Method of producing an adsorbent from bloating minerals and calcium

Abstract

The invention relates to a method of producing an adsorbent where an expanded granular bloating mineral and calcium sulfate hemihydrate are mixed to form a granulated material where the calcium sulfate hemihydrate is converted in toto into calcium sulfate dihydrate by the addition of a surplus of water, and where the free water is removed by drying. It is desirable that the proportion of bloating mineral be reduced, that the adsorption effect be substantially retained and the hardness of the adsorbent be increased without any additives. This is accomplished by mixing calcium sulfate hemihydrate and bloating mineral in such proportion that a weight ratio of calcium sulfate: bloating minerals>5:1 and up to 10:1 exists in the adsorbent, in that mixing is effected by calcium sulfate hemihydrate and the bloating mineral being poured together into a tank and mixed there together by a stirring tool to form a granulated mixture, in that the granulated mixture after the addition of the water and before drying is allowed a retention time of at least 4 minutes, and in that the dry calcium sulfate dihydrate is converted by calcining at 120.degree.-150.degree. C. in such a proportion into calcium sulfate hemihydrate that the adsorbent has a total water content of 1% by weight to 16% by weight. The adsorbent produced in this manner comprises, on the one hand, open-pore smaller particles which consist only of calcium sulfate and, on the other hand, open-pore larger particles where a bloating mineral core is coated with calcium sulfate.