SELECTIVE SEPARATION OF VANADIUM FROM MOLYBDENUM BY ELECTROCHEMICAL ION-EXCHANGE

This paper presents the results of work on the selective electrochemic al elution of vanadium co-adsorbed with molybdenum on Amberlite IRA 94 S resin. A three-compartment cell equipped with an RVC (Reticulated Vi treous Carbon) cathode mixed with ion exchange resin and two Ti-Pt ano des separated by a Daramic diaphragm was used. In the process, the pen tavalent vanadyl anion is selectively desorbed with respect to molybde num after its reduction to a tetravalent vanadyl cation. The subsequen t elution can therefore produce a pure molybdenum solution. At 323 K, using a 30 g.l(-1) H2SO4 eluant and a decreasing current intensity, 93 % V and only 7% Mo is eluted from the resin initially loaded with 1.25 equivalent (Mo7O246-+HV10O285-) l(-1) which corresponds to 9.3 kg V a nd 130 kg Mo m(-3) of wet settled resin. The further elution of molybd enum with an alkaline solution leads to the recovery of a pure molybda te solution characterized by a molar Mo/V ratio of 1000/1 after a post -precipitation at pH 8. (C) 1998 Elsevier Science B.V.