Modification of Elemental Migrations of Vanadium-Bearing Slags by CaO, V₂O₃ and “FeO”

Abstract

In this study, we clarified the elemental migrations among various phases in vanadium-bearing slags modified using V₂O₃, CaO and “FeO” at 1380 °C, where the main methodology included high temperature experiments, quenching and electron probe X-ray microanalysis. We quantified the oxide distributions between the spinel and the liquid phases, including the major oxides such as “FeO”, CaO, SiO₂, V₂O₃ and Cr₂O₃, etc., and the minor oxides such as Al₂O₃, MnO and MgO, etc. We first found that V₂O₃ and Cr₂O₃ were mainly present in the spinel phase, determining the primary phase of this system. With an increasing total V₂O₃ content, the V₂O₃ concentration in the spinel phase remarkably increased, and the Cr₂O₃ concentration decreased; while those in the liquid phase remained at a low level. More CaO induced an increasing V₂O₃ concentration in the liquid phase moved from the spinel phase, and correspondingly the Cr₂O₃ concentration in the spinel phase increased. In comparison, “FeO” mainly affected the chemical compositions of the spinel phase but not the liquid phase, i.e., with an increasing total “FeO” content, the “FeO” concentration in the spinel phase gradually increased at the cost of V₂O₃ and Cr₂O₃. Our study thus provided useful clues for process design and in-site modification of vanadium-bearing slags toward clean utilizations.