Sulfate-activated mineral carbonation of olivine minerals with mechanisms explained by shrinking core models and by machine learning algorithm

Document Type

Article

Publication Date

12-2024

Department

Department of Chemical Engineering

Abstract

Direct aqueous mineral carbonation of olivine minerals has been extensively investigated in the past. However, the effect of inorganic electrolytes, particularly sodium sulfate (Na2SO4), on mineral carbonation rate has not been investigated yet. In this work, we report experimental results on the CO2 uptake rate of ultrafine olivine-rich rocks using Na2SO4 and sodium chloride (NaCl) as inorganic catalysts under hydrothermal conditions. The reaction mechanism was explained using both a shrinking core model and a machine learning model. One major and unexpected finding was that the use of Na2SO4 significantly increased the carbonation efficiency compared to the baseline with and without using sodium chloride (NaCl) as an inorganic electrolyte. The results showed that an increase in the carbonation kinetics in the presence of Na2SO4 was evident, particularly at a temperature range of 145–185 °C. At this temperature range, the reaction kinetics are predominantly governed by the product layer diffusion control mechanism. The presence of Na2SO4 electrolyte likely contributed to a promoted dissolution of silica and divalent ions from the hosting rocks/minerals. Results obtained from machine learning modelling confirmed that both the temperature and Na2SO4 additive were key parameters for mineral carbonation compared with other process variables. The present study demonstrates the catalyzing role of Na2SO4 in direct aqueous mineral carbonation of olivine minerals.

Publication Title

Minerals Engineering

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