PROCESS FOR SEPARATELY RECOVERING ZINC AND LEAD VALUES FROM ZINC AND LEAD CONTAINING SULPHIDIC ORE

摘要

A process for separately recovering zinc and lead values from zinc and lead containing sulphidic ore which also contains iron comprises subjecting ground ore to a first flotation step to float an initial lead concentrate containing zinc and produce zinc and iron containing tailings. The zinc and iron containing tailings are subjected to a second flotation step to float an initial zinc concentrate containing iron and also produce tailings. The initial zinc concentrate is subjected to a third flotation step to float a further zinc concentrate containing iron and also produce zinc and iron containing tailings. The zinc and iron containing tailings from the third flotation step and at least a lead and zinc containing portion of the initial lead concentrate are leached in a first leach step under oxidizing conditions at a temperature in the range of from about 130 DEG to about 170 DEG C. in aqueous sulphuric acid solution with a stoichiometric excess of sulphuric acid relative to the zinc content of from about 50 to about 150% so as to give a terminal acidity of from about 50 to about 80 g/L to produce a lead-containing residue and a first leach solution containing zinc and iron. The lead containing residue is separated from the first leach solution and the first leach solution is treated with the further zinc concentrate or calcine produced therefrom by roasting to dissolve zinc therefrom and precipitate a substantial amount of dissolved iron, thereby producing an iron containing residue and a second leach solution containing zinc. The iron containing residue is separated from the second leach solution, and the second leach solution is treated to recover zinc.