Process for recovering tungsten as an ammoniacal tungstate compound in which ammoniacal tungstate liquors are reclaimed
US5417945A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Nov 14, 1991 |
| Grant date | May 23, 1995 |
| Priority date | — |
| Expiry date | Nov 14, 2011 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC01G41/00
- WIPO fieldMaterials, metallurgy
- WIPO sectorChemistry
Abstract
A process for recovering tungsten as an ammoniacal tungstate which comprises reacting a tungsten containing material with sodium hydroxide to produce sodium tungstate and forming a first aqueous sodium tungstate solution therefrom, crystallizing sodium tungstate from the first aqueous sodium tungstate solution, dissolving the resulting sodium tungstate crystals in an aqueous medium to form a second aqueous sodium tungstate solution, extracting tungsten from the second aqueous sodium tungstate solution with an organic extracting agent wherein the extracting agent containing tungsten is capable of being stripped of the extracted tungsten by ammonia, and thereafter stripping the extracted tungsten from the organic extracting agent with ammonia to form an ammoniacal tungstate solution, crystallizing a portion of the tungsten contained in the ammoniacal tungstate solution to form a two phase system wherein an ammoniacal tungstate compound comprises the first phase and wherein the resulting mother liquor containing the balance of the contained tungsten comprises the second phase, and repeating the process using the mother liquor as at least a portion of the aqueous medium to dissolve the…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.