Processing of rare earth ores
US4976939A · kind A · utility
2Cited by
8References
12Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | May 3, 1990 |
| Grant date | Dec 11, 1990 |
| Priority date | — |
| Expiry date | May 3, 2010 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC01F17/206
- WIPO fieldMaterials, metallurgy
- WIPO sectorChemistry
Abstract
Rare earth hydroxides are recovered from the rare earth ores, e.g., monazite, xenotime and/or bastnasite, by treating the ore with an aqueous solution of an alkali metal hydroxide, under agitation and essentially constant pressure, at a temperature of from about 100.degree. to 220.degree. C., and wherein the ratio by weight of alkali metal hydroxide/ore ranges from about 1.4 to 0.5, e.g., a weight ratio of sodium hydroxide/ore of from about 1 to 0.5, or a weight ratio of potassium hydroxide/ore of from about 1.4 to 0.7.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.