Abstract: Embodiments describing an approach to aligning multiple time series. Calculating an indicator function. Estimating a coefficient vector based on the indicator function. Updating the coefficient vector. Determining if a change in the coefficient vector is less than a predetermined value, and responsive to determining the change in the coefficient vector is less than the predetermined value, outputting a target time series for controlling aluminum smelting.

Abstract: A raw gas collection system for collecting raw gas from a plurality of aluminum smelting pots is equipped with a plurality of branch ducts (28d), each of which is arranged to channel a respective branch flow (38d) of raw gas from an aluminum smelting pot to a collection duct (26A), which is common to and shared by the branch ducts (28d). Each of said branch ducts (28d) is, near an outlet (52d) thereof, equipped with a curved section (50d) for aligning the branch flow (38d) with a flow direction of raw gas (27A) already present in the common collection duct (26A), and a constriction (54d) for accelerating the branch flow (38d) through the branch duct outlet (52d) into the common collection duct (26A). Furthermore, each of said branch ducts (28d) is equipped with a heat exchanger (40d) for removing heat from the respective branch flow (38d) of raw gas.

Abstract: According to one embodiment, a method of separating and recovering metals whereby a mixture containing at least a first metal and a second metal, the second metal having a higher standard electrode potential than that of the first metal, is connected to an anode in a molten salt, and the first metal and the second metal are precipitated on a cathode in the molten salt by electrolysis, the method of separating and recovering metals comprising: a detection step of detecting a concentration change in each of a first metal ion and a second metal ion in the molten salt by a concentration change detection unit; a first electrolysis step of electrolyzing the first metal; a first recovery step of recovering a precipitated substance according to a detection in which a concentration decrease of the first metal ion, which is predefined in the concentration change detection unit, is detected in the detection step; a second electrolysis step of electrolyzing the second metal; and a second recovery step of recovering a pre

Abstract: The subject invention concerns an electro-decomposition process wherein a cathode comprising a metal compound is contacted with a fused salt electrolyte in an electrochemical cell. The metal compound is a compound between a metal and another substance, and a voltage is applied between the cathode and an anode such that the substance is removed from the metal compound. In the improved method, the applied voltage increases with time, either continuously or stepwise, up to a predetermined maximum voltage. In addition, or in the alternative, the fused salt composition is selected so as to maintain a predetermined concentration of the substance in the fused salt during electro-decomposition.

Abstract: Systems and methods for stereoscopic imaging and viewing of aluminum electrolysis and related operation and/or maintenance activities are disclosed. The system may produce stereoscopic images based at least in part on images obtained from two or more imaging devices. The system may display the stereoscopic images for viewing to facilitate aluminum electrolysis cell operation and/or maintenance.

Abstract: A method for starting up an electrolytic cell (20) for aluminum production having a cathode block (26) with an upper surface (32), the method comprising: disposing contact resistance material (46) over the upper surface (32) of the cathode block (26); lowering a plurality of anodes (28) to abut the contact resistance material (46); filling the electrolytic cell (20) and covering the anodes (28) with solid electrolyte material (72) comprising crushed electrolytic bath material, cryolite, or mixtures thereof; delivering electrical current to the anodes (28) to at least partially melt the solid electrolyte material (72) and raising the anodes (28) when a predetermined depth of molten electrolyte material has been reached.

Abstract: A method of monitoring an electrolytic cell including detecting information indicative of a thermite reaction, comparing the information indicative of a thermite reaction to a threshold, generating a thermite response signal according to the comparison, and reacting to the thermite response signal by adjusting the operation of the electrolytic cell.

Abstract: System, method and apparatus for measuring electrolysis cell operating conditions and communicating the same are disclosed. The system includes a selectively positionable member coupled to an analytical apparatus, wherein the selectively positionable is configured to move the analytical apparatus into and out of physical communication with a bath. The system may also include a crust breaker for breaking the surface of a bath and an electronic device for measuring bath level.

Abstract: In the method and system, a number of electrolytic cells are arranged as a cell group, which cells are separated by a number of partition walls; in each cell, a number of anodes and cathodes are arranged in an alternating order, so that in each cell, next to each anode, there is arranged a cathode, and so that in each cell, each individual anode is fitted in the same anode line with the anode of the adjacent cell, and in each cell, each individual cathode is fitted in the same cathode line with the cathode of the adjacent cell, and each anode is galvanically connected to at least one cathode of the adjacent cell. The flowing direction of the current passing in the cell group is deviated in different directions in order to make the current flow mainly in the direction of the cell group.

Abstract: An apparatus for producing a fluorine gas, comprising at least one fluorine generating cell, and at least one fluorine generating cell detector for detecting components of products obtained by the fluorine generating cell, wherein at least one of the fluorine generating cells is connected with the fluorine generating cell detector.

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 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 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 present invention provides methods and apparatus for controlling catalytic processes, including catalyst regeneration and soot elimination. An alternating current is applied to a catalyst layer and a polarization impedance of the catalyst layer is monitored. The polarization impedance may be controlled by varying the asymmetrical alternating current. At least one of water, oxygen, steam and heat may be provided to the catalyst layer to enhance an oxidation reaction for soot elimination and/or to regenerate the catalyst.

Abstract: The present invention relates to a method for determining the extent of electrochemical extraction of a metal (M) from a metal (M) oxide caused by a voltage applied between a cathode comprising (or consisting essentially of) or in contact with the metal (M) oxide and an inert metal alloy anodein an oxygen-dissolving molten electrolyte.

Abstract: The invention relates to a method of producing aluminium in an electrolysis cell, which includes setting up a succession of control periods of duration T, identifying perturbative tending operations on the cell that can introduce superfluous alumina in the electrolytic bath, noting the performance of the perturbative tending operations, determining a regulation feed rate B(k?) for each control period k? and setting a specified feed rate SR(k?) equal to M(k?)×B(k?), where M(k?) is a predetermined modulation factor that modulates the regulation feed rate B(k?) so as to take into account a reduction of the needs of the cell induced by the superfluous alumina. The method of the invention makes it possible to significantly reduce the rate of occurrence of anode effects.

Abstract: A method of stabilizing an electrolysis cell with a boundary, a liquid metal layer and an electrolyte layer having specific operational and geometric parameters, and comprises the steps of determining amplitude and frequency values for a desired external, time-varying and/or alternating magnetic field through wave reflection analysis on a theoretical wall whose parameters are representative of the cell wall's parameters; and imposing on said cell an external, time-varying and/or alternating magnetic field having substantially the same amplitude and frequency values determined in the wave reflection analysis so that the resultant magnetic field imposed on the cell tends to parametrically and dynamically desynchronize the occurrence of resonance instability near the cell's walls.

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: An apparatus for controlling a molten salt electrolyzer in which an electrolytic bath in a solid form as contained in the electrolyzer is melted to automatically attain a state allowing electrolysis, which apparatus comprises detecting means for detecting the changes in state of the electrolyzer by means of detectors fitted to the electrolyzer, and adjusting means for adjusting, after using the detecting means, the liquid electrolytic bath levels to a state allowing electrolysis.

Abstract: The invention provides a method and apparatus for current control in gas generators capable of generating a fluorine or fluoride gas by and in which the electrolysis can be maintained in an optimum condition, stable operation is possible and no manpower is demanded. According to the method of current control in gas generators for generating a fluorine or fluoride gas by electrolysis of an electrolytic bath 5 comprising a hydrogen fluoride-containing mixed molten salt using a carbon electrode as the anode 4a, the range of voltage fluctuation between the cathode 4b and anode 4a as occurring when a certain current is applied to the gas generator is measured, and current application is continued while varying the current amount to be applied according to the voltage fluctuation range.

Abstract: The invention relates to a regulation method for an electrolytic cell for the production of aluminium by means of reduction of alumina dissolved in a molten cryolite bath, wherein a solidified bath ridge is formed on the internal walls of the pot, a quantity B, referred to as the “ridge variation indicator”, which is sensitive to the variation of said solidified bath ridge, is determined and at least one of the setting means of the pot (such as the anode-metal distance) and/or at least one control operation (such as the addition of AlF3) is modified as a function of the value obtained for said indicator. The indicator may be determined from electrical measurements on the pot and/or from measurements of the liquid metal surface area. The method according to the invention makes it possible to regulate an electrolytic cell effectively at currents of up to 500 kA with an electrolyte bath with an AlF3 content greater than 11% and reduce the number of AlF3 content measurements in the bath considerably.

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 relates to a regulation method for an electrolytic cell for the production of aluminium by means of reduction of alumina dissolved in a molten cryolite bath and comprises the addition, in the electrolyte bath, during pre-determined time intervals p referred to as “periods”, of a determined quantity Q(p) of aluminium trifluoride (AlF3) determined by the following equation: Q(p)=Qint(p)?Qc1(p)+Qt(p), where Qint(p) is an integral (or “self-adaptive”) term which represents the total actual AlF3 requirements of the cell and which is calculated from a mean Qm(p) of the actual AlF3 supplies made during the last N periods, Qc1 is a compensating term corresponding to the so-called “equivalent” quantity of AlF3 contained in the alumina added to the cell during the period p, and Qt(p) is a corrective term which is a typically increasing function of the difference between the measured bath temperature T(p) and the set-point temperature To.

Abstract: The invention relates to a method for the improvement of current efficiency in electrolysis. According to the method, a theoretical cell voltage is first calculated, which is compared with the measured voltage. The cumulative difference between the theoretical and measured cell voltage is monitored constantly and when this difference is proportioned to the current efficiency, information on the status of the process can be obtained continually. A decrease in current efficiency is a clear indicator of short circuits between the electrodes, and by means of the method according to the invention, it is possible to concentrate the short circuit removal work onto the correct cell groups, from the point of view of the current efficiency of the electrolysis.

Abstract: Operations in a cell for electrolytic production of aluminum are controlled by establishing a standard rate of addition of aluminum fluoride to a molten electrolyte covered by a crust; establishing a target temperature for a duct carrying offgas from a chamber containing the molten electrolyte; measuring an actual temperature in the duct; and, in response to the actual temperature measurement in the duct, performing at least one of (1) when the actual temperature is greater than the target temperature, inspecting the crust for a crust hole and then repairing any observed crust hole, and (2) varying an actual rate of addition of aluminum fluoride to the electrolyte by increasing the actual rate above the standard rate when the actual temperature is greater than the target temperature and by reducing the actual rate below the standard rate when the actual temperature is less than the target temperature. Controlling operations in accordance with the invention improves cell energy efficiency.

Abstract: The invention relates to a regulation method for an electrolytic cell for the production of aluminium by means of reduction of alumina dissolved in a molten cryolite bath and comprises the addition, in the electrolyte bath, during pre-determined time intervals p referred to as “periods”, of a determined quantity Q(p) of aluminium trifluoride (AlF3) determined by the following equation: Q(p)=Qint(p)−Qc1(p)+Qt(p), where Qint(p) is an integral (or “self-adaptive”) term which represents the total actual AlF3 requirements of the cell and which is calculated from a mean Qm(p) of the actual AlF3 supplies made during the last N periods, Qc1 is a compensating term corresponding to the so-called “equivalent” quantity of AlF3 contained in the alumina added to the cell during the period p, and Qt(p) is a corrective term which is a typically increasing function of the difference between the measured bath temperature T(p) and the set-point temperature To.

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 measuring method is provided for monitoring of aluminum electrolysis cells, together with a corresponding measurement arrangement that includes an immersion sensor. In order to obtain reproducible measurements, the bath electrode of the immersion sensor is arranged on a carrier.

Abstract: A method and a device for controlling the movement of a combined alumina feeding and crust breaking chisel in an aluminum production cell, wherein the chisel is moved downwards and upwards by means of a pneumatic cylinder which is alternatively fed with pressurized air, wherein electrical contact between the chisel and the melt is detected when the chisel reaches the melt, wherein it is monitored whether said electrical contact has been reached within a predetermined time interval, and if not, air at a second, high, pressure is fed to said first, and wherein air at high pressure is fed to the second side of the cylinder after said electrical contact has been established so as to quickly withdraw the chisel from the hot melt in order to minimize heat transfer from the melt to the cylinder.

Abstract: The present invention provides a method of detecting a short incident in an electrochemical cell (e.g., a Simons electrochemical fluorination cell or bipolar flow cell) using means for detecting vibration to detect vibration of an external piece on the cell. The present invention further provides a system for detecting a short incident in an electrochemical cell.

Abstract: An amperometric in situ apparatus and technique for measuring the concentrations and transport properties of easily dissociable oxides in slags is described. The technique consists of a combination of different measurements utilizing an electrolyte to separate a reference-gas compartment from the slag of interest. A method and apparatus for metals extraction is also described which includes a vessel for holding a molten electrolyte, the electrolyte comprising a mobile metallic species and an anionic species having a diffusivity greater than about 10−5 cm2/sec; a cathode and an anode, the cathode in electrical contact with the molten metal electrolyte, the cathode and molten electrolyte separated from the anode by an ionic membrane capable of transporting the anionic species of the electrolyte into the membrane; and a power source for generating a potential between the cathode and the anode.

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: The present invention provides a method and apparatus for determining the current densities in an alumina reduction cell by the measuring of magnetic fields without contact with the anodes or cathodes. The current density is modelled by determining the currents in the anodes and/or cathodes by measuring the magnetic field produced by the anodes or cathodes, or the conductors feeding them, and electronically correcting for ambient effects. The apparatus consists of Hall Effect devices to measure the magnetic field and electronics to correct, display, log and analyze the data.

Abstract: A method is described for controlling the supply of aluminium oxide to electrolysis cells for the production of aluminium in which the control is based on measurement of the electrical resistance between the electrodes of the electrolytic furnace and in which the value of this resistance is registered at fixed intervals of time. On the basis of the resistance values registered, at a given time an angle can be calculated between two lines, where one line is formed on the basis of values registered after said time and the other line is formed on the basis of values registered before said time. A curve can be generated on the basis of the angle. By comparison with periods of underfeeding and overfeeding, it is possible to obtain information on the oxide concentration in the electrolysis bath of the cell.

Abstract: This invention provides apparatus and a method for measuring the concentration of alumina in a molten electrolyte in a smelter. A test anode (101) (a mimic of the actual cell anode) supplied from a computer-controlled voltage source (303) with several to about (100) rapid cyclic voltammetry sweeps the voltage at which the anode effect occurs, as sensed by current measurement (305). In order to derive a measurement the voltage is compared within the computer (301) to previous measurements made from a calibration set of alumina samples in known concentrations. Brief rapid cycles and an improved electrode configuration help to provide results from the invention which are reproducible and accurate, and in addition the test electrode has a long life.

Abstract: An amperometric in situ apparatus and technique for measuring the concentrations and transport properties of easily dissociable oxides in slags is described. The technique consists of a combination of different measurements utilizing an electrolyte to separate a reference-gas compartment from the slag of interest. A potentiometric measurement (type I) provides information on the thermodynamic properties of the slag; an amperometric measurement (type II) yields information concerning the type and transport properties of dissociable oxides; an electrolysis measurement (type III) determines the concentration of dissociable oxides. A method and apparatus for metals extraction is also described which includes a vessel for holding a molten electrolyte, the electrolyte comprising a mobile metallic species and an anionic species having a diffusivity greater than about 10.sup.-5 cm.sup.

Abstract: A clutch mechanism, particularly for automatically operated automotive transmissions, for engaging shift ranges of continuously variable transmissions or step-by-step variable transmissions, and having at least two independently axially movable clutch rings with clutch profiles which cooperate with respective corresponding mating clutch rings clutch profiles, a clutch carrier mounted on a transmission element for rotation therewith in a fixed axial position, and having fluid actuated pressure pistons for shifting the movable clutch rings toward the mating rings. The clutch system can be disengaged under load and requires a small construction space. It can be produced at low cost and is almost free from drag losses. Clutch times and clutch travels are short. The shift pressures are very low. In addition, several clutches can be combined into a compact and relatively small clutch assembly.