Chemical State Analysis of Metal Oxides for Slag Control on Smelting of High-Quality Chromium Steel

Abstract

The chemical states of Fe and Cr in CaO-SiO₂-MgO based oxide glasses prepared assuming actual chromium steel slag with different compositions and different melting conditions were investigated using X-ray absorption near edge structure (XANES) measured by X-ray absorption spectroscopy (XAS), and the valence ratios of each metal were determined. The results showed that the valence ratios changed depending on the oxygen partial pressure during melting, the basicity (CaO/SiO₂ weight ratio), and the coexistence of Fe and Cr. It was also found that Fe was a two-component system with divalent and trivalent valences coexisting, while Cr had divalent, trivalent, and hexavalent valences, but only divalent and trivalent or trivalent and hexavalent valences coexisted. In particular, the effect of coexistence is complicated by the chemical states of Fe and Cr. The effect of MgO addition is not as large as that of metal oxide coexistence, but it is not only as a basic oxide. The usefulness of direct and quantitative analysis of metal chemical states by XAS was demonstrated.