Iron-bearing minerals are reactive phases of the subsurface environment and could potentially trap CO2-SO2 gas mixtures derived from fossil fuel combustion processes by their conversion to siderite (FeCO 3) and dissolved sulfate. Changes in fluid and mineral compositions resulting from reactions, involving the co-injection of SO2 with CO2 were observed both theoretically and experimentally. Experiments were conducted with a natural hematite (??-Fe2O3) sample. A high pressure-high temperature apparatus was used to simulate conditions in geologic formations deeper than 800 m, where CO2 is in the supercritical state. Solid samples were allowed to react with a NaCl-NaOH brine and SO2-bearing CO2-dominated gas mixtures. The predicted equilibrium mineral assemblage at 100??C and 250 bar became hematite, dawsonite (NaAl(OH)2CO3), siderite (FeCO 3) and quartz (SiO2). Experimentally, siderite and dawsonite, derived from the presence of kaolinite (Al2Si 2O5(OH)4) in the parent material, were present in residual solids at longer reaction time intervals, which agreed well with results from the modelling work. ?? 2011 Published by Elsevier Ltd.
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Experimental and simulation studies of iron oxides for geochemical fixation of CO2-SO2 gas mixtures
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10th International Conference on Greenhouse Gas Control Technologies