Method for removal of tin from ammonium tungstates
US4448755A · kind A · utility
3Cited by
2References
7Claims
0Family size
Assignee
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Key dates
| Filing date | Dec 1, 1983 |
| Grant date | May 15, 1984 |
| Priority date | — |
| Expiry date | Dec 1, 2003 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC01G41/00
- WIPO fieldMaterials, metallurgy
- WIPO sectorChemistry
Abstract
In a process for producing pure ammonium paratungstate from ammonium tungstate solutions containing tin, sulfide is added to the ammonium tungstate solution in an amount sufficient to form a soluble complex of the sulfide with the tin. The solution is then evaporated to a volume at which essentially all of the tungsten is in the form of insoluble ammonium paratungstate and essentially all of the tin is in the mother liquor in the form of a soluble complex along with other impurities. The solid ammonium paratungstate is then separated from the mother liquor by filtration.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.