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:
Nov. 18, 1986
Filed:
Mar. 21, 1985
Richard A Scheithauer, Towanda, PA (US);
Clarence D Vanderpool, Towanda, PA (US);
Michael J Miller, Towanda, PA (US);
GTE Products Corporation, Stamford, CT (US);
Abstract
A method is disclosed for producing relatively pure ammonium paratungstate from an impure tungsten solution. The method involves first adding hexamethylenetetramine to the tungsten solution and adjusting the pH to from about 1.0 to about 2.0 with a mineral acid to form a first precipitate of a tungsten hexamethylenetetramine product, which is then separated from its mother liquor. The precipitate is then slurried in water and the pH adjusted to from about 7.0 to about 8.5 with ammonia to dissolve the precipitate. The resulting solution is then adjusted to from about 1.0 to about 2.0 with a mineral acid to form a second precipitate of the tungsten hexamethylenetetramine product which is then separated from its mother liquor. The second precipitate is then slurried in a solution of water and sufficient ammonia to form ammonium paratungstate which crystallizes out on evaporation of the slurry. The ammonium paratungstate is then separated from its mother liquor.