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:
Sep. 16, 1986
Filed:
Feb. 25, 1985
Tai K Kim, Towanda, PA (US);
Martin B MacInnis, Towanda, PA (US);
Robert P McClintic, Monroeton, PA (US);
GTE Products Corporation, Stamford, CT (US);
Abstract
A method is disclosed for producing crystalline ammonium metatungstate from ammonium paratungstate. The method involves heating the ammonium paratungstate at from about 100.degree. C. to about 250.degree. C. for from about 1 hour to about 8 hours to remove some ammonia and water, digesting a solution of the heated ammonium paratungstate in water at from about 80.degree. C. to about 100.degree. C. for from about 2 hours to about 6 hours at relatively constant volume while maintaining the pH of the slurry at from about 4.2 to about 3.0 by addition of ammonia as necessary to form a solution of ammonium metatungstate in water. The ammonium metatungstate solution is then evaporated to concentrate it. Any insoluble material is separated from the solution. Ammonium metatungstate is then crystallized from the resulting concentrated ammonium metatungstate solution.