CO2 mineralization projects, techniques, mechanisms, potential and future outlook in basalt: a review

Basalt mineralization offers a dependable approach for CO2 sequestration. A comprehensive evaluation of its feasibility and applicability is essential for guaranteeing safe and long-term storage. Nonetheless, foundational research and engineering exploration into basalt CO2 sequestration is still in the early stages, with a limited investigation into the reaction kinetics of mineralization. This work systematically reviews current basalt CO2 mineralization projects and the relevant experimental techniques, summarizing critical sequestration mechanisms and quantitative evaluation methods for storage in basalt. The representative Wallula project and CarbFix project have demonstrated the efficiency and safety of basalt-based CO2 sequestration. Many studies have experimentally confirmed that conditions such as temperature, pressure, and pore-fracture characteristics significantly facilitate carbonate mineral formation, and pyroxene and plagioclase essentially ensure cation supply. Dissolution of CO2 sequentially generates bicarbonate and carbonate anions, which react with divalent ions to form stable carbonates. The review also compares the calculation principles and the application scenarios of the unit mineralization method, mineral substitution method, and pore-filling method for quantifying the mineralization potential of basalt. Using the mineral substitution method, the theoretical storage capacities of basalt-rich countries and regions have been quantified. Russia, Brazil, Ethiopia, India, the United States, and Iceland demonstrate considerable sequestration potential, ranging in 1.7–6.7 × 105 Gt. In China, regions like Yunnan-Guizhou-Sichuan, the Tarim Basin, and Xilin Gol present notable storage potential, collectively estimated at approximately 4.7 × 104Gt. Generally, current research offers valuable insights into the assessment and optimization of basalt mineralization efficiency. These findings hold substantial practical implications for addressing global climate change and implementing carbon reduction strategies.