Process for producing ammonium metatungstate
US4504461A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Sep 2, 1983 |
| Grant date | Mar 12, 1985 |
| Priority date | — |
| Expiry date | Sep 2, 2003 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC01G41/00
- WIPO fieldMaterials, metallurgy
- WIPO sectorChemistry
Abstract
A process is provided for producing ammonium metatungstate comprising fluid bed roasting ammonium paratungstate at a temperature over the range of about 275.degree. C. to 305.degree. C. for a time at least sufficient to provide a roasted product in the form of a precursor of ammonium metatungstate, forming an aqueous slurry of the precursor and digesting the precursor at a pH of about 3 to 4 for a time at least sufficient to effect substantially complete dissolution of said precursor, filtering the digested slurry to produce a clear filtrate, and further processing the clear filtrate by evaporation to provide crystals of substantially pure ammonium metatungstate.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.