粗バナジウム，V<SUB>2</SUB>C，およびVCを陽極材とするバナジウムの電解製造について

Abstract

The cathodic deposition of vanadium was investigated using the V-C-O alloys (crude vanadium, V2C and VC) produced by carbothermic reduction as the anode materials, and two kinds of molten salts, KCl(44)-NaCl(44)-NaF(7)-K2NaVF6 (5 mol%) and KF(62)-NaF(33)-K2NaVF6 (5 mol%), as the electrolytes. The cathode current efficiency depended strongly on the anode current density and little on the cathode current density. Initial anode current densities more than 200 A/m2 was necessary to obtain high cathode current efficiencies. It was found that crude vanadium (C: 0.45∼1.27, O: 0.66∼3.66 wt%) is more suitable for the anode material than V2C and VC, and the KCl-NaCl-NaF-K2NaVF6 molten salt is more appropriate for the electrolyte than the KF-NaF-K2NaVF6 molten salt. Without special purification of the bath, pure vanadium which contained oxygen ranging from 1600 to 3000 ppm and carbon ranging from 90 to 270 ppm was easily obtained from the crude vanadium (C: 0.45∼1.27, O: 0.66∼3.66 wt%) in the KCl-NaCl-NaF-K2NaVF6 bath under the electrolytic conditions of the initial anode current densities of 210 to 290 A/m2, the initial cathode current density of 10000 A/m2, and the bath temperature of 725°C. The microvickers hardness number of vanadium obtained ranged from 159 to 220 (1 kg-load). Eighty-five percent of vanadium in the crude vanadium was recovered at the cathode.