Investigation of Roast-Leach of High Sulphur Containing Slag from Luanshya, Zambia

CopperCopper smelting slagSlag from LuanshyaLuanshya town in the Copperbelt province of ZambiaZambia contains significant amounts of elemental sulphurSulphur (about 37 weight %) which was dumped by the community. Leached tests with and without pre-treatmentPre-treatment were carried out on the materialMaterials. Direct leachingLeaching (without pre-treatmentPre-treatment) yielded maximum recoveryRecovery of about 26% for copperCopper, while cobaltCobalt and chromiumChromium could not be extracted. Pre-treatment was done by roasting the materialMaterials in air at a temperatureTemperature range of 150–700 °C. The roasted calcine was leached at 33% solids and pH of 1.8. CopperCopper leach efficiency of about 82% was obtained. The dissolution of cobaltCobalt and chromiumChromium during leachingLeaching was dependent on roasting temperatureTemperature. Leach efficiency for cobaltCobalt and chromiumChromium decreased with increase in roasting temperatureTemperature. It was concluded that high sulphurSulphur containing slagSlag materialMaterials should be processed via air roasting followed by leachingLeaching.