Recovery of manganese and lead from electrolytic manganese anode slime based on a roasting and acid leaching reduction system

Electrolytic manganese anode slime (EMAS) is a complex solid waste containing lead that is generated in the anode chamber during the production of electrolytic manganese metal, which poses challenges in its treatment. In this study, a sulfur-based reduction-roasting-acid-leaching system was developed based on thermodynamic calculations and wet leaching principles. The influences of the roasting temperature, manganese-to-sulfur ratio, roasting time, solid-liquid ratio, leaching temperature, leaching time, and sulfuric acid concentration on the separation of lead and manganese were investigated. The acid leaching process was kinetically fitted, and the leaching conditions were optimized using response surface methodology. The results showed that under optimal reduction-roasting-acid-leaching conditions, the leaching rate of manganese was 98.77 %, and the acid leaching process were conformed to the chemical reaction model 1-(1-x)1/3 = kt. The lead content in the filter residue was 45.23 %, meeting the requirements for lead concentrate ore. The SO2 gas generated during roasting was effectively treated by alkaline solution absorption, thereby achieving the separation, harmless treatment, and resource utilization of lead and manganese in EMAS.