Synergistic effects of ferric sulfate addition and mechanical activation on leaching of Sarcheshmeh copper sulfide concentrate

In this paper, the leaching of a sulfide concentrate, from “Sarcheshmeh Copper Complex”, by sulfuric acid is studied. The influences of sulfuric acid concentration and leaching temperature were scrutinized to optimize the processing parameters and to disclose the kinetics of the extraction process. The leaching rate of copper was not significantly improved with enhancing the temperature and concentration of sulfuric acid. The formation of elemental sulfur was found as a reducer of the leaching rate. Only ~70% of copper was extracted by adding 1M ferric sulfate as the oxidant agent, as well as increasing the leaching temperature up to 85 °C. By leaching the mechanically activated concentrate in Fe2(SO4)3-doped H2SO4 at 85 °C, the amount of extracted copper was ~90% after 180 min. The experimental results were excellently fitted with the diffusion-controlled kinetic model as the activation energy of ~27 kJ/mol was estimated.