Preparation of ammonium rare earth double oxalates and rare earth oxides produced therefrom
US5662874A · kind A · utility
76Cited by
3References
18Claims
0Family size
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Key dates
| Filing date | Apr 24, 1995 |
| Grant date | Sep 2, 1997 |
| Priority date | — |
| Expiry date | Apr 24, 2015 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC07C51/412
- WIPO fieldOrganic fine chemistry
- WIPO sectorChemistry
Abstract
Particulate ammonium rare earth double oxalate crystals, homogeneous in particle size and having a narrow particle size distribution and readily converted into rare earth oxide particles by simple calcination, e.g., yttrium oxide particles, are prepared by (a) intimately admixing, in an aqueous medium, (i) at least one precursor compound adapted to liberate oxalate ions in aqueous solution with (ii) at least one water-soluble rare earth compound and (iii) at least one ammonium salt, (b) separating the double oxalate precipitate thus formed, and (c), optionally, washing and drying such double oxalate precipitate.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.