SELECTIVE LEACH RECOVERY OF ZINC FROM A COMPOSITE SULPHIDE ORE DEPOSIT, TAILINGS, CRUSHED ORE OR MINE SLUDGE

摘要

Zinc and lead are usually concomitantly present in Zn-Pb ores and tailings. A novel non-polluting hydrometallurgical process for selectively leaching and recovering zinc (Zn) from a composite lead (Pb) and zinc sulphide containing mineral, crashed untreated rock or unconsolidate mineral particles, mill tailings and/or agglomerated or unagglomerated sulphidic zinc containing waste material without necessitating smelting and refining operation has been developed. This technology can be employed either in-situ or ex-situ based on the amenability of a particular type of mineral deposit or feed ore. A process and leachant composition are provided for selective leaching of zinc from mixtures and ores containing zinc sulphide comprising contacting the mixture or ore with an aqueous leachant comprising: 1) an oxidant selected to oxidize the sulphur present only to elemental sulphur, and 2) alkali metal hydroxide in amounts sufficient to form soluble alkali metal zincate; extending the contact time between leachant and solids to give the desired zinc recovery and selectivity in the leachate while maintaining operative reagent concentrations; separating the desired leachate from the residual solids; and recovering zinc from the leachate.