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:
Mar. 12, 1985
Filed:
Sep. 02, 1983
Kent H Carpenter, Ann Arbor, MI (US);
John M Laferty, Wheat Ridge, CO (US);
Amax Inc., Greenwich, CT (US);
Abstract
A process is provided for producing ammonium metatungstate comprising fluid bed roasting ammonium paratungstate at a temperature over the range of about 275.degree. C. to 305.degree. C. for a time at least sufficient to provide a roasted product in the form of a precursor of ammonium metatungstate, forming an aqueous slurry of the precursor and digesting the precursor at a pH of about 3 to 4 for a time at least sufficient to effect substantially complete dissolution of said precursor, filtering the digested slurry to produce a clear filtrate, and further processing the clear filtrate by evaporation to provide crystals of substantially pure ammonium metatungstate.