Hazard-free treatment of electrolytic manganese residue and recovery of manganese using low temperature roasting-water washing process

Abstract A combined low-temperature-roasting and water-washing process is investigated as a hazard-free method to treat electrolytic manganese residue (EMR) and recover manganese. In this study, the phase transformation characteristics and a thermodynamics analysis of the low temperature roasting process of EMR are evaluated. In addition, the effects of temperature and time on the phase transformation of EMR in the roasting process and the washing characteristics of roasted EMR samples are also investigated. Results reveal that some unstable phases within EMR are transformed into more stable phases depending on the treatment time/temperature conditions used and EMR roasted for 60 min at 600 °C (R60min/600°C) exhibit the highest rate of manganese recovery, 67.12 %. After 25 minutes of deionized water washing, the concentration of manganese in solution from R60min/600°C material become stable, whereas after 6 washing cycles the concentration of manganese in the solution is