The harmless and value-added utilization of red mud: Recovering iron from red mud by pyrometallurgy and preparing cementitious materials with its tailings

Red mud (RM) is an alkaline waste residue discharged in alumina production. RM accumulation harms the environment and human health, making it urgent to find harmless treatment methods. RM contains abundant iron resources and potential pozzolanic activity minerals. The industrial utilization of RM has a positive impact on low-carbon and sustainable development in the steel and cement industries. This paper reviews a large-scale and harmless treatment method for high-iron red mud (HRM) that involves recovering iron from HRM using pyrometallurgy and utilizing the tailings after iron extraction from high-iron red mud (HRMT) to prepare cementitious materials. The paper elaborates on the general principles of iron recovery from HRM by pyrometallurgy, the activating principle of RM's pozzolanic activity by pyrometallurgy, the mechanical performance enhancement principle of HRMT-cement-based cementitious materials (HRMT-CM), and the stable solidification principle of hazardous elements in HRMT-CM. Finally, suggestions and prospects are proposed for the industrial utilization of RM.