Preparation of Red Mud-Based Desulfurizer and its Desulfurization Mechanism by Adding Polymer Microspheres

Red mud, a byproduct of the alumina industry, poses significant environmental challenges due to its alkaline nature and large-scale accumulation. This study explores the potential of red mud as a desulfurizer by incorporating polymer microspheres, along with the addition of fly ash, sodium silicate, and calcium hydroxide (\ (Ca (OH) ₂\) ) to enhance its desulfurization efficiency. The preparation process involves the modification of red mud-based desulfurizer with polymer microspheres, followed by characterization using X-ray diffraction (XRD), scanning electron microscopy (SEM), and Brunauer–Emmett–Teller (BET) analysis. The desulfurization performance was evaluated in a fixed-bed reactor under simulated flue gas conditions. The results indicate that the addition of polymer microspheres significantly improves the surface area and porosity of the red mud-based desulfurizer, leading to enhanced sulfur dioxide (SO 2) adsorption capacity. The desulfurizer prepared with an addition of 8% polymer microspheres and a calcination temperature of 550 ℃ exhibited the best performance, with a penetration time of 498 min and a penetration sulfur capacity of 20. 3 mg/g. The desulfurization mechanism was elucidated, revealing that the removal of SO 2 by calcites and metal oxides mainly involves three aspects. Effective desulfurization components such as CaCO 3, Fe 2 O 3, Al 2 O 3 etc. can react with SO 2 to generate sulfates under the action of lattice oxygen, adsorbed oxygen, and oxygen vacancies. This study provides a novel approach for the valorization of red mud and offers a cost-effective and environmentally friendly solution for flue gas desulfurization.