Investigation of Mineral Weathering Products Following CO₂ Injection and High Pressure Tests

Successful carbon sequestration is predominantly controlled by host rock minerals, their alteration products, and the rate of their formation following exposure to a CO2 injected environment with high pressure/temperature conditions. By reproducing these conditions in a lab setting utilizing mineral species originally tested in Goldich’s (1938) classic weathering series, it was concluded the minerals that reacted more rapidly, ergo were more susceptible to weathering, had a higher capacity for promoting carbonate mineral formation. A Hitachi S570 Scanning Electron Microscope was used in conjunction with X-Ray Microanalysis (EDS), to locate and identify newly precipitated mineral phases and their chemical composition. The most notable comparisons contrary to the Goldich series are the amphibole (hornblende) tests, which yielded faster reactions and greater alteration results than pyroxene (augite) samples. It was confirmed via SEM-EDS analysis that a concentrated region of white precipitate material contained microcrystalline particles with a rhombohedral morphology, called magnesite (MgCO3).