Rare earth phosphate colloidal dispersion and preparation method
US7169820B2 · kind B2 · utility
Assignee
Inventor
Key dates
| Filing date | Dec 7, 2001 |
| Grant date | Jan 30, 2007 |
| Priority date | — |
| Expiry date | Oct 17, 2022 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S977/773
- WIPO fieldChemical engineering
- WIPO sectorChemistry
Abstract
The invention concerns a colloidal dispersion of a phosphate of a rare earth and a process for its preparation. The dispersion is characterized in that it comprises anisotropic and disaggregated or disaggregatable particles of a phosphate of at least one rare earth and an anion of a monobasic acid, soluble in water and with a pKa of at least 2.5. It is prepared by a process in which a solution of a salt of at least one rare earth is mixed with phosphate ions while controlling the pH of the reaction medium to a value in the range 4 to 9 and in the presence of a monobasic acid, soluble in water and with a pKa of at least 2.5; the mixture obtained optionally undergoes a maturing step; the precipitate is then separated from the reaction medium; and said precipitate is then dispersed in water.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.