An Experimental Investigation of Alkaline Zinc Electrowinning Using Magnesium Alloy as Cathode
This paper presents an experimental investigation of the novel alkaline zinc electrowinning process by using magnesium alloy as cathode and stainless steel as anode. The alkaline electrolyte with 40 g/L Zn2+ and 200 g/L NaOH was selected to be in accordance with the industrial practice. Effects of several electrolysis variables, i.e. current density (500, 1000, 1500 A/m2), temperature (30, 50, 70 °C) and impurities (lead and tin) on the morphology of deposited zinc were investigated. The current efficiency was always 100% and the deposited zinc always in powdery form. Specific energy was low, even at 1000 A/m2, and decreased with rising temperature, being only 2.27 kWh/kg Zn at 50 °C, which was much lower than the energy consumption of 3.3-3.4 kWh/kg Zn in the conventional acidic electrowinning.