RECOVERY OF ZINC FROM ZINC BEARING SULPHIDIC ORES AND CONCENTRATES BY CONTROLLED OXIDATION ROASTING

摘要

ROGERS, BERESKIN /A PARR TITLE: RECOVERY OF ZINC FROM ZINC BEARING SULPHIDIC ORES AND CONCENTRATES BY CONTROLLED OXIDATION ROASTING INVENTORS: MURRY C. ROBINSON DONALD W. KIRK DR. BRUCE JUE A process is described for the controlled oxidation roasting of zinc bearing sulphidic ores and concentrates by adjusting the furnace temperature and residence time together with the oxygen availability to the sulphide retention requirements in the calcine. The obtained calcine is subsequently subjected to various physical and chemical process steps to separate the unreacted sulphides which are then dead roasted and treated for zinc recovery, according to one embodiment of the process. In another embodiment the separated, unreacted sulphides are returned to the controlled oxidation roasting step. The chemical separation process steps include sulphur dioxide leaching. In one embodiment zinc is preferentially dissolved as sulphite and the solution obtained is further treated for zinc recovery. In other embodiments sulphuric acid, or ammonical ammonium carbonate or similar leaching reagents are used for the preferential dissolution of the zinc oxide present in the calcine.