The saturation vapour pressure and decomposition potential of ThCl4 solutions in molten alkali chlorides

✍ Scribed by M.V. Smirnov; V.Ya. Kudyakov

• Publisher: Elsevier Science
• Year: 1984
• Tongue: English
• Weight: 479 KB
• Volume: 29
• Category: Article
• ISSN: 0013-4686
• DOI: 10.1016/0013-4686(84)80040-7

✦ Synopsis

The partial pressures of the components (ThCl,, MC1 and MThCl,) in the saturated vapours of ThC& solutions in molten LiCl, NaCl, KCI, RbCl and CsCl are determineci as a function of temperature (900-1200 K) and ThCl, wnccntration (2-W mol % ThCI,) by dynamic method. Thorium tetrachloride volatility is shown to exceed that of alkali chloride from the melts containing less than 98 LiCl of NaCl, 83 KCI, 67 RbCl and 48 mol 3 CsCl. From experimental observations the decomposition potential of the electrolytes under investigatron was estimated in temperature and concentration ranm of our measarb ments. Under otherwise equal conditions, it increases in the series of alkali chlorides from LiCl to CsCl. INTRODUCT ION Thorium tetrachloride solutions in molten aikah chlorides can be used for producing and refming metallic thorium and its alloys by electrolysis. The important properties of these electrolytes are their volatility at elevated t.emperatures and decomposition potential (the potential difference between the cathode and anode on which the metal is deposited and chIorine is evolved when the current of electrolysis is tending to zero). The saturation vapour pressure was measured as a function of temperature by Ionov et ar[I] for the melts the composition of which corresponded to the wmpounds Na,ThCl,, K,ThCl, and Cs3ThC1,, and later by Su Myan'-tszen' and Novikov[Z] for ThQ solutions in molten KC1 containing 2550 and 75 mol "/, ThC14. The double compounds of thorium tetrachloride with alkali chlorides (MThCl,) were established to exist in the vapour phase. The decomposition potential of ThQ solutions in molten alkali chlorides can be found directly by measuring the emj of the cells Th(s)]NThCl,, + (I -N)