The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
May. 15, 1990
Filed:
Mar. 31, 1989
Tomoo Kirihara, Hirakocho-Higashi, JP;
Ippei Nakagawa, Aichi, JP;
Yoshinobu Seki, Ibaraki, JP;
Yutaka Honda, Ibaraki, JP;
Yasuo Ichihara, Ibaraki, JP;
Mitsubishi Nuclear Fuel Company, Ltd., Tokyo, JP;
Abstract
A process for separation of hafnium tetrachloride from zirconium tetrachloride and electrode is disclosed. Zirconium tetrachloride containing hafnium tetrachloride in natural ratio dissolved in a molten salt is reduced in the first phase electrolysis using an anode composed of a substance formed by firing a mixture of more than one kind of compound selected from the group consisting of silica, silicate containing zirconium or zirconium oxide and carbon with a binder under maintenance of an initial concentration of the zirconium tetrachloride in order to produce zirconium trichloride containing a hafnium content lower than that of the zirconium tetrachloride at a cathode. Next, by using the former cathode as an anode and another cathode in the second phase electrolysis the zirconium tetrachloride is further reduced to yield zirconium trichloride of a lower hafnium content at another cathode and evolve on the anode gaseous zirconium tetrachloride having a high pressure by oxidizing the zirconium trichloride produced in the first phase electrolysis. The evolved zirconium tetrachloride is recovered as zirconium tetrachloride with a low hafnium content. Further, the zirconium tetrachloride with a low hafnium content and the zirconium trichloride with a lower hafnium content are produced by exchanging polarities of the cathode and the anode when the zirconium trichloride on the anode decreases. The second phase electrolysis is carried out repeatedly. After hafnium tetrachloride is concentrated to an expected value in the molten salt in the above mentioned electrolysis, the molten salt is transferred to a separate vessel and is heated to evaporate the tetrachloride highly concentrated hafnium. Thus, zirconium tetrachloride and hafnium tetracholoride are respectively separated with high efficiency. A hafnium content of zirconium tetrachloride separated is able to reduce to less than 100 ppm, and a zirconium content of hafnium tetrachloride separated is also reduced to less than 25 wt %.