Abstract: A method for the utilization of ash from coal-fired plants, in which openss ash is drawn off when it is dry for further use. According to one embodiment of the invention, the open-pass ash is used as a raw material and fuel in cement production. According to another embodiment, the open-pass ash is used as bed sand with combustible constituents in fluidized-bed firing. According to still another embodiment, the ash is used for the purpose of influencing sinterability in the production of sintered lightweight aggregates. The mineral constituents can be separated from carbon-containing constituents, which are capable of being used as fuel or activated coke, and used as fine sand in any of these embodiments.

Abstract: The invention relates to the use of open-pass ash from coal-fired plants as bed sand in fluidized-bed firing.

Abstract: The invention relates to a process for manufacturing brickworks mouldings by mixing a compound containing a granular clay-containing material with a lean material and, if required, other additives from which moulding compound green products are moulded, dried and burnt. This process permits a recycling of residual materials by using as clay-containing material a residual material consisting predominantly of clay minerals, especially a dry fraction, predominantly composed of annealed clay minerals, of an ash, preferably brown coal ash, and by producing the moulding compound by mixing the fraction with the lean material and other additives as well as water, where water is used in such a quantity as to produce an earth-moist moulding compound which is then pressed in portions on a press to form individual, inherently stable green products.

Abstract: A novel binder for interior plasters having a calcium sulphate component capable of binding in the presence of water and a finely divided residual material component comprised primarily of calcium sulphite, where the residual material is a product of flue gas desulphurization of coal-fired combustion plants.

Abstract: The invention relates to a process for producing heat-insulating material from silicate-containing material, hydrated lime, water, foam and a reactive aluminates-containing quick-setting cement, from which a pourable raw mixture is produced which is poured into molds, the green moldings formed in the molds being demolded and autoclaved after sufficient setting. To achieve very low bulk densities, it is provided that, as silicate-containing material, a quartz powder with a specific surface area according to BET of at least approx. 3 m.sup.2 /g, in particular approx. 4 to 5 m.sup.2 /g, is used, the raw mixture is produced with a weight ratio of water/solids (excluding foam) of at least approx. 1.25 and an essentially stoichiometric amount, with respect to the virtually complete reaction of the quartz powder and the reactive aluminates, of hydrated lime with a surface area according to BET of at least approx. 15 m.sup.

Abstract: The invention relates to a process for reprocessing plastic wastes, in which the plastic wastes filled into vessels are autoclaved as coherent, porous bundles with high water absorption capacity in a steam atmosphere at approximately 150.degree. to 220.degree. C., preferably 165.degree. to 190.degree. C., and melted by this means, at the end of the autoclaving process, the resulting bodies of molten plastic are at least partly dried by re-evaporating the water contained therein and are cooled.

Abstract: The invention relates to a process and an apparatus for drying sludge, in particular sewage sludge, or moist bulk material, wherein the material to be dried is heated by supplying energy by means of an electromagnetic alternating field generated between electrodes in a sealed pressurized vessel at an overpressure and the material moisture evaporated by the heating is used as heat transfer medium for heating the material to be dried in a step which is separate from the heating in the electromagnetic alternating field. In this process, the material to be dried is received with electrically insulated contiguous contact with the electrodes located in the pressurized vessel at least for a dwell time which is necessary for the heating and is then subjected to a flash drying.

Abstract: A method of autoclaving porous piece-goods, by steam under pressure, wherein the autoclaving operation includes sequential phases of heating with steam, holding, and then relaxing the pressure and temperature, wherein the holding phase includes a drying process. In order to obtain as dry a product as possible with the smallest possible energy input, it is provided that a drying process is carried out within the holding phase in which the autoclave is heated more than to compensate for heat losses and to a temperature above the temperature of vaporization of the water so that the material is dried by controlled discharge of steam from the interior of the autoclave. The steam discharged from one or more autoclaves during the drying process is used to heat up at least partially an autoclave to be heated.

Abstract: An autoclave for treating charged materials (6) with vapor under pressure, with a substantially cylindrical inner chamber (2) surrounded by an autoclave casing (1) and with a heating device (8) responsive to a heated heat transfer medium to generate vapor in the inner chamber (2). In order to provide the heating in a way which is favorable structurally and in terms of energy, it is provided that the heating device (8) is arranged within one of the curved side regions of the autoclave casing (1), and consists of at least one flue (10) arranged substantially vertically in the autoclave and a heat exchanger (11) arranged in the lower inflow region of the flue (10) and through which flows a heat transfer medium, so that a convection flow results circulating substantially in the circumferential direction of the casing (1) of the autoclave.

Abstract: A method and composition for the preparation of calcium silicate bounded shaped articles comprising mixing SiO.sub.2 containing powder, unslaked or slaked lime, calcium hydroxide, with a waste paper pulper slurry containing cellulosic particle of less than 1.1 mm in length is described. Additionally, Portland cement, alumina cement, calcium sulfate anhydride, plaster of Paris, a foam, and a thermally activated accelerator may also be added to the mixture which is then shaped into blanks, and autoclaved.

Abstract: Calcium sulfate alpha hemihydrate and foundry sand are milled to cement fineness and form a hydraulic binder, as a mixture with both high early setting strength and excellent water resistance. The composition relies upon a sulfate activation of the foundry sand rather than an alkali activation thereof.

Abstract: A process for producing lightweight, panel or block-shaped gypsum building materials with a pore structure, in particular wall panels, wherein calcium sulphate alpha-hemihydrate, water in a slightly more than stoichiometric quantity, setting retarders and/or accelerators and additives are mixed to form a pourable suspension and subjected to suitable forming. The ground calcium sulphate alpha-hemihydrate, having a Blaine specific surface area greater than 2000 cm.sup.2 /g, is combined if appropriate, with calcium sulphate beta-hemihydrate in a quantity of up to about 30% by weight relative to the calcium sulphate alpha-hemihydrate, and mixed before forming with a surfactant foam of a defined apparent density in the range from 40 to 80 kg/m.sup.3 and a uniform defined pore size, in a quantity for adjusting the apparent density of the gypsum building material to a defined value in the range from 300 to 1200 kg/m.sup.3.

Abstract: In a process for preparing calcium sulphate alpha hemihydrate essentially the form of primary crystals, the hemihydrate is milled to specific surface area of 1200 to 4000 cm.sup.2 /g, the fines are removed by screening, and a retarder and liquefier in the form of at least one fruit acid and/or its or their salt(s) are admixed. The product obtained is characterized by delayed onset of rigidity, rapid development of resistance and high resistance, and is used in particular as an injection mortar.

Abstract: The process makes calcium sulfate alpha-hemihydrate from finely divided calcium sulfate dihydrate by transforming the calcium sulfate dihydrate in the presence of saturated steam. A molded body is formed from the calcium sulfate dihydrate which has a plurality of pores having a pore volume amounting to 15 to 60% by volume of the total volume of the entire molded body. More than 5% by volume of the pore volume contains air. The molded body is fed to the autoclave. In the presence of a sufficient water quantity in the pores the crystal habit and the crystal growth of the calcium sulfate alpha-hemihydrate crystals which grow in an aqueous solution phase are controlled by a process temperature in the range between 110.degree. to 180.degree. C. by the pressure of the process atmosphere in the autoclave. The molded body is removed from the autoclave after recrystallization transformation and delivered for use. Key products of this process and their derivatives are also described.

Abstract: The process makes calcium sulfate alpha-hemihydrate or essentially plaster of paris from finely divided gypsum made by desulfurizing flue gas obtain from a power plant fired by brown coal by transforming the calcium sulfate dihydrate in the presence of saturated steam. A molded body is formed from the calcium sulfate dihydrate which has a plurality of pores. The pore volume amounts to 15 to 60% by volume of the total volume of the entire molded body. More than 5% by volume of the pore volume contains air. The molded body is fed to an autoclave. In the presence of a sufficient water quantity in the pores, the crystal habit and the crystal growth of the calcium sulfate alpha-hemihydrate crystals which grow in an aqueous solution phase are controlled by a process temperature in the range between 110.degree. to 180.degree. C. by the pressure of the treatment atmosphere in the autoclave. The molded body is removed from the autoclave after recrystallization transformation and delivered for use.

Abstract: The invention is concerned with a method for controlling the quick setting of a pourable raw mixture having a filler material, water, a cement that contains at least in part an aluminate capable of reacting with calcium hydroxide, in particular aluminum oxide cement, with an organic substance, in particular, hydro-oxycarboxylic acid, serving as a set-up retarder for the aluminate, complex forming, and stunting the growth of calcium aluminum sulfate hydroxide, and further of calcium hydroxide and in some instances, foam. In order to come up with the minimum possible number of cement components for the hardening of the raw mixture, and in order to achieve good control of the charging time and set-up process with the possibility of achieving adequate hardness in a matter of minutes, the aluminate is premixed with the organic set-up retarder and the calcium sulfate in a calcium hydroxide-free environment sometimes together with additional stabilizing components of the raw mixture.

Abstract: The method relates to the hardening of form substances made of building materials and containing binding agents in a pressure chamber of an autoclave to which is conveyed a gaseous heating medium, the temperature of which is increased during a heating-up phase up to a given upper limit value. During a holding phase, the temperature is maintained at least until a given equalization temperature is reached on the inside of the form substances. Subsequently, during a cooling-down phase, the temperature is reduced by reducing the pressure to the expulsion temperature. Porous light building materials in a conventional process would absorb a high amount of water through the condensation of water resulting from steam having been conveyed into the autoclave for the purpose of hardening.

Abstract: The invention relates to an appliance for heating an electroconductive material, preferably one which hardens as a result of this heating process, this material being in the form of a continuous strand which is guided inside a channel (14). In this appliance, a high-frequency generator (23) is provided, two capacitor-plates (30) being arranged on two oppositely-located sides of the channel (14), which sides are formed by walls (10 to 13) composed of an electrically insulating material, these capacitor-plates (30) being staggered by at least their length and being connected to a non-earthed terminal of the high-frequency generator (23), while two further capacitor-plates (31, 32) are arranged on each of the two sides, adjacent to the two capacitor-plates (30), these further capacitor-plates (31, 32) being connected to the earthed terminal of the high-frequency generator (23) and extending along the channel (14) for a distance such that the strand outside the heating zone is no longer at a potential.

Abstract: An apparatus for the production of calcium silicate based stone blanks including at least one mold into which a crude mixture is poured, the mixture comprising granulated silicate-containing material, lime, water, a cement and foam. The mold has a cover, a bottom and side plate, with one of the plates being movable to open and close the mold. The crude mixture is heated in the mold essentially uniformly to a temperature between 45.degree. C. and 90.degree. C. until achieving the desired blank-strength by strength-forming reactions of the cement in the crude mixture. The heater used for this purpose is a high frequency voltage heater using two parts of the mold as condensor plates connectable with a high frequency voltage source. The formed stone blanks are thereafter removed from the mold and transferred to a transport station.

Abstract: A process and apparatus is provided for the production of calcium silicate-containing stone blanks which are useful in constructing building walls. A crude mixture, of a granulated silicate-containing material, lime, water, a cement and a foaming agent, is subjected to no more than a minimum application of external pressure and is subsequently hardened in an autoclave. The cement produces the necessary strength for the blank, so that the latter becomes transportable while the final strength is achieved by reaction of the silicate-containing material during the autoclave treatment. In order to arrive at acceptable molding times and in order to achieve a simplified process with slight fragment bulk density and optimal head damping characteristics, the crude mixture is rendered pourable, is filled into molds in a quantity corresponding to the fragment volume of the stone blank, and the crude mixture in the mold is heated essentially uniformly to a temperature between 45.degree. C. and 90.degree. C.