Abstract: The instant invention is concerned with the post-treatment of ?-hemihydrate plasters for the purpose of stabilization. The invention relies in the addition of a retardant to the calcined ?-hemihydrate. It is also the purpose of the invention to provide stabilized ?-hemihydrate plasters which exhibit advantageous properties.

Abstract: The instant invention is concerned with the post-treatment of ?-hemihydrate plasters for the purpose of stabilization. The invention relies in the addition of a retardant to the calcined ?-hemihydrate. It is also the purpose of the invention to provide stabilized ?-hemihydrate plasters which exhibit advantageous properties.

Abstract: A process for manufacturing set cellular cement, including the steps of: (i) mixing cementitious material, water, foaming agent and optionally additives into a free flowing slurry having a slump of at least 100 mm; subsequently (ii) injecting and distributing air into the slurry of step (i) to form a cellular slurry; subsequently (iii) casting the cellular slurry of step (ii); and finally allowing the cellular slurry to set. And, an apparatus for carrying out the process.

Abstract: A process for manufacturing set cellular cement, including the steps of: (i) mixing cementitious material, water, foaming agent and optionally additives into a free flowing slurry having a slump of at least 100 mm; subsequently (ii) injecting and distributing air into the slurry of step (i) to form a cellular slurry; subsequently (iii) casting the cellular slurry of step (ii); and finally allowing the cellular slurry to set. And, an apparatus for carrying out the process.

Abstract: A process for manufacturing set cellular cement, including the steps of: (i) mixing cementitious material, water, foaming agent and optionally additives into a free flowing slurry having a slump of at least 100 mm; subsequently (ii) injecting and distributing air into the slurry of step (i) to form a cellular slurry; subsequently (iii) casting the cellular slurry of step (ii); and finally allowing the cellular slurry to set. And, an apparatus for carrying out the process.

Abstract: A continuous process for manufacturing a sound absorbing tile made from a slurry including, quick setting cement, water, fibers and foaming agent, the process including the steps of (i) mixing cementitious material, water, foaming agent but without incorporation of prefabricated foam with fibers into a slurry; subsequently; (ii) injecting and distributing air into the slurry of step (i) to form a cellular slurry; subsequently; (iii) forming tiles or precursor products of tiles from the cellular slurry; and finally; (iv) allowing the cellular slurry to set into the desired tile or a precursor thereof.

Abstract: A continuous process for manufacturing a sound absorbing tile made from a slurry including, quick setting cement, water, fibers and foaming agent, the process including the steps of (i) mixing cementitious material, water, foaming agent but without incorporation of prefabricated foam with fibers into a slurry; subsequently; (ii) injecting and distributing air into the slurry of step (i) to form a cellular slurry; subsequently; (iii) forming tiles or precursor products of tiles from the cellular slurry; and finally; (iv) allowing the cellular slurry to set into the desired tile or a precursor thereof.

Abstract: A process for manufacturing set cellular cement, including the steps of: (i) mixing cementitious material, water, foaming agent and optionally additives into a free flowing slurry having a slump of at least 100 mm; subsequently (ii) injecting and distributing air into the slurry of step (i) to form a cellular slurry; subsequently (iii) casting the cellular slurry of step (ii); and finally allowing the cellular slurry to set. And, an apparatus for carrying out the process.

Abstract: Production of plasterboard includes spreading of a mixture formed of gyps fibers and water onto a continuously moving belt to form a spread layer subsequently precompressed to 110% to 180% of a final board thickness and successively wetted from both sides and thereafter compressing the wetted layer to the final board thickness.

Abstract: Process and apparatus for the continuous production of gypsum fiber plates in which the fiber component is dewatered and rediluted with water recovered from the gypsum-fiber suspension after it has been spread on a belt, passed over at least two suction boxes and densified on the last suction box by a densifying device engaging the filter cake layer from the top.

Abstract: A process and apparatus for the continuous production of a uniform layer of oose material on a forming belt has a receiving belt onto which the loose product is deposited by a gravity chute in strips transverse to a travel direction of the receiving belt. A smoothing device above the receiving belt engages the strip layer over the entire length thereof on the receiving belt and smooths the material before it passes to a dispersing device directly or via said dispersion belt.

Abstract: The invention is directed to an apparatus for the production of plate-sha bodies from a mixture of plaster and fibrous materials. The apparatus has a conveying means, spreading means, a first and second press, an afterwetting station and a setting and drying station. The afterwetting station is located between the first press and the second press and has separate means for wetting the upper side and the underside of a raw board being processed. The separate wetting means can be independently controlled.

Abstract: Plasterboard is made by first spreading a mixture of plaster, fibers and er and then pressing this moist mixture to form the raw board. The upper and lower surfaces of the raw board are then wetted and the thus wetted raw board is pressed with a pressure less than the original consolidation pressure.

Abstract: In a process for the conversion of calcium sulfate dihydrate originating in flue gas desulfurization units into an alpha-hemihydrate, a salt solution is used as a medium. The salt solution consists substantially of concentrated scrubbing liquid from the flue gas desulfurization process containing alkali-earth chloride in a chloride concentration of 10% to 60% by weight.

Abstract: An installation for the production of sheet-like members from a mixture of plaster and fibrous material comprises, in addition to a device which prepares the raw materials and mixes them in the dry state in a desired ratio, as well as a device, which adds and mixes in an accurately dosed quantity of water, a spreading device, which spreads a mat of material on a forming line. The mat of spread-out material is compacted in a continuously operating belt press. The latter comprises in known manner two endless steel belts, which are guided around two movable press plates of the belt press, which are spaced apart. The mat of spread-out material is compacted between the forming line, on which it rests, and an endless-belt screen, which bears on the upper steel belt of the belt press and thus acquires a side marked by the endless-belt screen. After being cut up by a cutting device, the individual sheets are turned through 180.degree.

Abstract: A method and apparatus for continuously producing molded member, especially sheets, from a mixture of gypsum and fibrous material. In a first mixing stage, measured-out quantities of gypsum and fibrous material are thoroughly mixed together, with the dry mixture being weighed and subsequently moistened in a second mixing stage by supplying water thereto in conformity to the weight of the dry mixture. The moistened mixture is subsequently dispersed onto a support to form molded members, with the surface of each molded member being additionally moistened, and the latter then being compacted. To achieve higher strength, the mas flow of the gypsum/fibrous material mixture is divided into independent partial mass flows that are dispersed in layers to form the multi-layer molded member, with each partial mass flow forming one of the layers of the molded member.

Abstract: A method for continuously producing molded members. Prior to dispersing the material for the molded members onto the molding belt, the edge zones of the molding belt are covered by protective belts that move along with the molding belt. This prevents the edge zones of the molding belt from getting very dirty.

Abstract: A method and apparatus for continuously forming a uniform layer of material that is being dispersed. This material, in the form of a stream of material, is deposited on an intermediate conveyer belt, as strips, transverse to the direction in which the material is fed to a dispersal mechanism. In the direction of travel of this intermediate conveyer belt, the strips abut one another in such a way that no gaps exist between them.

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.