Study of integrated leaching and electrowinning of copper from chalcopyrite ore using chloride media

Hydrometallurgical recovery of copper from chalcopyrite ore using chloride media has several advantages over sulfate based processes: faster kinetics; high solubility of metals; easy oxidation of sulfides; reduced energy consumption step due to utilization of one electron per atom of copper formation, rather than two in most electro winning operations; and conversion from water hydrolysis to ferric ferrous half-cell reaction, which reduces cell voltage. Disadvantages include corrosivity and reduced limiting current density during electrowinning. A comparison of advantages and disadvantages indicates that leaching of sulfide ore or concentrate in chloride media may be advantageous. Several chloride media have been examined for copper extraction. Cupric chloride and ferric chloride solutions have already proven to be efficient leaching agents; ferrous chloride has been utilized for copper production by means of the Hunt and Douglas process. Cupric/cuprous ion ratio plays a vital role for leaching kinetics. Individually, ferric and cupric ions have proven to be good leaching agents; a combination of ferric/ferrous and cupric/cuprous ions has been explored in this research by conducting factorial design of experiments. Simultaneous leaching and electrowinning is explored in this study as a way to reduce processing and energy costs. Electrowinning has been performed using a solution similar to that being utilized for leaching; factorial design experiments were also conducted to study various factors which affect electrowinning. In summary, this study is focused on determining the effects of Fe3 + ' Fe2 + ' Cu2 + , Cu+ and acid concentration on leaching of chalcopyrite as well as the electrowinning of copper from the resulting leaching solution using a chloride medium. A lab scale design of experiments for integrated leaching and electrowinning of copper from ore is discussed. Possible variations of experimental parameters to improve performance are also discussed. Results showed that high hydrochloric acid and cupric ion concentration assisted leaching; on the other hand, electrowinning of copper from chalcopyrite ore leaching solution using chloride media is much feasible when acid and cupric ion concentrations are low (0.05 M/l and 0.01 M/l, respectively).