Research on the Characterization of CO ₂ Mineralization Rate and Its Impact on the Physical and Mechanical Properties of Basalt

Basalt mineralization storage is widely recognized as a secure, permanent method for large‐scale CO 2 sequestration. At present, the majority of research endeavors are centered around the investigation of reaction mechanisms and microscopic properties. However, research on standard basalt rock samples (before/after storage) and the quantification of CO 2 consumption during reactions remains limited. This study explored CO 2 ‐water‐rock interactions, focusing on how mineral carbonation alters rock physical/mechanical properties and how to characterize CO 2 consumption rate. Experiments were conducted using a self‐designed rock reactor on standard cylindrical basalt samples (from Wenchang, Hainan) under 12 MPa and 70°C for 0, 10, 20, 30, and 60 d. A theoretical CO 2 consumption calculation method (based on pressure drop, accounting for gas‐liquid‐solid three‐phase systems) was proposed. Validated against actual consumption data (from water and rock weigh changes in the reactor), it showed an average absolute deviation (AAD) <5%, confirming high reliability. CO 2 consumption data were fitted with a double exponential function to derive the reaction rate curve, which peaked initially, then decreased continuously, and finally flattened. Changes in uniaxial compressive strength, tensile strength, Poisson's ratio, elastic modulus, porosity, T 2 and mineral composition were observed at different reaction times. Though siderite and calcite precipitated on sample surfaces, rock dissolution dominated—increasing porosity, reducing mechanical properties and leaving yellowish‐brown precipitates (more pronounced with longer reactions). These findings support safety evaluation of basalt reservoirs.