Kinetics of flue gas CO2 mineralization processes using partially dehydroxylated lizardite

A systematic approach to characterize and to predict the CO2 mineralization performances of partially dehydroxylated lizardite particles at low temperatures (⩽90°C) and at low CO2 partial pressures (⩽1bar) was developed in this study. The dissolution kinetics of partially dehydroxylated lizardite particles was accurately described, and the passivating effect of amorphous silica precipitation on the dissolving particles was quantitatively measured. The passivation by amorphous silica was found to inhibit the Mg release rates, and the inhibitory effect was stronger at 60 °C than at 30 °C. An empirical correction to the dissolution rates was found to be sufficient to describe this inhibitory effect. A well controlled, semi-continuous experimental set-up that could run both single- and two-step CO2 mineralization experiments was built, and the empirical correction together with the kinetic models that describe the various events that occur during a CO2 mineralization process were quantitatively validated. The presence of NaCl or NaHCO3 did neither reduce the passivation behavior of amorphous silica nor enhance the CO2 mineralization performances significantly at these operating conditions.