Ozone whitening of synthetic gypsum
US4344925A · kind A · utility
3Cited by
5References
9Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Jan 15, 1981 |
| Grant date | Aug 17, 1982 |
| Priority date | — |
| Expiry date | Jan 15, 2001 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC01F11/468
- WIPO fieldMaterials, metallurgy
- WIPO sectorChemistry
Abstract
A process for the whitening of phosphogypsum comprising treating a phosphogypsum in aqueous suspension with an amount of ozone equal to at least 150 parts by weight per million parts by weight of phosphogypsum calculated as Ca SO.sub.4.2H.sub.2 O, the pH of the aqueous suspension being lower than or equal to 3, to yield a whiteness grade of phosphogypsum higher than 75, according to French Standard NF Q 03-038.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.