Abstract: An aluminum-based welding filler wire is made with an aluminum alloy that contains between 0.1 and 6 wt. % titanium, including one portion in the form of TiB2 particles, TiC particles, or a combination thereof, and another portion in the form of free titanium. The filler wire can be used in welding aluminum-based materials.

Abstract: A process for the production of alumina trihydrate by alkaline digestion of bauxite using the Bayer process in which aluminate liquor and insoluble residues are separated using a solid/liquid separation device (E; W2; DC) characterised in that the said slurry (21a; 41; 230?) is at least partially passed through a hydrocyclone (H1; H21; H22; H3) to improve and accelerate the separation of the sodium aluminate liquor from the insoluble residues in the slurry (21a; 41; 230?) containing the said liquor and the said residues and that supplies or is derived from the said liquid-solid separation device. In a first embodiment, at least one hydrocyclone is used at the upstream side of the settler-thickener, as clarifier of the pregnant liquor. In a second embodiment, at least one hydrocyclone is used as a thickener of insoluble residue mud. In a third embodiment, a hydrocyclone is used in combination with the causticisation settler.

Abstract: A Bayer process comprises grinding and then digestion of bauxite by bringing it into contact with a sodium aluminate liquor. Digestion consists of forming a slurry that is then treated to separate insoluble residues from the sodium aluminate liquor. The liquor is then crystallized and recycled back to green liquor after having been separated from the alumina trihydrate precipitated during crystallization. The process comprises a predesilication treatment during which the ground bauxite, before digestion, is brought into contact with an aqueous sodic solution that has a content of carbonates, sulphates and possibly chlorides which, expressed as a percentage related to the caustic concentration, has less than half of the corresponding impurities content of the spent liquor. Preferably, the pure caustic soda used to compensate for caustic soda losses in the Bayer circuit, previously injected just after evaporation, is now added in the aqueous sodic solution for the predesilication treatment.

Abstract: This invention relates to an anode assembly (1) to be used in a fused bath electrolysis aluminium production cell. This assembly comprises one inert anode (2) in the shape of a ladle, one connection conductor (3, 4, 5), mechanical connection means capable of cooperating so as to set up a mechanical link between the conductor and the anode, one metallic joint (31) that is or could be formed by brazing being located between all or part of at least one surface (20, 20?, 20?) of the open end (22) of the anode (2) and all or part of at least one surface (40, 40?, 40?) of the connection end (42) of the conductor (3, 4, 5). The invention simplifies manufacturing of anode assemblies comprising one inert anode.

Abstract: The invention relates to ring furnaces of which at least one of the inner partitions is formed by a plurality of bricks made of refractory material including at least a first brick (15a) and a second brick (15b) placed above or below a third brick (15c) and separated from one another by a space (13, 14) of width J, in which the first brick (15a) has at least one recess (158d, 158?d) on its assembly face opposite the third brick (15c), the third brick (15c) has at least one projection (155d, 155?d) on its assembly face facing the first brick (15a), wherein the projection is inserted into the recess, the dimension E of said recess (158d) in the longitudinal direction of the partition is greater than the dimension B of said first projection (155d) in the same direction, and said recess (158d) is positioned at a determined distance Se from the end face (152) adjacent to said space (13, 14).

Abstract: The invention relates to a series (1) of electrolysis cells for the production of aluminum by fusion electrolysis, comprising at least two lines of cells, arranged transversely, an internal correction circuit (200) with at least one internal correction conductor (20, 20?) per line, adjacent to the neighboring line and a main connection circuit (400) between the final cells of the lines (101, 101?). In at least one line, the main connection circuit (400) comprises a layer of conductors, each conductor of which extends from the end of the final cell of the line to a given distance (D2, D2?) therefrom and the internal correction circuit (200) comprises a section of transverse conductors, arranged at a given distance (D1, D1?) from the final cell (101, 101?) running along the final cell for a given part L of the length thereof Lo. The invention permits a reduction in the mean supplementary vertical fields to very low values for electrolysis currents of a value greater than 300 kA.

Abstract: The present invention relates to a method of pre-heating a pot provided with anodes and cathodes for the production of aluminium by electrolysis, said method including a first step, prior to the pot being supplied with current, during which a layer of a granular conductive material is deposited then crushed between the anodes and the cathodes, characterized in that the granular conductive material is graphite-based and in that the layer of granular conductive material only extends, after crushing, over a part of a lower surface of each anode and takes the form of contact blocks.

Abstract: Device for equipment of a cell (1) comprising an electrolytic bath (4) covered with a crust (5), with a chisel (13) that can be moved vertically between a high position in which it is above the crust (5) and a low position in which the crust (5) is perforated and in which contact is made with the bath (4), the device (11) comprising means of detecting electrical contact between the chisel (13) and the bath (4), these means comprising an electrical circuit (19) capable of making an electrical measurement between the chisel (13) and a point (20) in the cell used as an electrical reference, and taking immediate action on the actuator to cause vertical upwards displacement of the chisel when a predetermined value of an electrical measurement is reached.

Abstract: A process for the production of alumina trihydrate by alkaline digestion of bauxite using the Bayer process in which aluminate liquor and insoluble residues are separated using a solid/liquid separation device (E; W2; DC) characterised in that the said slurry (21a; 41; 230?) is at least partially passed through a hydrocyclone (H1; H21; H22; H3) to improve and accelerate the separation of the sodium aluminate liquor from the insoluble residues in the slurry (21a; 41; 230?) containing the said liquor and the said residues and that supplies or is derived from the said liquid—solid separation device. In a first embodiment, at least one hydrocyclone is used at the upstream side of the settler—thickener, as clarifier of the pregnant liquor. In a second embodiment, at least one hydrocyclone is used as a thickener of insoluble residue mud. In a third embodiment, a hydrocyclone is used in combination with the causticisation settler.

Abstract: An ingot mold for metals which is intended for the production of an ingot through the cooling and solidification of a liquid metal mass. The mold includes a wall which defines a base and an inner surface having a part S, known as the cooling surface, which can discharge all or part of the heat energy released by the metal mass during the cooling and solidification thereof. The cooling surface S includes at least one flat surface element Si which forms all or part of the base (4) of the ingot mold. There is also at least one point C on a plane Pi which is tangential to each surface element Si, such that all of the segments of a straight line D connecting every point R of the cooling surface S to point C are only located inside the mold. Further, the total area of surface elements Si is at least equal to 10% of the surface S. The ingot mold can be used to accelerate the production of ingots.

Abstract: The purpose of the invention is a coating precursor comprising a silicone resin, a mineral filler and an organic solvent capable of dissolving the said resin and putting the said mineral filler into suspension, the said silicone resin and the said mineral filler being capable of chemically reacting so as to produce a solid layer on a substrate after the organic solvent has evaporated and a cohesive refractory layer after a calcination operation. Another purpose of the invention is a method for coating a given surface of a substrate with at least one refractory layer containing silicon in which the substrate is coated with a coating precursor according to the invention so as to form a green layer and a heat treatment is carried out to calcine the said green layer and to form a cohesive refractory layer. The invention is a means of obtaining a protective coating capable of resisting oxidizing environments, liquid metal and solid or molten salt.

Abstract: The purpose of the invention is a coating precursor comprising a silicone resin and a mineral filler capable of chemically reacting so as to produce a solid layer on a substrate and a cohesive refractory layer after a calcination operation. The precursor may also include an additive capable of reducing its viscosity. Another purpose of the invention is a method for coating a given surface of a substrate with at least one refractory layer containing silicon in which the substrate is coated with a coating precursor according to the invention so as to form a green layer and a heat treatment is carried out to calcine the said green layer and to form a cohesive refractory layer. The invention is a means of obtaining a protective coating capable of resisting oxidising environments, liquid metal and a solid or molten salt.

Abstract: A method for the production of aluminum from bauxites containing aluminum monohydate of the diaspore or boehmite type which may contain more than 1.5% by weight of calcium carbonates. The ore is digested by producing feeding a suspension produced from milled bauxite ore and concentrated aluminate liquor to a plant with a series of autoclaves and a series of regulators supplying tubular reheaters across the autoclaves with steam. The suspension first travels across the series of autoclaves, and on exiting, the digestion of the ore is practically complete, and the suspension then travels across the series of regulators. The condensation water from the steam coming from the regulator and feeding the reheater is collected in a purge pot. Within the series of regulators, the suspension is diluted on entering a regulator with the water coming from the condensation of the steam from one or several upstream regulators.

Abstract: The invention relates to a ring furnace pit (2) cooling method, comprising the production of a flux F of cooling fluid inside the pit (2) and the flow of at least a part Fr of said flux F in a roughly vertical manner along determined surfaces of the walls (2A, 2B) of the pit (2). The invention also relates to a device capable of implementing the method. The invention makes it possible to accelerate the cooling rate of ring furnace pits considerably.

Abstract: The invention concerns an additive-containing ground calcined alumina used as constituent of a refractory material precursor characterized in that it comprises an organofunctional silane, the organic function being typically an epoxy function, an alkyl function, an alcohol function or a diol function. Preferably said organofunctional silane is an oxyranyl-alkyl-silane, of chemical formula C9H20O5Si. Said additive-containing alumina can be obtained by adding said organofunctional silane during grinding to take advantage of its anti-caking properties, the intimate and homogeneous mixture being obtained as a result of grinding. It may also result from a post-grinding mixing.

Abstract: Method for conveying a pulverulent material making it possible to divide said pulverulent material, from a single storage capacity (10), between several conveyors (50) with a controlled flow rate in each of said conveyors, characterized in that said storage capacity is linked to said conveyors by at least one aero-pipe (30) and in that a hyperdense fluidized meter (40), is connected to said aero-pipe, said hyperdense fluidized meter being intended to feed each of the conveyors.

Abstract: A method for measuring degree and homogeneity of calcination of alumina utilizing an image analysis device equipped with a sensitive camera in a spectral analysis window corresponding to a wavelength range equal to or in the vicinity of visible light. The method includes the steps of mixing alumina under analysis in a liquid wherein the refractive index is, in the wavelength range, between the refractive index of a lightly calcined alumina and the refractive index of a strongly calcined alumina, preparing a slide for observation of the mixture in the image analysis device, the mixture being illuminated by stable polychromatic radiation compatible with the spectral analysis window, receiving an image by the camera and processing a signal resulting in the definition of an image composed of a given number of pixels with three calorimetric components, and statistically processing the pixels using their calorimetric components and determining the calcination degree and the homogeneity of the calcination.

Abstract: The invention concerns fibre-free precursor pastes of refractory material characterised in that they contain an elastomeric polymer filled with alumina and alumina hydrate and a silylating agent, generating Si—O bonds. The invention also concerns the method for making said paste and the material and the use thereof.

Abstract: In a BAYER circuit, a process for controlling precipitation in which particle size quality of alumina hydrate produced in the circuit and circulating in feed tanks is monitored utilizing a calibration step and a control step. In the calibration step, cumulative percentage of alumina hydrate particles circulating in the feed tanks in the circuit that are finer than X2 ?m, defined as CPFT X2, is measured vs. time and cumulative percentage of alumina hydrate particles circulating in the feed tanks in the circuit that are finer that X1 ?m, defined as CPFT X1 vs. time, is measured, where X1 and X2 are predetermined particles sizes and X1 is smaller than X2. A relationship R between CPFT X1 and later changes in CPFT X2, is determined and upper and lower trigger thresholds of CPFT X1 which correspond to maximum permissible variation in CPFT X2 are defined. In the control step, CPFT X1 and CPFT X2 are regularly measured, and R and the correlation between CPFT X2 and the particle size of hydrate produced are updated.

Abstract: The invention relates to a simplified production process with which it is possible to obtain carbon blocks, in particular anodes intended for aluminium production using the Hall-Héroult electrolysis process, which have high thermal shock resistance. This process comprises a grain size distribution adjustment operation of a carbon aggregate which includes: a) separating an initial ungraded carbon aggregate AC into a first fraction F1 made up of grains whose sizes are smaller than X, and into a second fraction F2 made up of grains whose sizes are X or greater, X lying between 0.2 and 2 mm; b) crushing B1 the first fraction F1 and part P1 of the second fraction F2 such as to obtain a powder F comprising a controlled proportion of ultra-fine grains; c) mixing the remaining part P2 of fraction F2 and said powder F in proportions with which it is possible to obtain crude carbon blocks whose so-called “Gr/S” ratio between the proportion PGr of grains larger than 0.