Process for synthesis of uniform colloidal particles of rare earth oxides
US5015452A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jan 16, 1987 |
| Grant date | May 14, 1991 |
| Priority date | — |
| Expiry date | Jan 16, 2007 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC01P2006/22
- WIPO fieldMaterials, metallurgy
- WIPO sectorChemistry
Abstract
An improved process for the preparation of monodispersed spherical colloidal particles from rare earth salts is disclosed. These colloidal particles are obtained in this process by homogeneous precipitation techniques involving the forced hydrolysis of rare earth salts in aqueous media. More specifically, this process initially involves the formation of hydrolyzed cations which are precursors or intermediate to precipitation of the desired colloidal particle. The objective in the formation of this precursor species is to reach critical supersaturation concentration of this particle forming species so that only one burst of nuclei occurs. Colloidal particle formation is then effected by diffusion of solutes onto the existing nuclei. The improvements of this process reside, in part, in the ability to control the kinetics of formation of this intermediate species. Such control permits the formation of colloidal dispersions having very narrow particle size distribution. The colloidal dispersions of these particles are also quite stable. The rare earth colloidal particles prepared by this process are useful in both industrial and biologic environments.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.