Abstract: Pot tending machine for a series of electrolysis cells designed for the production of aluminum by igneous electrolysis including: a) an overhead traveling crane which can be relocated above said electrolysis cells, b) a tool carriage onto which is fixed a service module comprising tools; c) a tapping winch, interdependent of said overhead traveling crane, designed to grasp and position near cell a tapping assembly including a ladle, a tapping tube and a vacuum device; d) a freestanding device able to generate compressed air; characterized in that said compressed air generating device of includes a first compressor, able to provide a flow of compressed air at least equal to the minimum air flow necessary for operations other than tapping, and at least one second compressor mounted in such a way that, when operating simultaneously with said first compressor, the unit provides a flow of compressed air at least equal to the minimum output of air necessary during tapping.

Abstract: A handling device for hoods of an aluminum production cell by fused bath electrolysis, including a positioning device and a hood-gripping device. The positioning device includes a vertical guide device, a mobile support mounted on the guide device so that it can be moved in at least a vertical direction during use, an articulated arm, a first framework mounted on the articulated arm so that it can pivot about a first rotation axis A substantially horizontal during use, a motor to make the first framework pivot about the first rotation axis A, a second framework mounted on the first framework so that it can be moved along the first translation axis B that is substantially horizontal during use, and means of displacing the second framework along the first translation axis B. The hood-gripping system is fixed to the second framework and includes a set of gripping devices designed to grip a set of hoods at a number of fixing points.

Abstract: Electrode containers and associated methods are provided. In one embodiment, an electrode container includes sides and a top, and the top includes an opening adapted to receive a rod of an electrode. A plurality of flexible members are interconnected about the perimeter of the opening, wherein at least some of the plurality of flexible members overlap with one another. In one embodiment, a method includes removing an electrode from a metal electrolysis cell and placing the electrode into a container, where the placing step includes the steps of engaging at least one lever of a top flap of the container with a surface of the electrode and, concomitant to the engaging step, moving the top flap from a first position to a second position.

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.

Abstract: A process for removing in a single step the thimbles attached to the stubs of an anode leg, including the following steps: a) said anode stem leg is placed between a stop device and an attacking device, said stop device surrounding, at least partially, each stub of said anode stem leg and having a stop surface that stops the corresponding thimble from moving forward; b) movement of the attacking device in the direction of the stop device until said anode leg enters into contact with said stop device; c) continuation of the movement of said attack device so that each thimble, blocked by the associated stop surface, is detached from the corresponding stub; f) stop and withdraw of the attacking device; In this process, a stop device is used comprising at least two stop surfaces, separated from one another by an axial distance such that the thimbles blocked by a first stop surface are detached from the stubs before the other thimbles are blocked by the other stop surface.

Abstract: System and method for measuring alumina qualities and communicating the same are disclosed. In one example, a system includes an aluminum electrolysis cell, a feeder configured to supply a feed stock using a feed stream to the aluminum electrolysis cell, and a measurement device in communication with the feed stream, the measurement device adaptable to receive, release, and determine at least one attribute associated with the feed stock.

Abstract: The present invention relates to a method of improving the current efficiency (CE) in an electrolytic aluminum production cell with an electrolytic bath, at least one anode and at least one cathode, and passing current between said anode and said cathode through said bath and feeding an aluminum containing feedstock to the cell. The CE is improved in that the aluminum containing feedstock is prepared in a manner where it contains substantially no humidity or water before it is fed to the cell, where the electrolytic process is carried out at conditions with reduced amount of hydrogen present.

Abstract: A tending module (7) for a series of electrolytic cells (2) to be used for the production of aluminum by fused bath electrolysis including a frame (8) that can be fixed to a trolley (6) and a turret (9) fitted on the frame (8) so as to pivot about a vertical axis A, and equipped with a set of tools including a crust breaker (11), a bucket shovel (12), at least one first anode clamp (13) and a hopper (15) fitted with a retractable duct (16), and a balcony or a cab (18) having controls that will be used to maneuver the module and the tools, and a control station (19) from which an operator can actuate the controls.

Abstract: A process for changing an anode of a cell for the production of aluminum by fused bath electrolysis including a plurality of anodes. According to the invention, an anode handling tool is used including a positioning device, a gripping device and a sensor detecting the vertical position of the gripping device, and the position sensor is used to measure the vertical distances traveled by the gripping device with respect to a reference level N. At least one sound or electromagnetic waves beam is then produced in a determined reference line or plane and the passage of the anode in the beam is used to measure the distances. The vertical position of the replacement anode in the cell is determined starting from the values obtained for the traveled distances and the replacement anode is put into this position in the place initially occupied by the spent anode.

Abstract: A method of controlling an aluminum reduction cell including the following steps: maintaining alumina concentration within preset limits by alternating base, underfeed and overfeed modes; measuring cell voltage and potline amperage; calculating current normalized voltage value and a rate of changing thereof in time; comparing the calculated values of the normalized voltage with preset values thereof and correcting anode-cathode distance when passing from the base mode to the overfeed or underfeed modes; and measuring a number of alumina feed doses in the underfeed mode and overfeed mode over a time period sufficient for the alumina to dissolve.

Abstract: Process for early detection of an anode effect in an aluminum production cell based on molten salt electrolysis. The cell comprises at least one anode, at least one cathode and cathode connecting conductors and anode connecting conductors.

Abstract: The invention is relative to an electrolytic cell comprising electrodes spaced apart from the back-wall by means of ribs, wherein a portion of the contact surface between the electrodes and the ribs is free from constraints in order to permit the complete removal of the electrodes once they have to be replaced by removing only partially the original contact surface, so that positioning of the substitute electrodes is allowed on the residual portion. A method for substituting the electrodes of the cell which leaves the distance between the electrode surface and the back-wall unvaried is also disclosed.

Abstract: An apparatus and method for removing thimbles (12) from stubs (20) of an anode yoke which includes the step of advancing a ram (20) towards each stub with the force applied by the ram against the stub being limited to a preset maximum, and another step of advancing the rams at the same speed to push the stubs through the thimbles.

Abstract: An improved method is described for adding alumina to a Söderberg or pre-bake type electrolytic cell fed by schedule crust breaking. Instead of adding the full amount of alumina required following each crust breaking, as is traditional, the standard dose of alumina is now split into two smaller doses. Thus, a major proportion, e.g. about 50 to 90% by weight, of the theoretically required alumina to sustain the electrolysis between crust breakings is added following a crust breaking. The electrical resistance of the electrolyte is monitored between crust breakings, and if the resistance begins to rapidly increase indicating the approach of an anode effect, the anodes are activated into a pumping action thereby breaking the crust adjacent the anodes, allowing alumina to flow into the molten electrolyte, and also creating a stirring action within the molten electrolyte. This lowers the resistance such that any anode effect is avoided until the next full crust breaking.

Abstract: A cell of advanced design for the production of aluminium by the electrolysis of an aluminium compound dissolved in a molten electrolyte, has a cathode (30) of drained configuration, and at least one non-carbon anode (10) facing the cathode both covered by the electrolyte (54). The upper part of the cell contains a removable thermic insulating cover (60) placed just above the level of the electrolyte (54). Preferably, the cathode (30) comprises a cathode mass (32) supported by a cathode carrier (31) made of electrically conductive material which serves also for the uniform distribution of electric current to the cathode mass (32) from current feeders (42) which connect the cathode carrier (31) to the negative busbars.

Abstract: A method is provided for retrofitting conventional aluminum smelting cells with inert anode assemblies which replace the consumable carbon anodes of the cell. The inert anode assemblies are pre-heated prior to introduction into the operating cell. Insulation may be installed for reducing heat loss during operation of the retrofit cells.

Abstract: Conventional aluminum smelting cells are retrofitted with inert anode assemblies which replace the consumable carbon anodes of the cell. The inert anode assemblies may include multiple inert anodes, and may also include insulation for reducing heat loss during operation of the retrofit cells.

Abstract: A cell for the electrowinning of aluminium comprising one or more anodes (10), each having a metal-based anode substrate, for instance comprising a metal core (11) covered with an metal layer 12, an oxygen barrier layer (13), one or more intermediate layers (14; 14A, 14B) and an iron layer (15). The anode substrate is covered with an electrochemically active transition metal oxide layer, in particular an iron oxide-based outside layer (16) such as a hematite-based layer, which remains dimensionally stable during operation in a cell by maintaining in the electrolyte a sufficient concentration of iron species and dissolved alumina. The cell operating temperature is sufficiently low so species and dissolved alumina.

Abstract: The present invention provides a method of producing a highly pure aluminum primary base metal having a purity of at least 99.95 wt % (3N5), or a still higher purity close to the 4N that is a purity value of a secondary refined base metal. Alumina, the Si component of which is decreased by acid cleaning, is placed in a Hall-Heroult electrolysis cell as a main raw material. An aqueous solution of sulfuric acid, an aqueous solution of sulfuric acid plus hydrofluoric acid, or the like is used for acid cleaning. In order to remove Si, an acidic aqueous solution heated to at least 40° C. is preferred. Use of deashed coke and/or pitch as a carbon material for anode in addition to the use of acid-cleaned alumina produces a highly pure aluminum primary base metal in which the Si and Fe components are further decreased.

Abstract: A process for repairing a hole in the crust of an electrolytic cell. The hole is repaired by covering it with a receptacle containing solid particles. The receptacle comprises a polymeric material. More preferably, the receptacle comprises a cellulosic material, such as paper, polymer-impregnated paper, or cardboard. A closed paper bag having at least two paper layers and weighing about 15-20 lb. (6.8-9.1 kg) is particularly preferred. When the electrolytic cell produces aluminum by electrolysis of alumina, the solid particles comprise an aluminum compound such as alumina, aluminum fluoride, cryolite, or a mixture of such compounds. Two preferred forms of alumina include smelting grade alumina (SGA) and alumina dust collected by an electrostatic precipitator (ESP dust).

Abstract: A method of producing commercial purity aluminum in an electrolytic reduction cell comprising ceramic inert anodes is disclosed. The method produces aluminum having acceptable levels of Fe, Cu and Ni impurities. The ceramic inert anodes used in the process may comprise oxides containing Fe and Ni, as well as other oxides, metals and/or dopants.

Abstract: A non-carbon, metal-based high temperature resistant anode of a cell for the production of aluminum has a highly conductive metal-based substrate coated with one or more electrically conductive adherent intermediate protective layers and an outer layer which is electrically conductive and electrochemically active. The electrochemically active layer contains one or more electrocatalysts fostering the oxidation of oxygen ions as well as fostering the formation of biatomic molecular gaseous oxygen from the monoatomicnascent oxygen obtained by the oxidation of the oxygen ions present at the surface of the anode in order to inhibit ionic and/or monoatomic oxygen penetration. The intermediate layer(s) constitute(s) a substantially impermeable barrier to ionic, monoatomic and/or biatomic gaseous oxygen to prevent attack of the metal-based substrate. The electrocatalyst can be iridium, palladium, platinum, rhodium, ruthenium, silicon, tin, zinc, Mischmetal oxides and metals of the Lanthanide series.

Abstract: A cell of advanced design for production aluminum by the electrolysis of an aluminum compound dissolve in a molten ectrolyte, has a cathode (30) of drained configuration, and at least one non-carbon anode (10) facing the cathode both covered by the electrolyte (54). The upper part of the cell contains a removable thermic insulating cover (60) placed just above the level of the electrolyte (54). Preferably, the cathode (30) comprises a cathode mass (32) supported by a cathode carrier (31) made of electrically conductive material which serves also for the uniform distribution of electric current feeders (42) which connect the cathode carrier (31) to the negative busbars.

Abstract: The invention relates to a method of producing aluminum in an electrolytic cell, particularly in a drained cell, such cell comprising a cathode (20) and facing anodes (10), each anode (10) being spaced apart in its operative position from the cathode (20) by an anode-cathode reduced distance defining an anode-cathode gap containing the bath being electrolyzed. The method comprises: feeding alumina into the electrolyte where it is dissolved; electrolyzing an alumina-rich bath in the anode-cathode gap; and periodically moving at least one anode (10) in order to intake rich-alumina electrolyte into the anode-cathode gap thereby distributing alumina-rich electrolyte under the entire anode surface.

Abstract: An electrolytic cell (40) for the electrowinning of aluminium comprises a plurality of anodes (60) immersed in a molten electrolyte (50), each anode (60) having an oxygen-evolving active surface of open structure facing and spaced by an inter-electrode gap from a cathode (70); a thermal insulating cover (45) above the surface (51) of the molten electrolyte (50); and an alumina feed device (10) arranged above the molten electrolyte surface (51) for spraying and/or blowing alumina (55) to an area of the molten electrolyte surface (51), from where the alumina (55) dissolves as it enters the electrolyte (50) and alumina-rich electrolyte flows to the inter-electrode gaps where it is electrolysed to produce oxygen gas on the anodes (60) and aluminium on the cathode (70).

Abstract: This method of managing the operation of a plant for the production of aluminium by igneous electrolysis, of the type having a set (2, 3) of two electrolysis tankrooms, each having a series of tanks, the tankrooms being mutually parallel and symmetrical with respect to a central passageway (4) in which the handling of the liquid-aluminium tapping ladle is carried out, consists in carrying out the various handling operations at each of the tanks, necessary for the operation of the plant, in a closed loop, the members (13, 13′, 13″, 13′″, 14, 14′, 14″, 14′″) needed for the operation being moved over all the tanks of the two tankrooms of continuous cycles. The invention also relates to the plant for implementing this method.

Abstract: A method is provided for retrofitting conventional aluminum smelting cells with inert anode assemblies which replace the consumable carbon anodes of the cell. The inert anode assemblies are pre-heated prior to introduction into the operating cell. Insulation may be installed for reducing heat loss during operation of the retrofit cells.

Abstract: A process is provided for controlling the AlF3 content in cryolite melts for aluminum reduction, wherein the temperature of the melt is measured. In order to produce a very precise process which makes it possible to perform the aluminum reduction at the lowest posssible temperature, and thus as energy-saving as possible, the liquidus temperature of the cryolite melt is measured and compared with a first target value. AlF3 is added to the bath if the measured liquidus temperature is higher than the first target value. If the measured liquidus temperature is lower than the first target value, the measured liquidus temperature is compared with a second target value which is lower than the first target value. NaF or Na2CO3 is added to the bath if the measured liquidus temperature is lower than the second target value.

Abstract: A tool holder module intended to be used in lifting gear, characterized in that it is equipped with two independently motorized lifting member: a first member, which consists of a lifting system with cable(s) wrapped over electrically motorized drum(s) and returned at a sheaving system, the first member being intended to displace a load at a relatively high speed and over a relatively large distance; a second member, one of the constituent elements of which is secured to the end of the cable or cables of the first member after return at the sheaving system and is intended, in cooperation with this system, to displace a heavier load vertically at a lower speed and over a limited distance.

Abstract: An apparatus for breaking the anode butt (15) and stripping the thimbles (13) from the yoke stubs (12) of an anode. The apparatus includes a support frame (20), a fixed plate assembly (21) secured to the supporting frame (20) and a ram assembly (22) extendible towards the fixed plate assembly (21). The fixed plate assembly (21) comprises a substantially rigid fixed plate (23) having recesses (24a) to receive the yoke (11) and yoke stubs (12). The recesses (24a) are shaped such that the thimbles (13) on the yoke stubs (12) of the anode butt (15) abut against the fixed plate assembly (21) during the extension of the ram assembly (22) to contact and break the anode butt. The fixed plate assembly (21) may be provided with a stub locating mechanism which locates the stubs in position and abuts against the thimbles (13) on the stubs (12) during the extension of the ram assembly (22). The stub locating mechanism also abuts against and is supported by the substantially rigid fixed plate (23).

Abstract: In an electrolysis cell wherein powdered material are added to a bath of molten electrolyte, the anode is provided with a duct through which the powdered material may be fed to the electrolyte. Simultaneously, a gas which is preferably inert, is also fed together with the powdered material through the duct, and both are injected beneath the surface of the electrolyte.

Abstract: A cell for the electrowinning of aluminium by the electrolysis of alumina dissolved in a molten fluoride-based electrolyte comprises a cathode composed of a carbon body having an aluminium resistant aluminium-wettable surface layer containing particulate titanium or other refractory hard metal boride and a bonding material providing a porous layer which contains cathodic molten aluminium. Molten cathodic aluminium external to the aluminium-resistant and aluminium-wettable surface contains refractory hard metal and boron in a total concentration sufficient or just below that sufficient to inhibit dissolution into the molten aluminium of the refractory hard metal boride. Alumina is fed to the cell whereby the required amount of titanium in the aluminium results from the alumina feed while, when boron is not present in a sufficient amount, boron is added to bring the total titanium and boron content to or just below the equilibrium solubility product.