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:
Jul. 13, 1976
Filed:
Feb. 20, 1975
Applicant:
Inventors:
Assignee:
Nittetsu Mining Company, Ltd., Tokyo, JA;
Primary Examiner:
Int. Cl.
CPC ...
C01G / ; C01G / ;
U.S. Cl.
CPC ...
423 58 ; 423 55 ; 423593 ; 423561 ;
Abstract
This invention relates to a process for recovering tungsten from an alkaline leaching solution of tungsten ores. This invention comprises adjusting the pH of an alkaline leaching solution which is obtained by lixiviating ore containing tungsten with an alkaline solution to 7-8 with acid to oxidize molybdic acid ions in the solution, adding a sulfide donor, then precipitating molybdenum sulfide compounds by adjusting the pH value of the solution to 2-3, and recovering tungstic acid ions as calcium tungstate by the addition of a calcium ion donor after the molybdenum sulfide compounds are separated.