RECOVERY OF ZINC FROM ZINC SULPHIDES BY DIRECT PRESSURE LEACHING

摘要

Rapid and substantially complete extraction of zinc from zinc and iron containing sulphides is obtained by leaching the sulphides under oxidizing conditions at a temperature above the melting point of sulphur with an aqueous sulphuric acid solution containing at least the stoichiometric amount of acid required to combine with the zinc content of the sulphides as zinc sulphate and, also, containing an additive which is effective to prevent or at least substantially inhibit the molten sulphur from occluding unleached zinc sulphide particles thereby enabling the leaching reaction to continue until substantially all zinc values are extracted. Additives which are suitable for the process include lignins, lignosulphonates, tannin compounds, particularly quebracho, and other tree bark extracts, and alkylaryl sulphonates.