Electrodeposition behavior rules of cadmium in lead smelting dust leachate

Cadmium is commonly associated with zinc, lead-zinc and copper-lead-zinc ores. Thus, approximately 95% of cadmium is recycled as a byproduct in the lead and zinc smelting process, among which smelting dust is one of the main raw materials for cadmium recovery. In this paper, the electrolytic deposition behavior of cadmium in a sulfuric acid leach solution of lead smelting soot was investigated, mainly the influence laws of current density, temperature and the concentration of Cd²⁺ on the current efficiency, specific power consumption, purity and morphology of cathode cadmium. The results show that the current efficiency of electrodeposition for 4 h can reach 96.14% with a specific power consumption of 1.769 kW·h/kg and a cadmium purity of 97.75% at a current density of 150 A/m², a temperature of 30 ℃ and a cadmium concentration in the immersion liquid of 40 g/L. The increase in temperature and current density and the consumption of Cd²⁺ reduce the current efficiency and increase the unit power consumption, respectively. Furthermore, the electrode reaction kinetics show that the reduction process of cadmium ions in the cathode region is controlled by ion diffusion.