Continuing Studies on Direct Aqueous Mineral Carbonation of CO{sub 2} Sequestration
Direct aqueous mineral carbonation has been investigated as a process to convert gaseous CO{sub 2} into a geologically stable, solid final form. The process utilizes a solution of sodium bicarbonate (NaHCO{sub 3}), sodium chloride (NaCl), and water, mixed with a mineral reactant, such as olivine (Mg{sub 2}SiO{sub 4}) or serpentine [Mg{sub 3}Si{sub 2}O{sub 5}(OH){sub 4}]. Carbon dioxide is dissolved into this slurry, by diffusion through the surface and gas dispersion within the aqueous phase. The process includes dissolution of the mineral and precipitation of the magnesium carbonate mineral magnesite (MgCO{sub 3}) in a single unit operation. Activation of the silicate minerals has been achieved by thermal and mechanical means, resulting in up to 80% stoichiometric conversion of the silicate to the carbonate within 30 minutes. Heat treatment of the serpentine, or attrition grinding of the olivine and/or serpentine, appear to activate the minerals by the generation of a non-crystalline phase. Successful conversion to the carbonate has been demonstrated at ambient temperature and relatively low (10 atm) partial pressure of CO{sub 2} (P{sub CO2}). However, optimum results have been achieved using the bicarbonate-bearing solution, and high P{sub CO2}. Specific conditions include: 185 C; P{sub CO2}=150 atm; 30% solids. Studies suggest that the mineral dissolution rate is not solely surface controlled, while the carbonate precipitation rate is primarily dependent on the bicarbonate concentration of the slurry. Current and future activities include further examination of the reaction pathways and pretreatment options, the development of a continuous flow reactor, and an evaluation of the economic feasibility of the process.
- Research Organization:
- Albany Research Center, OR (US)
- Sponsoring Organization:
- USDOE Office of Fossil Energy (FE) (US)
- OSTI ID:
- 821898
- Report Number(s):
- DOE/ARC-2002-003; R&D Project: AE-FY-02-01; AE-FY-02-01; TRN: US200412%%191
- Resource Relation:
- Conference: 27th International Technical Conference on Coal Utilization and Fuel Systems, Clearwater, FL (US), 03/04/2002--03/07/2002; Other Information: PBD: 4 Mar 2002
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
42 ENGINEERING
58 GEOSCIENCES
ACID CARBONATES
AMBIENT TEMPERATURE
CARBON DIOXIDE
COAL
FUEL SYSTEMS
HEAT TREATMENTS
MAGNESIUM CARBONATES
PARTIAL PRESSURE
SILICATE MINERALS
SODIUM CHLORIDES
AQUEOUS MINERAL CARBONATION
SEQUESTRATION