Carbon Storage and CO2 Mineralization

Engineered carbon mineralization is better known as a potential technology for storing CO₂ with a great long-term stability. Geologic storage is an important component of global efforts to mitigate emissions and reduce the concentration of atmospheric carbon dioxide. Permanent, solid storage of CO₂ in inert, non-toxic environmentally benign minerals, via carbon mineralization in mafic and ultramafic rocks, e.g.,

Mg₂SiO₄ (olivine) + CO₂ = MgCO₃ (magnesite) + SiO₂ (quartz)

has long been considered as a storage option, in part because by storing it in solid state in subsurface environments, it may reduce the potential cost of monitoring mobile forms of CO₂. Mineralization occurs naturally during weathering of Mg- and/or Ca-rich, Al-poor materials (e.g., “ultramafic rocks” composed mainly of the minerals olivine, serpentine, brucite, and/or wollastonite). In the Park group, we focus on the potential for the same kinds of chemical reactions to be used not only for storage, but for removal of significant quantities of CO₂ from air.

We are motivated by examples of extensive, natural carbon mineralization that occurs during weathering of ultramafic rocks. Most ultramafic rocks at and near the Earth’s surface are “peridotites” that come from the upper mantle, where the most abundant minerals are Mg-rich olivine (Mg_1.8Fe_0.2SiO₄) and pyroxenes (Ca,Mg,Fe)₂Si₂O₆. Mantle peridotite is brought to the surface by plate tectonics together with faulting and erosion. It is very far from equilibrium with the atmosphere and oceans, and reacts rapidly to form Mg-hydrates (serpentine Mg₃Si₂O₅(OH)₄, brucite Mg(OH)₂), iron oxides, and carbonates (magnesite MgCO₃, dolomite CaMg(CO₃)₂, calcite CaCO₃). Our research seeks to make feasible the implementation of subsurface carbon sequestration into solid carbonates at large scales needed for significantly reversing global warming by evaluating the key feedbacks, reaction rates and other basic parameters in carefully controlled experiments and modeling.

Active projects:

• Carbon mineralization in peridotite for CO₂ removal from air and solid storage: Chemo-mechanical feedbacks and kinetics
• Carbon Storage Assurance Facility Enterprise (CARBONSAFE)
• Assessment of the CO2 Mineralization Potential of Tamarack’s Ultramafic Bowl-Shaped Intrusion