Method for the preparation of fine hollow glass spheres coated with titanium oxide
US6110528A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Feb 19, 1999 |
| Grant date | Aug 29, 2000 |
| Priority date | — |
| Expiry date | Feb 19, 2019 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC03C2218/111
- WIPO fieldMaterials, metallurgy
- WIPO sectorChemistry
Abstract
Disclosed is a method for the preparation of fine hollow glass spheres coated with titanium dioxide from particles of a volcanic vitreous deposit sand occurring in nature. The method comprises the steps of: (a) dispersing the starting particles in an aqueous medium containing hydrogen chloride (or sulfuric acid) and titanium chloride (or titanium sulfate); (b) admixing the aqueous dispersion of the particles with an aqueous alkaline solution such as a solution of ammonium hydrogencarbonate to effect hydrolysis of the titanium chloride (or sulfate) into hydrous titanium oxide forming a coating layer on the particles; and (c) subjecting the particles coated with hydrous titanium oxide to a heat treatment for expansion of the vitreous particles into hollow glass spheres with simultaneous conversion of the hydrous titanium oxide into titanium dioxide forming a coating layer on the hollow glass spheres.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.