| 摘要 |
TITLE: IMPROVEMENTS IN CALCINATION APPARATUS 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 by the direct introduction of a hot gas through a tube 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 with a relatively cool substance, for example, powdered gypsum or recycled exhaust gases, in an outer tube. The cooling material in the outer tube contacts the material in the bed before the latter is contacted by the hot gas. |
