Environmentally sustainable technology for the treatment of electrolytic manganese residue: Enabling harmless disposal and utilization in building materials

Electrolytic manganese residue (EMR) is an industrial solid waste discharged by the electrolytic manganese metal (EMM) industry with a growing stockpile that currently exceeds 160 million tons in China. EMR contains impurities and harmful ions such as Mn²⁺ and NH₄⁺ that cause severe environmental pollution. Fortunately, EMR also contains a high concentration of CaSO₄, similar to industrial gypsum, which makes EMR an alternative to gypsum in building materials. In addition, the harmful elements are stabilized and essentially eliminated when EMR is used as a building material. To facilitate future research with EMR, this paper provides a comprehensive review on the harmless treatment of EMR and its use as a building material. The harmless treatment methods for EMR include leaching (e.g., chemical, biological, electrochemical), solidification/stabilization (e.g., via chemical reagents or other industrial wastes) and roasting. The use cases of EMR as a building material include cement, concrete, bricks, road base materials, backfill materials, geopolymers, ceramic and ceramsite. After reviewing each of the aforementioned processes separately, their challenges and prospects are discussed together. Finally, several ways are proposed to better streamline current EMR research toward more efficient large scale industrial applications.