Mineral dissolution—Congruent and incongruent dissolution—

Since mineral dissolution and precipitation are important chemical reactions in geological processes such as metamorphism and hydrothermal alteration, they are considered to be significant for understanding the fundamental mechanisms of Earth scientific phenomena such as volcanic eruptions and earthquakes. The key points in Carbon dioxide Capture and Storage (CCS) and Carbon dioxide Capture, Utilization and Storage (CCUS) technologies can be thought of as the dissolution and precipitation of minerals. This reaction is not only a heterogeneous solid-liquid reaction through the surface layer between a mineral (solid) and water or carbon dioxide (fluid), but also a complex process involving a mixture of physical processes such as adsorption-desorption, chemical reactions, and transfer phenomena (diffusion, advection, etc.) across the interface between the mineral and fluid. When we consider mineral dissolution in terms of stoichiometry, it can be classified into congruent dissolution and incongruent dissolution. Congruent dissolution refers to dissolution that results in dissolved species consistent with the stoichiometry of the host mineral and rock, while incongruent dissolution is dissolution that shows non-stoichiometric behavior.