The Future of CO2 Geological Sequestration: An Overview of Mineralization in Aqueous and Supercritical States

CO2 mineralization is a safe and stable geological sequestration method that plays an important role in reducing and mitigating global carbon emission. Currently, the Carbfix project in Iceland and the Wallula project in the United States represent two different mineralization sequestration modes of CO2 aqueous solution and wet supercritical CO2. In the microscopic process, the main difference between the two is that the CO2 aqueous solution follows the dissolution-precipitation theory, and wet scCO(2) follows the adsorption-complexation process. We verified the changes of the components before and after mineralization as well as the evolution of the morphology and structure through different characterization methods and established three mineralization models. Furthermore, starting from the chemical reaction mechanism of the two methods, we modified the crystallization kinetics Avrami equation, and obtained the theoretical law of the mineralization rate under different conditions. Eventually, the effects of temperature, pressure, ore size and type, additives and water content on the mineralization efficiency were further explored. This paper discusses the various challenges to mineralization sequestration and its potential opportunities, especially in the field of biomineralization. These results are important for understanding the mechanism of CO2 mineralization under geological conditions and proposing a potential strategy for the enhancement of sequestration efficiency.