Abstract:
The electroplating sludge was treated for the comprehensive recovery of copper, chromium and nickel with procedures including sulfuric acid leaching, copper precipitation, chromium removal by two-stage neutralization, and nickel carbonate concentrating. Various processing factors were studied and the optimum conditions were obtained as follows:0.5 h, 50℃, and 0. 8 times of stoichiometric sulfuric acid addition for sulfuric acid leaching; 1 h, 85℃, and 1.2 times of stoichiometric copper precipitator addition for copper precipitation; the two-stage chromium removal method decreases nickel loss in the precipitation process. More than 98% of copper, 99% of chromium and 94% of nickel originally contained in the sludge were successfully recovered by using this process.