Gallium recovery by cyclone electrowinning from alkaline electrolyte with titanium cathode

A process for gallium recovery by cyclone electrowinning was proposed to inhibit concentration polarization and improve current efficiency (CE). The diffusion coefficient of GaO 2 − in 120 g/L NaOH solution was determined to be 1.65×10 −7 cm 2 /s by electrochemical study. The effect of various parameters on gallium electrowinning was investigated, and the optimum conditions were determined as: titanium cathode, current density of 750 A/m 2 , gallium concentration of 39.9 g/L, NaOH concentration of 120 g/L, and circulation flow of 200 L/h. Under these conditions, the CE and gallium recovery of electrowinning were 47.9% and 90.2%, respectively. The precipitated gallium can be easily separated from the cathode, and the final purity of gallium after washing was 99.993%. The energy consumption (EC) of gallium cyclone electrowinning was about 9048 kW·h/t. Overall, it is suggested that cyclone electrowinning is a promising process for gallium production with high CE and low EC.