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.:

US 6800268 B1

PDF
Full Text
Expired
Date of Patent:
Oct. 05, 2004

Filed:

Jul. 26, 2002
Applicant:
Inventors:

Yoshitsugu Uchino, Tokyo-To, JP;

Masanori Kinoshita, Tokyo-To, JP;

Attorney:
Primary Examiner:
Int. Cl.
CPC ...
C01G 3/500 ;
U.S. Cl.
CPC ...
C01G 3/500 ;
Abstract

Disclosed herein is a method for producing potassium fluoroniobate crystals by which highly pure, large-sized potassium fluoroniobate crystals can be obtained in high yield and which is advantageous from the viewpoints of material cost and material-dissolving operation; and potassium fluoroniobate crystals. This production method comprises the first and second steps (a) and (b) of (a) adding a potassium-containing electrolyte to a starting material comprising niobium to precipitate potassium oxyfluoroniobate and/or fluoroniobate as coarse crystals, and separating the coarse crystals by filtration, and (b) dissolving the coarse crystals in a recrystallization solvent that is an aqueous solution comprising 12 to 35% by weight of hydrofluoric acid and that has been heated to a temperature of 50° C. or more, and cooling the solution to 40° C. or lower at a cooling rate of less than 20° C./h to precipitate potassium fluoroniobate as crystals.


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Uchino, Yoshitsugu. (2004). Method for producing potassium fluoroniobate crystals and potassium fluoroniobate crystals (U.S. Patent No. 6800268). U.S. Patent and Trademark Office. https://idiyas.com/patent/badge/6800268

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