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. 16, 1982
Filed:
Jan. 19, 1981
Amax Inc., Greenwich, CT (US);
Abstract
A process for the soda ash digestion of refractory tungsten concentrates is provided, the process comprising forming a slurry of the concentrate in an aqueous solution to which sodium carbonate is added in stages while digesting the slurry in an autoclave at a selected elevated temperature of at least about 180.degree. C. to control the concentration of the sodium carbonate during digestion to provide high extraction yields of the contained WO.sub.3. The total amount of the Na.sub.2 CO.sub.3 added stage-wise to complete the digestion is substantially inversely correlated to the digestion temperature and substantially directly correlated to the Na.sub.2 CO.sub.3 /WO.sub.3 weight ratio such as to effect dissolution of at least about 97%, and generally at least about 98%, of the WO.sub.3 in the concentrate and provide a pregnant liquor containing WO.sub.3, the stage-wise addition of the sodium carbonate being such as to inhibit the dissolution of gangue minerals, such as silica, contained in the concentrate.