An innovative and sustainable way for production of vanadium (V) is to co-process V titanomagnetite ores with V-bearing steel slag, via reduction. V-slag produced from highly enriched Fe-V melt contains as high as 20 mass% V. The phase relationship in FeO-SiO 2 based slag with V fixed at 20.4 mass% was investigated experimentally at 1673 K. The compositions covered the normal production range, viz. Al 2 O 3 from 0 to 6 mass%, CaO from 1 to 5 mass% and SiO 2 from 10 to 17 mass%. The content of MnO was fixed at 5.5 mass%. Samples quenched at 1673 K were found to be solid-liquid mixtures, either in a 2-phase region consisting of liquid and a solid spinel phase, or in 3-phase region consisting of liquid, spinel phase and silica phase. Free silica was only found in samples with a composition of 0 mass% Al 2 O 3 , 1 mass% CaO and 17 mass% SiO 2. Formation of free silica was prohibited in samples with 1 mass% CaO and up to 17 mass% SiO 2 by adding 5 mass% Al 2 O 3. Addition of 4 mass% Al 2 O 3 was also sufficient to prevent the presence of free silica in samples with 3 mass% CaO and 13.5 mass% SiO 2. Most of the V was kept in the spinel phase, while the solubility of V in the liquid was generally less than 1 mass% as V 2 O 3. Fe, Mn and Al coexisted in both liquid phase and spinel phase. On the other hand, Si and Ca only distributed in the liquid phase. The fraction of solid phase, viz. spinel was found to decrease with increasing SiO 2 content.

An innovative and sustainable way for production of vanadium is to co-process vanadium titanomagnetite ores with vanadium-bearing slag from steel industry, via reduction, producing a hot metal containing about 2 mass% vanadium, 0.1 mass% phosphorus, and 0.4 mass% silicon. A vanadium-extraction method was developed for these hot metals using a semi-industrialscale converter. Oxidation was carried out with an air jet enriched to 50 vol% oxygen and by top-charging up to 70 kg iron ore pellets per ton hot metal. The complete dissolution of pellets was achieved by deliberately creating good stirring conditions utilizing high momentary decarburization rates. The temperature could be controlled to around 1677 K at the blowing endpoint after the pellet coolant had been dissolved. Produced vanadium slags contained as high as 20 mass% V. The semifinished product contained about 3 mass% carbon and 0.1 mass% vanadium, corresponding to a vanadium yield of 94%. The phosphorus distribution to the slag was low when good stirring was maintained. The slag composition had a more significant impact than the temperature on the vanadium distribution. Laboratory-scale study also showed that the temperature impact on the composition of the liquid phase was minor.