Process for producing ammonium metatungstate from ammonium tungstate by digestion in silica
US3956474A · kind A · utility
10Cited by
5References
3Claims
0Family size
Assignee
Inventor
Key dates
| Filing date | Jan 27, 1975 |
| Grant date | May 11, 1976 |
| Priority date | — |
| Expiry date | Jan 27, 1995 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC01G41/00
- WIPO fieldMaterials, metallurgy
- WIPO sectorChemistry
Abstract
A process for producing ammonium metatungstate (AMT) from ammonium tungstate (AT) solution is described which involves the addition of about 3.6 percent by weight of silica to an AT solution, digestion for at least about 4 hours at a temperature of at least about 98.degree.C, followed by filtration to remove the silica from the AMT solution. Typically about 0.4 percent by weight of silica remains after filtering. The resulting AMT solution may be further processed to recover solid AMT, such as by evaporation or spray drying.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.