From Waste to Functional Materials: Upcycling Red Mud as Oxygen Carriers in Chemical Looping Technology

Abstract Red mud (RM) has an annual output of over 200 million tons. Its improper disposal can cause harm to the surrounding ecosystem and human health. RM mainly contains Fe 2 O 3 , Al 2 O 3 , etc. Preparing it into oxygen carrier (OC) can reduce the impact on the environment and achieve resource reuse. However, the summary of red mud oxygen carrier (RMOC) preparation methods and the progress of its current research are still lacking. Therefore, this paper first reviews the modified methods of mechanical mixing, calcination, acid pre‐treatment, and impregnation for preparing RMOC. The RMOC can be applied for chemical looping combustion (CLC), chemical looping gasification (CLG), and chemical looping (CL) desulfurization and dechlorination. It is found that RM, when used as the OC for the CLC, can achieve a selectivity and purity of CO 2 over 90%. In contrast, when applied to CLG of different fuels, syngas output will vary depending on the type of fuel (the H 2 production range is 0.47–370 mL g −1 ). Therefore, in order to promote the further development of RMOC, it is proposed to further understand RM by using various methods. This study provides some references for the efficient utilization of RMOC in the field of energy and environment.