The effect of silver on the acidic ferric sulfate leaching of primary copper sulfides under recycle solution conditions observed in heap leaching. Part 2: Synergistic additives

The leaching of a chalcopyrite-bearing ore in sulfate solutions typical of heap leaching systems with various additives present was investigated. The catalytic effects of Ag ions and other additives, which included ethylene glycol, chloride ions and a wetting agent, were investigated experimentally for potential synergistic effects. It was established that the benefit of low Ag ion concentrations on Cu extraction can be enhanced significantly by the presence of additional components in the leach solution. The presence of Ag ions and ethylene glycol resulted in increased Cu extraction compared to just Ag ions. It was observed that in the presence of both chloride ions and Ag ions, the Cu extraction was significantly higher at high chloride concentrations than at lower concentrations. A strong synergistic effect on Cu extraction was observed also between Ag ions and a wetting agent. Cu extractions exceeding 80% after 10 days were observed when Ag ions and the wetting agent were both present. Only a small amount of the wetting agent was required to produce this result.