Rapid solubility and mineral storage of CO2 in basalt

Abstract

The long-term security of geologic carbon storage is critical to its success and public acceptance. Much of the security risk associated with geological carbon storage stems from its buoyancy. Gaseous and supercritical CO 2 are less dense than formation waters, providing a driving force for it to escape back to the surface. This buoyancy can be eliminated by the dissolution of CO 2 into water prior to, or during its injection into the subsurface. The dissolution makes it possible to inject into fractured rocks and further enhance mineral storage of CO 2 especially if injected into silicate rocks rich in divalent metal cations such as basalts and ultra-mafic rocks. We have demonstrated the dissolution of CO 2 into water during its injection into basalt leading to its geologic solubility storage in less than five minutes and potential geologic mineral storage within few years after injection [1][2][3]. The storage potential of CO 2 within basaltic rocks is enormous. All the carbon released from burning of all fossil fuel on Earth, 5000 GtC, can theoretically be stored in basaltic rocks [4].

Experimental study to better understand factors affecting the CO2 mineral trapping potential of basalt

“…Instead we only observed growth of the calcium carbonate polymorphs, calcite, and aragonite. The growth of the Ca‐carbonates is not surprising and has been shown to occur during CO 2 ‐basalt interactions over a range of temperatures . Rogers et al .…”

“…The growth of the Ca-carbonates is not surprising and has been shown to occur during CO 2 -basalt interactions over a range of temperatures. 43,44 Rogers et al 27 found that calcite is the only carbonate that is commonly found associated with basalt weathering and low temperature alteration in Iceland. This natural weathering however occurs at low temperatures and also at lower CO 2 pressures, preventing the formation of Mg-carbonates such as dolomite and magnesite (high activation energies prevent low-temperature formation).…”

A review of developments in carbon dioxide storage

“…Basaltic rocks form approximately 8% of the continents and much of the ocean floor. Therefore, there is an enormous potential CO2 storage capacity in basaltic rocks [109]. The key positive aspects of their potential for CO2 storage are their high reactivity and abundance of divalent metal ions in such rock which can potentially fix CO2 for geological timescales [110].…”

Negative emissions technologies and carbon capture and storage to achieve the Paris Agreement commitments

“…This NET may not become legal to implement. (7) Subsurface mineralization, forming carbonate minerals by direct injection of dissolved CO 2 to contact reactive minerals in the subsurface, has been successfully trialled at a very small pilot [59]. Scale up during a 10 year period, using conventional technology could increase this to significant impact, although long-term evolution of porosity and permeability, thus sustainability of this storage method, has yet to be proven.…”