Quantifying kinetics of mineralization of carbon dioxide by olivine under moderate conditions

Abstract

Global warming mitigation is an urgent issue all over the world and the mineralization for CO2 sequestration is one of the best methods to permanently store CO2 gas. The current work has developed a quantified mineralization formula through the systematic investigation of the kinetics of mineralization of a dunite containing high-grade olivine under the chemical reaction control. The effect of the most important CO2 partial pressure, addition of sodium bicarbonate, specific surface area of the olivine, addition of sodium chloride and reaction temperature can be quantified to the 1.6th, 0.8th, 0.7th, 0.34th power and 47.97 kJ/mol activation energy respectively with a relative error less than ±5%. When there was high addition of sodium bicarbonate, the effect of sodium chloride was not significant. Once the addition of sodium bicarbonate and the CO2 partial pressure were high enough, the mineralization was always controlled by dissolution of olivine. The following quantified mineralization formula has been developed. α = (1 − (1 − k0 × [S]0.7 × [PCO2]1.6 × [NaHCO3]0.8 × e(−Ea×1000/RT) × t)3) × 100%, where k0 is the correction factor, related to the mineralization capability of the material and others. The developed formula and the transformations can be applied to predict the mineralization efficiency, the necessary requirements of reaction time, required sodium bicarbonate and the relationship between the required specific surface area and CO2 partial pressure. It can be theoretically suitable for the materials where the majority are olivine and it is necessary to carry out several pre-tests to determine the value of the correction factor (k0).