In situ QXAFS observation of the reduction of Fe2O3 and CaFe2O4

In situ QXAFS studies of the reduction of alpha-Fe2O3 and CaFe2O4 were conducted to determine their reduction kinetics and mechanisms. The reduction of alpha-Fe2O3 involved two steps, the first being a very fast process in which Fe3+ was reduced to Fe2+, and the second being the reduction of Fe2+ to Fe metal over a longer period. In contrast, the reduction of Fe in CaFe2O4 was a single first-order reaction, although an induction period was clearly observed at the beginning of the reduction process. The reduction processes were successfully studied using a combination of in situ QXAFS spectra at the Ca and Fe K-edges.