| Abstract Scope |
We have developed a sodium carbonate looping process[1] to accelerate CO2 mineralization using steel slags or fly ash by almost ten times compared to traditional aqueous mineralization, achieving carbon storage capacities up to 2.79 mmol C g-1 slag. Our techno-economic analysis has estimated levelized CO2 capture and mineralization costs of $50 ton⁻¹ for point-source capture and $252 ton⁻¹ for air capture. Including revenues, the process is projected to have payback periods under two years. Specifically, the process feedstock can be silicate minerals, basic oxygen furnace (BOF) steel slag, electric arc furnace (EAF) steel slag, or fly ash, and the products include a carbonate-rich material composed primarily of calcium carbonate, and an amorphous silica phase. In addition to permanently storing CO2, the mineralization process eliminates expansive phases commonly present in steel slag while producing pozzolanically active silica. Elemental analysis further shows low levels of alkali impurities in the carbonate-rich product.
[1] K. Shank, et al. Energy Environ. Sci., 2026 |