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Carbon sequestration via reaction with basaltic rocks: geochemical modeling and experimental results

Geochimica et Cosmochimica Acta

By:
, , ,
DOI: 10.1016/j.gca.2012.04.042

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Abstract

Basaltic rocks are potential repositories for sequestering carbon dioxide (CO2) because of their capacity for trapping CO2 in carbonate minerals. We carried out a series of thermodynamic equilibrium models and high pressure experiments, reacting basalt with CO2-charged fluids over a range of conditions from 50 to 200 °C at 300 bar. Results indicate basalt has a high reactivity to CO2 acidified brine. Carbon dioxide is taken up from solution at all temperatures from 50 to 200 °C, 300 bar, but the maximum extent and rate of reaction occurs at 100 °C, 300 bar. Reaction path simulations utilizing the geochemical modeling program CHILLER predicted an equilibrium carbonate alteration assemblage of calcite, magnesite, and siderite, but the only secondary carbonate identified in the experiments was a ferroan magnesite. The amount of uptake at 100 °C, 300 bar ranged from 8% by weight for a typical tholeite to 26% for a picrite. The actual amount of CO2 uptake and extent of rock alteration coincides directly with the magnesium content of the rock suggesting that overall reaction extent is controlled by bulk basalt Mg content. In terms of sequestering CO2, an average basaltic MgO content of 8% is equivalent to 2.6 × 108 metric ton CO2/km3 basalt.

Additional Publication Details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
Carbon sequestration via reaction with basaltic rocks: geochemical modeling and experimental results
Series title:
Geochimica et Cosmochimica Acta
DOI:
10.1016/j.gca.2012.04.042
Volume
89
Year Published:
2012
Language:
English
Publisher:
Elsevier
Contributing office(s):
Pacific Coastal and Marine Science Center
Description:
18 p.
Larger Work Type:
Article
Larger Work Subtype:
Journal Article
Larger Work Title:
Geochimica et Cosmochimica Acta
First page:
116
Last page:
133
Number of Pages:
18