Search Results (2)

Vanadium titanomagnetite is an important mineral resource. It is a raw material for ironmaking, vanadium extraction, strategic metal titanium production, and titanium dioxide production. In this study, high chromium vanadium titanomagnetite (High-Cr VTM) and ordinary iron ore were used as raw materials for pelletizing. The effect of V₂O₅ on the preparation and properties of High-Cr VTM pellets was studied. The influence of V₂O₅ on the properties of the green pellets, the compressive strength of oxidized pellets, the reduction swelling index and reduction degree, softening-melting behavior, and the migration law of Fe, Ti, and Cr in the reduction process were studied by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The results show that with the increase in V₂O₅ content, the properties of the green pellets basically showed a trend of first decreasing and then increasing but all met the basic requirements of pelletizing. When the added amount of V₂O₅ in the pellet was 6%, the compressive strength of the oxidized pellet was the lowest at only 2565 N/pellet but it still met the quality requirements for pellets in blast furnace production. As the dosage of V₂O₅ increased, the reduction swelling index and reduction degree of the pellets showed a trend of first increasing and then decreasing. The addition of V₂O₅ can increase the softening initial temperature, softening final temperature, melting start temperature, and dripping temperature of the High-Cr VTM pellets, narrowing the softening interval, and expanding the melting dripping interval. The experimental results provided a data reference for revealing the influence of V₂O₅ on High-Cr VTM pellets during the blast furnace smelting process. Full article

The loss of permeability affects the reduction of the ferrous burden in the cohesive zone of a blast furnace (BF). Vanadia–titania magnetite (VTM) burden of various chemical compositions have different metallurgical properties. The reduction and softening-melting-dripping properties of different kinds of VTM were investigated. The results showed that the core of sinter or pellet is indirectly reduced to wustite and (Fe,Ti)O_x, and the periphery contains interlinked metallic iron and CaSiO₃ in the cohesive zone. Wustite and (Fe,Ti)O_x are directly reduced in the melting-dripping zone. The aggregate (Fe, V, Cr) present in the non-dripping causes a loss of valuable components. With the increase in TiO₂ content, the substrate phase of molten slag changes from melilite to titanaugite, and the mass of dripping decreases gradually. In addition, the permeability index S increased and the melting zone widened, which indicates that the increase in TiO₂ content negatively affected the melting-dripping performance. The mass of the dripping is directly proportional to the pellet ratio. Considering the adverse effect of TiO₂ on softening-melting-dripping properties, it is recommended that high TiO₂ VTM is smelted while mixed with ordinary ores or with an increased pellet ratio in the burden structure. Full article