Factors on Leaching Zinc and Copper from Zinc Leach Residue
It is found that cuprous sulfite, zinc sulfate and zinc sulfide were the main phases of copper and zinc in zinc leach residue, through analyzing its composition and phase characteristics by XRF and XRD. The method that cooperate sulfuric acid leaching with oxidant was chosen. 60 g/L H2SO4 at 60 °C for 2 h with 4% KMnO4 and liquid/solid ratio of 5..1, 84.29 % of Cu and 92.02 % of Zn are extracted. The ion concentration of copper and zinc are tested by UV-VIS spectrophotometer and EDTA titration respectively. The results show that the amount of acid is sufficient for leaching at the condition of 60 g/L H2SO4 and liquid/solid ratio of 5..1. At the same time, copper change from low valence into high valence after adding KMnO4 which strengthen the leaching, and the chemical reaction can reach balance at 60 °C for 2 h. This method has good extraction effect on copper and zinc.