Solidification/stabilization and separation/extraction treatments of environmental hazardous components in electrolytic manganese residue: A review

Electrolytic manganese residue (EMR), a by-product of the electrolytic manganese metal production process, contains several hazardous components such as ammonia nitrogen (NH3-N), soluble manganese, and heavy metals. In recent years, although a great number of treatment methods have been proposed, there is no mature and economical industrial process for treating EMR. Therefore, previous studies on separation/extraction (S/E) and solidification/stabilization (S/S) treatments of EMR are reviewed and are of great significance for further studies. The various treatment methods are summarized and evaluated, and the existing problems or prospects are given. The use of external field enhancement methods and appropriate auxiliary leaching agents in the S/E process can effectively improve the leaching efficiency. In the S/S treatment, it is found that the synergism of multiple solid wastes can increase the waste treatment capacity, which has significant environmental benefits and even can realize resource utilization. The research on manganese treatment has been found to have achieved remarkable results, but the problem of ammonia nitrogen in EMR still cannot be ignored and future research still has challenges. Further, based on the existing problems with harmless treatments of EMR, some suggestions are provided and the remaining challenges for future research are identified.