Lead, copper, zinc and silver recovery from sulphide concentrates - by sequential sulphuric acid, lime and chloride leaching

摘要

Pb, Cu, Zn and Ag are selectively recovered from sulphide concentrates by (a) contacting the concentrate with sulphuric acid in the presence of oxygen at elevated temp. and pressure (pref. =100 degrees C and 60-80 psi) to extract Cu and Zn values; (b) contacting the concentrate with lime (pref. at 95 degrees C) to remove elemental S; and (c) contacting the concentrate with a mixt. of CaCl2 and FeCl3 to extract Pb and Ag values. The metals are recovered in high yields from low grade materials such as smelter dusts, metal drosses, middling concentrates from flotation, etc. Pyrite gangue in the concentrate remains inert at all stages of the process.