Treatment of copper-cobalt alloy with molten magnesium for metal extraction

Abstract

Cu-Co alloy is an intermediate product from the pyrometallurgical processing of cobalt oxide ores, which mainly contains metallic components of Cu, Co, Fe and Si. This research aims to extract Cu from Cu-Co alloy by selective dissolution using molten Mg. The alloy particles were mixed with Mg and held at temperatures in the range 700–900 °C for 0.5–2 h. The residual Fe-Co-Si alloy settled to the bottom of the melt due to the density difference between the alloy and molten Mg. Under optimal conditions, as much as 99 wt% Cu can be selectively extracted from the alloy by dissolution into the molten Mg. Vacuum distillation at 900 °C was applied to the obtained Mg-Cu alloy, resulting in the formation of Cu power with 80 wt% purity. The recovered Mg metal after distillation could potentially be recycled for re-use. Therefore, this process achieved efficient extraction of Cu without the consumption of Mg and generation of waste, representing an effective and environmentally-sound approach for the processing of Cu-Co alloy.