Calcination apparatus
US5011668A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Mar 2, 1989 |
| Grant date | Apr 30, 1991 |
| Priority date | — |
| Expiry date | Mar 2, 2009 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC04B11/0281
- WIPO fieldMaterials, metallurgy
- WIPO sectorChemistry
Abstract
In a method and apparatus for calcining calcium sulphate dihydrate or like heat sensitive material, in which a bed of the material is heated in a vessel (41) by the direct introduction of a hot gas through a tube (21) extending downwardly into the bed, the proportion of insoluble anhydrite (II) in the product is reduced by lowering the temperature of the hot gas before it contacts the material of the bed. This is done by indirect heat exchange through the wall of the tube 21 with a relatively cool substance, for example, powdered gypsum or recycled exhaust gases, in an outer tube (26). The cooling material in the outer tube contacts the material in the bed before the latter is contacted by the hot gas.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.