Preparation of vanadium powder and vanadium-titanium alloys by the electroreduction of V_2O_3 and TiO_2 powders

摘要

Electroreduction of solid V_2O_3 pellets (～0.7 g) to V in molten CaCl_2 at 900 ℃ has been studied by cyclic voltammetry and potentiostatic electrolysis, together with scanning electron microscopy, energy dispersive x-ray, and elemental analyses. The intermediate products of the potentiostatic electrolysis are various, forming some lower valence state compounds (VO, V_(16)O_3, V_7O_3, VO_(0.2)) and higher valence state which are likely VO_2, CaVO_3, or CaV_2O_5. At potentials more negative than -0.6 V versus Ag/AgCl, fine vanadium powder (aggregates of nodular ～500 nm particles) can be prepared by electrolysis of porous solid of the V_2O_3 pellets. The current efficiency and energy consumption were satisfactory, about 53.4% and 2.5 kW h/(kg V) at -0.6 V versus Ag/ AgCl, respectively. Moreover, V-20Ti alloys were electrochemically synthesized by constant voltage electrolysis at the indicated potentials, the control of composition as well as the reduction optimization of the mixtures were demonstrated. This electrochemical route is efficient and offers a product with controlled stoichiometry, with particular advantage of manufacturing of low cost alloys and intermetallics directly from mixed oxide precursors, and has potential to produce functional vanadium alloys.