Iron oxides as efficient sorbents for CO2 capture

Carbon dioxide capture/release reactions using magnetite, Fe3O4, and hematite, Fe2O3, as sorbents were studied. Kinetics of mechanically activated chemical reactions between iron oxides and CO2 was investigated as a function of CO2 pressure and planetary ball mill process parameters. It was found that complete carbonation of iron oxides can be accomplished at room temperature and elevated CO2 pressure (10-30 bar). Siderite calcination was studied in vacuum and argon atmospheres. FeCO3 can be decomposed at 367 degrees C yielding magnetite, carbon and/or iron. This mixture can reversibly re-absorb carbon dioxide in multiple carbonation-calcination cycles. These results suggest that siderite or iron oxides are prospective and efficient reversible sorbents for CO2 capture. (C) 2019 The Authors. Published by Elsevier B.V.