Optimizing ulexite-based mineral carbonation for CO2 capture and boron recovery in aqueous systems

One of the urgent environmental issues today is the excessive release of CO 2 , which accelerates global warming and climate change. Researchers worldwide are developing methods to slow or prevent rise of these emissions. Among the promising approaches, mineral carbonation using calcium- and magnesium-rich minerals has gained attention as an effective way to capture CO 2 from flue gases. Ulexite, a natural boron mineral, shows strong potential for this application. In this study, the CO 2 capture ability of ulexite in aqueous systems was systematically investigated. Experiments were designed and optimized using the Taguchi method, with temperature, particle size, reaction time, and solid-to-liquid ratio selected as key operational parameters. Pure CO 2 was employed under atmospheric conditions. The optimal conditions were identified as 70 °C, particle size below 250 µm, a reaction time of 120 min, and a solid-to-liquid ratio of 125 g ulexite per 500 g water, achieving a theoretical CO 2 retention efficiency of 94.65 ± 8.94%. The results confirm that ulexite can effectively capture CO 2 in aqueous environments, indicating its potential as a cost-effective and environmentally friendly sorbent for CO 2 mitigation technologies. Moreover, the simultaneous formation of sodium pentaborate pentahydrate (NaB 5 O 8 ·5H 2 O) provides an economic advantage and enhances industrial applicability of the process.