Experimental study of CO₂ sequestration and H₂ generation potential through mineral carbonation in Saudi red mud

This study examines the potential of Saudi red mud for CO₂ sequestration through mineral carbonation and its concurrent hydrogen generation. Two batch experiments were conducted under neutral (deionized water) and acidic (1 wt% HCl) conditions at elevated temperature and pressure. Under neutral conditions, the interaction between CO₂ and red mud led to measurable mineralization, with approximately 8.3% of the injected CO₂ converted into Minerals. In contrast, the acidic system induced extensive mineral dissolution and precipitation, releasing higher concentrations of reactive elements into solution. Increasing the amount of red mud in the reaction to twice that used in the DIW case resulted in approximately twice the amount of CO₂ being mineralized. This indicates a strong relationship between red mud mass and its CO₂ sequestration capacity, highlighting that providing more reactive solid material directly enhances the system’s ability to lock CO₂ into stable carbonate minerals. Gas analysis verified hydrogen generation, along with notable hydrogen sulfide formation, particularly under acidic conditions. Overall, the findings reveal that while red mud can facilitate partial CO₂ mineralization and hydrogen evolution, its reactivity strongly depends on pH, with acid-assisted reactions enhancing mineral mobility rather than stable carbonate formation.