Reaction Kinetics of CO2 Carbonation with Mg-Rich Minerals

Due to their low price, wide availability, and stability of the resulting carbonates, Mg-rich minerals are promising materials for carbonating CO2. Direct carbonation of CO2 with Mg-rich minerals reported in this research for the first time could be considerably superior to conventional liquid extraction processes from an energy consumption perspective due to its avoidance of the use of a large amount of water with high specific heat capacity and latent heat of vaporization. Kinetic models of the reactions of the direct CO2 carbonation with Mg-rich minerals and within simulated flue gas environments are important to the scale-up of reactor designs. Unfortunately, such models have not been made available thus far. This research was initiated to fill that gap. Magnesium silicate (Mg2SiO4), a representative compound in Mg-rich minerals, was used to study CO2 carbonation reaction kinetics under given simulated flue gas conditions. It was found that the chosen sorbent deactivation model fits well the experimental data collected under given conditions. A reaction order of 1 with respect to CO2 is obtained from experimental data. The Arrhenius form of CO2 carbonation with Mg2SiO4 is established based on changes in the rate constants of the chosen deactivation model as a function of temperature.