Abstract: The present invention relates to a method for dry desulfurizing flue gases from rotary cement kilns, for which additives suitable for binding SO.sub.2, such as quick lime and/or dry calcium hydroxide, are supplied to the kiln, the additive being introduced into a flue gas-carrying zone at the kiln head at a injection angle of 2.degree. to 12.degree. to the axis of the kiln and at an injection velocity of 20 to 80 m/sec.

Abstract: A cyclone heat exchanger including a plurality of arranged one above another cylone separators forming, respectively, a plurality of heat exchange stages, a first inlet for delivering raw meal to the heat exchanger, a first outlet for delivering the heated raw meal from the heat exchanger, a second inlet for delivering a hot gas to the heat exchanger, a second outlet for delivering the cooled gas from the heat exchanger, and at least one motor-driven conveyor device arranged between at least two heat exchange stages, located immediately one above the other, and defined by respective cyclone separators for transporting the raw meal between the stages.

Abstract: A device for continuously preparing a hydraulically setting mass comprises a tubular housing having a downstream outlet opening and an upstream supply station for a dry component material of the mass, the supply station including a storage bin for the dry material. A driven rotating shaft extends from the storage bin through the tubular housing towards the outlet opening, rotation of the shaft causing a feed flow in the direction of the outlet opening, and the rotating shaft is equipped with a dosing screw feeding the dry material out of the storage bin, a plurality of radially projecting mixing blades for mixing the material fed by the dosing screw, and an implement for finely granulating the mixed material downstream of the mixing blades, the granulating implement being comprised of at least two interdigitating comb-like elements, one of the comb-like elements being carried by the shaft for rotation therewith and another comb-like element being affixed to the tubular housing.

Abstract: A multi-layer load-bearing board comprising at least three layers of different composition includes a core or basic layer comprised of a cementitious inorganic material, a cover layer of a fiber-reinforced resin subjectable to forces and an intermediate layer of a hydrophilic and water-dilutable or water miscible resin interconnecting the core or basic layer and cover layers in a force-transmitting manner.

Abstract: A method for drying coal in a coal mill and pneumatically conveying it to a kiln for burning, with a portion of the coal-dust-laden air generated thereby being diverted to a clinker cooler adjacent the kiln in order to ignite the suspended particles and supply hot air for burning the coal. The diverted air is later recirculated back to the coal mill to help dry the coal.