Local structure examination of mineral-derived Fe2O3 powder by Fe K-edge EXAFS and XANES

Abstract

Fe K-edge XANES (X-ray Absorption Near Edge Structure) and EXAFS (Extended X-ray Absorption Fine Structure) spectra have been used to investigate the local structures of hematite (Fe2O3) powders which were synthesized from local iron stone. The formation of hematite with various calcination temperature (500, 650, 800) °C was observed from XRD data of each powder, and Fe K-edge EXAFS and XANES were performed to sample with calcination temperature 800 °C. The XANES spectra confirmed the oxidation state of the powders. The energy position of the first pre-edge peak at (7113.5 ± 0.5) eV confirm Fe3+. The absorption edges of Fe2O3 powders was 7123.41 eV. The first EXAFS data analysis showed that Fe2O3 powder exhibited nearest-neighbor distances RFe-O = 1.56449 Å and RFe-Fe = 3.01449 Å. The XRD lattice parameter values for the sample is in a fair agreement with the nearest-neighbor distances according to the EXAFS data.