Abstract: A method for optimizing stability in an electrolysis cell of the Hall-Héroult type where the cell has suspended prebaked anodes and a cathode panel. The panel comprises several cathode blocks or cathode block sections. A metal pad and an electrolytic bath are located between said anodes and the cathode panel. The force field acting on the metal pad is calculated and monitored in a computer based model of the cell, whereby the local current paths and correspondingly the local forces in the metal above the cathode panel are modified by influencing selectively the current distribution in individual cathode blocks or block sections in the computer based model. At least one modification is implemented in the cell. The invention also relates to a correspondingly modified cell.

Abstract: Provided is a method for producing metal by molten salt electrolysis, by which the metal can be efficiently produced. A method for producing metal by using an apparatus for molten salt electrolysis having an electrolytic cell and an electrode pair, wherein the molten salt electrolysis in the electrolytic cell and heating of the molten salt by a Joule heat generation between a pair of electrodes for electrolysis are simultaneously performed; and wherein the apparatus for molten salt electrolysis has at least two sets of electrode pair, and at least one set of the electrode pairs is electrically opened.

Abstract: The present disclosure related to an economic and environmental safe process for obtaining one or more metals from the red mud slag, bauxite, karst bauxite, lateritic bauxite, clay and the like. The present disclosure also related to a process for obtaining elemental aluminum by electrolyzing AlCl3 in the electrolysis cell.

Abstract: There is provided a quartz glass article having a surface treated with novel coating materials which provides a reduced chemistry, wherein the quartz glass surface having a reduced chemistry upon exposure to melted silicon or similarly corrosive environments, forms crystalline structures covering at least 30% of the coated surface of the quartz glass crucible. Said crystalline covered surface provides a more stable surface of contact with the silicon melt and the growth of single crystal silicon. In one embodiment of the invention, the coating material comprises at least a methyl group for providing at least one of a hydrogenated and a methylated surface on the coated surface, forming rosette structures, or other crystalline morphologies covering at last 80% of the coated surface. In another embodiment of the invention, the coating material is selected from at least one of an amine, an organosilane halogen and mixtures thereof.

Abstract: The present technology discloses a method for producing aluminum from alumina in an electrolytic cell through the use of carbon monoxide as a partial or total reactant with aluminum oxide. The present technology also discloses the structure of an electrolytic cell configured to house this reaction.

Abstract: The invention relates to a method of producing aluminum 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: The present invention relates to an electrode composed of an Al-M-Cu based alloy, to a process for preparing the Al-M-Cu based alloy, to an electrolytic cell comprising the electrode, to the use of an Al-M-Cu based alloy as an anode and to a method for extracting a reactive metal from a reactive metal-containing source using an Al-M-Cu based alloy as an anode.

Abstract: A pot tending module for an aluminum production plant comprising a frame and a rotary part including a hopper mounted on said frame so as to pivot about a substantially vertical axis, said rotary part being equipped with at least one tool mounted on a telescopic arm, said pot tending module comprising a first bearing structure to carry all of said rotary part mounted on said frame so as to be pivotable about a substantially vertical axis, a fixed member of said telescopic arm being mounted on a second bearing structure of said rotary art through attachment means fixed to an attachment part of said fixed member placed between the ends of said fixed member. A pot tending machine, a port tending assembly comprising the pot tending module described above, and use of said pot tending assembly.

Abstract: An apparatus and method for smelting has a smelting pot for containing electrolyte, alumina and a layer of liquid aluminum. A wall in the form of one or more TiB2 or alumina plates extends from the bottom of the pot to a height exceeding the height of the liquid aluminum layer formed in the bottom of the smelting pot during smelting. The wall partitions the bottom of the pot and impedes movement of the aluminum under the influence of MHD forces, diminishing the maximum crest height of waves in the aluminum and allowing a reduction in the ACD to reduce electrical resistance and power consumption. The wall may equal or exceed the height of the anode and may, when conductive, act as a cathode, drawing a horizontal current. The wall may be composed of alumina, e.g., in the form of blocks, undergoing electrolytic reduction and being replaced periodically.

Abstract: An objective of the present invention is to provide a method and system for use for control of layer formation over an extended area in an aluminium electrolysis cell and exploitation of heat. A second object of the invention is to provide a method and system for use for control of layer formation suited for retrofitting to an aluminium electrolysis cell and maintainability during operations of the cell. The present invention attains the above-described objectives by a flat heat tube for attachment to the steel casing of an aluminium electrolysis cell. This heat tube can be a heat pipe or a thermosyphon. Preferably the heat tube is provided with a substantially flat surface. Preferably the heat tube has a meandering shape.

Abstract: The invention provides a sodium cryolite for aluminum electrolysis industry, which has a molecular formula: mNaF.AlF3, wherein m is from 1 to 1.5. The low-molecular-ratio sodium cryolite (mNaF.AlF3, and m is from 1 to 1.5) provided by the invention is used for aluminum electrolysis industry, and can reduce the temperature of electrolysis and the consumption of power, raise the efficiency of electrolysis and lower the comprehensive production cost.

Abstract: The disclosure provides an electrolyte supplement system in an aluminium electrolysis process, which includes low-molecular-ratio cryolite, wherein the low-molecular-ratio cryolite is selected from mKF.AlF3, nNaF.AlF3 or mixture thereof, where m=1˜1.5 and n=1˜1.5. When the electrolyte supplement system provided by the disclosure is applied to the aluminium electrolytic industry, electrolytic temperature can be reduced obviously in the aluminium electrolysis process without changing the existing electrolytic process; thus, power consumption is reduced, volatilization loss of fluoride is reduced and the comprehensive cost of production is reduced.

Abstract: The disclosure provides low-molecular-ratio cryolite for aluminum electrolytic industry, which consists of potassium cryolite and sodium cryolite with a mole ratio of 1:1˜1:3, wherein the molecular formula of the potassium cryolite is mKF.AlF3 and the molecular formula of the sodium cryolite is nNaF.AlF3, where m=1˜1.5 and n=1˜1.5. When the low-molecular-ratio cryolite provided by the disclosure is applied to the aluminum electrolytic industry, electrolytic temperature and power consumption can be reduced and electrolytic efficiency is improved.

Abstract: The invention provides a potassium cryolite for aluminum electrolysis industry, which has a molecular formula: mKF.AlF3, wherein m is from 1 to 1.5. The low-molecular-ratio potassium cryolite (mKF.AlF3, and m is from 1 to 1.5) provided by the invention is used for aluminum electrolysis industry, and can improve the dissolvability of aluminum oxide, thus reducing the temperature of electrolysis and the consumption of power, raising the efficiency of electrolysis and lowering the comprehensive production cost.

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: Grid energy storage is very challenging due to its large scale, required quick response, versatility, round trip efficiency, and new system infrastructure. However, the benefit is also huge because it would enable utilisation of intermittent renewable energy, leverage load, and allow energy management in hours/diurnal to seconds/minutes. A new invention is described to store up to 4-6% the entire grid energy by aluminum production, while returning its baseload back to the grid by idling aluminum smelter cells. The round trip efficiency will be close to 100%; switching between storage and load release can be instantaneous.

Abstract: Provided is a method for producing fine metal particles, wherein metal oxide powders can be used as a source of fine metal particles, and a method for producing fine metal particles can be provided avoiding the contamination of the molten salt electrolyte bath and the produced fine metal particles. A method for producing fine metal particles (112) is provided which comprises generating cathodic discharge outside and over the surface of an electrolyte bath (100) comprising metal oxide powders (110) suspended therein, whereby the metal oxide powders (110) are electrochemically reduced into the fine metal particles (112).

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 relates to an electrolytic cell for obtaining aluminum, including a pot shell, at least one cathode block arranged at least partially in the pot shell, at least one anode suspended above the cell and dipping into the upper portion of the electrolytic cell, and an insulation at least partially covering the internal surface of the pot shell and located between the cathode block and the pot shell, the pot shell and the elements that it contains delimiting a crucible intended to receive an electrolytic bath in contact with the cathode block, characterized in that the insulation is at least partially made of carbon-based blocks having a heat conductivity lower than 1 W/m/K.

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: The disclosure provides an electrolyte supplement system in an aluminium electrolysis process, which includes low-molecular-ratio cryolite, wherein the low-molecular-ratio cryolite is selected from mKF.AlF3, nNaF.AlF3 or mixture thereof, where m=1˜1.5 and n=1˜1.5. When the electrolyte supplement system provided by the disclosure is applied to the aluminium electrolytic industry, electrolytic temperature can be reduced obviously in the aluminium electrolysis process without changing the existing electrolytic process; thus, power consumption is reduced, volatilization loss of fluoride is reduced and the comprehensive cost of production is reduced.

Abstract: An apparatus and method for smelting has a smelting pot for containing electrolyte, alumina and a layer of liquid aluminum. A wall in the form of one or more TiB2 or alumina plates extends from the bottom of the pot to a height exceeding the height of the liquid aluminum layer formed in the bottom of the smelting pot during smelting. The wall partitions the bottom of the pot and impedes movement of the aluminum under the influence of MHD forces, diminishing the maximum crest height of waves in the aluminum and allowing a reduction in the ACD to reduce electrical resistance and power consumption. The wall may equal or exceed the height of the anode and may, when conductive, act as a cathode, drawing a horizontal current. The wall may be composed of alumina, e.g., in the form of blocks, undergoing electrolytic reduction and being replaced periodically.

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: A process for production of polysilicon and silicon tetrachloride is provided in which a raw material that is supplied stably and is available at low cost can be used, chlorination reaction can be smoothly promoted, impurities generated after chlorination reaction can be controlled, and production efficiency is superior in a polysilicon producing step. The process includes a step of chlorination in which a granulated body consisting of silicon dioxide and carbon-containing material is chlorinated to generate silicon tetrachloride, a step of reduction in which silicon tetrachloride is reduced by a reducing metal to generate polysilicon, and a step of electrolysis in which chloride of the reducing metal by-produced in the reduction step is molten salt-electrolyzed to generate the reducing metal and chlorine gas.

Abstract: An apparatus and a method for tapping molten metal from below a molten electrolyte layer less dense than the metal is described. The apparatus comprises a pipe comprising a protruding enlarged wall portion at an operative end which is immersed in the molten electrolyte and metal during tapping operation. The enlarged wall portion helps to minimize entrainment of electrolyte residue from the electrolyte/metal interface during tapping. The orientation of the enlarged wall portion may be in the general direction of the crucible.

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: 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: Systems, methods and apparatus for facilitating removal of molten metal from an electrolysis cell are provided. In one embodiment, a system includes a container and an electrical source coupled to the container. The electrical source may be configured to provide complementary current to a spout of the container. This complementary current may create a complementary electromagnetic field at least proximal a tip portion of the spout. When the spout of the container receives the complementary current, and when the spout is in liquid communication with the molten liquid of the electrolysis cell, the complementary electromagnetic field of the complementary current may at least partially assist to increase the flow of molten metal into the spout of the container.

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 aluminum (50) from alumina, comprises an inclined plate-like or grid-like open anode structure (25) which has a generally v-shaped configuration in cross-section. The anode structure (25) has a downwardly-oriented sloping electrochemically active surface that is generally v-shaped in cross-section and spaced above an upwardly-oriented corresponding sloping cathode surface (11) by an anode-cathode gap (40) in which alumina dissolved in a circulating electrolyte (60) is electrolysed. The anode structure (25) has a plurality of anode through-passages (45) distributed thereover for an up-flow of alumina-depleted electrolyte (60) from the anode-cathode gap (40).

Abstract: A cell for the electrowinning of aluminium from alumina dissolved in a fluoride-containing molten electrolyte, comprises a non-carbon metal-based anode having an electrically conductive metallic structure. This anode structure comprises an outer part with an electrochemically active anode surface on which, during electrolysis, oxygen is anodically evolved, and which is suspended in the electrolyte substantially parallel to a facing cathode. The anode structure has one or more flow-through openings extending from the active anode surface through the metallic structure, the flow-through opening(s) being arranged for guiding a circulation of electrolyte driven by the fast escape of anodically evolved oxygen. The outer part of the anode comprises a layer that contains predominantly cobalt oxide CoO to enhance the stability of the anode.

Abstract: A slurry comprises suspended aluminum particles in a colloid having dispersed colloidal particles of a metal oxide such as a hydroxide. The metal oxide is reducible by metallic aluminum. The slurry has such a basic pH that dissolution of the aluminum particles in the slurry is inhibited so that when the slurry is subjected to a heat treatment, the undissolved aluminum particles are reactable with the colloidal particles to form an aluminum-based mixture resistant to chemical attack made of aluminum oxide, metal aluminum and the metal of the colloidal particles. The slurry can be used to form an aluminum-based protective coating on a component, in particular of an aluminum electrowinning cell or an apparatus for treating molten aluminum.

Abstract: A cell for the electrowinning of aluminium comprises a metal-based anode (10) containing at least one of nickel, cobalt and iron, for example an anode made from an alloy consisting of 50 to 60 weight % in total of nickel and/or cobalt; 25 to 40 weight % iron; 6 to 12 weight % copper; 0.5 to 2 weight % aluminium and/or niobium; and 0.5 to 1.5 weight % in total of further constituents. The anode (10) may have an applied hematite-based coating and optionally a cerium oxyfluoride-based outermost coating. The cell contains a fluoride-containing molten electrolyte (5) at a temperature below 940° C., in which the anode is immersed and which consists of: 5 to 14 weight % dissolved alumina; 35 to 45 weight % aluminium fluoride; 30 to 45 weight % sodium fluoride; 5 to 20 weight % potassium fluoride; 0 to 5 weight % calcium fluoride; and 0 to 5 weight % in total of one or more further constituents.

Abstract: Compositions for making wettable cathodes to be used in aluminum electrolysis cells are disclosed. The compositions generally include titanium diboride (TiB2) and metal additives. The amount of selected metal additives may result in production of electrodes having a tailored density and/or porosity. The electrodes may be durable and used in aluminum electrolysis cells.

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: The subject invention pertains to methods for processing a solid material (M1X) comprising a solid solution of a non-metal species (X) in a metal or semi-metal (M1) or a compound between the non-metal species and the metal or semi-metal is immersed in a molten salt (M2Y). A cathodic potential is applied to the material to remove a portion of the non-metal species by electro-deoxidation. To remove the non-metal species at lower concentrations, a source of a reactive metal (M3) is immersed in the molten salt and is electronically connected to the material. Reactions occur at the material, where the non-metal species dissolves in the salt, and at the reactive metal, which reacts with the non-metal species dissolved in the salt to form a reaction product more stable than a compound between the non-metal species and the metal or semi-metal (M1). The non-metal species is thus removed from the solid material.

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: An anode for electrowinning of aluminium from alumina comprises a cobalt-containing metallic outer part that is covered with an integral oxide layer containing predominantly cobalt oxide CoO. The integral oxide layer can be formed by surface oxidation of cobalt from the metallic outer part before use.

Abstract: A cell for electrowinning a metal, in particular aluminium, from a compound thereof dissolved in an electrolyte (30) comprises an anode (40) and a cathode (10,11) that contact the electrolyte (30), the cathode (10,11) being during use at a cathodic potential for reducing thereon species of the metal to be produced from the dissolved compound. The electrolyte (30) further contains species of at least one element that is liable to contaminate the product metal (20) and that has a cathodic reduction potential which is less negative than the cathodic potential of the metal to be produced. The cell further comprises a collector (50) for removing species of such element (s) from the electrolyte (30).

Abstract: An anode for electrowinning aluminium comprises an electrically conductive substrate that is covered with an applied electrochemically active coating comprising a layer that contains predominantly cobalt oxide CoO. The CoO layer can be connected to the substrate through an oxygen barrier layer, in particular containing copper, nickel, tungsten, molybdenum, tantalum and/or niobium.

Abstract: A process for online cut out of an aluminum reduction cell (pot) including the steps of leveling of the side beams of the reduction cell to around 150 mm; punching holes on both sides of the pot to ensure that the bath does not get overflow and ensure the dipping of the anodes through these punch holes; blowing air thoroughly all around the insulated shorted joints of all the risers to clean the joints from dust and large chunks of bath; applying lubricating oil to the shorted joint bolts to conform proper movement of nuts; breaking the side crust of all the four corner anodes; tapping the bath with at least one ladle; lowering the anodes such that there is no liquid overflow over the deck plate onto the catwalk; lowering of the beam by around 70 mm to 100 mm until the voltage falls below around 1.0 V-1.

Abstract: A cell for electrowinning aluminium from alumina, comprises: a metal-based anode having an electrochemically active outer part comprising a layer that contains predominantly cobalt oxide CoO; and a fluoride-containing molten electrolyte in which the active anode surface is immersed. The electrolyte is at a temperature below 950° C., in particular in the range from 910° to 940° C. The electrolyte consists of: 6.5 to 11 weight. % dissolved alumina; 35 to 44 weight % aluminium fluoride; 38 to 46 weight % sodium fluoride; 2 to 15 weight % potassium fluoride; 0 to 5 weight % calcium fluoride; and 0 to 5 weight % in total of one or more further constituents.

Abstract: Alumina-containing dust is agglomerated into granules by mixing the dust with an organic binder to form a mixture; feeding the mixture into a rotating drum; adding water to the mixture while the drum is rotating; stirring the mixture with a rotor hastening agglomeration of the dust particles into granules; collecting moist granules from an open end of the drum; and drying the moist granules. Granules produced by the process are suitable feedstock material for production of aluminum by electrolysis of alumina in a cell containing a molten salt bath, anodes, and a cathode.

Abstract: The invention relates to a sintered material which is based on transition metal diborides and comprises a) as main phase, 90-99% by weight of a fine-grained transition metal diboride or transition metal diboride mixed crystal comprising at least two transition metal diborides or mixtures of such diboride mixed crystals or mixtures of such diboride mixed crystals with one or more transition metal diborides, where the transition metals are selected from sub-groups IV to VI of the Periodic Table, b) as second phase, 1-5% by weight of particulate boron carbide and/or silicon carbide and c) optionally as third phase, up to 5% by weight of a non-continuous, oxygen-containing grain boundary phase.

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: This invention relates to a method for controlling additions of powder materials into an electrolytic cell designed for the production of aluminium by fused bath electrolysis. The method according to the invention, which can easily be automated, can be used to maintain monitoring of operation of the feed even during anode effects.

Abstract: The present invention relates to a dimensionally stable oxygen-evolving anode for use in an electrolytic cell for the production of aluminium. The anode comprises of a container made from an alloy comprising aluminium and at least one metal more noble than aluminium; a fluid bath in the bottom of the container having the ability to dissolve aluminium, said fluid having a density that is higher than the density of molten aluminium at the operating temperature of the cell, a pool of molten aluminium floating on top of the fluid bath in the bottom of the container; a refractory layer arranged on the inner sidewalls of the container at least in the area of the pool of molten aluminium, said refractory layer protecting the molten aluminium from contacting the inner sidewalls of the container.

Abstract: A method for operating one or more electrolysis cells (43, 154, 243) for production of aluminium, the cell comprising inert or substantially inert anodes, where an oxygen containing gas (21, 126, 221) evolved by the electrolysis process in the cell is gathered and removed therefrom. The oxygen containing gas is introduced into a combustion chamber (38, 149, 238) where it is reacted with a carbon containing gas (7, 116, 209) in a combustion process. Emisions of CO2 and NOx can be reduced.

Abstract: Process for the electrolysis of Al2S3, using a bath of molten salt, preferably a bath of molten chloride salt, in which Al2S3 is dissolved characterized in that measures are taken to improve the electrical conductivity of the bath, so as to enable an increase in the current density in the bath.

Abstract: A slurry comprises suspended aluminium particles in a colloid having dispersed colloidal particles of a metal oxide such as a hydroxide. The metal oxide is reducible by metallic aluminium. The slurry has such a basic pH that dissolution of the aluminium particles in the slurry is inhibited so that when the slurry is subjected to a heat treatment, the undissolved aluminium particles are reactable with the colloidal particles to form an aluminium-based mixture resistant to chemical attack made of aluminium oxide, metal aluminium and the metal of the colloidal particles. The slurry can be used to form an aluminium-based protective coating on a component, in particular of an aluminium electrowinning cell or an apparatus for treating molten aluminium.