A laboratory-scale investigation of alkaline zinc electrowinning

The possibility of utilizing alkaline electrolysis technique in zinc electrowinning has been investigated. Effects of electrolysis conditions on the morphology of deposited zinc were also studied. The composition of the electrolyte was selected to be in accordance with the industrial practice, 25 g/l Zn2+ and 240 g/l NaOH. The investigated parameters were current density (500, 1000, 1500 A/m2) and electrolyte temperature (35, 50, 65 °C). Considerably high current efficiencies (97–99%) were obtained with energy consumptions of 2.46–2.7 kW h/kg Zn as compared to 3.25–3.4 kW h/kg Zn of industrial electrowinning, which resulted in 20% energy savings. Zinc deposits obtained were in spongy and powdery form.