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.

Abstract: The invention concerns a gypsum construction board in which a gypsum core is faced with a two-layer laminate comprised of a nonwoven fiber felt and a glass fiber web of crossed glass fibers wherein the glass fiber web of crossed glass fibers is embedded in the gypsum core and the laminate is in the form of a laminate sheet which extends across the width of the board.

Abstract: Fiber containing plaster boards are prepared by superimposing a plurality of board blanks one on top of the other such that the direction of the fiber orientation in the superimposed blanks deviates one from the other. The board blanks are formed in a conventional manner from a suspension of calcium sulfate capable of setting, reinforcing fibers and a quantity of water beyond the quantity of water necessary for setting the calcium sulfate capable of setting. After mechanically removing excess water from the suspension to form the board blanks, two or more of these blanks are placed one on top of the other and are connected under pressure and dried. Thereafter, a predetermined number of board blanks having a direction of the fiber orientation deviating one from the other, are placed one on top of the other and are pressed together prior to or during the setting of the calcium sulfate.

Abstract: Pelletized calcium sulfate is prepared from finely divided, natural or synthetic calcium sulfate, wherein the particle size of the finely divided calcium sulfate is at least about 90 per cent by weight less than 200 .mu.m, there being no particles larger than 500 .mu.m, and wherein the finely divided calcium sulfate has a free water content of from about 0.5 to about 4 per cent by weight, by pressing the finely divided calcium sulfate in the presence of water with a roll press using a surface pressure of 1 to 5 Mp per cm roller length.

Abstract: Calcium sulphate produced by reacting crude phosphate with sulphuric acid is washed with aqueous solutions of condensed and complex aluminium fluorides of the general formulae MeAlF.sub.4, Me.sub.2 AlF.sub.5 and Me.sub.5 Al.sub.3 F.sub.14 as well as AlF.sub.3.nH.sub.2 O, in which Me represents an alkali metal, ammonium or thallium-I ion and n is a number between 1 and 9.

Abstract: A multi-layered gypsum board for construction purposes in which a mixture of gypsum, water and fibers provide the center or core of the board, and a composite coating of a fiberglass layer and a layer of fiberglass fleece covers one of the major surfaces of the core, with the fiberglass layer being embedded into the mixture and plaster favorably adhering to the outer surface of the fiberglass fleece layer. The other major surface of the core may be covered with a similar coating, or a layer, for example, of pasteboard.