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. 21, 1989
Filed:
Apr. 30, 1987
John A Powers, New Albany, PA (US);
James C Patton, Towanda, PA (US);
James N Christini, Towanda, PA (US);
GTE Products Corporation, Stamford, CT (US);
Abstract
A tungsten extraction process wherein tungsten values are extracted from an aqueous alkali metal tungstate solution by an organic solution containing an amine extractant wherein the organic solution consists essentially of from about 6% to about 10% by volume of said amine extractant, and the balance of said organic solution being an aromatic solvent consisting essentially of a mixture of alkyl benzenes wherein the alkyl benzenes have molecular weights of 120, 134, or 148 and the total number of carbon atoms in the alkyl chains attached to the benzene ring are either 3, 4, or 5, and thereafter the tungstate values are removed from the organic solution by stripping with aqueous ammonia, is improved by carrying out the stripping step in the aqueous continuous mode, and having as the stripping agent, an aqueous solution of ammonium metatungstate having a tungsten concentration which allows the strip solution to have a specific gravity of no greater than about 1.5, the stripping agent having sufficient ammonia to maintain the pH of the stripping agent at from about 5 to about 8, with the temperature of the stripping agent being no greater than room temperature.