Mineral carbonation reactions under water-saturated, hydrothermal-like conditions and numerical simulations of CO2 sequestration in tholeiitic basalt of the Eastern Deccan Volcanic Province, India

作者：Kumar Amit; Shrivastava J P^*; Pathak Vamdev

来源：Applied Geochemistry, 2017, 84: 87-104.

DOI：10.1016/j.apgeochem.2017.05.021

• CO2 sequestration
• Carbonation reaction
• EQ3/6
• Deccan basalt
• Numerical simulation models
• CO2-Water-basalt interaction

Previous water-CO2 interaction studies have studied few basalt types (rich in Ca, Mg, and Fe cations) to determine pyroxene, olivine and plagioclase reaction rates; however, limited research has examined the Deccan basalt. Therefore, in this study, basalt-CO2-water-saturated interaction experiments and numerical simulations were performed under hydrothermal-like conditions. X-ray Diffraction (XRD) data revealed the appearance of calcite, aragonite, ankerite, huntite and siderite; additionally, smectite, chlorite, smectite/chlorite mixed layers and chabazite were also formed. SEM images showed that tiny calcite crystals developed over larger calcite crystals, incipient-disordered calcite formed with imperfections on its crystal faces and cubic chabazite crystals were bounded by smectite grains. Furthermore, these observations were confirmed by EDS analyses and mineral formulae calculations. Major shifts in the carbonate peaks observed at 155 and 282, 178, and 849 cm(-1) on Raman spectra confirmed the formation of calcite, dolomite and aragonite, respectively. Mixing trends between basalt and Ca-Mg-Fe carbonates and chlorite/smectite were observed in the case of phyllosilicates. However, ankerite, calcite and siderite recorded the enrichment of (i) Ca, (ii) Fe-Mg and (iii) Fe. High degrees of carbonation and progressive mineral growth were observed with the increasing pH of the solution. The formation of secondary carbonates predominated over that of silicates in short-term experiments; however, with increasing reaction time, the carbonates no longer persisted in the system, as they were dissolved and replaced by silicates. However, the degree of carbonation increased with the increasing pCO(2) and pH of the solution.
Transition-state-theory (TST)-based numerical simulation models do not agree well with the results of experiments, as carbonate growth was greater in the former case. These models work well to predict the dissolution rates of most minerals but overpredict the growth of non-hydrous Mg carbonates at low temperatures.

• 出版日期2017-9