Abstract: An apparatus for refining a process liquor that includes solids, which apparatus includes a vessel having a base and a side wall that define an internal volume for containing the process liquor and for allowing gravity settling of the solids in the liquor, whereby to produce a refined liquor toward a top of the internal volume and a slurry toward a bottom of the internal volume, the apparatus further includes solids displacement elements disposed within the internal volume for directing settled solids and/or settling solids in the vicinity of the side wall or of the base toward a flow path of the slurry being extracted from the slurry outlet. A processing plant including the above refining apparatus and a method for refining a process liquor.

Abstract: An electrolytic cell is suitable for production of aluminium, and includes at least one collector bar made of first metal and at least one complementary bar made of a second metal having an electrical conductivity greater than the first metal and arranged adjacent to one of the side faces of the collector bar so that the external end of the complementary bar is at a specified distance from a specified end face of the block. The second end terminates so as to limit heat losses from said cell. The cell makes it possible to obtain significantly lower voltage drops while avoiding excessive heat losses through the collector bars.

Abstract: The invention concerns a method for separating solid and liquor components of a process slurry comprising solid material entrained in a liquor, said method comprising: (a) a pre-treatment step of adding a flocculent to the process slurry and mixing the flocculent and the slurry by selecting a higher extent of mixing in an early stage of said step than in a later stage of said step, and (b) a solid/liquor separation step of allowing separation of solid material, including aggregates of solid material, and liquor of said process slurry to produce process outputs of a clarified liquor and solid material with some entrained liquor. The invention also concernes a method and an apparatus for adding a flocculent to a process slurry.

Abstract: The electrical connection device connecting the cells in series comprises: a first conductor (16) connected to the cathode assembly of cell (N?1) and to the anode frame of cell (N), having a portion (19) located between said pots (N?1) and (N) in which the current (I) flows in the direction of the alignment axis (x) of the pots; a second conductor (24) connected to the cathode assembly of cell (N) and to the anode frame of cell (N+1), having a portion (23) located between said pots (N?1) and (N) in which the current flows away from the axis. short-circuiting wedges (20, 21) housed between said portions (19, 23) of said conductors (16, 24); a third conductor (27) to balance the current flowing through the wedges.

Abstract: Extraction device designed to extract a short-circuiting wedge inserted between two conductors to take an electrolysis cell offline. The extraction device includes a means of gripping said wedge and, in conjunction with the upper horizontal face of each conductor, at least one jack directed vertically and including a body and a stem, stem (or said body) being interdependent with at least one horizontal support face directed downwards and laid out so that, when said extraction device is placed above said wedge to extract it, the upper horizontal face of each conductor is in line with one horizontal support face, b) said body (or said stem) being connected to said means of gripping said wedge, so that, when said jack is actuated to extract the wedge, said jack exerts opposing forces on said conductors and said wedge, tending to separate them.

Abstract: Extraction device designed to extract a short-circuiting wedge inserted between two conductors to take an electrolysis cell offline. The extraction device includes a means of gripping said wedge and at least one jack directed vertically and including a body and a piston stem. said body (or stern) being interdependent with at least one horizontal support face directed downwards and laid out so that, when said extraction device is placed above said wedge to extract it, the upper horizontal face of each conductor is in line with one horizontal support face, b) said stem (or said body) being connected to said means of gripping said wedge, so that, when said jack is actuated to extract the wedge, said jack exerts opposing forces on said conductors and said wedge, tending to separate them.

Abstract: A process for transporting a powder material, in which a device is fitted between a supply zone and a zone to be supplied, the device including at least one substantially horizontal conveyor which includes a lower duct and an upper duct being separated by a porous wall, the upper duct provided with a balancing column. The upper duct is filled with powder material and the lower duct is supplied with gas at a pressure that allows the potential fluidization of the powder material in the upper duct. The minimal bubbling speed, which corresponds to the maximum void fraction, is determined and the fluidization pressure is set to a value such that the fluidization speed of the gas is between 0.8 and 1.5 times the minimal bubbling speed, preferably between 0.9 and 1.3 times the minimal bubbling speed.

Abstract: A multi-layer cathode block (30) for an electrolytic cell (10) has at least a surface layer (32) with a surface expansion index and a second layer (34) with a second expansion index. The surface layer (32) includes a surface wetting agent in a first total amount. The second layer (34) includes a wetting agent in a second total amount. The surface layer (32) is directly superposed to the second layer (34). The second wetting agent in the second layer (34) includes metal boride precursors that react together to generate a metal boride component in situ when the cathode block (30) is exposed to start-up and operation conditions of the electrolytic cell (10). The second total amount is lower than the first total amount and is selected so as to minimize the difference between the expansion indexes of the surface layer (32) and the second layer (34).

Abstract: A metallic oxygen evolving anode for electrowinning aluminum by decomposition of alumina dissolved in a cryolite-based molten electrolyte, and operable at anode current densities of 1.1 to 1.3 A/cm2, comprises an alloy of nickel, iron, manganese, optionally copper, and silicon. Preferably, the alloy is composed of 64-66 w % Ni; Iron; 25-27 w % Fe; 7-9 w % Mn; 0-0.7 w % Cu; and 0.4-0.6 w % Si. The weight ratio Ni/Fe is in the range 2.1 to 2.89, preferably 2.3 to 2.6, the weight ratio Ni/(Ni+Cu) is greater than 0.98, the weight ratio Cu/Ni is less than 0.01, and the weight ratio Mn/Ni is from 0.09 to 0.15. The alloy surface can comprise nickel ferrite produced by pre-oxidation of the alloy. The alloy, optionally with a pre-oxidized surface, can be coated with an external coating comprising cobalt oxide CoO.

Abstract: An aluminium extrusion having a minimum section thickness and made from an aluminium alloy includes, in weight percent, between approximately 1.0 and 1.7 manganese, and between approximately 0.5 and 1.1 silicon, less than 0.3 iron with the balance being Al and inevitable impurities each less than 0.05 weight % and totaling less than 0.15 weight %, the extrusion being formed with an extrusion ratio less than 125 to retain a fibrous grain structure in which less than 40% of the minimum section thickness is recrystallized.

Abstract: The invention relates to a device (50) and a method for short-circuiting a specified electrolysis in a row of electrolysis cells intended for the production of aluminum. This device includes a bridging member (60) including at least two opposite contact arms and at least one bridging conductor electrically that electrically connects the contact arms. The contact arms are shaped like a wedge. The device further includes a clasping member (70) including a frame and a least two opposite thrust members. The clasping member (70) is fit to embrace the bridging member (60) so that each thrust member bears on each contact arm and so that, upon moving the contact arms with respect to the clasping member, each thrust member urges the corresponding contact arm towards the conductors (201, 202) inserted between the contact arms, so as to create and secure a short-circuit. The invention makes it possible to short-circuit electrolysis cells with increased amperages.

Abstract: The subject of the invention is a cast part with high static mechanical strength, and high hot creep strength, made of aluminum alloy of chemical composition: Si: 0.02-0.50%, Fe: 0.02-0.30%, Cu: 3.5-4.9%, Mn: <0.70%, Mg: 0.05-0.20%, Zn <0.30%, Ni: <0.30%, V: 0.05-0.30%, Zr: 0.05-0.25%, Ti: 0.01-0.35%, other elements in total <0.15%; and 0.05% each, the remainder being aluminum. It more particularly relates to cylinder heads for supercharged diesel or gasoline internal combustion engines.

Abstract: The process involves pouring a smothering powder onto a spent anode placed on a support to cover it, with the aim of limiting fluorinated gas emission by the anode. The support may include a temporary tank, pre-filled with powder and provided with an opening for discharging the powder towards the anode on the support.

Abstract: Device for transporting powder comprising a conveyer, which includes a lower channel in which a gas circulates, and an upper channel, designed for the circulation of powder and said gas, said lower channel and said upper channel being separated by a porous wall that said gas can pass through, the lower channel being supplied with gas at a pressure allowing the potential fluidization of said powder in said upper channel, said upper channel being provided in its upper part with transverse walls placed so that they delimit with the upper wall of said upper channel at least one upper zone in which a gas bubble under pressure is formed as a result of putting said air chute under potential fluidization pressure. At the level of at least one bubble so formed, the wall of the upper channel includes a means of removal for fluidization gas provided with a means of creating pressure drop, which creates a substantially constant pressure drop.

Abstract: A population of extrusion billets has a specification such that every billet is of an alloy of composition (in wt. %): Fe<0.35; Si 0.20-0.6; Mn<0.10; Mg 0.25-0.9; Cu<0.015; Ti<0.10; Cr<0.10; Zn<0.03; balance Al of commercial purity. After ageing to T5 or T6 temper, extruded sections can be etched and anodised to give extruded matt anodised sections having improved properties.

Abstract: A spout (10) is removably mounted to a hopper (1) of an electrolytic cell by a coupling (28) allowing the spout (10) to rock relative to the spout when jarred. A handler (40) is provided for the mounting of the spout (10) onto the hopper (1) without an operator entering into the electrolytic cell.

Abstract: The subject of the invention is an anode block (13, 13a-13e) made of carbon for a pre-baked anode (4) for use in a metal electrolysis cell (1) comprising a higher face (24), a lower face (23), designed to be laid out opposite a higher face of a cathode (9), and four side faces (21,22,34), and including at least one first groove (31a-31e) leading onto at least one of the side faces, in which the first groove has a maximum length Lmax in a plane parallel to the lower face, and characterized in that the first groove does not lead onto said lower or higher faces, or leads onto said lower or higher faces over a length L0 less than half the maximum length Lmax.

Abstract: Control process for a furnace for baking carbon anodes comprising: longitudinal hollow partitions in each of which a flow of hot baking gas may circulate, hollow partitions together defining cells to receive the anodes to be baked, and a heating system rotating in relation to the hollow partitions comprising an upstream blowing ramp blowing air into the various partitions, a downstream suction ramp sucking gas from the various partitions and at least one heating ramp. This process comprises a natural pre-heating phase of the partitions and anodes which release combustible, volatile matter which burns inside the hollow partitions as a degassing in a natural pre-heating zone of the furnace downstream of the heating ramp. According to the invention, gas flows circulating in the hollow partitions are modified so as to control gas flows passing through a first natural pre-heating zone from gas flows leaving a second natural pre-heating zone to control the location of the degassing front.

Abstract: A process for shutting down an operating electrolytic cell for the production of aluminium is described. The process includes: lowering anodes until a lower portion of the anodes is immersed in an aluminium layer; allowing the aluminium layer and an electrolyte bath to cool down with the lower portion of the anodes immersed in the aluminium layer; determining if the electrolyte bath is solidified, and if the electrolyte bath is solidified, raising the anodes before solidification of the aluminium layer to create a space between the solidified electrolyte bath and the anodes and the aluminium layer.