INFLUENCE OF SILICON CONTENT IN HOT METAL ON MINERALOGICAL CHARACTERIZATION AND PHYSICO-CHEMICAL PROPERTIES OF VANADIUM SLAG

摘要

Extracting vanadium from vanadium containing hot metal into vanadium slag by BOF is the main vanadium production process in China. In this paper, the influence of Si content in hot metal on the quality of vanadium slag is analyzed. Synthetic vanadium slag with different SiO_2 content were melted at 1673 K and then cooled to 303K at the cooling rate of 3°Cmin. Optical microscopy, SEM, EDS and XRD were used to analyze the mineralogical phases and crystallization behavior of vanadium slag. The results show that vanadium slag mainly contains spinel phase and silicate phase; V is enriched in the spinel phases while Si is concentrated in Fe_2SiO_4 CaFeSi_2O_6 and (Fe,Mn)_2SiO_4 as silicate phase. The melting point of slag increases gradually with the addition of SiO_2; whereas viscosity decreases with an addition of 15～19% SiO_2 and increases with an addition of 19～27% SiO_2.