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 digestion of mixed wolframite and scheelite concentrates is provided, the process comprising forming a slurry of the mixed wolframite and scheelite concentrates in an aqueous sodium carbonate solution and then digesting the slurry in an autoclave at a temperature of at least about 180.degree. C. During digestion a predetermined amount of sodium hydroxide is added calculated stoichiometrically to react with NaHCO.sub.3 formed as a result of the hydrolysis of FeCO.sub.3 or FeCO.sub.3 and MnCO.sub.3 produced during the digestion of the wolframite and convert it to Na.sub.2 CO.sub.3. The concentration of the Na.sub.2 CO.sub.3 solution 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 ranging from about 0.9 to 2 such as to effect dissolution of at least about 95% of the WO.sub.3 in the concentrate and provide a pregnant liquor containing said WO.sub.3.