Study on de-aluminization and iron extraction from high-iron Bayer process red mud

Red mud is the industrial waste produced in the process of extracting Al₂O₃ from bauxite, of which the proportion of high-iron red mud is increasing, and the iron content of high-iron red mud is higher than that of ordinary red mud, so the de-alumination and iron extraction of high-iron red mud is not only of important significance for resource recovery, but also able to reduce the environmental pollution. The common methods for the removal of aluminum and extraction of iron from high-iron red mud include biological, physical, chemical and combined physical-chemical methods. The biological extraction method, which selectively separates minerals by utilizing specific bacteria and their metabolites to interact with the minerals, has a high potential for eco-friendliness, but still faces challenges such as technical and economic feasibility in large-scale applications. The physical separation method is simple and low-cost, but the iron ore concentrates obtained through this method are of low grade and the added value of the product is low. Chemical separation method can obtain higher grade iron ore concentrate and higher quality aluminum concentrate, but it generally has problems such as complicated process flow, high energy consumption and accompanied by environmental pollution. In order to further optimize the method of iron removal from high-iron red mud, the combined physical-chemical method has become an emerging research field for iron removal from high-iron red mud, which improves the effect of iron removal from red mud through the processes of reduction roasting-magnetic separation and leaching-magnetic separation, but it still faces the problems of process complexity and high energy consumption. Therefore, the process of magnetization roasting-alkali leaching-magnetic separation of high-iron Bayer process red mud is proposed to realize the simultaneous enrichment technology of aluminum extraction and iron. The activation of high-iron red mud can improve the efficiency of de-alumination and iron extraction, reduce energy consumption, simplify the process flow, and provide new ideas for the resource utilization of red mud.