Preparation of a calcium sulfate anhydrite material of low chloride content
US4495162A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Aug 31, 1982 |
| Grant date | Jan 22, 1985 |
| Priority date | — |
| Expiry date | Aug 31, 2002 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC04B22/145
- WIPO fieldChemical engineering
- WIPO sectorChemistry
Abstract
A calcium sulfate anhydrite material is prepared from a spent absorbent resulting from desulfurization of flue gases. First the sulfite in the spent absorbent is oxidized into sulfate, preferably by heating in an oxygen containing gas, and thereafter the chloride content of the spent absorbent is reduced by heating the spent absorbent at a temperature of 600.degree.-950.degree., preferably 750.degree.-950.degree. C. together with fly ash. Said fly ash may be recovered together with the spent absorbent in the desulfurization process, or it may have been recovered separately and mixed with the spent absorbent. The product may be used as cement additive or for other purposes in which calcium sulfate anhydrite is conventionally utilized.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.