shell of reaction products, which includes anhydrite (CaSO4) and oxidized copper, and to cause oxidation of the copper sulfide minerals at the shell/core interface whereby SO2 formed in the reaction must pass through the shell before release and is largely converted to anhydrite. The temperature is controlled to prevent escalation, thereby to retain the sulfur in solid form during the roast and also to prevent formation of copper ferrite (CuO.Fe2O3). Copper is recovered from the pellet product by sulfuric acid leaching followed by direct electrowinning in a preferred embodiment although solvent extraction/electrowinning and cementation are contemplated.