Nonpolluting recovery of rare earth values from rare earth minerals/ores
US5011665A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Mar 5, 1990 |
| Grant date | Apr 30, 1991 |
| Priority date | — |
| Expiry date | Mar 5, 2010 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S423/15
- WIPO fieldMaterials, metallurgy
- WIPO sectorChemistry
Abstract
Rare earth values are nonpollutingly recovered from a rare earth mineral/ore, especially one containing but minor amounts of the rare earths, by (a) leaching/decomposing such rare earth mineral/ore with a solution of nitric acid to solubilize the rare earth values contained therein, (b) optionally separating insoluble residue from the resulting leach solution, (c) separating the rare earth values from the leach solution, (d) treating the leach solution thus stripped of rare earth values with a hydroxide of a metallic cation M to precipitate solubilized impurities and separating the thus precipitated impurities therefrom, (e) treating the resulting purified solution with sulfuric acid to precipitate metal sulphates and separating the thus precipitated sulfates therefrom to regenerate the above nitric acid solution, and (f) optionally recycling such regenerated solution of nitric acid to the leaching/decomposition step (a).
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.