Effect of Cr2O3 on Physicochemical Properties of CaO-SiO2-FetO Slags during BOF Smelting Process of Chromium-Bearing Iron

Abstract

The productivity of basic-oxygen-furnace (BOF) smelting process is directly affected by the slag-forming speed during the initial stage of converter. Therefore, it is essential to study the effect of different Cr2O3 content on the physicochemical properties of the primary slag in the smelting process of chromium-bearing semi-steel. In this work, Factsage8.1 software, X-ray diffraction (XRD), scanning electron microscope (SEM), energy dispersive spectroscopy (EDS) and a high-temperature melting point tester were used to study the effects of different Cr2O3 content on the melting temperature, solidification behavior, mineral composition, and other physicochemical properties of the CaO-SiO2-FetO system. The results showed that the melting temperature of slag samples increased from 1223 °C to 1354 °C as Cr2O3 increased from 0 wt% to 9.09 wt%. With the increase of Cr2O3, the content of CaFeSi2O6 decreased. Moreover, due to the addition of Cr2O3, the chromium-bearing spinel solid solution (Fe(Fe,Cr)2O4) began to form in the slag. Furthermore, Cr2O3 promoted the increase in the volume of free solid particles in the slag, resulting in an increase in slag viscosity. All in all, the increase of Cr2O3 content in the CaO-SiO2-FetO system will adversely affect the semi-steel steelmaking process.