Selective hydrometallurgical separation of lead from complex lead- zinc- copper sulfide ores or derived concentrates

摘要

A quantitative hydrometallurgical process for the selective conversion of lead sulfide (galena) to its sulfate form under ambient conditions of temperature and pressure. The process works in the presence of associated zinc - copper - iron sulfides which survive the process in a relatively unaltered condition. It is directly applicable to ores or derived concentrates of complex sulfide systems. The lead sulfate is isolated from the ore or concentrate system by a brine wash with subsequent conversion to lead chloride. A free concentration of cupric ion is maintained during the leaching stages to act as an oxidation catalyst and to inhibit the dissolution of zinc sulfide. The forward reaction in terms of lead sulfation is controlled by a chlorite-type mineral with both anion and cation exchange capacity added to, or maintained in a dilute sulfuric acid leach cycle. The evolution of hydrogen sulfide is inhibited by the reaction rate under aeration conditions in the presence of a rigidly controlled concentration of soluble iron programmed into the leach system by imposed reducing and oxidizing conditions.