Thermodynamics And Kinetics Of The Reduction For Acid Vanadium-titanium Slags In Electric Furnace

Focused on the reduction process of acid vanadium-titanium slag in electric furnace, the basic thermodynamics study on the distribution of vanadium between molten iron and slag and the kinetics of the reduction of acid vanadium-titanium slag were performed in this paper. As well as, the vanadium-titanium slags in the different time of the reduction process were analyzed to investigate the evolution of phases and transformation of existing status of V and Ti in the acid vanadium-titanium slags.Based on reviewing the progress of the fundamental studies on reduction process of vanadium-titanium bearing slag, synthetic slag was used to simulate the acidic slag of the metallic pellet for investigating the reduction reaction of V2O5 in slag in this paper. The influence of factors including temperature, ratio of slags to molten iron, initial content of FeO, V2O5, TiO2 in slags on the reduction of vanadium oxide were studied. The results show that as reaction temperature 1580℃, slag/iron ratio 1/4 and the compasition of synthetic slag same as the composition of the acidic slag of the metallic pellet, the reduction reaction of vanadium oxide is relatively quick within 70min, and the reduction rate is about 80%. While the balance is established in 120min, the reduction rate can reach 92.9%. It's helpful to the reduction of vanadium oxide and the improvement of the reduction rate that with higher temperature, more molten metal and larger initial content of V2O5 in slags. On the contrary,more initial content of FeO and TiO2 in slags will stunt the reduction and slown the reaction rate.The main phases of slags of different reduction efficiency are Pyrope containing little Diopside and MgTi2O5 containing little FeO, and most Ti are in the MgTi2O5.In the early stages of reaction in which the reduction efficiency is the range of 28.75% and 38.34%, Ti mainly exists in the strip-like phase of Mg3Al4Ti3O25-MgTi2O5 solid solution while the others are dispersed in the phases of silicate and small block. Ti gradually precipitates from the silicate phase and combines the small block-like phase to develop into the strip-like phase of Mg3Al4Ti3O25-MgTi2O5 solid solution then exists finally and steadily in the phase.In the initial stage of the reduction in which the reduction efficiency is in the range of 28.75% and 38.34%, V mainly coexists with Ti in both block-like phase and strip-like phase. With the reacting reduction, V is reduced into the molten iron gradually. In the final stage of reaction in which the reduction efficiency is in the range of 71.41% and 76.68%, the unreacted V is left in the phase of silicate.