A review of carbon mineralization mechanism during geological CO storage.

The CO trap mechanisms during carbon capture and storage (CCS) are classified into structural, residual, solution, and mineral traps. The latter is considered as the most permanent and stable storage mechanism as the injected CO is stored in solid form by the carbon mineralization. In this study, the carbon mineralization process in geological CO storage in basalt, sandstone, carbonate, and shale are reviewed. In addition, relevant studies related to the carbon mineralization mechanisms, and suggestions for future research directions are proposed. The carbon mineralization is defined as the conversion of CO into stable carbon minerals by reacting with divalent cations such as Ca, Mg, or Fe. The process is mainly affected by rock types, temperature, fluid composition, injected CO phase, competing reaction, and nucleation. Rock properties such as permeability, porosity, and rock strength can be altered by the carbon mineralization. Since changes of the properties are directly related to injectivity, storage capacity, and stability during the geological CO storage, the carbon mineralization mechanism should be considered for an optimal CCS design.