Can dawsonite permanently trap CO{sub 2}?
- University of Bergen, Bergen (Norway). Department of Physics and Technology
Thermodynamic calculations indicate that although dawsonite (NaAlCO{sub 3}(OH){sub 2}) is favored to form at the high CO{sub 2} pressures associated with carbon dioxide injection into sandstone reservoirs, this mineral will become unstable as CO{sub 2} pressure decreases following injection. To assess the degree to which dawsonite will persist following its formation in sandstone reservoirs, its dissolution rates have been measured at 80 {+-} 3{sup o}C as a function of pH from 3 to 10. Measured dawsonite dissolution rates normalized to their BET surface area are found to be nearly independent of pH over the range of 3.5 < pH < 8.6 at 1.58 10{sup -9} mol/(m{sup 2}{center_dot}s). Use of these dissolution rates in reactive transport calculations indicate that dawsonite rapidly dissolves following the decrease of CO{sub 2} pressure out of its stability field, leading mainly to the precipitation of secondary kaolinite. This result indicates that dawsonite will provide a permanent mineral storage host only in systems that maintain high CO{sub 2} pressures, whereas dawsonite may be an ephemeral phase in dynamic settings and dissolve once high CO{sub 2} pressure dissipates either through dispersion or leakage. 32 refs., 5 figs., 3 tabs.
- OSTI ID:
- 20681279
- Journal Information:
- Environmental Science and Technology, Vol. 39, Issue 21; Other Information: aagaard@geo.uio.no; ISSN 0013-936X
- Country of Publication:
- United States
- Language:
- English
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