Gypsum anhydrite fillers and process for making same
US7556791B2 · kind B2 · utility
3Cited by
24References
16Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Dec 20, 2006 |
| Grant date | Jul 7, 2009 |
| Priority date | — |
| Expiry date | Jun 8, 2027 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC04B11/02
- WIPO fieldMaterials, metallurgy
- WIPO sectorChemistry
Abstract
A process is disclosed for making dead burn calcium sulfate anhydrite. The process includes a slurry calcination step to produce calcium sulfate anhydrite followed by removing free water from the anhydrite while avoiding substantial rehydration. Also disclosed are dead burn calcium sulfate anhydrite particles with high aspect ratios, e.g. fibers having an average aspect ratio of at least 4:1, or very fine particle size, e.g., at or below 2 micrometers average, combined with very low water content, e.g., less than 0.5, preferably less than 0.3, wt. % water. These particles are typically useful as fillers.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.