Preparation Of Vanadium Alloy By Electrochamical Reduction Of Solid In Molten Salt

In contemporary industry, the vanadium metal and vanadium-based alloys has played an important role because of their high-performance. The superiority of vanadium is mainly reflected in its low density, high melting point, hardness, good thermal conductivity, corrosion resistance, neutron absorption, etc. Vanadium and vanadium-based alloys are widely used in steel, chemicals, aerospace, medicine and other industries. And the reserve of vanadium resources is large on global scale, the reserve of vanadium in china ranks third in the world after South Africa and Russia, so the development and use of vanadium resources is essential for the entire industrial production.This paper was committed to research new method of preparation of metal vanadium and vanadium-based alloys using electro-deoxidation in molten salt method. Traditional preparation methods mainly include thermal reduction of magnesium, thermal reduction of calcium, thermal reduction of aluminum method, carbothermal reduction vacuumly, thermal reduction of metal chlorides, thermal decomposition of vanadium nitride and thermal reduction of silicon method, etc. However, the mature production technology could not hide its shortcomings such as process complexity, long production cycle, can not be producted continuesely. These result in high cost during the process of producting vanadium, and restrict the widely use of vanadium, so electro-deoxidation in the molten salt arises at the historic moment, which is a direct electrolysis the elemental metal oxides in the molten salt method, it has the characteristics of short process, low power consumption, low energy consumption, low pollution, it is a green metallurgical process.In this paper, we studied the process of electro-deoxidation in Molten Salt, compressed the V2O3powder and other metal oxides into tablets under a pressure of135MPa and sintered at1000℃for1h as the cathode and graphite was as an anode to a mass ratio of7:3CaCl-NaCl as the electrolyte and direct electrolysis to prepare of metal vanadium and vanadium-based alloys.Under the conditions of700℃the electrolysis temperature, the voltage, the sample porosity on the electric current and the products were investigated. Discussed the electro-deoxidation process and course of oxydation reactive by electrolysis time. Through the analysis of the reaction product by XRD patterns, SEM diagrams to determine optimum of electrolysis voltage is3V-3.1V, and as the porosity increases, the reaction speed the process up, but the current efficiency reduces, so the optimum electrolysis voltage is3.0V Efficiently producing metal vanadium, V-20T1alloy and V-4Cr-4Ti alloy.In the preparation of V-4Cr-4Ti alloy process, through V, Cr, Ti thermodynamics calculation of gradual reduction, determined the order of separating out of V, Cr, Ti oxides, the first order is Cr, followed is V, and last is Ti.Discussed the lectrolytic reduction reaction mechanism according to the time-current curves and XRD patterns, SEM images of the preparation of vanadium-based alloys:V2O3, O2O3, TiO2are reduced to metal elemental progressively, the valency of three metals continues to be reducted to the lower finally to0. V2O3as the main oxides reacts with CaO to generate occurs products as CaV2O5to main. Finally, because of the valence of vanadium becomes lower and lower, and chemical properties becomes more and more stable, these made the current efficiency lower and lower, the current value is small and stable.