Enhancing Mg extraction from lizardite-rich serpentine for CO₂ mineral sequestration

Carbon capture and storage by mineralisation (CCSM) is a promising technology that sequesters CO2 from flue gases into stable mineral carbonates. Although the development of indirect pH swing processes (dissolution at acid pH and carbonation at basic pH) able to recycle the chemicals used are promising, there are still limitations in reaction rate of mineral dissolution being slow in view of a large deployment of the technology. The extraction of Mg from lizardite using magnesium bisulphate has been studied as a function of temperature, reagent concentration, solid to liquid ratio, thermal and mechanical pre-activation. Although the overall highest Mg extraction (95%) was obtained after 3 h, the reduction of the dissolution time to 1 h can consistently reduce the volumes to be treated per unit time leading to low capital costs in a hypothetical mineralisation plant. About 80% of Mg was extracted from lizardite in 1 h at 140 degrees C, 2.8 M NH4HSO4, particles