| 摘要 |
<p>(A) An installation, for prepn. of high strength plaster from natural or synthetic calcium sulphate (e.g. gypsum), includes an endless chain transporter which is fitted with tiltable pallets and which travels on return pulleys forming upper and lower strands. A starting material feed hopper is positioned above the first upper strand and a heating device directs hot gas into chambers located between each upper and lower strand. (B) A process for treating calcium sulphate starting material to obtain plaster, using the installation, comprises (a) crushing the starting material to powder and moistening at ambient temp. to obtain a water content of 15-30 (pref. 15-20)%; (b) feeding the material into the installation within a treatment chamber superheated to 500-600 deg.C so that high vol. steam prodn. is obtd. by boiling of the water contained in the powder material, simultaneously with powder entrainment by the pallets; and (c) following the boiling action, after initial start-up in the treatment chamber, by subsequent permanent stirring of the powder material while the temp. is progressively decreased.</p> |
