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: The invention provides method and system for cooling over a large area, suitable for use for control of layer formation over an extended area in an aluminium electrolysis cell and exploitation of heat. The objective is achieved by a manifold from which a plurality of hot end heat tubes extend, representing the hot end or ends, wherein the cold end or condenser can be provided inside the manifold or can extend outside the manifold.

Abstract: A measuring device is provided having a protective cover and a sensor arranged in the protective cover. The protective cover has a carrier tube made of metal and closed on one end. A first coating made of an aluminum non-wettable material is arranged on an outer surface of the carrier tube, and a further coating made of aluminum-wettable material is applied on the first coating.

Abstract: A cell for the electrowinning of aluminium has a cavity for containing electrolyte (20) and one or more non emerging active anode bodies (5) that are suspended in the electrolyte. The electrolyte's surface (21,21?) has an expanse extending over the cavity and is substantially covered by a self-formed crust (25) of frozen electrolyte. The crust is mechanically reinforced by at least one preformed refractory body (30, 30?,30?). The electrolyte crust is formed against the preformed refractory body and bonded thereto so as to inhibit mechanical failure of the crust and collapse of the crust into the cavity.

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: Disclosed is a method for the continuous production of aluminum from alumina including a first step of converting alumina (Al2O3) into aluminum sulfide (Al2S3) and a second step of separation of aluminum from aluminum sulfide in a separating reactor. Wherein in the first step in a conversion reactor alumina is dissolved in a molten salt to form a melt and a sulfur containing gas is fed through the melt whereby the sulfur containing gas acts as a reagent to convert at least part of the alumina into aluminum sulfide and at least part of the melt is used in the second step. Further the invention relates to an apparatus for operating the method.

Abstract: Operations in an electrolytic cell for producing aluminum are controlled by sensing infrared radiation on an outer surface of a cell chamber to determine an actual temperature. When the actual temperature is greater than a target temperature, a crust hole is repaired or the actual rate of addition of aluminum fluoride to the cell is increased. When the actual temperature is less than a target temperature, the actual rate of addition of aluminum fluoride to the cell is reduced.

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: 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: 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: An electrolytic cell for producing aluminum from alumina having a reservoir for collecting molten aluminum remote from the electrolysis.

Abstract: The present invention relates to an electrolytic cell for the production of aluminum comprising an anode and an electrolytic tank where the electrolytic tank comprises an outer shell made from steel and carbon blocks in the bottom of the tank forming the cathode of the electrolytic cells. At least a part of the sidewall of the electrolytic tank consists of one or more evaporation cooled panels, and wherein high temperature, heat resistant and heat insulating material is arranged between the evaporation cooled panels and the steel shell. The invention also includes a method for maintaining a crust on the sidewall of the tank and for recovering heat from the cooling medium inside the panel for transformation into electrical energy.

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 iron oxide-based outside layer (16), in particular a hematite-based layer, which remains dimensionally stable during operation in a cell by maintaining in the electrolyte a sufficient concentration of iron species. The cell operating temperature is sufficiently low so that the required concentration of iron species in the electrolyte (5) is limited by the reduced solubility of iron species in the electrolyte at the operating temperature, which consequently limits the contamination of the product aluminium by iron to an acceptable level.

Abstract: A cell for the electrowinning of aluminum using anodes (10) made from a alloy of iron with nickel and/or cobalt is arranged to produce aluminum of low contamination and of commercial high grade quality. The cell comprises a cathode (20) of drained configuration and operates at reduced temperature without formation of a crust or ledge of solidified electrolyte. The cell is thermally insulated using an insulating cover (65,65a,65b,65c) and an insulating sidewall lining (71). The molten electrolyte (30) is substantially saturated with alumina, particularly on the electrochemically active anode surface, and with species of at least one major metal present at the surface of the nickel-iron alloy based anodes (10). The cell is preferably operated at reduced temperature from 730° to 910° C. to limit the solubility of these metal species and consequently the contamination of the product aluminum.

Abstract: Insulation assemblies provide reduced heat loss from electrolytic metal production cells such as inert anode aluminum production cells. The insulation assemblies may be located at the end, side and/or center aisles of the cell, and may be supported by the anodes and deckplate of the cell. The assemblies reduce heat loss and bath vaporization losses, and permit stable operation of the inert anode cell.

Abstract: A method of producing aluminum in an electrolytic cell comprising the steps of providing an anode in a cell, preferably a non-reactive anode, and also providing a cathode in the cell, the cathode comprised of a base material having low electrical conductivity reactive with molten aluminum to provide a highly electrically conductive layer on the base material. Electric current is passed from the anode to the cathode and alumina is reduced and aluminum is deposited at the cathode. The cathode base material is selected from boron carbide, and zirconium oxide.

Abstract: The present invention relates to an electrolytic cell for the production of aluminum comprising an anode and an electrolytic tank where the electrolytic tank comprises an outer shell made from steel and carbon blocks in the bottom of the tank forming the cathode of the electrolytic cells. At least a part of the sidewall of the electrolytic tank consists of one or more evaporation cooled panels, and wherein high temperature, heat resistant and heat insulating material is arranged between the evaporation cooled panels and the steel shell. The invention also includes a method for maintaining a crust on the sidewall of the tank and for recovering heat from the cooling medium inside the panel for transformation into electrical energy.

Abstract: The present invention is directed to methods for preheating a molten salt electrolysis cell having inert anodes (24) using recuperative gas heating by combusting a first gas outside the cell chamber (20) in a combustion chamber (2) and using to heat a second gas in recuperator (8) which second gas us passed to the cell chamber (20). The inert anode can be a cermet inert anode.

Abstract: A method of maintaining molten salt concentration in a low temperature electrolytic cell used for production of aluminum from alumina dissolved in a molten salt electrolyte contained in a cell free of frozen crust wherein volatile material is vented from the cell and contacted and captured on alumina being added to the cell. The captured volatile material is returned with alumina to cell to maintain the concentration of the molten salt.

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 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: An improved 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 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 the bottom, the liner being substantially inert with respect to the molten electrolyte. A plurality of non-consumable anodes and cathodes are disposed in the electrolyte and an electric current is passed through the anodes and through the electrolyte to the cathodes depositing aluminum on the cathodes and generating oxygen bubbles at the anodes, the bubbles stirring the electrolyte. Periodically, the electric current flow to the cell is reduced for extended periods.

Abstract: A solid cryolite/alumina mixture is used as the anode in an electrolytic aluminum winning process. The mixture may be used in the form of a crust formed on the electrolytic cell.

Abstract: The present invention is directed to methods for preheating a molten salt electrolysis cell having inert anodes (24) using recuperative gas heating by combusting a first gas outside the cell chamber (20) in a combustion chamber (2) and using to heat a second gas in recuperator (8) which second gas us passed to the cell chamber (20). The inert anode can be a cermet inert anode.

Abstract: An electrolytic bath for use during the electrolytic reduction of alumina to aluminum. The bath comprises a molten electrolyte having the following ingredients: (a) AlF3 and at least one salt selected from the group consisting of NaF, KF, and LiF; and (b) about 0.004 wt. % to about 0.2 wt. %, based on total weight of the molten electrolyte, of at least one transition metal or at least one compound of the metal or both. The compound may be, for example, a fluoride, oxide, or carbonate. The metal can be nickel, iron, copper, cobalt, or molybdenum. The bath can be employed in a combination that includes a vessel for containing the bath and at least one non-consumable anode and at least one dimensionally stable cathode in the bath. Employing the bath of the present invention during electrolytic reduction of alumina to aluminum can improve the wetting of aluminum on a cathode by reducing or eliminating the formation of non-metallic deposits on the cathode.

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 aluminum in an electrolytic cell containing alumina dissolved in an electrolyte. A plurality of non-consumable anodes are disposed substantially vertically in the electrolyte along with a plurality of monolithic hollow cathodes. Each cathode has a top and bottom and the cathodes are disposed vertically in the electrolyte and the anodes and the cathodes are arranged in alternating relationship. Each of the cathodes is comprised of a first side facing a first opposing anode and a second side facing a second opposing anode. The first and second sides are joined by ends to form a reservoir in the hollow cathode for collecting aluminum therein deposited at the cathode.

Abstract: A method of producing aluminum in an electrolytic cell containing alumina dissolved in an electrolyte. The method comprises the steps of providing a molten salt electrolyte in an electrolytic cell having an anodic liner for containing the electrolyte, the liner having an anodic bottom and walls including at least one end wall extending upwardly from the anodic bottom, the anodic liner being substantially inert with respect to the molten electrolyte. A plurality of non-consumable anodes is provided and disposed vertically in the electrolyte. A plurality of cathodes is disposed vertically in the electrolyte in alternating relationship with the anodes. The anodes are electrically connected to the anodic liner. An electric current is passed through the anodic liner to the anodes, through the electrolyte to the cathodes, and aluminum is deposited on said cathodes. Oxygen bubbles are generated at the anodes and the anodic liner, the bubbles stirring the electrolyte.

Abstract: Cathode connector means for low temperature aluminum smelting cell for connecting titanium diboride cathode or the like to bus bars.

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: A drained cathode cell for the electrowinning of aluminium comprises a cell bottom (20) arranged to collect product aluminium and thermic insulating sidewalls (40) lined with a molten electrolyte resistant sidewall lining (50), in particular containing silicon carbide, silicon nitride or boron nitride. The thermic insulating sidewalls (40) inhibit formation of an electrolyte crust on the lining (50), whereby the lining (50) is exposed to molten electrolyte. The cell bottom (20) has a peripheral zone from which the insulating sidewalls (40) extend generally vertically to form, with the cell bottom, a trough for containing molten electrolyte and aluminium produced on at least one drained cathode (32). The peripheral zone of the cell bottom (20) is arranged to keep the product aluminium from contacting and reacting with the molten electrolyte resistant sidewall lining 50).

Abstract: The process according to the invention solves the problem of the individual thermal regulation of electrolytic pots. It involves acting on the temperature of the pot by means of the setpoint resistance Ro which is modulated so as to correct the temperature both by anticipation and by reversed feedback. On the one hand, correction by anticipation, known as "a priori" correction allows for known, quantified disturbances and allows their effect on the temperature of the pot to be compensated in advance. On the other hand, reversed feedback correction, known as "a posteriori" correction, involves determining, from direct measurement at regular time intervals of the temperature of the electrolytic bath, a mean temperature corrected as a function of periodic operating procedures and allows the variations and deviations from the setpoint temperature to be compensated.

Abstract: A method of producing aluminum, comprising the steps of:a) providing an aluminum reduction Hall cell for reduction of alumina in molten fluoride electrolyte containing cryolite, the cell comprising a cathode, an anode and a sidewall, the sidewall having a thickness and comprising:i) a lining consisting essentially of a material selected from the group consisting of silicon nitride, silicon carbide, and boron carbide, and having a density of at least 95% of theoretical density, and no apparent porosity, andii) an insulating layer backing the lining,b) contacting the lining with an electrolyte comprising at least 60% cryolite and having a temperature of between 650.degree. C. and 1100.degree. C.

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.