Abstract: Disclosed is anti-alumina-buildup refractories for casting nozzles, which comprises a refractory aggregate including 20 mass % or more of CaO component, and 10 mass % or more of clinker particles each containing CaO as a mineral phase, on the basis of 100 mass % of the entire composition. At least a part of the surfaces of the CaO exposed from the surfaces of the corresponding clinker particles is formed with a CaCO3 film. The CaCO3 film releases CO2 gas through thermal decomposition to smooth an operative surface of the nozzle so as to prevent the accretion of metal thereon, so that CaO is continuously supplied to alumina attached on the operative surface to prevent alumina buildup. In addition, the CaCO3 film effectively prevents the hydration of CaO due to a hydration reaction.

Abstract: Disclosed is a magnesia-carbon based sleeve brick for steelmaking converters, which is obtained by adding, to a refractory raw material mix containing 60 to 95 mass % of a magnesia raw material and 5 to 20 mass % of graphite, a metal powder of one or more selected from the group consisting of Al, Si, Mg, Ca, Cr and an alloy thereof, in an amount of greater than 3 to 6 mass %, and an organic binder, in addition to 100 mass % of the refractory raw material mix, and subjecting the resulting mixture to kneading, forming and heat treatment, wherein the sleeve brick is used under a condition that a thickness thereof is set at 70 mm or less. This makes it possible to prevent cracking which would otherwise occur in the sleeve brick itself, to allow the sleeve brick to have enhanced durability. One or more selected from the group consisting of B, B4C, MgB2, CaB6, and CrB may be further added in an amount of 0.

Abstract: The present invention provides for a refractory aggregate composition comprising an improved calcium aluminate clinker having the formula CnAx wherein C is calcium oxide and A is aluminum oxide, wherein n is an integer from about 1 to about 12, wherein x is an integer from about 1 to about 24, and wherein said clinker has from zero to less than about fifty weight percent C12A7. Analogs, derivatives and hydrates of the improved calcium aluminate clinker are provided. A refractory composition and a sprayable refractory composition are disclosed comprising the improved calcium aluminate clinker. A method for improving the insulating character and/or penetration resistance of a liner in contact with molten aluminum in an aluminum manufacturing process or during aluminum transport is provided.

Abstract: Disclosed is a continuous casting nozzle having a refractory portion formed to contain a dolomite clinker and arranged to define a surface region adapted to be in contact with molten steel, which is capable of protecting a working surface of the nozzle from alumina build-up due to alumina in molten steel, while improving corrosion resistance, even during long-term continuous casting of molten steel. The refractory portion is prepared by adding a binder to a mixed material and subjecting the obtained mixture to kneading, forming and heat treatment. The mixed material comprises a dolomite clinker which has an average particle size of 0.8 mm or less and a CaO content of 50 mass % or less. The mixed material has a ratio W1/W2 of 0.33 or more, wherein W1 is a content by mass of CaO, and W2 is a content by mass of MgO. The mixed material comprises a dolomite clinker and a magnesia clinker. Alternatively, the mixed material comprises a dolomite clinker and a magnesia clinker.

Abstract: A graphite-containing monolithic refractory material comprises at least one component selected from alumina and alumina-magnesia spinel, which are divided into selected particle size regions, artificial graphite having a selected average particle size, and pitch powder. The refractory material may optionally comprise a selected amount of silicon carbide having a selected average particle size. The graphite-containing monolithic refractory material exhibits excellent casting workability at a low moisture content, and both excellent corrosion resistance and spalling resistance. The refractory material is suitable as a casting monolithic refractory material for lining a topedo ladle car.

Abstract: A barrier layer for prevention of solid fluorides penetration, e.g. NaF, from the interior of an aluminum production cell holding a fluoride-containing melt into a refractory layer intended to provide heat and electrical insulation for the cell. The barrier layer contains CaO, which may be derived from a CaO precursor such as calcite (CaCO.sub.2) by decomposition during cell start-up. Since CaO does not appear to react with sodium fluoride (NaF), and indeed according to thermodynamic calculations seems incapable of doing so at cell operating temperatures, it is effective for preventing the penetration of that compound when the latter is in the solid state. The barrier layer makes it possible to use insulating low cost refractories which are attacked by solid fluorides in the cell wall lining with improvement of the life of such materials.

Abstract: Molten steel in tundishes can be contacted with high surface area ceramic shapes which remove the alumina and other impurities contained in steel. Certain ceramic shapes, in particular tundish baffles, having a large surface area which acts as alumina traps for molten steel contained in tundishes are also disclosed.

Abstract: Novel preheatable molded refractory insulating liners and methods of use thereof for lining metallurgical vessels, such as hot tops, ladels, tundishes, troughs and pipes, etc., which serve to transfer molten metals, such as ferrous alloys, are disclosed. The new and vastly improved preheatable liners are suitable for developing effectively the required hot strength needed for casting molten metals at vessel preheat temperatures and casting temperatures. The unique preheatable liners additionally possess the needed hot strength during the range of casting temperatures as are experienced in the metal making industry.

Abstract: A ladle or other vessel for containing molten metal, for example molten steel, is lined with refractory at least some of which (e.g. in the slag line area) is unfired refractory bonded with a phosphate bond such as a long-chain glassy polyphosphate and containing, at least in the material smaller than 0.15 mm (-100 mesh), a high-lime periclase grain. This type of refractory shows unexpectedly high resistance to erosion and corrosion in the environment of a steelmaking ladle.

Abstract: The invention relates to a method for repairing slide plates of metallurgical containers. These types of slide plates consist of refractory material and have a passage opening for the discharge of the liquid metal, which is usually steel. Owing to corrosion and radial cracks, which orginate at the passage opening, these slide plates 5 become worn after a lengthy operating time. In order to be able to further use them to a large extent, the invention provides a bore, in the area of the opening, extending as far as the edge of the rim 6 of the slide plate, while the remaining refractory material is retained. Into this bore there is poured a refractory casting mass, the grain structure of which has a particular relation to the pore size of the retained refractory material. The essential fact is that the solid bodies of the refractory casting mass are predominantly smaller than the open pores, cut by means of the boring process, of the retained refractory material and can penetrate into the pores.

Abstract: Unfired refractory structural member in the form of a plate for the expendable lining of metallurgical vessels, especially for tundishes used in continuous steel casting, and comprising magnesia sinter and possibly olivine with a grading of 30-45% by weight under 0.09 mm, and 55-70% by weight 0.09 to 4 mm, including 20-40% by weight over 1 mm; cork or granulated ceramic fibers as a pore-forming material; an inorganic binder; and possibly other additives. This refractory structural member has good strength, a small ignition loss, a low content of volatile hydrogen-containing substances, a favorable peeling behavior, and good resistance to slag and molten steel.

Abstract: A method of manufacturing a composite refractory article having a flow passage through which a molten metal stream may be conducted and comprising a first body of refractory material which defines a surface of that passage, the first body being bonded to a second body of refractory material. The second body is provided to define a passageway of greater cross-sectional dimensions than the flow passage. Within the passageway, the first body of refractory material is provided for defining the flow passage surface, the first body being formed in the larger passageway by causing its refractory material to cohere and bond to the second body by fusion or partial fusion in situ.

Abstract: A method of operating "wet bottom" practice soaking pits to prolong useful period between bed replacement. Olivine is used to replace coke breeze in the bottom of the soaking pit to protect its refractory lining.Operating periods from 40-60 days are possible when olivine is used in the soaking pit. The olivine has excellent temperature stability, also, so it is well suited for this application, in which temperatures range from about 2400.degree.-2650.degree. F.

Abstract: Refractory products such as foundry articles and composite metal-ceramic articles are prepared from a sepiolite (2 MgO.3SiO.sub.2.2H.sub.2 O) and silicate containing aluminum titanate.

Abstract: A blast furnace hearth, or at least its internal surface layer, is built of carbon bricks whose pores have been reduced in size by an Si--N--O composition formed in them.

Abstract: An unburnt refractory mass, which can be in the form of a brick, for use in vessels employed in metallurgical refining consisting essentially of chromium-ore, sintered magnesia and a carbon-containing binder, said mass consisting essentially of:75 to 95% by weight chromium ore having a Cr.sub.2 O.sub.3 content of at least 30% by weight;0 to 19% sintered magnesia poor in iron content; and2 to 7% hard pitch combined with 1.5 to 5% carbon so as to provide an overall residual carbon of 3 to 6%.

Abstract: A crucible for melting a nickel-based superalloy containing one or more of the elements aluminium, titanium and hafnium is made of magnesia grains bonded by tinania, hafnia or yttria. The purity of the magnesia is not less than 97%.