The effect of sulfur and reduction temperature on cobalt dissolution during sulfuric acid leaching of metallic matte

In this work, the influence of sulfur content and distribution on the efficiency of cobalt dissolution during H2SO4 leaching of metallic matte (Fe-Co-Cu2S.FeS) has been investigated. The matte was formed by carbothermal reduction of copper slags containing 0.4% Co at temperatures between 1400-1800 degrees C in a submerged type DC are furnace operated at 40-70 kVA. The sulfur content of the metallic matte varied from 1.32% to 3.10% depending on the reduction temperatures. Low temperature carbothermal reduction (1400-1450 degrees C) produced homogeneous sulfur distribution which enhanced the dissolution of cobalt from matte granules obtained by atomizing. Granules having a sulfur content between 2.9-3.1% exhibited faulted structures. It was found that faulted structure having sulfur content higher than 2.9% was favoured cobalt dissolution. (C) 1997.