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. 21, 1978
Filed:
Jan. 27, 1977
Hans Peter Kasserra, Brockville, CA;
Denis Bertram Kelly, Mallorytown, CA;
Isaac Obadia, Kingston, CA;
Du Pont of Canada Ltd., Montreal, CA;
Abstract
A process is provided for treating tri (alkaline earth metals) tungstates with an aqueous solution containing cations selected from ammonium, sodium and potassium ions and mixtures thereof, and anions selected from hydroxide, carbonate, bicarbonate, and phosphate ions and mixtures thereof, to form a tungstate salt which is soluble in the solution and an alkaline earth metal compound which is insoluble in the solution. The tri (alkaline earth metal) tungstate can be prepared from iron tungstate, manganese tungstate, and/or an alkaline earth metal tungstate or from ores or concentrates of these tungstates, by a high temperature treatment with an alkaline earth metal donor compound, such as calcium oxide. A preferred soluble tungstate is ammonium tungstate, which can be further processed to yield tungsten trioxide and/or tungsten.