Process for the preparation of asbestiform crystalline calcium sodium metaphosphate fibers
US4690809A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Nov 5, 1986 |
| Grant date | Sep 1, 1987 |
| Priority date | — |
| Expiry date | Nov 5, 2006 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC01B25/45
- WIPO fieldMaterials, metallurgy
- WIPO sectorChemistry
Abstract
Asbestiform crystalline calcium sodium metaphosphate fibers are prepared by (a) forming a homogeneous melt of substantially crystalline calcium sodium metaphosphate having a composition on a dry basis equivalent to a CaO/Na.sub.2 O/P.sub.2 O.sub.5 mol percent ratio of about 29.0-34.0/16.0-18.0/50.0-53.0 and a degree of crystallinity from about 60% to about 75% as determined from density and differential thermal analysis measurements, (b) supercooling the homogeneous melt, (c) seeding the supercool melt with calcium sodium metaphosphate crystals, (d) maintaining the seeded supercooled melt at the seeding temperature under isothermal conditions for a time sufficient to form crystalline blocks of calcium sodium metaphosphate, and (e) fiberizing the crystalline blocks.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.