Recovery of rare earth values from gypsum
US5034201A · kind A · utility
5Cited by
10References
10Claims
0Family size
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Key dates
| Filing date | Sep 17, 1990 |
| Grant date | Jul 23, 1991 |
| Priority date | — |
| Expiry date | Sep 17, 2010 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC01F17/282
- WIPO fieldMaterials, metallurgy
- WIPO sectorChemistry
Abstract
Rare earth values are recovered from gypsum starting material by (i) dissolving such gypsum in water and separating therefrom the water-insoluble fractions which contain the rare earth elements (ii) treating such insoluble fractions with a solution of carbonate ions, (iii) next digesting the insoluble fractions thus treated with a mineral acid and converting at least the rear earth values into water-soluble salts thereof, and (iv) recovering such rear earth values from the medium of digestion.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.