Oxidative Leaching of Chalcopyrite by Cupric Ion in Chloride Media

In this study, chalcopyrite concentrate produced in Sarcheshmeh copper plant was subjected to oxidative leaching investigation by cupric ion to determine the effect of several parameters on the copper and iron dissolution, including temperature of leaching, time of holding and cupric concentration as oxidant agent in a range of 38–97 °C, 1.5–8.5 h and 0.2–0.8 M, respectively. The leaching media was chloride providing with 3 M HCl 37% and CuCl2. The experiments were designed by central composite design method. The dissolution of copper and iron was examined. The maximum dissolution of copper 62.64%, was obtained at 85 °C, 7 h and oxidant concentration of 0.7 M. The kinetics model of chalcopyrite leaching and an optimized condition with maximum dissolution of copper and minimum dissolution of iron was obtained by Minitab®18 software. Additionally, the thermodynamics of leaching was investigated by Pourbaix diagrams of copper and iron composition, using HSC Chemistry6 software. It was found that the oxidative leaching process is controlled by diffusion through passivation layer with an activation energy of 19.57 kJ/mol.