Process for making an adsorbent agent from expanded rocks and calcium sulfate-hemihydrate

摘要

The preparation method is characterised in that the calcium sulphate hemihydrate and expanded rock are mixed in quantities giving a weight ratio of calcium sulphate:expanded rock of 5:l up to 10:1 in the adsorbent agent, mixing is achieved by feeding the calcium sulphate hemihydrate and expanded rock together into a container and stirring these together by means of a stirring device to give a granulated mixture, the granulated mixture has a residence time of at least 4 minutes after addition of the water and before drying, and the dry calcium sulphate dihydrate is converted by calcination at 120-200@C to calcium sulphate hemihydrate in such a proportion that the adsorbent agent has a total water content of 1% by weight to 16% by weight.