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 ( \(\text{Ca}{(\text{OH})}_{2}\) ) 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 (SO2) 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 SO2 by calcites and metal oxides mainly involves three aspects. Effective desulfurization components such as CaCO3, Fe2O3, Al2O3 etc. can react with SO2 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.
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