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

Shichao He; Benjamin P Wilson; Mari Lundström; Zhihong Liu

doi:10.1016/j.jhazmat.2020.123561

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

J Hazard Mater. 2021 Jan 15:402:123561. doi: 10.1016/j.jhazmat.2020.123561. Epub 2020 Jul 26.

Authors

Shichao He¹, Benjamin P Wilson², Mari Lundström², Zhihong Liu³

Affiliations

¹ School of Metallurgy and Environment, Central South University, Changsha 410083, China.
² Hydrometallurgy and Corrosion, Department of Chemical and Metallurgical Engineering (CMET), School of Chemical Engineering, Aalto University, P.O. Box 16200, FI-00076, Aalto, Finland.
³ School of Metallurgy and Environment, Central South University, Changsha 410083, China. Electronic address: zhliu@mail.csu.edu.cn.

PMID: 32769004
DOI: 10.1016/j.jhazmat.2020.123561

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 (R_60min/600°C) exhibit the highest rate of manganese recovery, 67.12 %. After 25 min of deionized water washing, the concentration of manganese in solution from R_60min/600°C material become stable, whereas after 6 washing cycles the concentration of manganese in the solution is < 0.005 g/L. The R_60min/600°C material with three wash cycles results in a manganese-water solution concentration that is suitable for use in electrolytic manganese metal production. Finally, toxicity leaching tests show that the concentrations of ions present in the leaching solution are all lower than the regulatory limits mandated by the Chinese Integrated Wastewater Discharge Standard GB 8978-1996.

Keywords: Electrolytic manganese residue (EMR); Hazard-free treatment; Low temperature roasting; Recovery of manganese; Water washing.