Experimental Study of the Effect of Different Influencing Factors on the Interaction of CO2, Water, and Basalt

Basalt has been studied in recent years as a novel geological medium for CO2 sequestration, thus enriching and expanding the carbon sink potential of geological bodies. In this study, four sets of CO2–water–basalt interaction experiments were carried out for different ranges of temperature, pressure, particle size, and basalt type, while taking account of actual in situ temperature and pressure conditions in basalt strata. The aim was to provide a theoretical basis for the construction of future basalt CO2 mineralization and storage projects. It was demonstrated that basalt begins to form calcitic minerals above 36 °C, with the highest carbonate mineral formation occurring at 66 °C accompanied by minor hydration of magnesium carbonate minerals. Below 26 °C, the dissolution of calcitic minerals showed a gradually increasing trend at higher pressures, with small amounts of hydrated magnesium carbonate minerals and calcite being formed at 9 MPa and 13 MPa. Maximum mineral dissolution occurred at 30–35 mesh particle size. The dissolution reaction in porous basalt was more intense for different basalt types (e.g., porous basalt and massive olivine basalt).