Abstract: This paper first studied the key factors affecting the initial manganese electrolysis process, including concentration of Mn²⁺, electrolysis time, overpotential, and then optimized these processing parameters with the chronocoulometry method under a three-electrode system. The results showed that, during the initial manganese electrolysis process, hydrogen evolution occurred more significantly on the stainless steel surface. As electrolysis process continued, manganese covered the stainless steel surface gradually, and hydrogen evolution reaction restrained which all contributed to the higher current efficiency. Besides, the limiting current density appeared at high overpotential region, and the reaction was controlled by diffusion process. In 0.02 g·L^-1 SeO₂ solution system with 40 g·L^-1 Mn²⁺ and 120 g·L^-1 (NH₄)₂SO₄, electrolysis time of 0.5 h overpotential of 0.151 V, bath temperature of 40 ^oC, pH of 6.6, the current efficiency was achieved as high as 95.3%. And an efficiency of 81.4% was also realized in the industrialized electrolyte system, which was 15% higher as compared to the previous operation parameters under the same electrolyte system.

Key words: manganese, electrolysis, electrochemical, current efficiency