(559s) Thermodynamic Investigation of the Ca-Mg-CO2 System

The mineralization of carbon dioxide (CO₂) into solid carbonates, e.g., calcite (CaCO₃), magnesite (MgCO₃), and hydromagnesite (Mg₅(CO₃)₄(OH)₂·4H₂O) amongst others, offers thermodynamically favorable routes to sequester CO₂ into stable solids that can also be used in the construction, heat storage, paper, food, and pharmaceutical industries. However, typical resources (e.g., industrial byproducts, desalination brines, etc.) that contain solubilized, or readily solubilized calcium and magnesium often include variable concentrations of aqueous species whose presence may impact not only the purity of the carbonates that form but also the thermodynamic pathway to form less desirable phases or alter the mass partitioning of compounds that may form. However, process parameters including the solution , p_CO2, and temperature can be manipulated to provide a thermodynamic environment to form the preferred phases, in controlled mass abundance and purity. Therefore, this work applies state-of-the-art geochemical modeling and self-consistent thermodynamic data to elucidate the effects of on phase formation, balances, stability, and transitions in the system CaO-MgO-CO₂-H₂O and to determine their effects at ambient pressure. This understanding forms a foundational basis to create synthetic pathways for CO₂ mineralization which not only can fulfill industrial demands for mineral carbonates but also may constitute the basis of a global mineralization-based CO₂ management strategy.