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:
Dec. 24, 1996
Filed:
Nov. 06, 1995
Masato Nakajima, Kashima-gun, JP;
Toshiaki Akahoshi, Kashima-gun, JP;
Masatoshi Sawahata, Kashima-gun, JP;
Yutaka Nomura, Kashima-gun, JP;
Kanji Sato, Kashima-gun, JP;
Kashima-Kita Electric Power Corporation, Ibaraki-ken, JP;
Abstract
A method for producing an electrolytic solution containing vanadium as positive and negative electrode active material, the electrolytic solutions being suitable for a redox battery which comprises: the steps of (1) a vanadium compound is dissolved in a solvent under an alkaline or neutral condition, a polyvanadate compound is precipitated and isolated by thermal polymerization of vanadium ions under an acidic condition; (2) a part of the polyvanadate compound is baked in an inert or oxidizing gas atmosphere so as to remove ammonium ions; (3) a trivalent vanadium compound is formed by treating another part of the polyvanadate compound under a reductive atmosphere; (4) a trivalent vanadium electrolytic solution is formed by dissolving the trivalent vanadium compound in an acid solution; and (5) vanadium pentoxide and a part of the trivalent vanadium compound are reacted by mixing so that mixed electrolytic solutions of V.sup.4+ and V.sup.3+ are formed. According to the present invention, a high purity vanadium electrolytic solution can be economically produced even from vanadium pentoxide and ammonium metavanadate raw materials containing large quantities of impurities.