Abstract: A removable electrode module for engagement with an electrolysis chamber comprises a first electrode, a second electrode, and a suspension structure. The suspension structure comprises a suspension rod coupled to the first electrode. The second electrode is suspended or supported by the suspension structure, which comprises at least one electrically-insulating spacer element for retaining the second electrode in spatial separation from the first electrode.

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: The method of process control is for a Hall-Héroult process of aluminum production from alumina ore in an industrial potline. The method includes measuring an array of sampled potline data including a plurality of cell voltages (V) and a plurality of line amperages (A) at a plurality of time points. The method also includes calculating a predicted voltage (PV) for each cell voltage and line amperage in the array. The method further includes controlling a plurality of alumina ore feed rates and a plurality of pot voltage settings based upon the predicted voltages. The method also includes calculating a plurality of bath temperatures based upon the predicted voltages. The PV variable is preferably used in an automated control environment. The PV variable is also preferably used to monitor cell noise levels, operating temperature, metal pad roll, and oscillatory electrical shorting events.

Abstract: A cell for the electrowinning of aluminium comprises an electrolysis chamber (20) in which alumina is electrolysed to produce aluminium (30) and a collection reservoir (40,40?) in which product aluminium is collected. The electrolysis chamber and the collection reservoir are in liquid communication so that aluminium produced in the electrolysis chamber can flow from the electrolysis chamber into the collection reservoir. The electrolysis chamber contains one or more metal-based anodes (15). Each anode has an active anodic surface (16) spaced above a facing cathodic surface (31) on which aluminium is produced. The cathodic surface is formed on a structural body (12) by a layer made of molten aluminium into which product aluminium is incorporated during operation. The anodic surface and the cathodic surface have a substantially constant operative position.

Abstract: A method for producing hydrogen by using different metals includes: providing a metal of lower reduction potential as an anode metal and a metal of higher reduction potential as a cathode metal, then immerse the anode metal and the cathode metal in an electrolyte, while the anode metal and the cathode metal can be combined with appropriate steps before or after being immersed in the electrolyte, whereby hydrogen and side-products generated from a reaction of electrochemistry caused by reduction potential difference between the different metals, that is, the method for producing hydrogen is through spontaneous chemical reaction without extra energy consumption.

Abstract: A method for electrolytic production of aluminium metal from an electrolytic (3) including aluminium oxide, by performing electrolysis, with at least one inert anode (1) and at least one cathode (2) thus forming part of an electorwinning cell. The anode evolves oxygen gas and the cathode has aluminium discharged onto it in the electrolysis process, where the oxygen gas enforces an electrolyte flow pattern. The oxygen gas is directed to flow into anode grooves and is drained away from the interpolar room, thereby establishing an electrolyte flow pattern between the electrodes (1) and (2) and between over the anodes (1). The invention also concerns and anode assembly and an electrowinning cell.

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: Object of the invention is an anodic structure for mercury cathode cells for the industrial electrolysis of sodium chloride. The new structure is constituted by a grid array comprising a multiplicity of vertically disposed and mutually parallel titanium blades, covered by an electrocatalytic coating specific for the discharge of chlorine. The ratio between the thickness and the height of the blades is comprised between 1:16 and 1:100 and the ratio between the surface of free passage between the blades and the projected surface is comprised between 15:17 and 25:30. The new grid array is perpendicularly fixed to new or existing frames having the function of mechanical support and current conduction to the grid array. Scope of the invention is simultaneously reducing the energetic consumption of the cell and the costs for restoring the exhausted electrocatalytic coating.

Abstract: A method of producing aluminum in an electrolytic cell containing alumina dissolved in an electrolyte, the method comprising the steps of providing a molten salt electrolyte at a temperature of less than 900° C. having alumina dissolved therein in an electrolytic cell having a liner for containing the electrolyte, the liner having a bottom and walls extending upwardly from said bottom. A plurality of non-consumable Cu—Ni—Fe anodes and cathodes are disposed in a vertical direction in the electrolyte, the cathodes having a plate configuration and the anodes having a flat configuration to compliment the cathodes. The anodes contain apertures therethrough to permit flow of electrolyte through the apertures to provide alumina-enriched electrolyte between the anodes and the cathodes. Electrical current is passed through the anodes and through the electrolyte to the cathodes, depositing aluminum at the cathodes and producing gas at the anodes.

Abstract: A method of producing aluminum in an electrolytic cell containing alumina dissolved in an electrolyte, the method comprising the steps of providing a molten salt electrolyte at a temperature of less than 900° C. having alumina dissolved therein in an electrolytic cell having a liner for containing the electrolyte, the liner having a bottom and walls extending upwardly from said bottom. A plurality of non-consumable anodes and cathodes are disposed in a vertical direction in the electrolyte, the cathodes having a plate configuration and the anodes having a flat configuration to compliment the cathodes. The anodes contain apertures therethrough to permit flow of electrolyte through the apertures to provide alumina-enriched electrolyte between the anodes and the cathodes. Electrical current is passed through the anodes and through the electrolyte to the cathodes, depositing aluminum at the cathodes and producing gas at the anodes.

Abstract: A cell for the electrowinning of aluminium comprises at least one non-carbon metal-based anode (10) having an electrically conductive metallic structure (12, 13, 15) which is suspended substantially parallel to a facing cathode (20, 21, 22). Such metallic structure (12, 13, 15) comprises a series of parallel horizontal anode members (15), each having an electrochemically active surface (16) on which during electrolysis oxygen is anodically evolved. The electrochemically active surfaces (16) are in a generally coplanar arrangement to form the active anode surface. The anode members are spaced apart from one another by inter-member gaps forming flow-through openings (17) for the circulation of electrolyte (30) driven by the escape of anodically-evolved oxygen. The electrolyte (30) may circulate upwardly and/or downwardly in the flow-through openings (17) and possibly around the anode structure (12, 13, 15).

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: 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 device for adjusting the distance between the anode and the cathode of an electrolytic cell having a compartment, at least one anode partially disposed in a molten metal producing salt bath and a layer of molten metal above a cathode. The device includes a displacement device partially disposed within the layer of molten metal, and an actuator to move the displacement device generally vertically.

Abstract: A dimensionally stable electrode is provided comprising a hollow substrate with an open upper end for confining a fluid containing a metal, a film covering portions of the external surface; and a mechanism for replenishing the film. Also provided is a method for maintaining the dimensions of an anode during electrolysis comprising adapting an interior surface of the anode to receive a fluid containing a metal, facilitating transport of the metal to an exterior surface of the anode, forming a protective film on the exterior surface, wherein the transported metal is a cation of the formed protective film, and maintaining the protective film on the exterior surface while the anode is in use.

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: A card reader (for example, a swipe card reader for reading bank or security cards) is disclosed which comprises a detector for detecting surface features of the card such as embossed characters. In this way, a security check for false cards is implemented.