Leaching behavior of copper using electro-generated chlorine in hydrochloric acid solution

Abstract

The leaching behavior of metallic copper has been investigated using chlorine electro-generated at the anode in 1.0 mol/L HCl solution. An electrochemical reactor divided into two compartments by an anion exchange membrane was employed for these experiments. Various parameters, viz., current density, chloride concentration, leaching temperature and time, and agitation speed, were studied to understand the mechanism of copper leaching. The leaching rate of copper increased with increasing current density, from 10 to 40 mA/cm 2, increasing agitation speed, from 200 to 600 rpm, and increasing temperature, from 25 to 50 °C. The addition of Cl − ions enhanced the leaching efficiency of copper remarkably by dissolving CuCl precipitated on the surface of the copper plate. Based on the results of the leaching experiment, the leaching of copper by electro-generated chlorine is proposed to proceed through three stages: stage I (ORP of leach solution ≈ 1300 mV SHE), stage II (380 mV SHE < ORP < 490 mV SHE), and stage III (ORP > 490 mV SHE).