In situ observation of reduction kinetics and 2D mapping of chemical state for heterogeneous reduction in iron-ore sinters

摘要

Iron-ore sinters constitute the major component of the iron-bearing burden in blast furnaces, and the mechanism of their reduction is one of the key processes in iron making. The heterogeneous reduction of sintered oxides was investigated by the combination of X-ray fluorescence and absorption fine structure, X-ray diffraction, and computed tomography. Two-dimensional mapping of the chemical states (CSs) was performed. The iron CSs Fe~(III), Fe~(II), and Fe~0 exhibited a heterogeneous distribution in a reduced sinter. The reduction started near micro pores, at iron-oxide grains rather than calcium-ferrite ones. The heterogeneous reduction among grains in a sinter may cause the formation of micro cracks. These results provide fundamental insights into heterogeneous reduction schemes for iron-ore sinters.