Abstract:When the electrowinning displacement method is used to recover cadmium from Copper-cadmium-bearing Slag, the electrowinning process will produce floating sponge cadmium, which leads to low cadmium recovery efficiency and is not conducive to the subsequent briquetting and smelting.Based on the analysis of the principle of cadmium electrowinning, the experiment of ultrasound-assisted cadmium electrowinning was carried out by using the cavitation of ultrasonic.The effects of current density、temperature、ultrasonic power、area ratio of cathode to anode and electrowinning time on the recovery rate of cadmium were investigated, and the following main conclusions were obtained.The results of cyclic voltammetry test show that cadmium in the electrolyte can be replaced by electrodepositionin the sulfate system, andthe precipitation of cadmium is better than thezinc, and zinc in the outer layer of cadmium will be partially dissolvedin the progress of electrowinning;The comparison test of cadmium electrodeposition with and without ultrasonic assistance showed that,the recovery rate of cadmium was 16.25% without ultrasonic assistance, and the electrodeposited cadmium was fluffy, porous and easy to float. The recovery rate of cadmium was 25.11% with 180W ultrasonic assistance, and the electrodeposited cadmium was dense and easy to fall off;The results of single factor experiment show that: the recovery rate of cadmium in leaching solution can reach 100% under the conditions of current density of 150A/m2, temperature of 35℃, ultrasonic power of 240W, area ratio of anode to cathode plate of 1∶3, and electrowinning time of 2.5h; The electrochemical experiments at different temperatures show that the increase of temperature is beneficial to the precipitation of cadmium, and the precipitated zinc is more easily oxidized and dissolved, cadmium is more difficult to oxidize and dissolve, thus improving the recovery rate and purity of cadmium.
