A new process of selective separation and extraction of copper and germanium during zinc hydrometallurgy

Abstract

ABSTRACT In view of the poor enrichment of copper and germanium and low recovery of copper during traditional zinc hydrometallurgy, this study develops a new process of acid leaching. The behaviours of zinc, iron, copper and germanium were studied under different conditions. The results showed that the final pH had significant impacts on the behaviour of metals during the leaching process. Under conditions of final pH 3.5–4.0, time 2.0 h, temperature 80°C and no oxidant, the copper leaching rate was 45.88% using weak acid leaching and the precipitation rates were 9.09% and 84.31% for germanium and iron, respectively. The next stage of low acid leaching under conditions including final pH 0.1–0.2, time 2.0 h and temperature 80°C, the total leaching rates were 92.66% and 65.64% for zinc and copper, respectively. The weak acid leachate was then subjected to copper reductive precipitation and neutralisation. The process showed that the Cu grade was 20.12% in the residue. The Cu, Fe and Ge precipitation rates were respectively 83.74%, 99.98% and 91.02% during the neutralisation, which was beneficial to the subsequent treatment. The proposed process provides high separation efficiency of copper and germanium and a high leaching rate of zinc and copper.