Preparation of ammonium rare earth double oxalates and rare earth oxides produced therefrom
US5665323A · kind A · utility
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19Claims
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Key dates
| Filing date | May 8, 1995 |
| Grant date | Sep 9, 1997 |
| Priority date | — |
| Expiry date | May 8, 2015 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC07C51/412
- WIPO fieldOrganic fine chemistry
- WIPO sectorChemistry
Abstract
Particulate and coarse ammonium rare earth double oxalate crystals, 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 rare earth neutral oxalate with (ii) at least one precursor compound adapted to liberate ammonium ions in water and (iii) at least one precursor compound adapted to liberate oxalate ions in water, (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.