Geochemical evolution of cumulate-gabbro Interaction with Seawater and Supercritical for Enhanced Mineral Carbonation. A study case.

Abstract

This study investigates the potential for mineral carbonation of carbon dioxide (CO2) in plutonic basicrocksthroughaseriesoflaboratoryexperimentsconductedintwostages, under pressure (8 MPa) and temperature conditions (313.15 K) akin to those near a CON injection well. Stage-I facilitateddissolutionwithcrushedrockexposedtoCO2supersaturatedseawater (0.6M), while Stage-ll promoted carbonation through cubic rock specimens in contact with subsaturated seawater (0.1 M). A multi-analytical approach was employed to track the mineralogical and geochemical evolution of the rock and seawater. Brine analyses shows significant increases in iron, magnesium, and calcium ions, with reductions in silicon and aluminium levels. The solid phase showed minimal geochemical and mineralogical changes. Nevertheless, new mineral phases like haliteanddolomiteweredetectedbyX-raydiffractionwithagrazinggeometry. In fact, although detected on a bulk analysis, on the surface of specimens, and after the 120 days experiment, carbonate phases were detected. The geochemical model developed in the CrunchFlow code successfully replicated behaviour over longer periods. The finding suggests a promising potential for mineral carbonation in plutonic basic formations, houghfurtherstudiesareneededtoscalethelaboratoryresultstofieldapplications