Copper and nickel recovery from acidic polymetallic aqueous solutions

Acidic polymetallic wastewaters are generated during the pyrometallurgical treatment of chalcopyrite for the production of primary copper. The most important wastewater streams originate from the copper refining and the electrolyte regeneration stages, characterized by medium to high concentrations of residual sulphuric acid and heavy metals such as Cu, Ni, Pb, Zn, Fe, As, Sb, Bi, etc. These industrial effluents lead to significant losses of valuable metals like copper and nickel. This study focuses on the treatment of synthetic solutions simulating industrial wastewaters from the copper pyrometallurgical plant in Bor, Serbia, proposing a treatment process involving copper electrorecovery followed by nickel precipitation through neutralization. The methodology includes thermodynamic analysis and experimental verification under various conditions, demonstrating that copper can be recovered electrolytically, while nickel can be subsequently recovered but is contaminated with Cu, Fe, Zn, and traces of bismuth, arsenic, and antimony. The proposed innovative treatment technology aims to mitigate environmental impacts and eliminate solid waste generation while efficiently recovering valuable metals.