MXPA00011167A - Method and apparatus for the treatment of a melt - Google Patents

Abstract

A method and apparatus for adding a metal, for example sodium, to a melt of a material, for example aluminium, in a vessel, in which a molten compound of the metal or a solution of a compound of the metal is provided in a container (12), the container being positioned outside the vessel, the compound is electrolytically decomposed and ions of the metal are caused to pass through a wall of a solid-state electrolyte (14) which is a conductor therefor, from a first side of the wall to an opposite second side thereof, and to combine with electrons at the second side of the wall and then to flow as molten metal from the container into the melt in the vessel.

Description

METHOD AND APPARATUS FOR TREATING A FUSION The invention relates to the addition of trace level amounts of metal to a melt. The invention particularly relates to the addition of a metal of Group A of the Periodic Table to a fusion of another metal, for example aluminum or zinc. Thus, the metal of Group IA may be, for example, sodium or lithium. The invention relates more preferably to the addition of sodium to molten aluminum or aluminum alloy in? The merger and, although it will be noted that it is not intended to limit this, will be described below for convenience reasons with specific reference to these metals. The addition of trace amounts of sodium, for example, amounts of less than about 200 ppm, to A fusion of aluminum is well known in the art. It can result in an improved quality of the castings and the castings can be more easily removed from the mold and subjected to reduction in shrinkage. Conventionally, sodium has been added to the fusion of aluminum in metallic form as bars or cans of aluminum or in the form of tablets of a sodium compound and while these methods have the advantage of simplicity, they are very inefficient. Due to the violence of the reaction that occurs, most of the added sodium is lost through oxidation and a significant generation of smoke is caused. Therefore frequent additions are required and the method causes significant waste, is not friendly to the environment and can not provide an amount • Controlled effective addition. 5 A method for overcoming these disadvantages is presented in EP-A-0688881. This method teaches the addition of sodium to a fusion of aluminum or aluminum alloy where an electrode comprising melted sodium or a melted sodium compound is immersed in the fusion of • 10 aluminum and is separated from the melt through a solid-state electrolyte that conducts sodium ions. A direct voltage is provided between this electrode and the fusion providing a second electrode in the fusion. While offering numerous advantages in principle, this technique can cause fusion problems, for example, if there is a failure in the solid-state electrolyte package. It is an object of the present invention to provide a (improved metal addition form) Accordingly, the invention offers a method for adding a metal to a melt of a material in a container, where a melted metal compound or a solution of a metal compound is supplied in a container, the container is placed outside the container, the compound is electrolytically decomposed and is caused the passage of metal ions through a wall of a solid-state electrolyte which is conductive for it, from a first side of the wall to a second opposite side and the combination with electrons is also caused on the second side of the wall and • afterwards, flow as molten metal is caused from the container 5 towards the melting. In another aspect of the present invention, an apparatus for adding a metal to a melt of a material in a container is provided, the apparatus comprises a container for a melted metal compound or a solution of the metal compound fflO, the container is placed outside the container, a device for electrolytically decomposing the melted or dissolved compound, a wall placed inside the container and formed of a solid-state electrolyte that is conductive for metal ions, whereby the metal ions formed can pass through the wall from a first side to a second opposite side, an electron source on the second side of the wall to be combined with the metal ions, and a device for passing the melted metal formed in this way from the second side of the wall towards the fusion. For embodiments of the invention in which the container is for a melted metal compound, the apparatus preferably includes a means for heating the metal compound to a melted form. For embodiments of the invention in which a solution of a metal compound is employed, the solvent is preferably an organic solvent, for example, acetamide or glycerol. When a solvent is employed, the invention includes • preferably a means to avoid substantial loss of the solvent through evaporation or boiling. As indicated above, the melting in the container will normally be a fusion of metal, for example zinc or preferably aluminum, but it will be appreciated that the invention can be applied in principle to non-metallic fusions. AlO Likewise, as indicated above, the metal to be added to the melt will normally be a metal of Group A of the Periodic Table and the invention is especially useful for the addition of sodium. The metal compound is preferably an ionic compound, but the invention can also be applied to the use of non-conductive metal compounds. A mixture of various metal compounds (ionic or non-ionic) can be used. When the metal compound or each of the metal compounds is ionic, the current can pass between a first electrode placed in the melting compound and a second electrode placed behind or on the second side of the solid-state electrolyte wall, whereas if one or more non-conductive metal compounds are used, the first electrode should be porous and placed to meet in the first side of the wall.

Thus, the electrolytic decomposition of the metal compound is effected, the melted metal is discharged into the second electrode and anionic species are discharged in the first • electrode The metal compound is preferably a metal salt, for example a metal hydroxide, carbonate or oxalate salt. The anionic species are preferably discharged to form one or several gases, for example, where sodium hydroxide is used as a metal compound, which produces water vapor and oxygen, and where sodium carbonate is used As a metal compound, carbon dioxide and oxygen are produced. (It will be noted that when water vapor is produced, said steam should normally be removed to avoid any possible contact with the melt in the container). At the beginning of the process, priming may be required in the second side of the solid state electrolyte wall. This can be achieved by contact between the second side and the second electrode or by supplying a quantity of melt material. The solid-state electrolyte wall can form conveniently a container. In one embodiment, this container also offers the container in which the metal compound is located. Thus, the first electrode for the required current passage is extended in the metal compound in the container or is in an internal part (first side) of the wall. The metal ions, therefore, pass through the vessel wall to the outside, are discharged and the liquid metal then passes from the outside of the wall through a passage to the melt in • the recipient. In a second embodiment, the container formed of solid state electrolyte is placed inside another container. This outer package can conveniently act as one of the electrodes for the required current passage. In this second embodiment, the metal compound may be contained either in the internal solid-state electrolyte container a-h 10 or outside this container but within the outer container. Then, the metal ions flow either through the wall of the inner pack from the inner part to the outer part or vice versa, and the electrical circuit is arranged as desired accordingly. The metal Liquid is therefore provided by a passage from the internal part or the external part of the inner container, as appropriate, to the melting in the container. The electrodes can be formed from any suitable electrically conductive material. So, the first electrode may be formed, for example, of nickel, stainless steel or graphite, and the second electrode may be formed, for example, of nickel, iron or steel, depending on the metal compound used. When the metal to be added to the fusion is sodium, the compound Sodium ion to provide the sodium ion source can be, for example, as indicated above, sodium hydroxide or sodium carbonate. Whichever compound is used, it should preferably be compatible with the solid state electrolyte, preferably it should not be toxic and should preferably produce non-harmful byproducts. When it is desired to employ sodium carbonate, it may be preferable to mix it with a proportion of sodium chloride to reduce the melting temperature of pure β 10 sodium carbonate of 858 ° C to say about 635 ° C for the mixture. (It will be noted that in these circumstances the chloride ions will not be discharged). Similarly, when it is desired to employ sodium hydroxide, it may be preferable to mix it with a proportion of sodium carbonate to reduce the melting temperature of pure sodium hydroxide from 322 ° C to about 285 ° C for the mixture. When the device is operated at an elevated temperature, care may be required during the addition of metal compound to compensate for the metal used in the process, since that the thermal shock could damage the solid Lito electrode, for example. The fresh compound can be added, for example, at a constant slow rate, or the solid electrolyte can be constructed to withstand a thermal shock. This can be doubled, for example, by ensuring that the electrolyte has a curve radius, preferably a small curve radius, in all areas in at least 2 directions. For example, in the case of tubular-shaped electrolytes, the diameter should be reduced to the smallest practical value. Likewise, solid electrolytes such as beta alumina can be hardened including about 12% zirconia in their structure. However, the preferred method in the invention is to use a separate compartment where the fresh metal compound is heated to a temperature close to the temperature of the liquid surrounding the solid electrolyte. In one embodiment of the invention, solid sodium hydroxide is melted in a separate container and the melted salt of this container is fed to the electrolysis section to maintain the level of salt melted there at a reasonably constant level. In a second modality, a The aqueous solution of sodium hydroxide is lowered into a vessel of melted sodium hydroxide. The result is rapid drying and melting of the solution. Again, the drying compartment is preferably sufficiently separated from the electrolysis compartment to prevent the solid electrolyte is damaged by thermal shock or chemical attack by water. The supply of energy for the electrolysis process is often a major part of the total cost, and therefore attention should be paid to minimize its energy and size. The voltage requirement can be minimized by using an easily decomposed salt and ensuring that all current carrying parts are as short as possible and have the greatest possible cross-sectional area. The requirement of 5 current can be reduced by eliminating intermittent operation of the device. Since the introduction of metal into the container is often required intermittently, the invention preferably includes a means for storing a small amount of metal inside the device 10 until required. A device is also included to feed the stored metal and produced when required. However, metallic sodium and other Group A metals present a safety problem, therefore the apparatus preferably includes a device to ensure the minimum possible amount of metal present at any given stage of the addition process. For this reason, an inert gas under pressure is the preferred method for pumping the molten metal from the electrolysis compartment into the container. When employs a secondary pumping system to move the metal from the apparatus to the container, it is desirable to include a sensor for the flow of metal in such a way that the flow can be established at an optimum rate. This sensor can also help detect blockages in the pipeline metal feed, for example. In the case in which gas pressure is used, one or more gas pressure gauges are preferably used. The solid state electrolyte for sodium addition is • Sodium beta preference "alumina Sodium sodium" alumina has a sodium ion conductivity similar to the conductivity of molten salts with negligible electronic conductivity over a wide range of temperatures but another electrolyte that conducts the proper sodium ion can be used. The solid state electrolyte for the addition of 10 lithium is preferably lithium beta alumina even when, again, any other electrolyte which conducts the suitable lithium ion can be used. Accordingly, it is possible through the present invention to control the addition of a metal to a melt by the control of the charge in the electrolyte in the solid state. The amount of material pumped through the solid state electrolyte is determined by Faraday's law. In the case of 26.8 ampere hours, one mole of monovalent ionized metal is pumped through the solid state electrolyte. A sensor can be inserted for the metal added, for example, for sodium, in the melt, and the addition of the metal can be monitored and controlled to a predetermined desired level. They can then be maintained at this level without needing add excess, thereby significantly reducing waste and smoke as well as slag production and these advantages are achieved without any risk of container failure within the merger. • A substantial amount of gas can be produced during the application of the method, such that the arrangement of the first electrode should preferably be such that the effect of the gas on the electrolytic process is minimized. For example, the gas produced by electrolysis may have difficulty leaving between the anode and the electrolyte. The ? The distance between the anode and the electrolyte can represent a compromise between being small enough to provide efficient electrolysis and large enough to allow the exit of the gas produced at the anode. In one embodiment, use is made of the fact that the gas produced at the anode decreases the overall density of the source material (i.e., melted metal compound or metal compound solution) where it is discharged. This difference in density is used to create a flow of source material between the anode and the source material in a direction that helps the removal of gas from this region. In addition, or alternatively, a pump may be used to circulate the source material and thereby assist in the removal of the gas. Advantageously, the anode can be permeable to gases, for example, porous. The first The electrode may comprise, for example, a gas permeable electrically conductive layer in the solid state electrolyte. The arrangement of the second electrode in relation to the container can be such that it minimizes the inventory of melted metal.

Alternatively, melted metal can be produced electrolytically on a continuous basis and held in a tank between the container and the container and pumped when required. The speed of electrolysis can be increased in this way. j < The first electrode can, for example, generally have the shape of a cylinder, preferably a hollow cylinder. Advantageously, the first electrode and the solid state electrolyte can have shapes such that they are separated by a substantially constant minimum distance. substantially over all of its opposite surfaces. This can substantially prevent the formation of a concentration of current at a particular point in the solid state electrolyte, which could cause its premature failure. This is especially important when the electrolyte is formed from beta alumina. The apparatus of the present invention preferably includes a control device, for example, a timer and / or a monitoring device, which causes the melted metal compound or melted metal compound solution be replaced periodically; the method of the present invention preferably includes a step of replacing the melted metal compound or melted metal compound solution, periodically. This periodic replacement (or # "purge") of the melted metal compound, or melted metal compound solution, preferably prevents substantially the accumulation of precipitates that can be formed, for example, from impurities or from the reaction of the metal compound with air. For example, if sodium hydroxide is used as the source material for mg, the metal (in this case, sodium) can react with carbon dioxide in the air to form carbonate which will normally have a slower electrolyte decomposition than hydroxide. sodium and can therefore accumulate over time and form a precipitate that could form a plug.

Alternatively, the production of carbonate can increase the melting point of the source material above the temperature of the operation, causing solidification which can prevent the source material from coming into contact with the first electrode. As based on the apparatus of the present invention is placed outside the container containing the melt, a wider range of container operating temperatures can be employed, allowing a wider range of metal compounds to be used. Particularly, the operating temperature of the apparatus can be minimized (compared to the temperature of the melting container), consequently allowing the use of cheaper materials and a simpler construction. If required, the sealing of the system can also be implemented in a generally simpler manner. In addition, the design of the apparatus of the present invention avoids thermal shock problems associated with the prior art designs where the container must be immersed in the melt in the container, and particularly in the case of fjßk 10 aluminum fusions, exceeds the problem that solid-state electrolytes are not stable in melted aluminum. The apparatus preferably includes a duct, for example, a feed duct for transporting the melted metal to the melt. The duct can be totally enclosed in such the metal is isolated from the external environment, for example, it may be submerged in the fusion. This is particularly important for the addition of sodium, for example. The duct can be a simple tube or the like, but preferably it is a rotor, for example, as illustrated schematically in Figure 5. The duct can be formed of refractory material, for example, a ceramic material (alumina is a possibility), or it can be formed from a metal that has a melting point higher than the melting temperature, for example, it can be formed from steel.

Alternatively, the apparatus may include a device, preferably a pump, that transports the melt material out of the container for the addition of the metal to the melt material at an external location relative to the container. Preferably, the melt is conveyed to the apparatus or adjacent to the apparatus for the addition of the metal to the melt in the apparatus or adjacent to the apparatus. The apparatus normally includes an external frame which 10 encloses the other components, for example, for thermal insulation (to protect the operators), and also to assist in its positioning and assembly in relation to the fusion vessel. In the following, embodiments of the invention will be described by way of example with reference to the accompanying drawings in which: Figure 1 is a partial cross-sectional detailed view of a container for a metal addition compound for use in compliance arrangement; with one embodiment of the present invention; Figure 2 is a similar view of an arrangement in accordance with an alternative embodiment of the present invention; Figure 3 is a cross-sectional representation of another embodiment of the invention; Figure 4 is a cross-sectional representation of an alternative embodiment of the present invention; Figure 5 is a cross-sectional representation of a further embodiment of the present invention; and Figure 6 is a schematic arrangement of an additional embodiment 5 of the present invention. An arrangement of a stainless steel 12 container and a beta alumina cap 14 is shown in Figure 1. The sodium beta alumina cap 14 sits within the container 12 and the ferrule contains a melt 15 composed of melted sodium at its lower end. A nickel tube anode 30 extends downward toward the bottom of the bushing 14 in the melt bath of melted sodium compound 15 and has a heating element 31 wrapped around its upper portion to provide the device to melt the sodium compound. The tube contains a 32 mesh nickel to prevent the sodium compound from passing through until it is melted. The container 12, which acts as a cathode, is in contact with a steel mesh 33, located between the container 12 and bushing 14 and offers an electrical path between them. The package 12 has an outer collar 34 adjacent to its upper end where it can be supported by fixation on a suitable structure at any desired location.

A heat resistant seal ring 35 seals the annular space 36 between the inner and outer containers, ie, between the container 12 and an upper extension 37 of the cap 14. This upper extension can be formed of alpha alumina or • any other material compatible with beta "alumina 5 An inlet 38 for an inert gas, for example, argon, leads to an annular space 36 to avoid unwanted oxidation reactions and / or to reduce the melted sodium inventory. When passing the current, the sodium ions present in the melted compound pass through the wall of the cap, they are discharged and the melted sodium then flows down through the outlet 39 into the base of the container 12 and into a container of An aluminum melt (not illustrated) Figure 2 shows an arrangement of a container 23 and a solid electrolyte in the form of a ferrule 24 wherein the ferrule is again inside the container but a sodium compound melted in the container. the container 23 is outside the bushing 24, the bushing extending into the melted compound In this arrangement, a solid sodium compound is fed downwardly from a socket 40 through a power supply. or 41 towards a tube 42 having an external nickel mesh 43. A heater 44 surrounds the lower portion of the tube 42 whereby the solid sodium compound, maintained by the mesh 43, can melt. The melted compound 25 flows down into the container 23, which contains a ^ ^ ^, Nickel tube 22 that acts as an anode. The package 23 is surrounded by a heater 45 to keep the compound in its melted state. • Inside the container 23 is a sodium cap "5 alumina 24. The base of the ferrule 24 leads to a passage provided by a stainless steel cathode tube 47, which extends exactly in the ferrule. from an alumina feed tube 48 to a container containing an aluminum melt (not shown AlO) between the ferrule 24 and the cathode 47 and in contact with them there is a steel mesh 46 which offers an electrical path between them The container 23 and the heater 45 are surrounded by an insulation 49 and the apparatus is fully maintained within a protective cover 50 through which the tube 47 extends. When passing current, the sodium ions present in the compound The gas flows through the wall of the ferrule 24 towards its internal part, discharges, and the melted sodium flows 20 downwards through the pipes 47 and 48 into the aluminum container. During the process, it escapes upwards through a vent 51 at the upper end of the container 23. In this arrangement, gas can be emitted into the ferrule from which it can exit more easily.

Figure 3 shows an alternative method for sealing the cathode 132 on the solid electrolyte 14 in the form of a cap. An airtight seal is formed between the bushing and the alumina ring 57 by a suitable cement or glass seal at 56. A transverse cut ring L is made from a thin section of metal and fastened on the alumina ring at point 77. The metal ring is then welded on the cathode at point 58 using a suitable technique such as laser welding. This assembly is then placed in the anode / source material container 131 using a support ring 134. When the electrolysis has produced enough metal to fill the electrolyte to the level of the orifice 133, the metal can be pumped through a tube 137 into the melt in the container by feeding inert gas through the tube 38. The source material 15 in the anode / container 131 is heated to the desired temperature using a heater 130. Fresh source material 139 in the container '138 is added by melting it with heater 140 and the melted metal drops are shown schematically (141). Electric power is provided for electrolysis to the cathode via cable 135, and 136 is the electrical connector to the anode. The gas created by the electrolysis process escapes through the orifice 55. The entire unit is assembled and protected by a casing 50 which may contain thermal insulation. In figure 4 the gas created at the cylindrical anode or first • Electrode 71 is accumulated from metal source material in the annular space between the space between the anode and the solid electrolyte 70 in the form of a ferrule. The gas rises and brings the source material 69 with it to the surface, the typical level of which is indicated by 91. The gas leaves the source material and rises to the steam or filter trap. , 10 before being ejected from the device (through a suitable tube if required). The source material without gas then flows down to the bottom of the device again through the tube 72. The source material therefore flows in the direction illustrated by arrow 94. The heater for the electrolysis compartment 74, surrounds the anode. There is a heater 92 for the source material heating compartment, and a partition 93 divides the two compartments avoiding thermal shock of the electrolyte when the valve 88 is opened to allow the entry of the electrolyte.

Source material, cool, cool through the feed tube 90. A flexible piece of conductive material 79 is placed in the solid electrolyte 70 in order to constitute the first electrical contact between the electrolyte and the second Electrode 75. Once the electrolysis has begun, the sodium fills the electrolyte until it reaches the orifice 76 and electric contact with most of the internal part of the electrolyte is established in this way. The second electrode or • cathode 75 contains a hole through which the sodium metal produced by electrolysis flows. The melted sodium falls to the bottom of the hollow cathode and using gas under pressure can be pumped through the tube 73 into the melt in the vessel (not shown). The gas under pressure is introduced through the valve 84 and, if it is desired to monitor the sodium flow rate, a sensor 78 can be installed. A feedback control system for the sodium flow rate can be established using a sensor 78 and a valve 84. An alumina collar 77 is fixed on the solid electrolyte using a material airtight to suitable gases, for example, ceramic cement and / or gas, and both electrodes are sealed against it. The figure shows an example of a sealing mechanism in < flb where graphite-based joints 82 are strongly pressed between the electrode with which they are in contact and the alumina ring. The pressure is created by a suitable mechanism that compresses by spring 80 towards the anode seal surface. A protruding ring with blade edge at the cathode 117 cuts into the aluminum ring 81 and prevents the sodium from being in contact with the graphite. A ring protruding 116 at the anode prevents graphite joints -.- fe ^^ «-» are compressed excessively or unevenly, since uneven compression could cause the electrolyte to come into contact with one of the electrodes and break. Additional protection against this problem is offered by rings 95 on the anode and cathode that maintain a regular spacing between the electrolyte and both electrodes. A tank of liquid source material 87 is connected to the device using a flexible tube 89. A 10 If, for any reason, excessive pressure builds up inside the device (for example, if the source material is an aqueous solution). and the trap 85 in the gas outlet orifice becomes blocked preventing the release of steam released by the evaporation of the liberated water), The tube 89 is detached from the pipe 90 and the source material no longer penetrates the device. To equalize the pressure in the package 87 there is an air vent 86. ß Figure 5 shows a cross-sectional representation of another embodiment of the invention having characteristics specifically adapted for the use of a relatively low boiling source material. A source material is brought up into the tube or channel 106 by the gas formed within the anode 71. The gas leaves the source material when it enters a holding tank 112, and then exits the tank through the mist filter 85. A fresh source material is added through the orifice 100 by removing the cover or cover 101 in such a way as to maintain the level near the line 102. m ^ A diverter 110 is present to ensure that the source material entering the channel or tube 107 contains the minimum amount of gas. The source material without gas at 107 is heavier than the material containing gas at 106 which promotes the circulation of material in the space between the anode 71 and the electrolyte 70. The holding tank AlO 112 is high to cause a circulation faster in such a way that the distance between the anode 71 and the electrolyte 70 can be minimized in order to minimize the resistance of the electrolysis circuit. A thermocouple 99 is used through a feedback control circuit to switching the heater 92 on to off in order to maintain the material in the tank 112 at an optimum temperature. The barrier at 108 can serve as a heat exchange surface in such a way that the material at 106 is cooled by the material at 107 which at its time is heated. This allows to obtain a temperature in the thermocouple 103 significantly higher than in 99. The heater 74 helps maintain that difference. This feature allows the electrolysis compartment to be operated at a temperature close to the boiling point of source material or even higher than said point of • - "* -'-" * '* -. »• --'.-- boiling the source material. For example, if the source material is sodium carbonate dissolved in acetamide, acetamide is expensive and it is desirable to minimize its ^ lost by evaporation. Typically, the compartment electrolysis should be maintained at a temperature close to the boiling point of acetamide which could cause unacceptably rapid evaporation in tank 112 if it were not cooled by heat exchange on surface 108. In addition, there may be a unit of? 10 condensation (not shown) associated with the cloudy trap 85. The cylindrical cathode 115 can be moved up and down in the guide 111 and through the seal 98. As the metal is pumped into the electrolyte by electrolysis, it is elevates the cathode. When the metal is required in the container, the cathode is pressed down and the metal flows through the tube 73 leading to the container (not shown). There is a sensor 78 for determining the flow velocity of the metal. The position of the cathode is controlled by preference for a mechanism operated by gas, or by a solenoid (or by another suitable mechanical device). The collar 77 and compressible rings 82 form a seal of conformity with the previously described but the compressive force comes from three or more bolts 96. These can not be To establish an electrical short circuit between the electrodes thanks to insulating spacers 97. The cathode guide 111 is long enough to ensure that the cathode does not come in contact with the electrolyte and also to maintain the seal as cold as possible. The elements 113 and 109 are electrical conductors for the electrolysis current towards the anode and cathode, respectively. A drain plug 104 is provided in such a way that the source material can be drained through a tube 105 to allow the bushing to be changed and / or to remove impurities accumulated from the source material after a period of time. period of use. It will be noted that in the embodiments illustrated in Figures 1 to 5, if the bushings crack, the melt flowing through the cracked ferrules will harden at the metal outlet pipe thus avoiding a dangerous flow of melted material in the melt. It may be desirable to add thermal and electrical insulation to several of the parts illustrated in Figures 1 to 5. Suitable arrangements will also be necessary to mount the device near the container. The control of the electrolysis current using information from the metal sensor in the fusion is also a desirable element. All described devices can be extended by using pieces of solid electrolyte. It is also possible to mount the electrolytes in the form of a cap horizontally instead of vertically mounted as illustrated in the figures. In figure 6, an apparatus for improving the diffusion of the melted metal, for example, sodium, in a • fusion of aluminum, for example. In element 60 represents the apparatus of the present invention to electrolytically produce the required melted sodium out of an aluminum melting container 61. Melt sodium flows down through a feed tube 63 into the base of the apparatus 60 and from there on the axis • hollow 64 of a rotor 65. Shaft 64 extends in fusion 62 and distributes inert gas through feed line 66 and sodium in the melt through head 67 of the rotor. The rotor 65 is preferably of the construction described in ! 15 European Patent No. 0332292. Excellent performance is achieved | distribution of material fed through the rotor in the fusion in accordance with that indicated by the arrows in the fusion. A derailleur 68 is placed in the melt to reduce turbulence. twenty

Claims (32)

1. CLAIMS 1. A method to add a metal to a metal melt in a container, where a melted metal compound or ^^ a solution of a metal compound is provided in a container, the container is placed outside the container, the compound is electrolytically decomposed and metal ions are passed through a wall of a solid-state electrolyte which is conductive for the latter, from a first side of the wall to a second opposite side of the wall, and to combine it with electrons on the second side of the wall and then to flow in the form of molten metal from the container towards melting.
2. 2. An apparatus for adding a metal to a melting of a metal in a container, the apparatus comprises a container for 15 a melted metal compound or a solution of the metal compound, the container is placed outside the container, a device for electrolytically decomposing the melted or dissolved ß compound, a wall placed within the container and formed of a solid state electrolyte which 20 is a conductor for metal ions whereby the metal ions formed can pass through the wall from a first side to a second opposite side thereof, an electron source on the second side of the wall to combine with the metal ions and a device to make 25 pass the melted metal formed in this way from the second .-, < -. - .., .- -? ..., .. ^ side of the wall towards the merger.
3. 3. A method according to claim 1, or an apparatus according to claim 2, wherein the container is for a metal melt compound, and a heating device is included which heats the metal compound to obtain a melted form. .
4. A method or apparatus according to any of the preceding claims, wherein the metal is a metal of Group IA of the Periodic Table, preferably sodium or lithium.
5. 5. A method or apparatus according to any of the preceding claims, wherein the metal compound is a metal salt, preferably a hydroxide, carbonate or oxalate salt.
6. 6. A method or apparatus according to any of the preceding claims, wherein the melt is a metal, preferably aluminum or zinc. 1 .
7. A method or apparatus according to any one of the preceding claims, wherein a current passes between a first electrode placed in the melted compound and a second electrode placed beyond or on the second opposite side of the wall of the solid state electrolyte.
8. 8. A method or apparatus according to claim 7, wherein the first electrode is an anode and the second electrode is a cathode and the source of electrons. . ~ - ^ --_ ", -? m r 9.
9. A method or apparatus according to any of claims 7 or 8, wherein the first electrode and the solid state electrolyte are formed such that they are separated by a substantially constant minimum distance substantially over all their opposing surfaces.
10. A method or apparatus according to any one of the preceding claims, wherein the electrolytic decomposition is initiated by contact between the second side of the wall of the solid state electrolyte and the second electrode, and / or by supplying a quantity of metal melted in contact with the second side of the solid-state electrolyte wall before initiating the electrolytic decomposition.
11. 11. A method or apparatus according to any of the preceding claims, wherein the solid-state electrolyte wall forms a (first) container.
12. 12. A method or apparatus in accordance with the claim 11. wherein the metal compound is in the first container, and the first electrode is located in the inner part of the first container in contact with the metal compound.
13. 13. A method or apparatus according to claim 11 or according to claim 12, further comprising an outer package wherein is the first package formed of electrolyte in the solid state.
14. 14. A method or apparatus according to claim 13, when dependent on claim 7, wherein the outer package comprises such an electrode.
15. 15. A method or apparatus according to claim 5, wherein the metal compound is in the outer package but outside the first package.
16. 16. A method or apparatus according to claim 7, or in accordance with any claim dependent thereon, wherein the first electrode is nickel, stainless steel or graphite, and the second electrode is formed of nickel, iron or steel.
17. 17. A method or apparatus according to claim 7, or in accordance with any claim dependent thereon, further comprising several combinations of first 15 electrode, electrolyte and second electrolyte, each of these combinations preferably has the form of a module. Wß¡
18. 18. A method or apparatus according to any of the preceding claims, further comprising a The device, for example, a storage container of metal compound, for restocking the electrolytically decomposed metal compound during use.
19. 19. A method or apparatus in accordance with the claim 18. wherein the device for refilling electrolytically decomposed metal compound 25 during use includes a device for allowing drainage of the metal compound after a period of use.
20. 20. A method or apparatus in accordance with the claim • 18 or according to claim 19, wherein the The device for replenishing the electrolytically decomposed metal compound during use includes a device for heating the metal compound, preferably up to the melting of the metal compound.
21. A method or apparatus according to claim 10, wherein the device for replenishing the electrolytically decomposed metal compound during use allows the boiling of a solution of the metal compound and the melting of the resulting metal compound. .
22. 22. A method or apparatus according to any of the preceding claims, wherein the solid state electrolyte is formed from sodium or lithium beta alumina, or sodium or lithium beta "alumina."
23. 23. A method or apparatus of conformity. with any of the preceding claims, further comprising a 20 sensor for the metal inserted or that can be inserted in the fusion, to monitor and control the amount of metal that is added to the fusion.
24. 24. A method or apparatus according to any of the preceding claims, further comprising a 25 pipe to transport the melted metal to the melt. w Emm * *
25. 25. A method or apparatus according to claim 24, wherein the molten metal is transported in the melt in a stream of inert gas.
26. 26. A method or apparatus according to claim 25, wherein the inert gas pressure is monitored through at least one pressure gauge.
27. 27. A method or apparatus according to any of claims 24 to 26, wherein the duct comprises a rotor.
28. 28. A method or apparatus according to any of claims 24 to 27, including a sensor for measuring the flow velocity of the molten metal through the duct.
29. 29. A method or apparatus according to claim 25 or in accordance with any claim dependent thereon, wherein the duct includes a shut-off valve to prevent oxidation of the molten metal in the case in which the inert gas stream is stopped. .
30. 30. A method or apparatus according to any of the preceding claims, further comprising a device for temporarily storing the melted metal.
31. 31. A method or apparatus according to any of the preceding claims, further comprising a device, preferably a pump, which transports the melt material out of the container for addition of the Ul. I * metal to the melting material in an external location in relation to the container.
32. 32. A method according to claim 31, wherein the melt is conveyed to the apparatus or to a location adjacent to the apparatus for the addition of the metal to the melt in the apparatus or at a location adjacent to the apparatus. .