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:
Oct. 12, 1982
Filed:
May. 07, 1981
Lucretia R Quatrini, Athens, PA (US);
Martin C Vogt, Monroeton, PA (US);
Brice E Martin, Towanda, PA (US);
GTE Products Corporation, Stamford, CT (US);
Abstract
Tungsten is recovered from tungsten ore concentrates in the form of sodium tungstate by a basic process in which ground ore is first digested in a sodium hydroxide solution followed by diluting the solution to dissolved sodium tungstate separating the solution from the caustic insoluble sludge and crystallizing soluble sodium tungstate, wherein the present invention permits improved recovery of tungsten from difficult to process ores by the process steps of comminuting said tungsten ore concentrate to a particle size less than about 200 mesh, adding the comminuted ore to an aqueous solution of sodium hydroxide at a temperature from about 10 to about 30 degrees centigrade, dispersing said comminuted ore in the aqueous solution of sodium hydroxide prior to digestion, digesting at a temperature of from about 75.degree. C. to about 150.degree. C. for a sufficient period of time to convert substantially all of the tungsten values to dissolvable sodium tungstate, and diluting the mixture to reduce the sodium hydroxide concentration to between about 4.5 and 5.5 molar at a temperature below about 90.degree. C. to substantially dissolve all of the sodium tungstate.