Red mud-mediated CO₂ capture for enhanced carbon reduction and waste-to-resource: A review

The direct and simplistic disposal of red mud, a strong alkalinity industrial byproduct, presents substantial environmental contamination hazards. This persistent challenge has severely constrained its application across multiple sectors, thereby impeding large-scale utilization. Thus, dealkalization continues to be the principal work priority for enabling effective red mud utilization. Herein, this study comprehensively examines the manufacturing process, composition, and properties of red mud, performs thermodynamic and kinetic evaluation, and assesses the performance of calcium-enriched system under diverse additive conditions. This review focuses on carbon sequestration in red mud, aiming to simultaneously achieve effective dealkalization, mitigate environmental pollution, and enable large-scale resource utilization. Additionally, it captures and utilizes CO₂ to mitigate greenhouse gas emissions, aligning with the dual-carbon goals and achieving coordinated treatment of waste gas and solid waste. The alkaline components in red mud exist in two forms: soluble alkali in the supernatant and insoluble alkali in the solid phase. Both can react with carbon dioxide during the carbonation process to form carbonates. These findings offer technical foundations for promoting large-scale low-carbon application research of red mud.