Molecular Insights into the CO₂ Mineralization Process with Tricalcium Silicate

CO₂ mineralization, a pivotal technology in CO₂ capture, storage, and utilization, promises to convert industrial waste into valuable industrial products. However, the intricate reaction mechanism and rate-limiting process remain inadequately elucidated. The suitable reaction conditions should be clarified when designing industrial produce. In this study, we comprehensively examined the reaction kinetics and conversion rates of C₃S under varying conditions and degrees of dispersion by reactive molecular dynamics simulation. Furthermore, we set up a sophisticated model depicting C₃S encased within a water film, mirroring its prevalent configuration in moist environments. The results show that the reaction is fast when the temperature is 328 K. The conversion rate tends to decrease under elevated pressure when it is higher than 1.0 MPa, while the temperature has a minimal impact. Fragmentation of solid waste can increase the degree of dispersion, disrupting the crystal structure and expanding the reaction surface area, thereby accelerating the reaction. The presence of a water film impedes mass transfer, consequently reducing the reaction speed. The present study sheds light on the reaction mechanism of the CO₂ mineralization process.