Mineral carbonation of red gypsum for CO₂ sequestration

Reduction of carbon dioxide (CO₂) emissions into the atmosphere is a key challenge to mitigate the anthropogenic greenhouse effect. CO₂ emissions cause lots of problems for the health of humans and increase global warming, in which CO₂ uptake decreases these environmental issues. The mineral carbonation process is an alternative method during which industrial wastes rich in calcium (Ca) or magnesium (Mg) react with CO₂ to form a stable carbonate mineral. In this research, the feasibility of CO₂ mineral carbonation by the use of red gypsum, as a Ca-rich source, was evaluated using an autoclave mini reactor. Wide-range conditions of procedure variables, such as reaction temperature, reaction time, CO₂ pressure, and liquid/solid ratio, on the rate of mineral carbonation were studied. The results showed that the maximum conversion of Ca (98.8%) is obtained at the condition that has an optimum amount of these variables. Moreover, the results confirmed that red gypsum has high potential to form calcium carbonate (CaCO₃) during the process of CO₂ mineral carbonation. It was concluded that the mineral carbonation process using red gypsum can be considered to be an interesting, applicable, and low-cost method in industry to mitigate a considerable amount of CO₂ from the atmosphere, which is the main issue in the current and coming years.