Abstract: The present document describes methods for drying an aqueous priming coating composition covering an external surface exposed to air of a carbon material, or an aqueous coating composition covering an intermediate substrate covering an external surface exposed to air of a carbon material, to form a layer thereon. Also described are systems for drying a coating composition covering a surface of a carbon material.

Abstract: The present document describes an electrolytic cell comprising a protective layer comprising elemental copper covering at least in part or all of a refractory material assembly covering an interior surface thereof. Also described is a copper oxide containing composition comprising copper oxide and any one of a reducing agent and a binder. Also described is a method of protecting a refractory material assembly covering an interior surface of an electrolytic cell, comprising covering at least in part, or all of the refractory material assembly with a copper sheet, a structure comprising elemental copper, a copper oxide, an elemental copper comprising composite material, a copper oxide containing composition and combinations thereof, to provide a protective layer comprising elemental copper.

Abstract: The present document describes an electrolytic cell comprising a protective layer comprising elemental copper covering at least in part or all of a refractory material assembly covering an interior surface thereof. Also described is a copper oxide containing composition comprising copper oxide and any one of a reducing agent and a binder. Also described is a method of protecting a refractory material assembly covering an interior surface of an electrolytic cell, comprising covering at least in part, or all of the refractory material assembly with a copper sheet, a structure comprising elemental copper, a copper oxide, an elemental copper comprising composite material, a copper oxide containing composition and combinations thereof, to provide a protective layer comprising elemental copper.

Abstract: The present document describes an aqueous coating composition for preventing or reducing air oxidation of a carbon material, and aqueous priming coating composition for application to a carbon material prior to application of the aqueous coating composition, chemical treatment of a carbon material comprising both the aqueous coating composition and aqueous priming coating composition, and methods of coating carbon material with the compositions.

Abstract: A method of manufacturing a shield assembly for protecting a thermocouple including assembling a first mold including a tubular shield having a cavity for receiving the thermocouple, assembling a second mold having a second tubular shield having a second elongated cavity with an open end, filling the first and second mold cavities with a liquid mix of refractory ceramic material and letting the liquid mix dry and thereafter disassembling the first and second molds to free the first and second tubular shields and curing the refractory ceramic material.

Abstract: A thermocouple shield assembly comprising a first tube having an upper portion and a lower portion with a lower end, the first tube including a first elongated cavity closed at the lower end and receiving the thermocouple, a second tube having a second elongated cavity with at least one open end and receiving the upper portion while a part of the lower portion containing the thermocouple extends out of the open end, and a gap between adjacent walls of the second elongated cavity and of the first tube such as to allow independent thermal deformations of the first and second tubes. In use, at least a portion of the part of the lower portion of the first tube is subjected to a given temperature while the second tube is subjected to a different temperature. Methods of manufacturing and of assembling such a thermocouple shield assembly are also presented.

Abstract: A refractory composition for use in contact with molten aluminum and molten aluminum alloys containing a refractory aggregate, a binder, and a treatment additive comprising a source of Sr. Methods comprising contacting a refractory composition with the Sr source to improve the resistance of the refractory to molten aluminum attack are also disclosed. Preferred treatment agents comprise Sr nitrate, Sr carbonate, Sr sulfate and Sr oxide.

Abstract: A thermocouple shield assembly comprising a first tube having an upper portion and a lower portion with a lower end, the first tube including a first elongated cavity closed at the lower end and receiving the thermocouple, a second tube having a second elongated cavity with at least one open end and receiving the upper portion while a part of the lower portion containing the thermocouple extends out of the open end, and a gap between adjacent walls of the second elongated cavity and of the first tube such as to allow independent thermal deformations of the first and second tubes. In use, at least a portion of the part of the lower portion of the first tube is subjected to a given temperature while the second tube is subjected to a different temperature. Methods of manufacturing and of assembling such a thermocouple shield assembly are also presented.

Abstract: For heterogeneous materials such as refractories and carbon electrodes, the measurement the elastic properties of the material is difficult to achieve with high level of repeatability. The present invention is directed to a method and system for the elastic properties measurement of a material including the Elastic and Shear Modulus, as well as the Poisson's ratio of heterogeneous materials, at room and high temperature, according to a non destructive acoustic technique.

Abstract: A temperature sensor is supported in a device which floats in a liquid, the temperature of which is to be determined. Typically the sensor is the hot thermocouple element of a thermocouple and the liquid is a molten metal; the device may be constructed to float with the temperature sensor disposed at a desired distance below the upper surface of the liquid.

Abstract: An elongated protective device for an immersion pyrometer. The device comprises a self-supporting inner sheath made of a ceramic material having virtually no open pores and a protective, crack-free outer ceramic casing at least partially surrounding the inner sheath. The inner ceramic sheath has an interior cavity extending from an open end of the sheath internally to a closed end for receiving a thermocouple element. The thermocouple element is then positioned within the cavity with the hot junction of the thermocouple element contacting the closed end of the ceramic sheath. The device provides good corrosion, shock and oxidation resistance for pyrometers when immersed into molten metals and by-products at high temperatures.

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: The amount of electrically conductive material in the bottom floor lining of a conventional aluminum reduction cell is reduced by using a non-conductive lining material in its place. The non-conductive material separates the remaining electrically conductive regions from the sidewall linings of the cell and preferably confines the electrically conductive material to the "anode shadow" region of the cell floor. In another embodiment joints between the conductive and non-conductive regions are positioned such that they are covered by cell freeze (solid electrolyte) during operation of the cell. This prevents liquid cell contents penetrating the joint and adversely affecting the cell lining, thus shortening the life of the cell. The non-conductive material preferably comprises a particulate alumina mixture made up of large shapes which firmly compact together and smaller particles which fill the remaining voids.

Abstract: Aluminum electrolysis cell having a refractory lining, said lining being produced by calcining red mud obtained as a byproduct of the Bayer process of producing alumina, grinding the calcined product to form particles of -4 Tyler mesh, mixing the ground product with a binder (e.g. colloidal silica, colloidal alumina, sodium silicate or sodium aluminate) and sufficient water to produce a formable mixture. The mixture is formed into a shaped product, fired and used, for example, as a monolithic lining, to form the internal surface of the aluminum electrolysis production cell.

Abstract: A process for producing a refractory material and to the material so-produced. The process comprises calcining red mud obtained as a by-product of the Bayer process of producing alumina, grinding the calcined product to form particles of -4 Tyler mesh, mixing the ground product with a binder (e.g. colloidal silica, colloidal alumina, sodium silicate or sodium aluminate) and sufficient water to produce a formable mixture. The mixture is then formed into a desired shape and fired, preferably after curing and drying. The resulting fired products have good resistance to high temperatures and to corrosive chemicals such as cryolite. Consequently, the products can be used as refractory linings for aluminium production cells, and in similar applications.

Abstract: The amount of electrically conductive material in the bottom floor lining of a conventional aluminum reduction cell is reduced by using a non-conductive lining material in its place. The non-conductive material separates the remaining electrically conductive regions from the sidewall linings of the cell and preferably confines the electrically conductive material to the "anode shadow" region of the cell floor. The non-conductive material preferably comprises a particulate alumina mixture made up of large shapes which firmly compact together and smaller particles which fill the remaining voids. Optionally, the mixture may be bonded together with amorphous alumina, in which case the mixture can also be used for cell wall linings. The linings can be used in reduction cells of conventional design and reduces undesirable magnetohydrodynamic effects as well as pollution hazards caused by conventional carbonaceous cell linings.

Abstract: The non-destructive testing of materials, particularly coarse grain materials such as the carbonaceous materials used in the anodes and cathodes of an aluminium smelting furnace, using longitudinal compression waves employs a waveguide to apply the waves to a specimen, the and specimen having a cross-sectional dimension Dg of between 3 and 5 times the material average grain size Dg. Alternatively, or in addition, the waves used preferably are of effective wavelength from about 30Ds to 50Ds. Alternatively, or in addition, the effective wavelength of the waves is preferred to be approximately equal to the length of the sample; the necessary very long samples may be obtained by connecting a plurality of smaller elementary samples end-to-end. The apparatus may include a controllable furnace for cycling the sample to determine the change with temperature of the physical characteristic that is being measured.

Abstract: The amount of electrically conductive material in the bottom floor lining of a conventional aluminum reduction cell is reduced by using a non-conductive lining material in its place. The non-conductive material separates the remaining electrically conductive regions form the sidewall linings of the cell and preferably confines the electrically conductive material to the "anode shadow" region of the cell floor. The non-conductive material preferably comprises a particulate alumina mixture made up of large shapes which firmly compact together and smaller particles which fill the remaining voids. Optionally, the mixture may be bonded together with amorphous alumina, in which case the mixture can also be used for cell wall linings. The linings can be used in reduction cells of conventional design and reduces undesirable magnetohydrodynamic effects as well as pollution hazards caused by conventional carbonaceous cell linings.