Optimizing hydrolytic purification of zinc electrolyte from selenium, tellurium, and arsenic impurities

This study addresses the improvement of hydrolytic purification processes for zinc electrolyte solutions obtained from zinc cinder leaching, with the goal of enhancing electrolyte quality for efficient electrolysis. A comprehensive mineralogical analysis of process residues was conducted using an Olympus BX51 microscope, a SIMAGIS XS3CU digital camera, and Mineral C7 software. The presence of selenium, tellurium, and arsenic in the electrolyte negatively impacts zinc cathode quality and energy efficiency, making their removal critical. A novel purification method was developed and experimentally validated, involving the addition of 1.0 L of an iron solution (0.5–1.0 g/L Fe) to 80 m3 of zinc electrolyte. This approach significantly reduced the concentration of harmful impurities. Characterization of precipitates formed during purification revealed that iron hydroxide facilitates the coagulation of silicic acid, thereby enhancing impurity removal. The improved purification method led to a measurable reduction in impurity levels, increased zinc yield, and decreased energy consumption during electrolysis. These findings demonstrate the effectiveness of the proposed hydrolytic purification approach and its contribution to the economic and operational performance of zinc production.