Electrochemical behaviour of thorium(IV) in molten LiF–CaF2 medium on inert and reactive electrodes

✍ Scribed by P. Chamelot; L. Massot; L. Cassayre; P. Taxil

• Book ID: 103828183
• Publisher: Elsevier Science
• Year: 2010
• Tongue: English
• Weight: 842 KB
• Volume: 55
• Category: Article
• ISSN: 0013-4686
• DOI: 10.1016/j.electacta.2010.03.073

✦ Synopsis

The electrochemical behaviour of the Th(IV)/Th system was examined in molten LiF-CaF 2 medium on inert (molybdenum), reactive (nickel) and liquid (bismuth) electrodes in the 810-920 • C temperature range by several electrochemical techniques. Experimental results showed that (i) thorium fluoride was reduced in a single step exchanging 4 electrons and limited by thorium ions diffusion in the solution, (ii) the oxide ions induce the precipitation of Th(IV) in the form of thorium oxide (ThO 2 ), in a process involving as intermediate compound a soluble oxifluoride (ThOF 2 ), (iii) the reduction of thorium ions on reactive (Ni and liquid Bi) electrodes yields compounds Ni-Th and Bi-Th with a potential shift of around 0.7 V (for Ni and Bi) more anodic than the reduction of Th(IV) on inert substrate.