What is the key chemical reaction involved in mineral carbonation for carbon storage?

The key chemical reaction involved in mineral carbonation for carbon storage is the reaction between carbon dioxide (CO2) and metal oxides, typically magnesium oxide (MgO) or calcium oxide (CaO), to form stable and environmentally benign carbonate minerals. Mineral carbonation is a process that permanently stores CO2 by reacting it with readily available rocks or minerals. The most common reaction involves CO2 reacting with magnesium- or calcium-containing silicate rocks, such as olivine or serpentine. These rocks are abundant and widely distributed, making them a promising resource for carbon storage. The basic chemical reaction can be represented as follows: MgO (or CaO) + CO2 -> MgCO3 (or CaCO3). For example, magnesium oxide reacts with carbon dioxide to form magnesium carbonate (MgCO3), which is a stable mineral similar to magnesite. Calcium oxide reacts with carbon dioxide to form calcium carbonate (CaCO3), which is the main component of limestone and chalk. These reactions are thermodynamically favorable and occur naturally over long periods. However, to accelerate the process for industrial applications, the reaction conditions (e.g., temperature, pressure, presence of water) may be optimized. The resulting carbonate minerals are very stable and pose minimal risk of CO2 leakage, making mineral carbonation a potentially safe and permanent method for carbon storage.