Hazard-Free Treatment of Electrolytic Manganese Residue and Recovery of High-Concentration SO2 Using High-Temperature Reduction Roasting Process

Abstract

A combined preparation of SO2 and recovery of solid products was investigated as a hazard-free method to use coke as a reducer to treat electrolytic manganese residue (EMR) at high temperature. In this study, the response surface prediction and thermodynamic analysis of the high-temperature calcination of EMR were evaluated. In addition, the effects of mole ratio of EMR to coke and temperature on the gas–solid phase and the feasibility of calcined solid products as cement raw materials were also studied. The results showed that the release of sulfur from EMR mainly depends on the mole ratio of EMR to coke and temperature. The best condition for preparing SO2 was EMR calcined for 60 min at 1000 °C and the molar ratio of C:CaSO4 = 0.78:1. At this time, the volume fraction of SO2 reached 7.6%, which meets the requirements for preparing sulfuric acid with SO2. Under this condition, the sulfur in desulfurization manganese residue (DMR) was reduced to 0.38%, and DMR was used as cement raw material to prepare cement. The cement prepared by adding 10% DMR meets the national standard GB175. The method realized the recovery of sulfur in EMR and calcined solid products and promoted the resource utilization of EMR.