Abstract: Apparatus for displaying, measuring the size of and counting individual inclusions in suspension in moving liquid metal using an ultrasound sensor including emission device for emitting ultrasound beam pulses and at least one reception device for detecting reflected ultrasound beam pulses. The apparatus also includes an echo acquisition and processing device for reflected ultrasound beams received by the at least one reception means, a display device for displaying echos as images of inclusions, an image analysis device to count and measure inclusions based on the displayed images, and at least one control reflector having predetermined dimensions and geometry stable over time and which can be selectively placed in path defined by the ultrasound beam pulses. The control reflector enables calibration of the apparatus.

Abstract: A process for continuous nickel plating of an aluminum conductor, by electrolytically pre-treating the aluminum conductor to improve adherence of a nickel coat thereon by passing the aluminum conductor through a pre-treating bath in which is disposed an electrode connected to a first current source at a first voltage, for supplying to the aluminum conductor a pre-treating current, then electrolytically plating the pre-treated aluminum conductor with nickel in a plating bath in which is disposed an anode connected to a second current source at a second voltage, in which a nickel coat is deposited on the conductor by action of a nickel plating current In. At least the nickel plating current In is transmitted to the conductor through a mechanical electrical contact which contacts the conductor between the pre-treating bath and the plating bath, the pre-treating improving the contact properties of the conductor sufficient to permit the transmitting through the mechanical electrical conductor.

Abstract: Process and apparatus for displaying, measuring the size of and counting individual inclusions in suspension in moving liquid metal using an ultrasound sensor including emission and reception devices. Using the emission device, a series of ultrasound beam pulses is emitted within the liquid metal, and echoes reflected by the inclusions are received using the reception device. The reflected echoes are successively acquired and processed, and displayed as images which are analyzed to count and measure the diameter of inclusions. The sensor is calibrated by selectively placing in a path defined by the beam pulses at least one control reflector having predetermined dimensions and a geometry stable over time, successively acquiring and processing reflected echoes from the control reflector, displaying the reflected echoes from the control reflector as images, and analyzing the control reflector echo images to determine a relationship between amplitude of the images and the control reflector dimensions.

Abstract: The invention relates to a method for producing metal shapes with a partially or totally polygonal cross-section by means of continuous casting in a double-flanged wheel and continuous rolling using a series of at least 3 pairs of rollers with a peripheral flange, whereby said rollers are alternately horizontally and vertically disposed in a symmetrical position with respect to said shape.

Abstract: An arrangement of electrolysis pots suitable for use for the production of aluminum by igneous electrolysis according to the Hall-Héroult process with an electrolysis current with intensity Io is disclosed. The arrangement comprises juxtaposed zones including an inner lateral zone. a central zone, and an outer lateral zone. The arrangement can be used, for example, in an electrolysis plant.

Abstract: A superconducting conductor and method for its production. The conductor is formed of least one superconducting core and an aluminum based cryogenic stabilizer which is a high purity Al—Fe—Ni aluminum alloy having a composition, in % by weight: 200 ppm≦Fe+Ni≦1500 ppm; 0.20≦Fe/(Fe+Ni)≦0.65; optionally, B<100 ppm; impurities other than Fe, Ni and B<0.01% total; and remainder aluminum.

Abstract: The object of the invention is an arrangement of an electrolysis plant for the production of aluminium using the Hall-Heroult process, with which it is possible to limit the pathway length of heavy flows, such as flows of liquid aluminium. According to the invention, the plant comprises: at least one liquid aluminium production zone (H) comprising electrolysis pots arranged in lines, specific operational support zones, including a zone (C) grouping together the supply and recycling installations for anode assemblies, a zone (B) grouping together the supply and recycling installations for electrolysis baths, and a zone (A) grouping together the liquid aluminium processing installations, transport means to convey so-called heavy intermediate products (such as liquid aluminium) between said operational zones, at least one transit zone (101, 102, 103, 104, 105, 106, 110, 111, 112, 113) reserved for all or part of said transport means for the heavy intermediate products.

Abstract: An aluminum bloom more than 99.95% pure is obtained by segregation of aluminum from an impure parent liquor. Heat supplied to the parent liquor during growth of the bloom is adjusted as a function of the height of the bloom.

Abstract: Process for conveyance of a powder material in a hyperdense bed to bypass an obstacle, in which an obstacle bypass device including at least upstream, intermediate and downstream caissons is inserted between two horizontal conveyors, an upstream conveyor, and the downstream conveyor. At a device entry, at the upstream caisson lower duct is supplied with gas at pressure P1, the upstream caisson further including an upper duct which is a column. The intermediate caisson is between the upstream caisson and the downstream caisson at a level that bypasses the obstacle, a lower duct of which is fed with gas at pressure P3 and an upper duct of which is connected to the upper duct of the upstream caisson and to an upper duct of the downstream caisson. At a device outlet, at the downstream caisson, a lower duct is supplied with gas at pressure P2. The three caissons remain full of powder material kept in a potential fluidization state at all times, with a pressure difference P1−P2 being kept strictly positive.

Abstract: An improvement in the Bayer process for producing alumina trihydrate in which bauxite ore is digested in a mixture with a digestion sodium aluminate liquor to produce a slurry, the slurry is settled to remove undigested residues therefrom and produce a pregnant liquor of sodium aluminate and alumina trihydrate is precipitated from the pregnant liquor in the presence of alumina trihydrate recycled as seed. When beginning the precipitation, an aliquot of the pregnant liquor with recycled alumina trihydrate is removed, subjected to mechanical action of an intensity and for a time sufficient to cause formation of seeds, and returned with the formed seeds to the beginning of the precipitation.

Abstract: Process for conveyance of a powder material (12) in a potential fluidization hyperdense bed using a device comprising at least one air pipe (3) comprising a lower duct (5) for circulation of a fluidization gas (G), an upper duct (7) for circulation of the powder material (12), the two ducts being separated by a porous wall (6), at least one pipe (8) supplying gas (G) and a balancing column (4, 4.2) in which the filling height (h) balances the potential fluidization pressure (pf), characterized in that a bubble (B1, B2) of pressurized gas is created in the upper duct (7) in the air pipe (3). This bubble is reliably located in the upper part (14) of the upper duct (7) of the said air pipe (3). Device to implement this process and to regulate the pressure of the gas bubble.

Abstract: An aluminum bloom more than 99.95% pure is obtained by segregation of aluminum from an impure parent liquor. Heat supplied to the parent liquor during growth of the bloom is adjusted as a function of the height of the bloom.

Abstract: A process for regulating a furnace which includes a sequence of sections, cooling sections, baking sections, and preheating sections, in which the preheating sections at the tail are fitted with exhaust pipes for combustion gases, and in the transverse direction with a series of flue walls and pits in which blocks containing carbon to be baked are stacked, in which gas streams circulate through the flue walls. The mass flow in each of the streams of combustion exhaust gases is regulated by measuring this flow and the temperature in order to obtain a predetermined set value of energy flux.

Abstract: An inert vessel for treating an oxidizable liquid metal includes a vessel body and a lid mounted thereon with bearing surfaces at a junction therebetween, the body and lid each including a metal wall having an inner face coated with a refractory lining. The vessel further includes movable auxiliary equipment passing through the lid, and optionally the body, with the vessel body including inlet and outlet means for the liquid metal and external atmosphere. An inflatable seal is disposed between the lid and the vessel body housed in a peripheral receptacle, the peripheral receptacle including at least one wall which is an extension of the lid, and at least one other wall which is an extension of the vessel body, the seal when inflated directly contacting the wall which is the extension of the lid and the wall which is the extension of the vessel body, and being directly adjacent the vessel body adjacent the junction.

Abstract: A process for treating an alumina monohydrate-based bauxite by high temperature caustic digestion includes the steps of introducing alumina trihydrate into the digested slurry at a temperature of less than 200° C., in order to obtain an aluminate liquor at atmospheric pressure having an alumina/caustic weight ratio between 1.20 and 1.30, and diluting the resultant aluminate liquor to result in a caustic concentration between 160 and 175 g Na2O/liter. After settling and filtration, the resulting supersaturated liquor undergoes a further dilution before or during a crystallization step. The alumina trihydrate product is filtered from the spent liquor, which is concentrated and recycled.

Abstract: An electrolytic pot for the production of aluminum by the Hall-Héroult electrolysis process includes a cooling device for blowing air with localized jets, advantageously with variable flow, in order to evacuate and dissipate thermal energy from the pot. An aluminum production plant using the Hall-Héroult electrolysis process has at least some pots which, either individually or in common, include at least one cooling device.

Abstract: A method for measuring temperature and electrolyte level of a molten electrolysis bath in a cell for production of aluminum by electrolysis of alumina includes the steps of: (a) piercing the crust of a solidified bath with a crust breaker and immersing into the electrolyte, an extremity of a temperature probe to a sufficient depth until an initial temperature reading of at least 850.degree. C.

Abstract: A rotary gas dispersion device for use in a liquid aluminium treatment vessel is disclosed. The device is useful for reducing surface disturbance, splashing and vortices while maintaining the effectiveness of the treatment. Said device includes a rotor (1) consisting of a set of blades (5) and a substantially flat disc (4) thereabove. Gas is injected through the central hub and side ports (10) between the blades. The ratio of the outer diameter of the rotor to the diameter of the central hub thereof is of 1.5-4.

Abstract: A process for control of the alumina content of the bath in a cell for production of aluminum by electrolysis of alumina dissolved in a molten cryolite-base salt, consisting of alternation of phases of alumina underfeeding and phases of alumina overfeeding compared with a theoretical mean rate of alumina consumption of the cell, the said alternation being a function of values, calculated at the end of each control cycle i of duration T, of the mean resistance R(i) measured at the cell electrode terminals, of the rate of change of this resistance or resistance slope P(i), of the rate of change of the resistance slope or curvature C(i) and of the extrapolated slope PX(i)=P(i)+C(i).times.T, these values being compared respectively with reference values Po, Co and PXo in order to modulate, according to an appropriate control algorithm, the alumina content of the bath in a very narrow concentration range between 1.5 and 3.5%.

Abstract: The furnace for baking carbonaceous blocks comprises, along the longitudinal X direction of the furnace, a series of sections, each section comprising, in the transverse Y direction, hollow walls (3) through which a heating gas flow comprising combustion gas or a cooling air flow circulates, alternating with pits containing carbonaceous blocks to be baked, each of the said hollow walls (3) in a section being in communication with a wall in an upstream section and/or a wall in a downstream section, so as to form a conduit through which the said gas flow circulates, each of the said walls of a section comprising two vertical lateral partitions (38) in the X-Z plane, and elements in the transverse Y direction for deflecting the said gas flow passing through the said wall and maintaining a constant spacing between the said lateral partitions (38), and characterized in that each wall (3) comprises a means of maintaining, over at least one third of the length L of said wall, a gas flow of rate D uniformly distribut