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. 08, 2014
Filed:
Mar. 12, 2013
Central South University, Changsha, CN;
Zhongwei Zhao, Changsha, CN;
Jiangtao Li, Changsha, CN;
Central South University, Changsha, CN;
Abstract
A method for extracting tungsten from scheelite by: 1) adding a mixed acid including HSOand HPOto a decomposition reactor; 2) heating the mixed acid to a temperature of 70-100° C.; adding scheelite while controlling the mixed acid present in an amount of 3-8 L per kg of scheelite; allowing the components in the decomposition reactor to react for 1-6 h, and filtering the resulting mixture to obtain a filtrate; 3) supplementing the filtrate with sulfuric acid consumed in the reaction; 4) crystallizing the filtrate to obtain phosphotungstic acid crystals and mother liquor; 5) dissolving the phosphotungstic acid crystals in water to obtain a phosphotungstic acid solution; 6) transforming the phosphotungstic acid solution into an ammonium tungstate solution for the purpose of preparing ammonium paratungstate; and 7) supplementing the mother liquor with phosphoric acid and water to an initial level and reusing the mother liquor for ore leaching.