A study on MgO-based mineral carbonation kinetics using pressurised thermo-gravimetric analysis

摘要

The carbonation of magnesium silicate mineral appears to be the only option for CO_2 capture and storage (CCS) in Finland. Current research in Finland focuses on the carbonation of silicate minerals and industrial wastes such as slag from iron and steel plants, using both dry (gas/solid) and wet (aqueous solution) methods. The kinetics of MgO (periclase) and Mg(OH)_2 (brucite) particle (75-125 μm) carbonation at temperatures and pressures up to 540°C and 45 bar was measured using pressurised thermogravimetric analysis. Conversion levels of 40 to 60 % after 6 h were obtained. Unreacted shrinking core (USC) modelling allowed for calculating initial reaction rates, showing also that intra-particle diffusion through presumably a MgCO_3 (magnesite) product layer becomes rate-determining after ～5 % conversion.