Effect of Thiourea on Copper Cathode from Simulated Leachate of Copper and Cadmium Residues by Cyclone Electrowinning Technology

摘要

The leachate of copper and cadmium residues is treated by cyclone electrowinning technology. The resulting copper cathodes are prone to the formation of nodules and dendritic copper particles during the recovery process. The addition of a suitable dose of thiourea (TU) can alter the preferential orientation of the crystals to refine the copper particles. A suitable current density can stabilize crystal growth fluctuations otherwise caused by the limited diffusion rate. In the study, it was found that the horizontal spacing of copper particles increases with low thiourea concentrations and that the vertical length of copper particles increases at high thiourea concentrations. At low current densities, defects such as pores, depressions, and bumps exist on the surface of the copper particles. At high current densities, the copper particles aggregate into cauliflower-like and dendritic shapes in turn. Optimum conditions are obtained with c(TU) = 3 mg/L and a current density of 250 A/m(2), at which point the copper cathode product is smooth and dense.