Chemical State Evolution of Iron Ore Sinter Investigated by Wide-Area Imaging XAFS

We have developed experimental and data analysis techniques of imaging XAFS (X-ray absorption fine structure) and investigated the Fe chemical state distribution in iron ore sinters over a field of view wider than 10 mm. Detailed spectral interpretation was provided for oxides and calcium ferrites at different stages of reduction. At lower temperatures, crack-driven propagation of reduction reaction was observed to penetrate deeper than 1 mm, while fine-grain primary hematite underwent reduction without forming cracks. Once the reduction of calcium ferrites begins, the reduction reaction changes to relatively uniform propagation, independent of mineral phases, resulting in a layered distribution of Fe chemical states.