Abstract: The present invention pertains to the use of a finely divided magnesium oxide micropowder for preparing ceramic masses and moldings.

Abstract: The present invention pertains to a device for preparing and feeding a monolithic ceramic mass into a metallurgical melting vessel, including a mixer 30 and a feeding device 32, characterized in that the mixer 30 and the feeding device 32 are designed as a compact unit 28 for arrangement above the metallurgical vessel, wherein the mixer 30 and/or the feeding device 32 are arranged relative to one another and movably such that the mass prepared in the mixer 30 can be directly introduced at any desired point of the metallurgical vessel via the feeding device 32.

Abstract: The invention relates to a metallurgical vessel, in particular a transport ladle or a treating ladle, for the production of steel with a bottom (2b) having a refractory lining (3) with a basic working layer (5). In order to create a durable lining it is provided that the working layer (5) consists at least in part of dry basic bulk material, the upper side of which is covered, before the vessel (1) is heated for the first time, by a chemically hardened protective layer (6) and which, after the vessel (1) has been filled, is partly present as a monolithic layer or the upper side of the working layer (5) is covered, before the vessel (1) is charged for the first time, by a monolithically fritted basic layer formed by heating the bulk material. The invention furthermore relates to a method of making the refractory linings of such vessels.

Abstract: The present invention pertains to a device for installing and removing gas purging plugs (17) for metallurgical vessels, comprising a guide (7) for axially displacing the gas purging plug (17). On the one hand, movement exactly in the axial direction can be achieved during introduction, and, on the other hand, the extracted gas purging plug can be brought into an ejection position by providing hinges (6, 11), which permit at least two independent pivoting movements of the gas purging plug (17) around different axes (6a, 11a).

Abstract: The present invention pertains to a system of sized bricks for lining spherical bottoms, especially of metallurgical vessels, wherein the individual sized bricks are defined by six, essentially flat surfaces, namely, the fire-side surface, the cold-side surface, the two lateral surfaces, as well as the inner and outer surfaces, and the said sized bricks are intended for arrangement in concentric rings wherein the sized bricks within each of these rings join each other with their lateral surfaces, and wherein the outer surfaces of the sized bricks of one ring border on the inner surfaces of the sized bricks of the next ring.

Abstract: The present invention pertains to a binding and plasticizing agent for preparing refractory materials, in which the binding agent contains a synthetic resin, a phosphate, and a surface-active agent.

Abstract: A finely powdery magnesium hydroxide especially suitable as a flame-retardant filler for plastic compounds, in which the particles are provided optionally with a thin coating of a surfactant. The grain size of the magnesium hydroxide, measured by laser diffraction, is below 10 .mu.m. The median value of the grain size is greater than 0.8 .mu.m, and the maximum of the median value of the grain size is 3 .mu.m. The contents of water-soluble ionic impurities, viz. Ca.sup.++, Na.sup.+, K.sup.+, SO.sub.4 --, Cl.sup.-, of the magnesium hydroxide are below the following limits (in parts by weight): Ca.sup.++ <1000 ppm, Na.sup.+ <20 ppm, K.sup.+ <20 ppm, SO.sub.4 --<1500 ppm, Cl.sup.- <1000 ppm. The contents of Mn, Cu and Ni are below the following limits (in parts by weight): MnO<100 ppm, NiO<100 ppm, CuO<10 ppm.

Abstract: A device for removing worn nozzle bricks or nozzle linings from the tap holes of metallurgical vessels including a spreading device, which can be introduced into the nozzle brick or tap hole, and a drive for extracting the nozzle brick or lining by means of the spreading device. The spreading device is arranged on a tool holder which can be displaced axially on a support, in particular a carriage. The tool holder can be connected to at least one drive. The tool holder advantageously includes an axial cavity in which a toothed shaft is rotatably mounted. The toothed shaft meshes with the toothing of at least two, and preferably three, spreading jaws which slide radially in the tool holder.

Abstract: A magnesium oxide in fine powder form, which can be used to manufacture high-density ceramics, has an MgO content greater than 95 wt. %, preferably greater than 98 wt. %, a particle size less than 15 .mu.m, and a BET specific surface area less than 20 m.sup.2 /g. The statistical mean of the particle shape factor of the primary particles lies between 1 and 1.5. The particles are coated with a hydrophobic, surface-active substance.

Abstract: Refractory, gas-permeable bubbling plugs for a vessel containing a molten metal have a cold end remote from the molten metal and a hot end facing the molten metal. The hot plug end is subject to wear by the heat radiated from the molten metal to leave a remaining plug size after wear, and such plugs comprise at least one measuring probe displaying the remaining plug size. According to the invention, the measuring probe comprises a small tube having a tip extending into the plug and spaced a predetermined distance from the cold plug end, and an end section protruding from the cold plug end, a wire movably mounted within the small tube, a spring preloading the wire, a connection connecting an end of the wire to the tip of the small tube and detachable by the effect of the radiated heat, and an optical display unit attached to the wire in the protruding end section of the measuring probe tube.

Abstract: A checkerwork for two upright regeneration chambers of a glass melting furnace defines a multiplicity of adjacently arranged vertical passages alternatingly providing upwardly directed fresh air flow and downwardly directed exhaust flow, the passages being connected by vertically spaced openings producing air turbulence, and the vertical distance between vertically adjacent openings becoming progressively smaller towards the uppermost checkerwork region.

Abstract: A checkerwork in a horizontal regenerator chamber of a regeneratively fired furnace, comprising an array of horizontally and vertically adjacent hollow prismatic bricks of refractory material, the bricks being arrayed in horizontal and vertical rows, and each brick having a horizontally extending longitudinal axis, a rectangular periphery and an axially extending bore of a rectangular cross section.

Abstract: A prismatic brick of refractory material for the checker work in chambers of a glass melting furnace, the brick having an octagonal bottom surface, an octagonal top surface, a longitudinal axis extending between the surfaces, a through passage of tetragonal cross section between the surfaces and coaxial with the longitudinal axis, inner walls defining the through passage, outer walls between the surfaces, the walls being parallel to the longitudinal axis, the bottom and top surfaces extending along major axes, one of the surfaces having elevated portions and the other surface having corresponding depressed portions extending in the direction of the major axes, and a passage extending from the through passage to a respective one of the outer walls from at least one of the inner walls.

Abstract: A grid lining of chambers of a glass melting furnace comprises a plurality of refractory bricks, each brick having a bottom surface, a top surface, a longitudinal axis extending between the surfaces, a through passage of tetragonal cross-section coaxial with the longitudinal axis, the passage having a hydraulic diameter of 120 to 200 mm, the hydraulic diameter being defined by the relationship: four times the passage cross-section divided by the periphery of the passage cross-section, and the ratio of the hydraulic diameter to the wall thickness of the brick, as measured in the direction of the main axes extending parallel to the bottom and/or top surface between 3 and 5.

Abstract: A taphole apparatus for a steel-making converter, which is comprised of a series of refractory blocks each defining a bore and the bores being aligned to define respective and successive sections of the taphole, the bore of a first one of the refractory blocks at a hot inlet end of the taphole being funnel-shaped and the bore of a last one of the refractory blocks at a cold outlet end of the tap hole having a smaller diameter than the funnel-shaped bore at the hot inlet end.

Abstract: An apparatus for building up and repairing a refractory lining of an industrial furnace by means of a rotary disc centrifugally throwing particulate refractory material against a portion of the lining to be repaired comprises a horizontal row of hollow bolts with bores to spray water into an inlet conduit of annular cross section whereby the material passing through the conduit to the disc will be uniformly wetted. Wiper elements in the conduit prevent jamming of the material therein and finely divided compressed gas is blown in the inlet funnel that supplies the material to the conduit.

Abstract: A refractory brick or mass is comprised of 60 to 97% of sinter magnesia, an amount of a carbon-containing substance producing a residual content of 2 to 30% of carbon in an end product after carbonization, as determined by ASTM norm C 831-76, and 1 to 20%, calculated as chromium metal, of metallic chromium or a metallic chromium compound, which is primarily fine-grained and at least 80% thereof, based on the chromium metal content, has a grain size of less than 1 mm, all percentages being by weight.

Abstract: The present invention relates to a process for the recovery of magnesium oxide of high purity in which the magnesium oxide is obtained by thermal decomposition of a magnesium chloride brine previously purified. The magnesium chloride brine itself is obtained by decomposition of impure starting material with hydrochloric acid and purified before the thermal decomposition. In doing so the brine obtained by the decomposition is first concentrated and the separation of the impurities is effected only then. Calcium is separated in form of calcium sulfate. Optionally calcium sulfate and other impurities may be separated together.

Abstract: In an apparatus for building up and repairing a refractory lining of an industrial furnace, the material is centrifugally deposited by a wheel rotated by a vertical drive shaft passing through a hopper and a mixing chamber connected thereto. A shut-off bell member having a bevelled lower edge is slidably mounted on the mounting housing of the shaft for vertical movement into selected positions wherein the bevelled lower edge defines an annular gap between the hopper and the mixing chamber for permitting the granular refractory material to flow from the hopper into the chamber and the bevelled lower edge engages the conical inside wall surface of the hopper for completely closing the annular gap for interrupting the flow. The vertical movement is effected by a pneumatic motor attached to the bell member by means of a linkage and rods.

Abstract: Apparatus for building up and repairing a refractory lining of an industrial oven or like hot-running vessel comprises a disc rotatable in a horizontal plane in either direction for centrifugally depositing a granular refractory material on a portion of the lining to be built up or repaired, a conduit having an outlet opening above the disc for feeding the granular material thereto, and a drive shaft for the disc and for mixing and conveying elements for the granular material in the conduit, these elements being capable of conveying the granular material to the rotatable disc in either one of the selected directions of rotation of the disc.