氟化物熔盐中快速电脱氧制备金属钒及其机理

以偏钒酸铵为原料,采用"煤气还原+原位烧结"工艺制备高活性V_2O_3阴极片,在氟化物体系熔盐中实现了快速电脱氧制备金属钒,并通过测定循环伏安曲线结合恒电位电解实验,研究了电解过程的反应机理。结果表明:V_2O_3在氟化物熔盐中可实现快速电脱氧,电解4 h后所得金属钒的氧含量降至0.218%(质量分数,下同);V_2O_3阴极电脱氧产生的O~(2-)在脱氧反应区可原位生成铝氧氟络合离子并进一步产生金属铝,从而引发阴极的铝热还原反应,导致V_2O_3熔盐电脱氧过程同时存在直接电还原反应和铝热还原反应,其中后者起着关键的加速作用;在熔盐中添加适量Al_2O_3可强化V_2O_3电脱氧过程,在其他条件不变的情况下电脱氧时间可缩短至3 h。

Preparation and Reaction Mechanism of Metallic Vanadium by Rapid Electro-deoxidization in Molten Fluorides

By using NH₄VO₃ as raw material, high-active V₂O₃ cathode pellets were prepared by reduction with coal gas and in-situ sintering, then were directly reduced to metallic vanadium by rapid electro-deoxidization in molten fluorides. The mechanism of V₂O₃ electro-deoxidization was studied by cyclic voltammetry experiments and constant potential electrolysis experiments. The results indicate that the rapid electro-deoxidization of V₂O₃ can be realized in molten fluorides, metallic vanadium containing 0.218 wt% oxygen can be obtained after 4 h electrolysis. The in-suit formation of aluminium-oxygen-fluorine complex ions, which further forming aluminum metal in deoxidation reaction zone, caused aluminum thermal reduction reaction of V₂O₃ cathode. So direct electro-deoxidation reduction and aluminum thermal reaction of V₂O₃ both existed in the deoxidation process of V₂O₃ cathode, and the latter reaction played a key role in acceleration action. Electro-deoxidization process of V₂O₃ cathode can be enhanced effectively by adding aluminium oxide in molten fluorides, the electrolytic time can be shortened to 3 h with other conditions unchanged.