Abstract:
The electrochemical reduction mechanism of W
6+ on the tungsten electrode at 973 K was studied by the methods of cyclic voltammetry, chronopotentiometry, chronoamperometry and square wave voltammetry, and by using NaCl-KCl-NaF and WO
3 as molten salt and raw material respectively. The results show that the reduction process of W(Ⅵ) ion is carried out in two steps: the first one is a two-electron transfer process, and the electrode reaction equation is W
6+ + 2e
-→W
4+; the second one is a four-electron one, and the electrode reaction equation is W
4+ + 4e
-→W. The two depositing processes of tungsten ion are both quasi-reversible reactions. The reduction process of W(Ⅵ) ion on the tungsten electrode is controlled by diffusion whose coefficient is 1.05×10
-9 cm
2 /s.