| To prepare the high purity vanadium metals, the purification procedures of commercial grade vanadium pentaoxide by cation ion exchange and aluminothermic reduction have been studied. After fusion of oxide with NH₄F·HF, hot water leaching and filtration have been carried out. The leaching solution is filtered and pumped onto the cation ion exchange columns to investigate the removal pattern of impurity ions. After three stages of ion exchange operation, total amounts of impurity have been reduced to $lt;150 ppm level. The purified oxide is then exothermically reduced with aluminum powder. The resulting V-Al nugget is arc melted in an argon atmosphere to remove the slag inclusions and residual volatile impurities. Vanadium alloy(V-5Al) containing $lt;75 ppmw Fe, $lt;10 ppmw Si and Cu, has been prepared by this investigation. |
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