Effect of Alkaline Types on the Production of Calcium Carbonate Particles from Gypsum Waste for Fixation of CO₂ by Mineral Carbonation

Industrial by-products have been used as an alternative raw material for the long-term storage of CO₂ as a mineral carbonate with various polymorphs and properties. For example; desulfurization gypsum (DG) obtained from a power station has great potential due to its high CaO content. This study used a mineral carbonation process to produce CaCO₃ particles (PCC) from DG wastes for fixation of CO₂ The effects of solid-to-liquid ratio (1:13, 1:9, and 1:7) and hydroxide sources (NaOH, NH₄OH) on properties of PCC were determined using XRD, SEM, FTIR, AAS, and wet chemical analyses. Calcite crystals were produced in all cases with the use of NaOH, whereas calcite crystals along with spherical vaterite crystals were observed in the presence of NH₄⁺. This study suggested a good option due to not only fixation of CO₂ but also production of PCC with a high purity.