Pre-reduction of carbon-containing pellets of high chromium vanadium–titanium magnetite at different temperatures

Abstract

Abstract The effect of temperature on phase transformation, metallization rate, carbon residue and agglomeration of metal Fe after the pre-reduction of carbon-containing pellets in high-chromium vanadium–titanium magnetite (HCVTM) was investigated. The results indicated that titanomagnetite was finally reduced to metal Fe and (Mg, Fe)Ti2O5 without low valence titanium oxide with increasing pre-reduction temperature from 950 to 1,250℃; Vanadium magnetite produces Fe, VO and VC0.88 without V, and chromite magnetite produces Fe, Cr2O3, CrC x and a small amount of Cr. With an increase in the pre-reduction temperature, the metallization rate in the metallized pellets gradually increases, while the content of the residual carbon gradually decreases. Meanwhile, the iron particles precipitated on the surface of ore particles begin to soften into strips and finally agglomerate to form spherical iron particles, which leads to the diameter of iron particles increasing from 8.23 to 182.35 μm. When the pre-reduction temperature is 1,250℃, the maximum metallization rate in the metallized pellets is 92.49 wt% and the minimum content of residual carbon is 10.37 wt%.