Abstract: An apparatus repairs a perforated brick employed in a wall of a metallurgical vessel and having an opening into which is to be fit a gas washing sink for introducing gas into molten metal within the metallurgical vessel, during which gas introduction the inner end of the gas washing sink and the perforated brick around such area become worn. The apparatus includes a casing having an outer contour corresponding to the outer contour of the gas washing sink and to be inserted into the worn opening of the perforated brick upon removal therefrom of the worn gas washing sink. The casing thus forms a template defining the contour of the opening to be repaired in the worn portion of the perforated brick. A repair material feed pipe extends through and is guided by the casing for supplying therethrough repair material for repairing the worn portion of the perforated brick. A spray head is attached to the inner end of the feed pipe for directing the repair material toward the worn portion of the perforated brick.

Abstract: A process of making carbon-bonded refractory shapes by preparing a mix of refractory materials, pitch or tar and a binder resin, molding the mix into shapes and hardening the shapes. A starting mix is used which, based on the added quantity by weight of pitch or tar, contains 1 to 10 weight % of hollow fibers. The refractory shapes have the advantage that they exhibit less cracking, and hardly any, or even no, breaking occurs during their fabrication.

Abstract: The invention relates to a closing member, for use in a slide gate for a molten metal container. The closing member can be formed as a ceramic block having flow channels formed therethrough and opening through different external surfaces thereof such that each flow channel has its own working surface and can be brought into operative position by rotating and/or sliding the closing member relative to the molten metal container. Alternatively, the closing member can be formed as a metal cage having recesses formed therethrough in which refractory plates can be inserted. The refractory plates each have an opening therethrough which aligns with a refractory sleeve extending through the cage. Each refractory sleeve, together with the opening through the corresponding refractory plate, forms a flow channel. Again, the different flow channels are arranged so that they can be brought into operative position by rotating and/or sliding the closing member relative to the molten metal container.

Abstract: A process for making silica bricks with increased bulk density from a starting mix containing graded granular quartzite (silica) and elemental silicon, wherein the starting mix contains 0.5 to 10 weight percent of the elemental silicon and also contains 1.5 to 8 weight percent of pyrogenic silicon dioxide based on the weight of the quartzite, elemental silicon and pyrogenic silicon dioxide in the starting mix.

Abstract: A tap spout, particularly for allowing molten metal to be discharged from oxygen-steel converters, includes a replaceable unit including a tubular wear lining and a jointing layer secured thereto. An inner lining of the tap spout may thus be repaired with relatively simple maintenance work by removing the inner lining and subsequently inserting the replaceable unit into an outer lining of the tap spout to form a new inner lining of the tap spout. The replaceable unit is adapted to facilitate either a press fit, and in particular, a fit ensured by axial compression of the jointing layer, or an expansion fit with the outer lining to secure the replaceable unit therein.

Abstract: A gas washing sink for use in introducing gas through a metallurgical vessel into molten metal therein includes a gas permeable refractory inner brick portion and a gas impermeable refractory outer brick portion surrounding the inner brick portion. The inner and outer brick portions define a first sink end to be exposed to the molten metal. The outer brick portion has an end face defining a second sink end to be directed away from the molten metal. A gas distribution chamber has a first end open to the inner brick portion and a second end opening onto the end face of the outer brick portion and defined thereat by an opening. A sealing surface extending concentrically of the opening has pressed thereagainst, at a pressure sufficient to achieve a seal therebetween, a closure member for closing the second end of the gas distribution chamber and having a gas inlet connection for introducing gas into the gas distribution chamber.

Abstract: A safety-type gas washing sink for use in introducing gas through a metallurgical vessel and molten metal therein includes a refractory wearable brick portion defining a first sink end to be exposed to the molten metal and becoming worn during use, such wearable brick portion having therethrough gas flow paths for the passage of gas into the molten metal, and a refractory safety brick portion defining a second sink end to be directed away from the molten metal and through which the gas can be delivered to the gas flow paths in the wearable sink portion. The safety brick portion has a higher thermal conductivity than the wearable brick portion, and the gas flow paths continue into the safety brick portion. Thus, any molten metal that breaks through the wearable brick portion to the safety brick portion will be caused to solidify at the safety brick portion due to rapid dissipation of heat thereby.

Abstract: A method and apparatus for uniting workpieces of silicon-infiltrated silicon carbide with large dimensions includes surrounding each of two silicon-infiltrated silicon carbide workpieces with at least one tightly closing shell in the vicinity of a junction between the workpieces, defining at least one intermediate space between the shell and the workpieces. A vacuum or an inert gas atmosphere is maintained in the intermediate space or spaces. Solder is placed at the junction and the junction is locally heated to soldering temperature for materially bonding the workpieces by soldering at the junction.

Abstract: The present invention is drawn to a regulating device of a metallurgical vessel for regulating the flow of molten metal from the vessel. The device includes a fixed refractory part defining a first cylindrical peripheral surface of the device and a movable refractory part that is rotatable and/or slidable relative to the fixed refractory part and defines a second cylindrical peripheral surface sealingly engaged with the first cylindrical peripheral surface. An actuating device is connected to the movable refractory part for rotating and/or sliding the movable refractory part relative to the fixed refractory part. The cylindrical peripheral surfaces of the refractory parts are spaced apart from one another so as to define an annular gap therebetween.

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: A refractory plate assembly for use in a sliding closure unit includes a sheet metal shell including a base portion and an integral peripheral portion. A refractory plate member having a sliding surface is positioned within the shell. Positioning or support structure locates the plate member within the interior of the shell, and fiber or granular thermal insulation material is positioned within the shell between the base portion thereof and the refractory plate member.

Abstract: Apparatus and method for reducing nitrogen oxides in flue gas within a flue gas duct includes a number of distributor tubes for the injection of a reducing agent into the flue gas within the duct. Each distributor tube includes a control valve to be able to set an appropriate injection of the reducing agent to respond to different concentrations of the nitrogen oxides within the flue gas over the cross section of the flue gas duct. Each distributor tube comprises at least two parallel distributor tube segments which extend from opposite sides of the flue gas duct to the center of the flue gas duct. The two parallel distribution tube segments include a plurality of openings along the lengths thereof to supply the reducing agent generally evenly throughout their aligned portions of the cross section.

Abstract: A rotary valve for controlling the discharge of molten metal from a metallurgical vessel includes a refractory rotor having a cylindrical outer peripheral surface and fitted within a recess defined by a cylindrical inner surface in a refractory stator and complementary to the outer surface. The rotor may be rotated about either a horizontal or a vertical axis relative to the stator and may be axially moved within the recess therein. The rotary valve may be mounted on the exterior of a bottom wall of a metallurgical vessel or alternatively may be mounted within a refractory lining of the metallurgical vessel, particularly in a transition area between a side wall and a bottom wall of the metallurgical vessel. Further alternatively, the rotary valve may be mounted within the refractory lining of the bottom wall of the metallurgical vessel, with the rotor extending through the bottom wall and being actuated for movement from below the bottom wall.

Abstract: Elastic, heat-insulating shapes of ceramic, refractory or fireproof fibers and, where needed, further refractory or fireproof substances, and temporary or inorganic binders, as well as a process for the preparation thereof. The heat-insulating shapes are characterized by the fact that they contain 5 to 40 weight % of fibrids comprised of organic polymers, as a result of which they have elastic properties and can be formed with ease at moderate temperatures. In preparing these shapes, a customary aqueous dispersion containing the fibers and binder is mixed with the fibrids of the organic polymer, and water is removed therefrom and the shapes are otherwise produced in a known manner.

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 valve for controlling the discharge of molten metal in a substantially downward direction from a metallurgical vessel has an outer valve part defining an inlet of the valve and an outlet port of the valve, and a refractory inner valve part disposed within the outer valve part in a sealing relationship therewith. The inner valve part has a groove extending therein at the outer peripheral surface which is communicable with the inlet and the outlet port of the outer valve part when the valve is in an open position. The provision of the groove at the outer peripheral surface of the inner valve part does not result in any significant reduction in strength of the inner valve part.

Abstract: A member formed of ceramic refractory material has therein an opening. A metal coupling member for attaching a metal member such as a rod or a tube, to the refractory member has an externally threaded portion extending into the opening in the refractory member. The coupling member has a head extending radially outwardly beyond the threads of the threaded portion and embedded in the refractory member. The opening in the refractory member may be internally threaded to receive the threads of the threaded portion of the coupling member.

Abstract: A rotary valve for controlling the discharge of molten metal in a substantially downward direction from a metallurgical vessel includes a refractory rotor rotatable about a substantially horizontal axis. The rotor has an outer peripheral surface, either conical or cylindrical, arranged symmetrically about the axis, and the rotor has therethrough a flow channel having inlet and outlet ports, at least the outlet port opening onto the outer surface. A refractory stator has therein a recess defined by an inner surface, either conical or cylindrical, complementary to the outer surface of the rotor, the stator having therethrough a discharge channel. The rotor fits within the recess in the stator, with the outer and inner surfaces thereof being complementarily positioned symmetrically about the axis.

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 movable refractory plate assembly for use in a sliding closure unit for controlling the discharge of molten metal from a metallurgical vessel includes a movable refractory plate having therein at least one aperture and having a sliding surface. A replaceable refractory erosion unit, which may be integral or which may include a separate erosion insert and a separate discharge nozzle, is positioned within the aperture of the movable refractor plate. The erosion unit has therethrough a discharge opening and has a sliding surface aligned with a sliding surface of the movable refractory plate. A frame supports the movable refractory plate for movement, and a support coupling removably mounts the erosion unit with respect to the movable refractory plate.