Effect of Pretreatment During Leaching of Chambishi Copper–Cobalt Air Roast–Leach Calcine Residue

CopperCopper–cobaltCobalt calcine leach tailingsTailings material from ChambishiChambishi township of Copperbelt province of ZambiaZambia is refractory in nature due to the presence of copperCopper/cobaltCobalt silicate and residual sulphide minerals. With the aim of solubilizing copperCopper and cobaltCobalt, the material was pre-treated by roastingRoasting in air alone and combination of air and elemental sulphur. As-received material was characterized by XRD and SEMScattering electron microscopy (SEM) techniques. LeachingLeaching without pre-treatment gave poor recoveries (< 45%) for copperCopper and cobaltCobalt. RoastingRoasting of the feed material in air alone had no and little effect on improving leach efficiencies of copperCopper and cobaltCobalt, respectively. On the other hand, copperCopper and cobaltCobalt recoveries of 70 and 80% were obtained after roastingRoasting the feed material with elemental sulphur. The effects of roastingRoasting temperature and dosing of elemental sulphur were studied.