Abstract: A feeder assembly for an alumina electrolysis cell includes an alumina dose holder (5) defined between inner and outer walls (6, 7, 7') with an inlet port in the outer wall above an outlet port in the inner wall. The inlet and outlet ports (8, 11) are closable and openable by valve means formed by relative movement between the outer wall (7, 7') and a valve seat (10, 12) cooperating with a seating edge of the outer wall (7, 7'). The valve means is moved by drive means (13) including a pneumatically operated piston (14) movable within a cylinder (15) concentric with the shaft (2) of an electrolyte crust-breaking plunger (1). The plunger shaft (2) is axially slidable within an annular sleeve (18) of the piston (14) which is connected to at least one movable component of the valve means.

Abstract: This invention relates to an apparatus for separating two fluids having different specific gravities. The invention also relates to a method for using the separating apparatus of the present invention. This invention particularly relates to the skimming of molten lithium metal from the surface of a fused salt electrolyte in the electrolytic production of lithium metal from a mixed fused salt.

Abstract: A process for electrowinning metal in a low temperature melt is disclosed. The process utilizes an inert anode for the production of metal such as aluminum using low surface area anodes at high current densities.

Abstract: A process and apparatus for melting metals that react rapidly with air at elevated temperatures to form a stable metal oxide and/or that contains a metal oxide prior to being exposed to elevated temperature, while reducing metal losses due to oxidation or the presence of the oxides. The process involves melting the metal in the presence of a molten metal salt metal salt mixture while electrolyzing metal oxide contained in the salt metal salt mixture to convert the oxide to elemental metal. The process requires an metal salt mixture which contains at least 25% by weight, and more preferably 100% by weight, of metal fluoride and which, for the metal being melted, has a composition which remains substantially unchanged during the electrolysis process. The fluoride improves oxide solubility in the metal salt mixture, making it possible to increase current densities without producing anode effects. The stable composition makes it possible to use the metal salt mixture for prolonged periods without change.

Abstract: An apparatus and method for feeding powderized raw material, such as aluminum oxide, into an aluminum producing electrolysis reaction, in which the electrolysis is produced by an anode and cathode apparatus and a powderized raw material is conveyed from a silo or equivalent to a feeding apparatus and then into an electrolyte melt. The feeding apparatus has a controlling box for controlling the raw material feeding and a feeding pipe connected thereto. The feeding apparatus has a feeding device arranged to operate within the box and connected through a piston shaft to a vibrator. The vibrator produces a substantially vertical vibration of the feeding device. An open lower end of the controlling box is positioned in the vicinity of the surface of the electrolyte melt so that the controlling box operates within the electrolyte crust.

Abstract: An electrical connector for use in an aluminum reduction cell is disclosed. The portion of the connector extending into the carbon anode block is formed from a steel alloy having at least about 0.8% by weight chromium and having electrical resistivity characteristics close to those of mild steel at the cell operating temperatures of the block.

Abstract: An apparatus and method for continuous production of liquid uranium alloys through the electrolytic reduction of uranium chlorides. The apparatus includes an electrochemical cell formed from an anode shaped to form an electrolyte reservoir, a cathode comprising a metal, such as iron, capable of forming a eutectic uranium alloy having a melting point less than the melting point of pure uranium, and molten electrolyte in the reservoir comprising a chlorine or fluorine containing salt and uranium chloride.

Abstract: A method and device for feeding a raw material, such as aluminum oxide, into an aluminum electrolysis using a reciprocatingly vibrating feeding means in which a raw material is carried into a controlling box positioned in proximity to the surface of electrolyte melt. Mechanical vibrations are directed at a feeding device positioned inside the controlling box. The vertical amplitude of the vibrations is selected in the range of about 0.5 cm to about 1.5 cm. The oscillation frequency of the vibrations is selected in the range of about 11 Hz to about 40 Hz. Raw material is continuously fed by the feeding device into the electrolysis through an opening produced in the crust of the electrolyte melt around the controlling box.

Abstract: A process and an electrolytic cell for the production of fluorine. A fluorine-containing electrolyte is passed in non-turbulent flow between an anode and a cathode of the electrolytic cell. The electrolyte emerging from between the anode and the cathode is divided into two streams. One stream emerges adjacent to the anode and has fluorine entrained therein, the other stream emerges adjacent to the cathode and has hydrogen entrained therein. The fluorine and the hydrogen are subsequently separated from their respective streams of electrolyte.

Abstract: A novel anode-cathode arrangement for the electrowinning of aluminum from alumina dissolved in molten sales, consisting of an anode-cathode double-polar electrode assembly unit or a continuous double polar assembly in which the anode and cathode are bound together and their interelectrode gap is maintained substantially constant by connections made of materials of high electrical, chemical, and mechanical resistance. Novel, multi-double-polar cells for the electrowinning of aluminum contain two or more of such anode-cathode double-polar electrode assembly units. This arrangement permits the removal of reimmersion into any of the anode-cathode double-polar electrode assembly units during operation of the multi-double-polar cell whenever the anode and or the cathode or any part of the electrode unit needs reconditioning for efficient cell operation.

Abstract: Apparatus for the controlled supply of alumina to an electrolysis tank having an electrolyte crust breaking plunger (2) includes a supply chamber (19) connected to the entry port (16) of a dose holder (10). Alumina leaving an exit port (15) of the dose holder (10) passes via an inclined wall (9) to a delivery chute (21) which directs the alumina to a hole formed in the crust by the plunger. Valve means (14) movable with the plunger (2) controls the opening of the dose holder entry and exit ports (16, 15), closing one port as it opens the other, and allowing alumina to flow through the delivery chute (21) as the plunger (2) is retracted from the crust. The plunger movement required to control the valve means is such that alumina can be fed into the tank substantially continuously without meeting interference from the plunger.

Abstract: A method for electrochemical refining of an impurity-containing melt using a solid electrolyte ionic conductor to remove the impurity from the melt is provided. Also provided are an apparatus for performing the method, and a batch and a continuous method for electrochemical refining of a melt.

Abstract: Single-component bodies useful in fuel cells and other electrochemical devices are provided. In preferred embodiments, the single-component bodies comprise an anodic region at a first side, a cathodic region at a second, non-adjacent side, and an oxygen ion-conducting region substantially free from anodic or cathodic character disposed between said anodic and cathodic regions. The single-component bodies comprise either transition metal perovskites or oxide electrolytes such as yttria-stabilized zirconia doped with multivalent cations.

Abstract: Method and apparatus for controlling the temperature of a molten salt, electrolytic demagging cell wherein an operating condition of the cell (e.g., current, temperature, etc.) is measured and a cathode immersed in the cell's electrolyte is moved to and fro the aluminum melt in the cell in response to the measured condition to vary the heat input to the cell.

Abstract: A crustbreaking assembly comprising elongated rails supported on a frame and a carriage moveable along the length of the rails. A slide assembly pivotally mounted on the carriage for rotation about an axis which is substantially parallel to the rails. A hammer assembly mounted on the slide assembly with a longitudinal axis substantially perpendicular to the rails and including a reciprocable cutting bit which reciprocates along the longitudinal axis of the hammer assembly.

Abstract: A method and apparatus for adjusting the distance between the anodes and cathodes in an electrolysis cell includes first and second anode beams, movably disposed in an upper and lower relationship. The anode beams are interconnected by a spindle having upper and lower portions which are oppositely threaded such that rotating the spindle in a first direction moves the beams towards each other and rotating the spindle in the other direction moves the beams away from each other. Cell anodes are selectively attached to one of the anode beams, dependant on the desired direction of adjustment. By attaching the anodes to one or the other anode beam, as they are cycled towards and away from each other, individual anode adjustment in either direction can be achieved. If desired, an essentially constant downward motion may also be provided, without requiring a halt in cell operation. Consequently, cell efficiency is increased and the cell remains on-line for longer periods, increasing production capacity.

Abstract: The present invention relates to a new electrolysis cell for the fusion electrolytic extraction of aluminum wherein the anode blocks are connected to one another using a compressed granulate packing. The invention also relates to a novel electrolytic cell wherein the cathode blocks are separated one from another and have sloped or curved upper surfaces allowing newly formed aluminum to drain into an underlying receptacle area.

Abstract: An oxidation resistant, non-consumable anode, for use in the electrolytic reduction of alumina to aluminum, has a composition comprising copper, nickel and iron. The anode is part of an electrolytic reduction cell comprising a vessel having an interior lined with metal which has the same composition as the anode. The electrolyte is preferably composed of a eutectic of AlF.sub.3 and either (a) NaF or (b) primarily NaF with some of the NaF replaced by an equivalent molar amount of KF or KF and LiF.

Abstract: The present invention relates to an apparatus for aligning the stubs disposed on the yoke of an anode rod used in an aluminum electrolytic extraction cell, the anode rod having a yoke portion to which are secured two outer and an inner stub and a rod portion, the apparatus comprising a platform, first and second receiving elements for grasping the two outer stubs, which are slideably mounted on the platform, and equipment attached to the platform for driving the first receiver element in a direction directly opposite the movement of the second receiver element.

Abstract: Improved electrolytic cells for producing metals by the electrolytic reduction of a compound dissolved in a molten electrolyte are disclosed. In the improved cells, at least one electrode includes a protective layer comprising an oxide of the cell product metal formed upon an alloy of the cell product metal and a more noble metal.In the case of an aluminum reduction cell, the electrode can comprise an alloy of aluminum with copper, nickel, iron, or combinations thereof, upon which is formed an aluminum oxide protective layer.

Abstract: A device for electrolytic production of elemental magnesium by electrolysis of magnesium chloride in a molten salt bath, including a magnesium transfer trough comprising a semicircular section of a standard steel pipe mounted straddling the upper edge of a steel cathode plate, with cross slots for utilization of the full channel, the trough everywhere curving away from its nearest approach to the anode surface, to minimize production of unwanted magnesium on its exterior surface. The method entails the use of a destructible spacer for placing the anode accurately in place between a pair of opposing cathode plates.

Abstract: An electrolysis cell for the production of metals is disclosed. Ther cell includes at least one anode that, under the operating conditions of the cell, dissolves into the cell electrolyte to provide a cell feed material. Additionally the anode is fabricated of a material that, under the operating conditions of the cell is electronically conductive as a solid and can provide an ionically conductive medium either when molten or when dissolved in a liuqid.

Abstract: The density of various refractory hard metal articles are controlled so that articles made from the refractory hard metals are able to float on the surface of molten aluminum. Floating such articles on aluminum has been found to both stabilize and protect the surface of molten aluminum. Floating cathodes for use in aluminum reduction cells is a particular application for the floating refractory hard metals.

Abstract: The present invention relates to an arrangement for closing the top of a Soderberganode used in an electrolytic cell for production of aluminum. The anode comprises an anode casing and vertical contact bolts for holding and for conducting electric current to the anode. The top of the anode is closed by means of at least one central cover having openings for the contact bolts and at least one side cover which can be opened in order to charge anode paste to the anode.

Abstract: A method of, and an apparatus for, introducing at least one halide into the bath of cell for dry electrolysis. The method confines a portion of the bath in an annular space and upward motion is imparted to the confined portion of the bath by introduction of a gas and halide into the annular space. The apparatus for carrying out the method consists of two concentric tubes: an inner tube through which the halide and the gas are introduced and which tube is open at its bottom end and which tube has orifices on its lateral wall; and an outer tube which is open at its bottom end, closed at the top end and provided on its lateral wall with apertures situated at a level higher than that of the orifices. The method and apparatus can be applied to the operation and construction of electrolysis baths in which the concentration by weight of the halide and its mean valency must be maintained within a narrow range and be able to be adjusted progressively and precisely.

Abstract: Improved methods and apparatus for carrying out the methods are disclosed for feeding alumina into a Soderberg type aluminum reduction cell (10), so as to maximize efficiency of the cell. The apparatus includes a continuous point feeder assembly (12) connected to the cell structure over an exposed peripheral portion of the cryolite bath. The feeder assembly includes as alumina feed hopper (40) and a pair of vertically disposed feeding bins (56). Each feeding bin receives alumina from the hopper. A piston and cylinder assembly (46) is connected to the feeder assembly and arranged to drive a crust breaking member (44) down through bath crust (17) to form a temporary opening.

Abstract: A method is used for regulating and stabilizing an AlF.sub.3 content (c), which is at least about 10% by weight, in the bath of an electrolysis cell for the production of aluminum from alumina dissolved in a cryolite melt.The individual state of an aluminum electrolysis cell, in particular of the cathodic carbon sump thereof, is analyzed for a period (t.sub.1) from a series of measured values, comprising a plurality of parameters. By means of a model calculation, the optimum time delay (ZV) between the addition of AlF.sub.3 and its effect in the electrolyte is determined. The additions (z) of AlF.sub.3 are calculated for a preset defined AlF.sub.3 content (c) allowing for the time delay (ZV), and AlF.sub.3 is added in portions or continuously.

Abstract: A process for controlling an aluminum smelting cell comprising monitoring the cell voltage and current, alumina dumps, additions, operations and anode to cathode distance movements, continuously calculating the cell resistance and the bath resistivity from said monitored cell voltage and current, monitoring the existence of low frequency and high frequency noise in the voltage of the cell, continuously calculating the time rate of change of resistance of the cell, suspending calculation for a predetermined time when an alumina dump, addition, operation or ACD movement occurs, establishing filtered resistance slope thresholds, determining whether the low frequency noise is above a predetermined threshold, and if so, increasing the filtered slope thresholds for low alumina concentration detection, calculating an alumina inventory from the alumina dumps, determining whether the cell is overfed, and if not feeding alumina to prevent an anode affect, calculating the heat supplied and heat required for aluminum pro

Abstract: A crust breaker device used to break crusts of aluminum electrolysis cells includes a member to be driven for instance a piston/cylinder device with a piston rod in axial movement, essentially in a vertical direction. To a lower part of the member is connected a cutter bar or crow bar which is designed to be moved through the crust and make a hole therein. The cutter bar is connected to, but electrically isolated from the member by means of a fire proof material having insulation properties and that is cast and then hardened.

Abstract: An aluminum electrolysis cell comprises a cathode and a continuous anode disposed above the cathode. The anode is composed of carbon elements which are glued or in some other way connected to one another. Onto the anode, there are added new elements to replace carbon material consumed during the electrolysis process. The anode is divided into sections defined by easily detachable holders or cassettes which are disposed close to one another in a row longitudinally of the cell. The cassettes are each provided at their upper ends with projections designed to be detachably connected to bearer walls or structures along the long sides of the cell.

Abstract: In a feeder for feeding additives such as aluminium oxide or fluoride to aluminium electrolysis cells, the additives are fed to the electrolytic bath of the cell through a hole in the bath crust via a pipe stub. The hole is made by means of a crust breaker having a crow bar connected to a piston/cylinder device. The point feeder is made of a housing comprising an upper part, wholly or partly open to the surroundings, and a lower part closed the crust and other parts of the surroundings. The crow bar extends down through a guide in the form of a bushing, which is provided between the upper and lower part. Further, the pipe is attached to the lower part, or is provided under the lower part, for instance on the gas apron of the anode casing in a Soederberg cell.

Abstract: The present invention relates to an arrangement for gas collection in electrolytic aluminium reduction furnaces equipped with Soderberg anode. The arrangement comprises a plurality of liftable cover plates 8-11 which cover the complete area between the sidewalls of the furnace and the anode casing 2. The cover plates 8-11 are gas tight sealed against the circumference of the anode casing 2 and against the furnace sidewalls 7. The cover plates 8-11 are on their upper side equipped with a plurality of ribs 12. A channel 13 comprising of a lower plate 14, and inclined plate 15 and an upper plate 16 is inserted in recesses in the ribs 12.

Abstract: In a method for the production of a polyvalent metal, particularly titanium, by the cathodic dissolution of a halide of the metal in an electrolyte of alkali or alaline earth metal halides and the electro-extraction of the dissolved metal ions, the electro-extraction stage is carried out with the use of a composite electrode including an anode and a framework surrounding the anode and provided with metal partitions capable of anodic dissolution for confining within the framework a bath of alkali or alkaline earth metal halides which does not contain ions of the metal to be produced, and then applying a potential between the anode and the framework to cause the formation of an accumulation of alkali metal or alkaline earth metal by cathodic reduction, after which a potential is applied between the anode and the cathode to cause the deposition of the metal to be produced at the cathode and the simultaneous anodic dissolution of the partitions.

Abstract: The invention relates to an apparatus for the continuous production of a polyvalent metal by electrolysis of a halide of the metal in a bath of at least one melted salt. The apparatus comprises an electrodismutation cell and a prereduction cell in a contiguous configuration sharing a common wall in the form of a grid which is electrically insulated from the cell walls. The electrodismutation cell includes at least one deposition cathode and at least two anodes which are connected to an at least partly direct current. The prereduction cell includes at least one anode and a cathode constituted by the grid, the anode and cathode being separated by a diaphragm and connected to an at least partly direct current power supply. Means are provided to cause bath flow by forced convection through the grid to produce a top-to-bottom movement in the electrodismutation cell and a bottom-to-top movement in the prereduction cell.

Abstract: An electrochemical process and apparatus for the recovery of uranium and plutonium from spent metal clad fuel pins is disclosed. The process uses secondary reactions between U.sup.+4 cations and elemental uranium at the anode to increase reaction rates and improve anodic efficiency compared to prior art processes. In another embodiment of the process, secondary reactions between Cd.sup.+2 cations and elemental uranium to form uranium cations and elemental cadmium also assists in oxidizing the uranium at the anode.

Abstract: The invention provides a method of transporting a liquid A past or around a barrier, by adding a solute S to liquid A on one side of the barrier and correspondingly removing solute S from liquid A on the other side of the barrier, the solute S being such as to change the density of the liquid A when dissolving in it, thereby providing a motive force for its motion around the barrier. An example of the application of the invention is in a two-part electrolytic cell (1) comprising electrowinning and electrofining half cells (2 and 3, respectively), wherein the metal, solute S, is electrowon into a liquid (16,16a), liquid A, on one side of the cell's common electrode (4), the barrier, in the electrowinning half cell (2), and electrolytically removed from the liquid (17,17a) on the other side of the common electrode (4), in the electrorefining half cell (3).

Abstract: An apparatus and process for reducing uranium and/or plutonium oxides to produce a solid, high-purity metal. The apparatus is an electrolyte cell consisting of a first container, and a smaller second container within the first container. An electrolyte fills both containers, the level of the electrolyte in the first container being above the top of the second container so that the electrolyte can be circulated between the containers. The anode is positioned in the first container while the cathode is located in the second container. Means are provided for passing an inert gas into the electrolyte near the lower end of the anode to sparge the electrolyte and to remove gases which form on the anode during the reduction operation. Means are also provided for mixing and stirring the electrolyte in the first container to solubilize the metal oxide in the electrolyte and to transport the electrolyte containing dissolved oxide into contact with the cathode in the second container.

Abstract: A method of electrolytically producing lithium includes providing an electrolytic cell having an anode compartment and a cathode compartment. The compartments are separated by a porous electrically nonconductive membrane which will be wetted by the electrolyte and permit migration of lithium ions therethrough. Lithium carbonate is introduced into the anode compartment and produces delivery of lithium ions from the anode compartment to the cathode compartment where such ions are converted into lithium metal. The membrane is preferably a non-glass oxide membrane such as a magnesium oxide membrane. The membrane serves to resist undesired backflow of the lithium from the cathode compartment through the membrane into the anode compartment. Undesired communication between the anode and cathode is further resisted by separating the air spaces thereover. This may be accomplished by applying an inert gas purge and a positive pressure in the cathode compartment.

Abstract: The present invention provides an apparatus for producing lithium from an aluminum-lithium alloy scrap comprising (a) a dryer for removing moisture from solid aluminum-lithium alloy; (b) a reservoir for heating and holding molten aluminum-lithium alloy; (c) a three-layered electrolysis cell comprising a most dense lowest layer of molten aluminum-lithium alloy, a middle layer of molten salt electrolyte, and an uppermost layer of molten lithium; and (d) a reactive gas fluxing unit to remove water present in the molten salt.

Abstract: A method of producing titanium. A quantity of titianium is heated in a crucible to provide a melt, and a layer of slag, containing an ionizable titanium compound, such as titanium dioxide, along with ionizable slag constituents, is disposed on the top of the melt. The slag is then heated to a molten state by direct current plasma arc heating with the melt being anodic. After the slag is molten, the polarity of the plasma arc heating is reversed so that the melt is cathodic, causing the slag to act as an electron transfer layer so that the titanium dioxide of the slag is reduced to titanium and any dissolved oxygen in the melt is converted to an ionic species of oxygen at the interface between the slag and the melt. The resulting liquid titanium is combined with the melt, while the ionic species of oxygen is carried upwardly through the slag and released from the slag layer by an oxidation process.

Abstract: An electrolytic cell for producing a metal, e.g. magnesium, by electrolysis has a housing in which are disposed one or more electrode assemblies each comprising a cathode assembly providing a vertical cavity in which are disposed an anode and one or more bipolar electrode assemblies disposed between the anode and cathode assembly, and baffles for preventing or impeding flow of electrolyte between adjacent cathode assemblies and/or between each cathode assembly and an adjacent wall of the housing.

Abstract: Method used in connection with the exchange of anodes in cells producing aluminum by electrolysis according to the Hall-Heroult process. Each cell comprises a cathode containing a fused salt bath or aluminum oxide dissolved in cryolite, and above the cathode is provided one or more carbon anodes which are partly submerged in the bath and are partly covered with and surrounded by a crust which forms on the bath. Immediately before a used anode is to be removed a cut is made in the crust all the way around the anode and as close to the anode as possible. A device for performing the method is in the form of a crust cutter comprising a share which is turnably mounted around a vertical axis on the outer end of a telescopic device. The telescopic device at its inner end is mounted for rotation about its longitudinal axis in a housing or frame construction which can be raised or lowered.

Abstract: An electrolytic cell recovery of metal comprising a first partition wall provided with partition openings situated beneath the level of an electrobath and disposed between a dissociated metal recovery chamber and an electrolytic chamber having an anode and a cathode and a second partition wall adapted to constitute an intermediate chamber between the first and second partition walls for recovery of dissociated Cl.sub.2 gas; and also the arrangement of bipolar electrodes in the electrolytic cell and the shape of a control plate for preventing the deposition of sludge.

Abstract: An apparatus and method for splitting a mass of fluidizable powder into a plurality of powder streams and conveying the powder streams through a plurality of ducts. The apparatus comprises a powder splitter defining a chamber, a plurality of hollow ducts each having an entrance communicating with the chamber, and a gas source including a plurality of gas nozzles within the ducts and directed outwardly of the chamber. The gas nozzles propel gas jets into the ducts so that portions of the fluidizable powder are conveyed through the ducts. A particularly preferred apparatus is utilized for conveying a plurality of alumina powder streams to an aluminum electrolysis cell.

Abstract: Method of feeding particulate material by the use of apparatus comprising a passage having an upstream section 10 provided with baffles 18, 20, leading to a chicane 14, 16 and then to a downstream section 12. A gas pipe 22 feeds low-pressure gas to a slot 26 through which a flow of gas can be started or stopped, so as to start or stop the passage of the material through the chicane.

Abstract: An improved alumina reduction cell is described in which the carbonaceous cathode includes refractory hard metal shapes forming the true cathode surface and inert refractory protective sleeves for the refractory hard metal shapes. Reduced amounts of refractory hard metal material are employed through an improved refractory hard metal support system.

Abstract: An electrochemical separation of oxygen from oxygen containing gaseous mixtures, such as air, using an oxygen containing molten inorganic salt electrolyte retained in a porous matrix between two gas porous catalytic electrodes wherein oxygen is separated from the gaseous mixture when electrical potential is applied across the electrodes providing movement of non-metallic oxygen containing ion from the cathode to the anode.

Abstract: A method for making light metal-alkali metal master alloy using alkali metal containing scrap comprises: (a) establishing an electrolytic cell divided into two or more laterally adjacent areas by porous alkali metal ion transport means, said cell including a first cell area supplied with alkali metal-containing scrap and a second cell area consisting essentially of molten light metal; (b) supplying current to this cell for transporting alkali metal ions from the first cell area to the second cell area; (c) forming master alloy by combining these ions with the molten light metal in said second cell area; and (d) withdrawing master alloy from the second cell area. An apparatus for making aluminum-lithium or magnesium-lithium master alloy using the lithium from aluminum-lithium alloy scrap is also disclosed.

Abstract: An electrorefining process and apparatus for the recovery of uranium and a mixture of uranium and plutonium from spent fuel using an electrolytic cell having a lower molten cadmium pool containing spent nuclear fuel, an intermediate electrolyte pool, an anode basket containing spent fuel, and two cathodes, the first cathode composed of either a solid alloy or molten cadmium and the second cathode composed of molten cadmium. Using this cell, additional amounts of uranium and plutonium from the anode basket are dissolved in the lower molten cadmium pool, and then substantially pure uranium is electrolytically transported and deposited on the first alloy or molten cadmium cathode. Subsequently, a mixture of uranium and plutonium is electrotransported and deposited on the second molten cadmium cathode.

Abstract: The invention relates to a process for regulating the acidity of the electrolytic bath by recycling fluorinated effluents emitted by the Hall-Heroult electrolytic cells for the production of aluminum, in which said fluorinated effluents are collected, by the dry route, on the alumina. It comprises the following stages:a reference value for the fluorine/alumina weight ratio is fixed in connection with the alumina leaving the collecting apparatus,a continuous measurement takes place of the fluorine and alumina quantities entering the collecting apparatus,the alumina flow rate is regulated so as to maintain the F/Al.sub.2 O.sub.3 ratio at its reference value, generally fixed between 0.