LIU Jin^1,2，ZHANG Junfang²，WANG Ji¹，NING Zengping³
(1.Guizhou Normal University, School of Geography and Environmental Science, Guiyang 550025;
2.Guizhou Environmental Science Research and Design Institute, Guiyang 550023;
3.State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081)

Abstract: This study explored the solidification effect and feasibility of red mud on Mn2+ of electrolytic manganese slag, and X-ray diffraction (XRD), scanning electron microscope (SEM) and X-ray fluorescence spectroscopy (XRF) and other analytical methods were used. Fresh red-mud, old red-mud (stacked for more than one year), quicklime, composite of old red-mud and quicklime at different dosages were tested for their solidification effects, and a preliminary explanation on the mechanism of Mn2+ solidification by red-mud was presented. The results show that the solidification effect of fresh red mud is better than that of old red mud, but worse than quicklime; when the addition amount of the fresh red mud is 30%, the solidification rate of Mn2+ is 93.7%, while the solidification rate with the same addition amount of old red mud is only 58.6%, the loss of some alkaline substances during the storage of old red mud may explain the difference. In addition, when 30% old red mud is combined with 5% quicklime, the solidification rate of Mn2+ can reach 99.8%, which is similar to the solidification effect of 10% quicklime, indicating that using red mud to replace part of the quicklime can also achieve comparative solidification effects and reduce the solidification costs. In short, red mud has the potential as a solidifying agent for electrolytic manganese slag, but considering that there are other hazardous substances in electrolytic manganese slag and red mud, it is necessary to comprehensively evaluate whether it will cause secondary risks before large-scale use.

Key word: electrolytic manganese slag; soluble manganese ions; red-mud; quick lime; solidification rate

EARTH AND ENVIRONMENT Vol.49, No.4, Tot No.342, 2021, Page 455