Direct mineral carbonation has been investigated as a process to convert gaseous CO 2 into a geologically stable final form. The process utilizes a slurry of water, with bicarbonate and salt additions, mixed with a mineral reactant, such as olivine (Mg 2 SiO 4 ) or serpentine [Mg 3 Si 2 O 5 (OH) 4 ]. Carbon dioxide is dissolved into this slurry, resulting in dissolution of the mineral and precipitation of magnesium carbonate (MgCO 3 ). Optimum results have been achieved using heat pretreated serpentine feed material and high partial pressure of CO 2 (P CO2 ). Specific conditions include: 155°C; P CO2 =185 atm; 15% solids. Under these conditions, 78% conversion of the silicate to the carbonate was achieved in 30 minutes. Process mineralogy has been utilized to characterize the feed and process products, and interpret the mineral dissolution and carbonate precipitation reaction paths.

Research on carbon capture and storage has been focused on CO 2 storage in geologic formations, with many potential risks. An alternative to conventional geologic storage is carbon mineralization, where CO 2 is reacted with metal cations to form carbonate minerals. Mineralization methods can be broadly divided into two categories: in situ and ex situ. In situ mineralization, or mineral trapping, is a component of underground geologic sequestration, in which a portion of the injected CO 2 reacts with alkaline rock present in the target formation to form solid carbonate species. In ex situ mineralization, the carbonation reaction occurs above ground, within a separate reactor or industrial process. This literature review is meant to provide an update on the current status of research on CO 2 mineralization.

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