Abstract: The invention concerns a refractory material based on chromium corundum, a chromium corundum brick made of said material as well as the use thereof.

Abstract: Very thin plates of ceramic material with low binding strength are difficult to manufacture, since the stability of the moldings is very low, so that they can hardly be fed to a subsequent treatment stage after shaping. Therefore, after the ceramic material is molded into plate-shaped moldings, these moldings are pushed onto a flat carrier in the plane of their plate surface and are heated on it for a few minutes, so that iron sulfates form, which impart dimensional stability to the moldings.

Abstract: This invention relates to a process for the manufacture of catalysts for the reduction of oxides of nitrogen from exhaust gases and in chemical air cleaning processes in which a catalytically active material containing iron ores, chromium ores and/or zeolite is placed in contact with a carrier means having a series of openings; e.g., wire mesh, expanded or perforated metal or any type of grid-like structure to form a catalytic member. The carrier means is etched with an acid etchant before forming the catalytic member or, instead, the catalytic member is etched with an acid etchant. The catalytic member is bonded by a thermal treatment; e.g., drying, tempering and/or fixing. This invention also relates to catalytic members or products produced by the process. This invention proposes the use of pressure bonding to obtain a catalytic member product which has significantly improved catalytic activity, greater mechanical strength and higher resistance to chipping.

Abstract: A process for the manufacture of catalysts for the reduction of nitrogen oxides in exhaust gases or for chemical air cleaning processes, in which catalyst moldings are produced from a mixture of solid primary materials which include iron oxide or mixtures of iron oxide and chromium oxide and/or manganese oxide, which are reduced to grain sizes less than 2 mm, with the use of inorganic binders and sulfuric acid, and with the possible addition of activating additives, wherein:(a) either the mixture of the solid primary materials is reacted with sulfuric acid, a mixture of sulfuric acid and phosphoric acid or mixtures of sulfuric acid and phosphoric acid containing sulfate, hydrogen sulfate, phosphate or hydrogen phosphate of ammonium, aluminum, iron, vanadium, manganese, molybdenum, chromium, copper and/or cobalt, and moldings are formed from this mixture, or the mixture of the solid primary materials is formed into moldings after the addition of fluid and/or phosphoric acid and/or phosphates, and these molding

Abstract: A composite refractory member includes at least one insert formed of an oxide ceramic material having a high resistance to molten material. The insert defines a discharge opening or other molten material contacting surface. A base structure encloses and supports the insert and is formed by molding a chemically setting refractory concrete including a refractory granulate of low-iron sintered magnesia with a MgO content of over 80 weight percent. Mold cores extend into the refractory concrete during molding such that the molded structure has expansion joints which later are filled with mortar.