Effect of MgO in Sinter and Primary‐Slag on Smelting Mechanism of Chromium‐Bearing Vanadium Titanomagnetite

Abstract

The effects of MgO in sinter and primary‐slag on smelting mechanism of chromium‐bearing vanadium titanomagnetite (CVTM) are investigated in this work. The XRF, XRD, ICP‐AES, FT‐IR, and rotating cylinder methods are applied to analyze CVTM sinter samples, primary‐slag, and dripped iron. The results show that the softening interval and melting interval decrease and the cohesive zone moves down mildly and becomes narrowly with increasing MgO. The free running temperature of the primary‐slag decreases from 1285 to 1234 °C, the initial viscosity decreases from 1.13 to 0.92 Pa s, and the high‐temperature viscosity decreases from 0.46 to 0.24 Pa s with increasing MgO. The depolymerization of the primary‐slag structure enhances with increasing MgO, which has a significant effect on the shrinkage of primary‐slag formation temperature interval and decreasing permeability of CVTM sinter burden. What's more, the dripping ratio increases from 82.7% to 97.7% and the dripping pressure drop increases from 1.1 to 1.9 kPa and reaches to a maximum value at 3.3% MgO. Moreover, both the recovery ratios of Cr and V increase from 20.49% to 28.07% and from 25.39% to 41.74%, respectively.