Effects of extracted-vanadium residue and MgO on the basic sintering characteristics of high-chromium vanadium–titanium magnetite

Abstract

Extracted-vanadium residue (EVR), formed during the smelting and extraction of High-chromium vanadium-titanium magnetite (HCVTM), should be used cyclically, and its use as a sintering material to prepare sinters for blast-furnace smelting is a viable option. The effects of EVR and MgO on the fundamental sintering characteristics of HCVTM, such as assimilative temperature, liquid phase fluidity index, adhesive phase strength, and crystal stock consolidation strength, were studied using X-ray diffraction and scanning electron microscopy, as well as phase composition analysis and microstructure analysis. The assimilative temperature (the lowest reaction temperature between sintering materials and CaO) of HCVTM by adding 0–8 wt% EVR decreased. The liquid phase fluidity index of HCVTM with six wt% EVR is best. The adhesive phase strength decreased from 1162 to 356 N. However, the crystal stock consolidation strength increased to the highest value of 2170 N by adding six wt% EVR. Based on the primary sintering characteristics effect of EVR on HCVTM, the optimum EVR amount is six wt%. After adopting the six wt% EVR added HCVTM with relatively good properties, the assimilative temperature of mixed ores increased from 1290 to 1320 °C with MgO added percent of 0–3 wt%. The liquid phase fluidity index decreased as a whole from 0.88 to 0.796–0.828, and the crystal stock consolidation strength also reduced from 2170 to 1090 N, indicating that both the liquid phase fluidity index and the crystal stock consolidation strength have changed slightly as a result of the addition of >1% MgO. However, adding 1% MgO improved the adhesive phase strength to a high value. The perovskite formation is restrained as Ti4+ diffuses into the liquid phase with the increase of MgO. Based on the effect of the fundamental sintering characteristics of EVR and MgO on HCVTM, a sintering blending ratio of 6 wt% EVR and one wt% MgO is recommended.