High density leucite based ceramics from zeolite
US5071801A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jul 25, 1990 |
| Grant date | Dec 10, 1991 |
| Priority date | — |
| Expiry date | Jul 25, 2010 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC04B35/19
- WIPO fieldMaterials, metallurgy
- WIPO sectorChemistry
Abstract
This invention relates to processes for preparing ceramic articles. One process involves taking a potassium exchanged zeolite, the zeolite characterized in that it has a SiO.sub.2 /Al.sub.2 O.sub.3 ratio of 3.5 to about 7.5, and calcining it at a temperature of about 900.degree. to about 1100.degree. C. for a time sufficient to collapse the zeolite framework and provide an amorphous powder. Next, the amorphous powder is formed into a shaped article and the article is sintered at a temperature of about 1150.degree. to about 1400.degree. C. for a time of about 0.5 to about 12 hours to give a ceramic article whose principal crystalline phase is tetragonal leucite, is substantially crack free, and has less than 5% porosity. When the zeolite is exchanged with cesium, one obtains a ceramic article whose principal crystalline phase is pollucite, when a rubidium exchanged zeolite is used one obtains a ceramic article whose principal crystalline phase is rubidium leucite, and when a potassium/cesium exchanged zeolite is used one obtains a ceramic article having as its principal crystalline phase a leucite/pollucite solid solution. The addition of pollucite to the leucite article provides a …
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.