Vanadium Speciation in Fused Alkali Chlorides

Electronic absorption spectra of vanadium ions were recorded between 450 and 750 • C in 3LiCl-2KCl, NaCl-KCl and NaCl-2CsCl based melts.Analysis of the spectra showed that vanadium in the oxidation states of +2 and +3 is present in the melts as complex chloro-ions.Vanadium(II) can form the complex ions in octahedral and tetrahedral coordination, the latter being favored by higher temperatures.Only six-coordinated V(III) ions were observed.Vanadium in the oxidation state of +4 can be present in chloride melts only in the form of vanadyl-based oxochloro-species.Main spectroscopic parameters of vanadium complex ions were determined.Electronic absorption spectroscopy was also applied for studying a variety of the red-ox processes in vanadium containing melts including electrochemical oxidation and reduction of various species, and reaction of vanadium containing melts with oxygen.