Accelerated Carbon Capture and Storage via Mineral Carbonation: A Laboratory-Scale Investigation

Abstract Carbon Capture and Storage (CCS) is globally recognized as a vital, strategic approach to reduce anthropogenic CO2 emissions and mitigate the adverse effects of climate change. Among various sequestration methods, mineral trapping is recognized for its superior safety and extensive CO2 storage capacity. This study presents a novel methodology for assessing the rapid mineral carbonation of CO2 through geochemical interactions with carbon-, magnesium-, and iron-rich minerals abundant in geological formations. Four minerals: olivine, dolomite, magnetite, and gypsum, have been selected as candidates for the study and exposed to CO2 at various heating rates and temperatures, utilizing Thermogravimetric Analysis/Differential Scanning Calorimetry (TGA/DSC) to establish the optimal conditions for carbon mineralization at atmospheric pressure. Furthermore, the study examined the effect of the aqueous phase with low and high ionic strength on minerals’ carbon uptake efficiency. A novel combined analysis of the minerals was conducted before and after CO2 exposure using Scanning Electron Microscopy/Energy Dispersive Spectroscopy (SEM/EDS) with the normalization by TGA/DSC data to quantify the total carbon uptake by each mineral, thereby identifying the best candidate for mineral carbonation. Results showed that olivine and dolomite in a dry state displayed the highest carbon uptake values at 200˚ and 100˚ C temperatures, respectively. Thus, it was proved that accelerated carbon mineralization is possible even in the absence of an aqueous phase. However, introducing a water phase with high ionic strength to the mineral surfaces resulted in a significant increase in carbon uptake, with an average rise of 5-15 mg per 100 mg of mineral in olivine and dolomite correspondingly. Furthermore, it was found that dolomite requires more heat to store large amounts of carbon facilitated by the high heating rate of 20˚C/min, whereas olivine demonstrated higher carbon uptake values at a low heating rate of 5˚C/min. Hence, strong correlations between carbon uptake values and the heating rates for both minerals have been established. Lastly, it was concluded that the surface void spaces of the minerals were highly affected by the addition of the aqueous phase to the mineral. The pioneering approach and findings of this paper reveal that carbon storage can be successfully implemented in a matter of hours under laboratory conditions even at atmospheric pressure, effectively bridging a significant gap in the literature where experimental investigation of mineral carbonation has not been extensively explored. The results of this work provide the petroleum industry with a reliable and safe approach for accelerated CO2 sequestration in various rock formations, thus enabling the companies to successfully meet their sustainability and decarbonization objectives.