EA029746B1 - Method and system for electrolytically reducing a solid feedstock - Google Patents

Abstract

In a method of electrolytically reducing a solid feedstock, for example a solid metal oxide feedstock, an electrode module (10) is positioned in a first position to be loaded with the feedstock. The loaded module is then transferred from the first position and engaged with an electrolysis chamber (220) containing a molten salt. A voltage is applied to the electrode module to reduce the solid feedstock. The loaded module may be transferred within a transfer module.

Description

The invention relates to an electrolysis method using an apparatus including an electrode module or assembly.

The level of technology

The present invention relates to a method for reducing a solid material containing a compound or metal compounds, such as metal oxide, to form a reduced product. As is known from the prior art, electrolytic processes can be used, for example, to reduce metal compounds or semi-metal compounds to metals, semi-metals or partially reduced compounds, or to reduce mixtures of metal compounds to form alloys. To avoid repetition, the term “metal” will be used to cover all products such as metals, semimetals, alloys, intermetallic compounds, and partially reduced products.

In recent years, great interest has arisen in the direct production of metals through the reduction of solid raw materials, such as solid metal oxide materials. One of such direct production processes is the electrolytic decomposition process of Sashpbds PPC (described in application SP 99/64638). In a PPC process, a solid compound, such as a solid metal oxide, is in contact with a cathode in an electrolytic cell containing molten salt. An electrical potential is applied between the cathode and the anode of the cell so that the connection is restored. In the PPC process, the potential that the solid compound produces is lower than the deposition potential for the cation from the molten salt. For example, if calcium chloride is used as the molten salt, the potential of the cathode, in which the solid compound is reduced, is lower than the deposition potential of metallic calcium precipitated from the salt.

Other reduction processes are proposed for the recovery of raw materials, in the form of a solid metal compound connected to the cathode, such as the polar process described in application \ 03 03/076690, and the process described in application 03/048399.

With the traditional implementation of the XRD process and other electrolytic reduction processes, as a rule, the production of raw materials in the form of a briquette or a precursor made from a solid compound powder to be reduced is included. This briquette is then carefully connected to the cathode, which ensures the flow of the restoration. When a row of briquettes is connected to the cathode, the cathode can be lowered into the molten salt and the briquettes can be restored. The operation of producing and joining briquettes to the cathode is very laborious. Although this method works well on a laboratory scale, it does not justify itself in the mass production of metal on an industrial scale.

The aim of the invention is to create a method of electrolysis, more adapted for the recovery of solid raw materials on an industrial scale.

Summary of Invention

The invention provides a method for the electrolytic reduction of solid raw materials, disclosed in the claimed independent claim, to which reference will be made. Preferred or predominant features of the invention are set forth in the dependent claims.

Thus, the method of electrolytic reduction of solid raw materials may include the following stages: installation of the electrode module containing at least one electrode in the position for loading raw materials, loading of solid raw materials in the electrode module, moving the electrode module from the position for loading raw materials and introducing the electrode module in contact with the electrolysis section, so that the raw material is in contact with the molten salt in the electrolysis section, applying voltage to the electrode module, so that the solid raw material is restored alos, and extracting the electrode module from the conveying section electrolysis unit configured to provide a controlled environment therein.

Preferably, the electrode module includes at least a cathode and an anode connected to an energy source such that a potential can be created between the anode and the cathode. The electrode module may contain one or more bipolar electrodes.

Preferably, the solid raw material is loaded in such a way that it is in contact with the cathode or the cathode surface of the bipolar electrode.

It may be advantageous for the electrode module to move from the feed position in the transport module. The transport module can take the form of a body forming a chamber into which the electrode module can be lifted. Preferably, the transport module is sealed in such a way that the electrode module can move under controlled conditions, for example, in an inert atmosphere. It may be preferable that the electrode module is heated to a predetermined temperature before being brought into contact with the electrolysis section. In a preferred embodiment, when the electrode module is in contact, the electrolysis section contains molten salt. If the electrode module is not located at an appropriate temperature, thermal deformation or thermal shock of the components of the electrode module may occur, which can lead to destruction of the components of the electrode module. Preferably, the electrode module is heated to a temperature close to the temperature of the molten salt. Therefore, the set temperature can be in the range of approximately from 500 to 1200 ° C, depending on

on molten salt temperature. In particular, preferred temperatures are in the range of from 700 to 1000 ° C, for example from 800 or 850 ° C.

Advantageously, the electrode module can be heated in an inert atmosphere in the transport module. The transport module may contain heating elements that, in order to heat the electrode module, raise the temperature in the module to a predetermined temperature. Alternatively, the transport module may include devices that provide heated gas to the transport module for heating the electrode module.

It may be preferable that the electrode module be moved from the transport module to the heating station to heat to a predetermined temperature. For example, the transport module can be connected to a heating station and move the electrode module to a separate heating station to provide heating of the electrode module. In this embodiment, the transport module itself does not necessarily contain heating elements.

Thus, it may be preferable for the electrode module to move from the loading station to the transport module, lower to the heating station, heat to a predetermined temperature, and rise back to the transport module to move to the electrolysis section.

The electrode module is preferably sealed in the transport chamber of the transport module by closing the gate. Preferably, the shutter is a gate valve in which the gateway is movable to seal the transport chamber with the transport module.

The opening of the electrolysis section, i.e. the opening through which the electrode module can move for contact with the electrolysis section is preferably closed by the opening gate. Particularly preferably, the valve is a gate valve that can be opened to allow the electrode module to pass to the electrolysis section.

After electrolysis, it may be desirable to remove the electrode module from the electrolysis section to return the recovered raw materials. It is preferable to remove the electrode module that is at the operating temperature of the electrolysis section (or near it) and under conditions in which the molten salt contained in the electrolysis section is still in the molten state.

It may be advantageous for the electrode module to cool down in an inert atmosphere in the transport module after being removed from the electrolysis section. If the electrode module is at a high temperature, for example 800 ° C, it is important that the module does not come in contact with oxygen or air until the temperature is sufficiently low to avoid self-ignition of any carbon components of the electrode module, or rapid oxidation of any recovered raw materials located in the electrode module.

After removal from the electrolysis section, the electrode module may cool down in an inert atmosphere in the transport module. Thus, the transport module may include cooling devices, such as water cooling pipes, or may include devices for the passage of cooling gas through the transport module to reduce the temperature of the electrode module.

Alternatively, the electrode module can move in the transport module to a separate cooling station, being cooled to a predetermined temperature in an inert atmosphere.

Preferably, the cooling station includes a cooling chamber into which an electrode module can be inserted for effective cooling. Thus, the method may include the steps of moving the electrode module to the cooling station in the shipping module, lowering the electrode module to the cooling station, cooling the electrode module to a predetermined temperature, and raising the electrode module back to the transporting module to move from the cooling station.

The molten salt remaining in the electrode module will solidify as the electrode module cools. Therefore, the electrode module after cooling will be covered with a film of solidified salt. It may be advantageous to move the electrode module to the washing station to wash out the salt from the recovered material. The washing station may include a washer suitable for directing jets of water to the electrode module in order to wash the salt from the raw materials. The washing station may also include devices for collecting used water from the washing process.

It may be advantageous for the electrode module to move to a separate discharge station to facilitate access to the electrode module for unloading the recovered raw materials. It is particularly preferable that the electrode module is provided with removable trays that can be detached from the electrode module. Thus, it may be preferable that the solid raw material is loaded into removable trays separately from the electrode module, and then the removable trays are connected to the electrode module to load the raw material into the electrode module. In addition, it may be advantageous for the trays to be removed from the electrode module to facilitate unloading of reproduction.

become raw materials.

Preferably, the raw material is loaded in such a way that it is in contact with the cathode structure of the electrode module, for example, the surface of the cathode or the cathode surface of the bipolar electrode. This is essential if the reaction to recover the raw material takes place using the PPC process. However, another recovery process may be used.

It is particularly preferable that the electrolysis reaction in this method takes place due to the electrolytic reduction of the solid raw material, for example, electrolytic reduction using the PPC process.

The method can be used for use with any electrode module that can be loaded with raw materials and brought into contact with the electrolysis section for the electrolysis of raw materials. There may be a number of specific embodiments of the electrode module that may preferably be used in this method.

In a preferred embodiment of the invention, it may be advantageous for the electrode module to be a movable electrode module for contacting the electrolysis section, the movable electrode module comprising a first electrode, a second electrode and a suspension structure including a suspension rod, preferably connected at one end of the rod with the first electrode in which the second electrode is suspended, or supported by a suspension structure, and in which the suspension structure contains at least one electrical insulator a spacer for holding the second electrode in spatial separation with the first electrode.

In a further preferred embodiment of the invention, it may be an advantage that the electrode module is a movable electrode module for bringing into contact with an electrolysis section, the movable electrode module including an anode and a cathode for holding a portion of solid raw material, when restored by electrolysis in a molten salt electrolyte, the raw material is kept in contact with the cathode.

In a further preferred embodiment of the invention, it may be advantageous for the electrode module to be a movable electrode module for bringing into contact with an electrolysis section, with a movable electrode module including a first electrode and a cover in which, when the movable electrode is brought into contact with an electrolysis apparatus, the first electrode is located in the electrolysis section so that it can be used for electrolysis, and the cover covers the opening of the electrolysis section.

In a further preferred embodiment of the invention, it may be an advantage that the electrode module is a movable electrode module for bringing into contact with the electrolysis section, the movable electrode module including a lifting element for lifting the module, a first electrode connected to the lower end of the suspension rod, and spring loaded devices, located between the lifting element and the upper end of the suspension rod.

The various aspects and variations of the invention disclosed herein are particularly suitable for the production of metal by reducing the solid raw material containing solid metal oxide. Pure metals can be formed by reducing pure metal oxides and alloys, and intermetallic compounds can be formed by reducing a raw material containing a mixture of metal oxides or a mixture of pure metal oxides.

Some reduction processes can be carried out only when the molten salt or electrolyte used in the process contains types of metals (reactive metals) that form a more stable oxide than the metal oxide or compound to be reduced. Such information can be easily obtained from thermodynamic data, especially Gibbs free energy data, and can be simply determined from the standard Ellingem diagram or the dominance diagram or the Gibbs free energy diagram. Thermodynamic data on the stability of oxides and Ellingem diagrams are available and understandable to electrochemists and specialists in the field of extraction metallurgy (the specialist in this case should be aware of such data and information).

Thus, the preferred electrolyte for the reduction process may contain a calcium salt. Calcium forms a more stable oxide than most other metals, and therefore can contribute to the reduction of metal oxide, which is less stable than calcium oxide. In other cases, salts containing other chemically active metals may be used. For example, the reduction process in accordance with any aspect of the invention disclosed herein may be performed using a salt containing lithium, sodium, potassium, rubidium, cesium, magnesium, calcium, strontium, barium, or yttrium. Chlorides or other salts may be used, including a mixture of chlorides or other salts.

By selecting the appropriate electrolyte, using the methods and devices disclosed here, almost any metal oxide can be reduced. In particular, oxides of beryllium, boron, magnesium, aluminum, silicon, scandium, titanium, vanadium, chromium, manganese, iron, cobalt, nickel, copper, zinc, germanium, yttrium, zirconium, niobium, molybdenum, hafnium, tantalum, can be reduced tungsten and lanthanides, including lanthanum, cerium, praseodymium, neodymium, samarium, and actinides, including actinium,

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thorium, protactinium, uranium, neptunium and plutonium, preferably using molten salt containing calcium chloride.

The specialist will be able to select an appropriate electrolyte that is suitable for the reduction of a separate metal oxide, and in most cases, an electrolyte containing calcium chloride will be suitable.

Specific Inventions

Specific embodiments of the invention will now be described with reference to the figures, in which: FIG. 1 is a perspective view of a movable electrode module embodying one or

several aspects of the invention;

in fig. 2 is a side view of the movable electrode module of FIG. one; in fig. 3 is a plan view of the movable electrode module of FIG. one;

in fig. 4 is a side cross-sectional view of the movable electrode module of FIG. 1, showing the structure of various electrodes and supporting components of the movable electrode module;

in fig. 5 is a schematic sectional view of an electrolysis apparatus having an electrolysis section suitable for receiving a movable electrode module in the embodiment shown in FIG. one;

in fig. 6 is a sectional diagram showing the movable electrode module of FIG. 1 in contact with the electrolysis apparatus shown in FIG. five;

in fig. 7 is a sectional diagram showing the movable electrode module of FIG. 1 placed in the transport module of the electrolysis apparatus of FIG. 5, in a state of readiness for bringing the electrode module into contact with the electrolysis section in the electrolysis apparatus;

in fig. 8 is a sectional diagram showing the movable electrode module of FIG. 1 after it has been removed from the transport module and brought into contact with the electrolysis apparatus of FIG. five;

in fig. 9 is a perspective view of a removable cathode tray structure suitable for use as a cathode tray in the movable electrode module of FIG. one;

in fig. 10 is a plan view of the cathode tray construction of FIG. 9; in fig. 11 is a side view of the cathode tray structure of FIG. 9;

in fig. 12 is a cross-sectional view of a second embodiment of a movable electrode module in accordance with one or more aspects of the invention;

in fig. 13 is a cross-sectional view of a third embodiment of a movable electrode module in accordance with one or more aspects of the invention;

in fig. 14 is a schematic cross-section of an alternative method for connecting the movable electrode module with lifting devices, in accordance with an embodiment of the present invention;

in fig. 15 shows a schematic representation of the electrode module located at the loading station, with the transport module located above the electrode module;

in fig. 16 shows a schematic representation of the electrode module held in the transport module above the heating station;

in fig. 17 shows a schematic representation of the transport module connected to the heating station;

in fig. 18 is a schematic representation of an electrode module held in a transport module over a cooling station;

in fig. 19 shows a schematic representation of a transport module connected to a cooling station;

in fig. 20 shows a schematic representation of an electrode module subjected to washing in a washing station.

The movable electrode module in accordance with the first embodiment of the present invention will now be described with reference to FIG. 1-4. The electrode module 10 contains a contact anode 20, a contact cathode 30 and seven bipolar electrodes 40, 41, 42, 43, 44, 45, 46, distributed with spatial separation from each other above the contact cathode 30 and below the contact anode 20. Contact cathode 30, the contact anode 20 and each of the intermediate bipolar electrodes 40, 41, 42, 43, 44, 45, 46 are essentially circular in shape and have a diameter of about 550 mm.

The contact cathode 30 has a composite structure consisting of a lower part and an upper part. The bottom part is essentially a cathode base element 30a made of a 310 grade stainless steel disc having a diameter of 550 mm and a thickness of 60 mm. The upper part is represented by a removable tray 30b assembled, mounted on the upper surface of the base element 30a. Removable tray assembly 30b is shown in FIG. 9, 10 and 11 and will be described in detail below. A central hole with a diameter of about 130 mm passes through the central part of the assembled tray 30b in the collection.

Each of the seven bipolar electrodes 40, 41, 42, 43, 44, 45, 46 has a composite structure including the lower part 40a, 41a, 42a, 43a, 44a, 45a, 46a and the upper part or tray 40b, 41b, 42b, 43b , 44b, 45b, 46b assembled. The top or tray assembly of each of the bipolar electrodes is identical 4 029746

on the top or on the tray 30b assembly of the contact cathode 30.

The lower parts 40a, 41a, 42a, 43a, 44a, 45a, 46a of each of the bipolar electrodes are made of carbon disks, for example, graphite, having a diameter of 550 mm and a thickness of 60 mm. Through the central part of each of the bipolar electrodes 40, 41, 42, 43, 44, 45, 46 passes a hole with a diameter of about 130 mm.

On the lower surface of each bipolar electrode, a plurality of channels 50 approximately 10 mm wide are made to facilitate the diversion of gas languages that form on the lower surface of each bipolar electrode to the outer circumference of each bipolar electrode.

The first bipolar electrode 40 is supported directly above the contact cathode 30 by means of the first electrically insulating spacer 60. The first electrically insulating spacer 60 is a tubular spacer made of alumina. The first electrically insulating spacer, alternatively, may be made of another electrically insulating ceramic material, such as yttria or boron nitride.

In some embodiments, the first electrically insulating spacer 60 is mounted directly on the cathode base member 30a. In other embodiments, the ceramic insert 70, made of a ceramic material that will not be restored under cell operating conditions, is located between the contact cathode base element 30a and the first electrically insulating spacer 60.

The bottom surface of the lower portion 40a of the first bipolar electrode 40 is mounted on the first electrically insulating spacer 60 such that the first bipolar electrode 40 is supported by the first electrically insulating spacer 60 through the base element 30a of the contact cathode.

The second bipolar electrode 41 is supported directly above the first bipolar electrode 40 by a second electrically insulating spacer 61. The second electrically insulating spacer 61 is a tubular element of alumina, which is almost identical to the first electrically insulating spacer 60. The second electrically insulating spacer is mounted on the upper surface of the lower part 40a of the first bipolar electrode 40. The lower surface of the lower part 41a of the second bipolar electrode, in turn, is installed on the second electrically insulating a strut in such a manner that the second bipolar electrode 41 is supported by the second electrically insulating strut 61 by the first bipolar electrode.

This support structure is repeated for each of the bipolar electrodes. Thus, the third bipolar electrode 42 is supported by the second bipolar electrode 41 through the third electrically insulating spacer 62. The fourth bipolar electrode 43 is supported by the third bipolar electrode 42 through the fourth electrically insulating spacer 63. The fifth bipolar electrode 44 is supported by the fourth bipolar electrode 43 through the fifth electrically insulating electrode through the fifth electrically insulating electrode via the fifth electrically insulating electrode 44. The sixth bipolar electrode 45 is supported by the fifth bipolar electrode 44 through the sixth electrically insulating spacer 6 5. The seventh bipolar electrode 46 is supported by the sixth bipolar electrode 45 through the seventh electrically insulating spacer 46.

The contact anode 20 is made in the form of a graphite disk having a diameter of 550 mm and a thickness of 60 mm. Channels are made on the lower surface of the anode in the same manner as defined above in connection with bipolar electrodes. One of the purposes of these channels is to facilitate the discharge of gas emitted on the lower surface of the contact anode 20. In the central part of the contact anode 20, a hole having a diameter of about 130 mm is made. The contact anode is supported directly above the seventh bipolar electrode 46 through the eighth electrically insulating spacer 67.

The movable electrode module 10 also includes an insulating ceramic cover 100 located directly above the contact anode 20. The cover 100 is made of aluminum oxide, although any thermally insulating ceramic material can be used, and it is designed to close the electrolysis section in the electrolysis apparatus during the electrolysis reaction . The cover 100 is held on the upper surface of the contact anode 20 by means of the ninth electrically insulating support element 68. The ninth electrically insulating support 68 is similar to the previously described electrically insulating support elements, but has a greater length.

In the cover 100, a central opening is made. Thus, the hole or cavity formed by it extends down through the movable electrode module from the upper surface 101 of the cover 100 through a tubular electrically insulating spacer 68, through the center of the anode and through each of the bipolar electrodes and the associated spacers. The suspension rod 110 passes through this hole or cavity and is connected to the cathode base element 30a of the contact cathode 30 by means of a thread, which is connected to a threaded hole made in the cathode base element 30a. Hanging rod 110 is not in contact with other electrodes or spacers. At the point where the suspension rod 110 passes through a central opening made in the lid 100, a seal is formed formed by means of graphite packing of a gland, for example braided graphite cord or similar materials 120 for packing a gland.

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At the top of the suspension rod 110 is connected to the connector 130 with a bayonet groove. The bayonet groove connector is a bayonet connector, well known for connecting pipe sections in the oil industry. The connection between the hanging rod and the bayonet groove connector is achieved using washers and nuts 111.

Hanging rod 110 can be used to lift the entire movable electrode module 10, for example, when raising or lowering the electrode module. It may be necessary to operate the suspension module at high temperatures. Therefore, the rod 110 and the nuts and washers 111 interacting with it, which connect the rod 110 and the connector 130 with the bayonet groove, are made of a high-alloyed nickel alloy suitable for operation at high temperatures.

The anode 20 is connected to two graphite risers 21, 22 for making electrical connection between the energy source (not shown) and the contact anode 20. The graphite risers 21, 22 are connected to the contact anode 20 by means of graphite contacts 23, 24. Graphite risers 21, 22 pass vertically above the contact anode 20, through holes made in the cover 100, so that when the movable electrode module is in contact with the electrolysis section of the electrolysis apparatus, the electrical connection can be made the uppermost part of the riser. The gap between the risers 21, 22 and the interacting holes, made in the cover 100, for the passage of the risers, is sealed by means of braided graphite cord or other similar materials 25 for stuffing box gland.

The movable electrode module 10 is designed to operate in three states of loading or support.

In the first of these three states, the movable electrode module is mounted on the lower surface of the cathode base element 30a. In this state, the weight of all the bipolar elements, the anode and the cover is transmitted through the cathode base element 30a, and the suspension bar 110 is not in a stressed state.

In the second loading state, the connector 130 with a bayonet groove is connected to the lifting mechanism, and the entire weight of the module is supported by the suspension rod 110, which is connected to the cathode base element 30a.

In the third loading state, the movable electrode module 10 can be maintained at several points on the bottom surface 102 of the cover 100. In this state, the weight of the module is supported by the cover 100, and is transmitted through the suspension rod 110, which is connected to the cathode base element 30a.

Thus, the module can be free-standing on the cathode base element 30a, it can be suspended using a bayonet-slotted connector 130 at the upper end of the suspension rod 110, or it can be suspended on the underside 102 of the lid 100.

Since the suspension rod 110 passes through the cover 100, the suspension rod 110 is covered or clad with an electrically insulating material 115 along the entire length, from the connection point of the cathode base element 30a to the sealing point with a braided graphite cord 120. The electrically insulating material is an aluminum oxide coating 115, but can be any high temperature electrically insulating material. For example, the coating 115 may be boron nitride. The coating may be applied in any known manner, for example by a dip coating or spray coating method.

A removable tray assembly, which forms part of the contact cathode 30 and each of the seven bipolar electrodes 40, 41, 42, 43, 44, 45, 46, is shown in FIG. 9, 10 and 11. Tray 30b, 40b, 41b, 42b, 43b, 44b, 45b, 46b assembly is made of two connecting parts 151, 152. When connected, the entire tray assembly is essentially round, and at room temperature has a diameter of about 542 mm. The assembled tray is metallic, and therefore, due to thermal expansion at the operating temperature of the moving electrode module (usually between about 500 and 1200 ° C when used in the electrolysis reaction in molten salt), its diameter can increase to about 550 mm.

The base 153, 156 of each of the parts 151, 152 of the tray assembly is made of a mesh suitable for holding solid material. A peripheral board extends approximately 30 mm above the level of the grid 153, 156 along the circumference of the assembled tray assembly. From the peripheral side 154 downwards a distance of about 10 mm below the level of the grid 153, 156 a row of legs 155 protrudes.

For the formation of the electrode in the electrode module, the entire tray assembly can be mounted on the upper surface of the interacting part of the electrode. For example, for the formation of the contact cathode 30, the tray 30b in the assembly can be mounted on the upper surface of the plate 30a of the base of the contact cathode, or to form a bipolar electrode, the tray 40b, 41b, 42b, 43b, 44b, 45b, 46b in the assembly can be mounted on the upper surface of the lower part the bipolar electrode 40a, 41a, 42a, 43a, 44a, 45a or 46a. Electrical contact is made between the tray assembly and the interacting part of the electrode, through downward legs 155.

When a movable electrode module including removable trays assembly 30b, 40b, 41b, 42b, 43b, 44b, 45b, 46b is located in the electrolysis section containing the molten salt, the molten salt can flow into the gap formed between the upper surface of the electrode portion which

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mounted tray assembly, and the base 153, 156 of the grid. Therefore, the molten salt can flow up through the base 153, 156 of the grid of the tray assembly and, thus, through any solid raw materials held on the base 153, 156.

The tray assembly is formed in such a way that it has a central opening surrounding the electrically insulating strut, for example, an electrically insulating strut 60 that supports the first bipolar electrode 40.

The tray assembly is formed of two connecting parts, i.e. the first part 151 and the second part 152, each part is essentially a semicircle. The two parts 151, 152 are connected by means of a pin and a slot. The pins 160 pass from the mating surface or the mating edge 162 of the second part through the slots 161 for receiving pins 160, made in the corresponding mating surface 163 of the first part 151.

During operation, each half or each portion 151, 152 of the tray assembly may be separately removed from the movable electrode module 10 for loading raw materials or unloading the reconstituted product.

Removable tray trays form the uppermost part of the contact cathode and each of the bipolar electrodes. When a moving electrode module is used for electrolysis, these parts of the respective electrodes become cathodic.

Removable tray assemblies 30b, 40b, 41b, 42b, 43b, 44b, 45b, 46b are made of stainless steel 310. Removable tray trays can be made of many other materials, and the choice of material may depend on the nature of the raw material being recovered. For example, it may be desirable to use a tray assembly made of metal that will not contaminate the reconstituted product. For example, if a movable electrode module is to be used to reduce tantalum oxide to metallic tantalum, it may be desirable to make a cathode tray assembly from tantalum or tantalum-coated metal.

The movable electrode module in accordance with the first specific embodiment described above may be particularly advantageous when used to recover solid raw materials in molten salt electrolyte. Removable assembly trays allow you to conveniently load solid materials into each individual part 151, 152 of the tray assembly and load them into a movable electrode module, setting the loaded parts of the tray assembly in the appropriate position in the electrode module.

At room temperature, the movable electrode module 10 has a total height from the bottom surface of the cathode base plate 30a to the bottom surface of the cover 100 about 1645 mm. The height from the bottom surface of the cathode base plate 30a to the top of the connector 130 with the bayonet groove is 2097 mm. As indicated above, the diameter of the electrodes 30, 40-46 is 550 mm. The maximum diameter of the cover 100 is 830 mm. Some of these sizes are subject to changes with temperature changes. In particular, at the operating temperature of the electrode module, the height values can increase by 5-10 mm.

The movable electrode module 10 in accordance with the first embodiment of the invention described above can advantageously be used in any electrolysis apparatus containing an electrolysis section suitable for installing module 10 in contact with it. A schematic representation of such an electrolysis apparatus 200 is shown in FIG. five.

The electrolysis apparatus 200 includes a housing 210 comprising an electrolysis section 220 formed inside a graphite crucible 230, an upper rim 231 of a graphite crucible 230 forming a hole in the electrolysis section 220. The upper surface of the rim 231 is covered with a layer of elastic graphite material 15 mm thick to seal the rim 231 and the bottom side of the cover 100 of the movable electrode module 10. The sealing material mounted on the upper rim 231 is a braided graphite packing of the gland that can deform and regain its shape.

The housing 210 further comprises furnace heating elements 240 for maintaining the temperature of the graphite crucible 230, the inlet 250 for the molten salt and the outlet 260 for the molten salt, to ensure the flow of the molten salt through the electrolysis section 220. To ensure the release of gas released during the electrolysis reaction in the electrolysis section, a gas vent line 270 is provided to the upper part of the electrolysis section 220. A cathode supply bus 280 is connected to the graphite crucible 230 and provides a direct connection of the entire graphite crucible 230 to the power source.

Graphite crucible 230 lined with lining 290 of alumina. An alumina lining 290 provides electrical insulation between the side walls of the graphite crucible 230 and any movable electrode module 10 brought into contact with the electrolysis section 220. Although the lining is made of alumina, it can be made of any electrically insulating ceramic material that is substantially inert under the processing conditions in electrolysis section 220.

The upper part of the electrolysis apparatus contains a gate 300 of the type of a gate valve, which provides external access to the electrolysis section 220. Gate 300 type gate valve

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includes a gateway 310, made of a material that creates a thermal barrier, for example, a ceramic material. The control device 320 allows the gateway 310 to move back and forth to open and close the gate valve 300, thus providing access to the electrolysis section 220 in the electrolysis apparatus 200.

FIG. 6 shows a movable electrode module in accordance with the first embodiment, previously described with reference to FIGS. 1-4, brought into contact with an electrolysis apparatus of the type shown in FIG. five.

The lower inner surface of the graphite crucible 230 is raised, forming a pedestal 232. When brought into contact with the electrolysis section 220, the movable electrode module 10 is mounted on the raised pedestal 232 in the graphite crucible 230. Thus, the lower surface of the contact cathode 30 of the movable electrode module is located in the physical and electrical contact with the inner surface of a graphite crucible 230.

The bipolar electrodes 40-46 and the anode 20 of the movable electrode module 10 are located in a portion of the electrolysis section in such a way that they are electrically isolated from the side wall of the crucible 230 with ceramic lining 290. The bottom surface 102 of the cover 100 of the movable electrode module 10 makes contact with the upper rim 231 of the graphite crucible 230. When the lid comes into contact with the rim 231, the material of the flexible graphite seal installed on the upper rim is deformed, ensuring the performance of sealing. It should be noted that the material of the graphite seal may, as an option or addition, be located on the bottom surface 102 of the cover 100.

During operation, the temperature inside the electrolysis section can vary significantly. Therefore, the dimensions of some components of the movable electrode module, for example, the suspension rod 110, can vary by a few millimeters. The resilient material mounted on the upper rim of the graphite crucible 230 preferably has sufficient resilience and deformability to adapt to any such thermal deformations and maintain a workable seal with the underside 102 of the lid 100.

The anode risers 21, 22 of the movable electrode module pass down through the cover 100. Electrical contact with these risers can be made using controlled anode tires 250 DC, which are brought into contact with the anode risers, and thus provides an electrical connection between the anode and the energy source .

During operation, the electrolysis section 220 is filled with molten salt, and the movable electrode module, loaded with recoverable raw materials, is brought into contact with the electrolysis section. The anode tires are brought into contact with the anode risers 21, 22, and a potential is created between the anode 20 (by means of anode risers and controlled anode tires 250) and the contact cathode 30 (by means of a graphite crucible 230 and a cathode bus 280 DC). The applied potential is sufficient to recover the raw materials. The required potential may vary depending on the type of raw material and the composition of the molten salt.

In many cases, in particular, for the restoration of solid raw materials in a molten salt electrolyte, it may be an advantage to have the possibility of introducing a moving electrode module into the electrolysis section of an electrolysis apparatus at operating temperature or at a temperature close to it. For many molten salt electrolytes, this means that the electrolysis section contains molten salt with a temperature of from 500 to 1200 ° C. If the mobile electrode module were introduced at room temperature into an electrolysis section containing molten salt at a temperature of, for example, 1000 ° C, the components of the mobile electrode module would probably be subjected to hard and fast thermal deformation. In particular, the ceramic components of the movable electrode module can be subjected to severe thermal shock and, as a result, to destruction. As a complication, if the movable electrode module described earlier with reference to the first version of the movable electrode module was preheated to a temperature of 1000 ° C in air, the graphite components of the movable electrode module would ignite.

It may be particularly desirable to be able to remove the movable electrode module from the electrolysis section immediately after the end of the electrolysis, without waiting for the electrolysis section to cool. Care should be taken to ensure that oxygen in the atmosphere, such as air, does not come into contact with the moving electrode module at high temperatures. Failure to protect against this can lead to ignition of the graphite components of the electrode module, ignition or oxidation of the recovered metal products located in the movable electrode module, and severe thermal deformation and destruction due to the rapid cooling of the module.

In order to ensure that the movable electrode module is brought into contact with the electrolysis section of the electrolysis apparatus at a temperature close to the working one, and in order to ensure that the movable electrode module is taken out of contact with the electrolysis section at a temperature close to the working one, it is desirable that the movable electrode module be removed to the shipping the module before transfer or transportation to the electrolysis device. The shipping module can

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include heating and / or cooling elements. The shipping module can be a conventional case in which an inert atmosphere can be maintained, isolating the preheated electrode module before loading into the electrolysis section, or an insulating electrode module recently removed from contact with the electrolysis section before being transported to a separate place for controlled cooling.

FIG. 7 shows the movable electrode module described previously with reference to FIG. 1-4, located in a variant of the movable transport module 400. The movable transport module 400 includes a housing 410, made of stainless steel 310, and lined with a refractory lining. The refractory lining may be a lining of ceramic bricks or any other suitable material, such as an asbestos board, which provides thermal insulation to the inside of the transport module. The interior of the transport module includes a transport cavity 420 in which a movable electrode module 10 may be located.

The shipping module may include devices for connecting with a bayonet slot on the top of the movable transport module, and devices for extracting the movable electrode module into the transport chamber 420. For example, the transport module 400 may include a winch for lifting the movable electrode module.

The upper part of the shipping module 400 includes devices for lifting the shipping module, such as a bracket or staples 430. Such lifting devices allow you to lift the entire shipping module and move it into and out of the electrolysis apparatus 200.

The lower part of the transport module 400 is closed by a gate valve 440. The gate valve contains a heat-resistant gateway 450, which is actuated to open and close the opening in the chamber 420 of the transport module. The shipping module including the gate valve can easily be installed over the gate valve of the electrolysis apparatus 200, as previously described, with reference to FIG. 5. By opening the slide gate valves cooperating with the transport module 440 and the electrolysis apparatus 200, access to the opening of the electrolysis section 220 can be provided. The movable electrode module 10 can then be lowered from the transport chamber 420, through an opening in both gate valves, a valve cooperating with the transport module, and a valve cooperating with the electrolysis apparatus to enable placement of the electrode module in electrolysis section 220. Then, the corresponding gate valves can be closed as shown in FIG. 8, and the shipping module 400 may be removed.

The first variant of the mobile transport module described above and shown in FIG. 1-4, includes eight efficient electrodes on which solid materials can be regenerated (i.e., the upper part of the contact cathode 30 and the upper part of each of the bipolar electrodes 40-46). For some reactions, it may be necessary to recover a smaller amount of solid material. For this purpose, it may be necessary for the mobile electrode module to have a smaller area of the cathode electrode surface. A second embodiment of the movable electrode module in accordance with one or more aspects of the invention is shown in FIG. 12.

The overall dimensions of the movable electrode module shown in FIG. 12 are the same as those of the movable electrode module shown in FIG. 1-4 and, thus, the second variant of the movable electrode module can be used in combination with the same electrolysis apparatus as the first variant. However, the movable electrode module 1200 of the second embodiment of the invention includes a contact cathode 1230 contact anode 1220, with only one bipolar electrode 1240 located between the contact anode 1220 and the contact cathode 1230. The contact anode, contact cathode and bipolar electrode are identical with the design of similar structures described earlier , with reference to the first embodiment of the invention. Since there are fewer bipolar electrodes between the contact anode 1220 and the contact cathode 1230, graphite electrode risers 1221 and 1222 are substantially longer than those described earlier with reference to the first aspect of the invention. If necessary, several sections of graphite risers can be connected by internal threaded rods 1226. The lid 1201 is held directly above the upper surface of the anode 1220 with a series of electrically insulating ceramic struts 1268.

In addition to these special devices required to provide the external dimensions of such a movable electrode module in the first embodiment of the invention, all other elements of the movable electrode module in accordance with the second embodiment of the invention are the same as previously described.

According to some aspects of the invention, it is not essential that the movable electrode module contains a bipolar electrode. FIG. 13 illustrates a third specific embodiment of a movable electrode module in accordance with one or more aspects of the invention. The third option includes a contact anode 1320 and a contact cathode 1330, but does not include a bipolar electrode. The contact cathode 1330 and contact anode 1320 are made in the same manner as the contact anode 20 and contact cathode 30, described earlier with reference to the first embodiment of the invention. The outer dimensions of the rolling

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the electrode module 1300 in the third embodiment are the same as the dimensions of the first and second versions of the movable electrode module. All other details of the third variant of the movable electrode module, as shown in FIG. 13, described above with reference to the first or second version of the movable electrode module.

In the embodiments described earlier, the suspension rod 110 is connected to the bayonet groove connector 130 by fixing the end of the rod 110 in the connector 130 by means of washers and bolts 111. All tolerances necessary to form a seal between the underside of the cover 100 and the rim 231 of the crucible 230, forming an opening in electrolysis section 220, achieved through the use of an elastic sealing material on the rim. FIG. 14 shows an alternative connection that can be used in a variant of the movable electrode module. For ease of reference, components identical to those present in the first embodiment described earlier are assigned the same reference numbers.

Alternatively, shown in FIG. 14, the suspension rod 110 of the electrode module is connected to the bayonet groove connector 130 via a flange 1410, which transfers the load through a series of disc springs 1400 and to the bayonet groove connector. The flange 1410 is attached to the spring 1400 by means of nuts 1420.

When the module is lifted, the module weight is transmitted through the suspension rod 110 and compresses the spring 1400. The spring is pressed upwards against the bottom surface of the flange 1410. The spring 1400 can be any suitable spring device. For example, the spring may include a coil spring.

The connection of the electrode module with a lifting device, such as a connector with a bayonet groove, with an elastic spring located between them, can be advantageous in use. For example, when the electrode module is lowered into the electrolysis section, as previously described, contact is made between the rim surrounding the chamber opening and the bottom surface 102 of the cover 100 to form a seal. In the embodiments described previously, to provide a cathode compound, the base plate 30a of the module must be installed in physical contact with the inner wall of the crucible. The use of spring-loaded devices, such as a Belleville spring 1400, located between the lifting devices and the suspension rod, can provide an additional stroke of the electrode module after the seal 100 is formed. In addition, such spring-loaded devices can advantageously adapt to the size variation of the suspension rod caused by thermal fluctuations.

A variant of the movable electrode module, which includes spring-loaded devices located between the suspension rod or rods supporting the electrodes and lifting devices, can be used as an alternative to or in addition to the elastic sealing material surrounding the opening of the electrolysis section.

In the following description of the method of electrolytic reduction of solid raw materials in accordance with a specific embodiment of the invention, a movable electrode module 10, described earlier, is used. The processing method can be divided into several stages.

Step 1. The movable electrode module 10 comprises eight layers of cathode electrodes (i.e., one cathode and seven bipolar electrodes that act as an anode and a cathode) and an anode. The upper surface of each working electrode includes a removable tray assembly, formed from two connected parts 151, 152. As a first stage of the process, the raw material, consisting of a series of solid oxide briquettes, is loaded onto the surface of each of the elements 151, 152 of removable trays assembly.

Stage 2. The loaded trays in the collection are moved to a movable electrode module located in the loading station of the electrode module. Loaded trays assembly are installed in the movable electrode module 10, and each pair of parts 151, 152 of the tray assembly forms the cathode part of the cathode electrode (for example, electrodes labeled 30, 40, 41, 42, 43, 44, 45, 46).

Stage 3. The loaded movable electrode module 10 rises into the transport chamber 420 of the transport module 400. To lift the movable electrode module 10 into the transport chamber 420, the transport module 400 is installed vertically above the work station. The gate valve 440 of the transport module 400 is actuated, causing the gateway 450 to move, to open and provide access to the transport chamber 420. The bayonet connection (not shown) is lowered using a winch 465 located on the transport module 400. The bayonet connection is connected to connector 130 with a bayonet groove on the movable electrode module 10, thus providing a lift of the movable electrode module 10 into the chamber 420 of the transport module.

Stage 4. The entire transport module 400 containing the movable electrode module 10 can be lifted and moved with a few staples 430. In stage 4, the entire transport module containing the electrode module is moved to a vertical position above the heating station. This is shown in FIG. 16. The shipping module 400 is connected to a heating station 500 with a movable electrode module 10 located directly above the heating chamber 510. The heating station includes a housing 501 comprising a heating chamber 510 surrounded by a plurality of heating elements 520.

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Stage 5. The electrode module is lowered using a winch 465 until the bottom surface 102 of the cover 100 is installed on the rim 502 of the heating chamber 510. The bayonet connection is removed from the bayonet slot 130 and the gateway 450 closes. The movable electrode module 10 is now brought into contact with the heating station, and the entire weight of the module is held by the bottom surface of the cover 100. This arrangement is shown in FIG. 17

Stage 6. The electrode module 10 is heated in the heating chamber 510 of the heating station 500 to a predetermined temperature. For electrolysis in molten salt, such a predetermined temperature is presumably from 500 to 1200 ° C. For example, the temperature can rise to 700 or 800 ° C. The heating rate of the module is adjusted so that the ceramic components of the electrode module are not subjected to thermal shock. Heating can be performed at a rate from 1 ° C / min to 10 or 20 ° C / min. For example, heating can be performed at a rate of about 5 ° C / min. Heating is performed in an inert atmosphere, for example, in an argon atmosphere or in a nitrogen atmosphere.

Stage 7. Once the electrode module is heated to a predetermined temperature, the electrode module 10 once again rises into the transport chamber 420 of the transport module 400.

Stage 8. The gate valve is closed, thus sealing the transport chamber 420. An inert atmosphere is maintained in the transport module, for example an atmosphere of argon or nitrogen.

Since the walls of the transport module are insulated, the rate of heat loss is low. Thus, after the electrode module 10 is heated to a predetermined temperature and sealed in the transport module 400, the temperature of the module 10 decreases slowly.

Stage 9. The transport module 400 containing the electrode module 10, at a given temperature, moves to a position directly above the electrolysis section. Access to electrolysis section 220 is restricted due to the presence of a gate valve 300 installed above the electrolysis section. This is shown in FIG. 7

Step 10. The shipping module 400 is connected to an electrolysis apparatus 200 containing an electrolysis section 220. The gate valve 440 associated with the transport module is combined with the gate valve 300 connected to the electrolysis apparatus in such a way that, when both gate valves are open, the electrode module 10 can gain access to the electrolysis section 220.

Stage 11. The slide valve 440 on the transport module opens.

Step 12. The slide gate valve 200 on the electrolysis apparatus opens.

Stage 13. The electrode module 10 is lowered until it comes into contact with the electrolysis section. The electrolysis section contains molten salt at or near the desired operating temperature. The pre-heated electrode module 10 is also at or near operating temperature. The operating temperature may be, for example, about 800 ° C. The electrode module is installed in the electrolysis section 220 such that the bottom surface of the contact cathode 30 of the electrolysis module 10 comes into physical contact with a graphite crucible 230, limiting the electrolysis section 220. This is described previously and shown in FIG. eight.

Stage 14. The anode tires 250 are moved to contact with the anode risers 21, 22 of the movable electrode module 10.

A potential is created between the anode 20 and the cathode 30 of the electrode module 10. This potential is sufficient to restore the raw material that is in contact with the cathode and the cathode surfaces of each of the bipolar electrodes. The potential required for the recovery of raw materials will depend on the nature of the system. So, to restore the raw materials of titanium oxide in the molten salt based on calcium chloride, the potential difference on each cathode surface of the electrode module 10 can be from 2 to 3 V.

The potential is fed for a period of time sufficient to restore the solid raw material.

After electrolysis, several subsequent processing steps can be performed to recover the raw material in order to extract the recovered product from the electrode module 10. Thus, the following steps are used to extract the recovered raw material after electrolysis in a particular embodiment of the invention.

Stage 15. The electrolytic cell current is turned off and, thus, the voltage from the surface of each electrode is removed.

Stage 16. Anode tires are derived from contact with graphite anode risers 21, 22.

Step 17. The electrode module rises from the molten salt to the transport module 400. The electrode module rises slowly to allow time for the molten salt to flow out of the electrode module 10.

Stage 18. Gate valve 300 on the electrolysis apparatus 200 is closed.

Step 19. The slide valve 440 on the transport module closes.

Stage 20. The shipping module containing the electrode module 10 is disconnected from

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electrolysis apparatus 200 and moves to a position directly above cooling station 600. This is shown in FIG. 18.

Stage 21. The shipping module 400 is connected to the cooling station 600.

Stage 22. Gate valve 440 is opened to allow access for the movable electrode module 10 to the cooling chamber 610.

Stage 23. The electrode module 10 is lowered into the cooling chamber until the bottom surface 102 of the cover 100 is installed on the upper rim of the cooling chamber 610. The cover 100 effectively forms a seal with the cooling chamber 610. This is shown in FIG. nineteen.

Stage 24. The cooling chamber includes walls 620 of a material with high thermal conductivity, for example, of a metallic material such as stainless steel. The walls comprise a water jacket 625, through which cold water is constantly supplied through an inlet 630 and an outlet 631. The water jacket provides effective heat removal from the hot module 10. The cooling rate can be adjusted by changing the speed of the water passing through the water jacket 625.

Stage 25. As soon as the electrode module 10 cools to a predetermined temperature, it rises into the transport module 400.

Stage 26. The cooled electrode module 10 in the transport module 400 moves to a position directly above the washing station.

Stage 27. The cooled electrode module is lowered into the washing station and sealed onto the cathode base plate 30a.

Stage 28. Water jets 700 are discharged from nozzles 705 connected to conduit 710. Water jets 700 are directed to the electrode module 10 and, in particular, are sent to an assembly tray containing recovered raw materials. The jets of water are preferably directed in such a way that they wash out any residues of salt solidified on the electrode module and the recovered raw materials.

Stage 29. After washing, the electrode module 10 rises in the transport module

400

Stage 30. The washed electrode module and the transport module are moved to a position above the unloading station.

Stage 31. The washed electrode module is lowered into place at the unloading station.

Stage 32. Electrode tray assemblies containing the recovered product are removed from the electrode module 10.

Stage 33. The recovered product is removed from the collection trays and packaged for further processing.

Specific variants of the method described earlier may not be used in all cases. For example, various stages may be used or some stages may be skipped.

Preferably, the reduction of the solid feedstock is performed by an electrolytic reduction reaction, such as the PTC process.

Claims (19)

CLAIM 1. An electrolysis system containing loading, heating, electrolysis, cooling and unloading sections, an electrode module for loading solid materials, a transporting module for moving the electrode module between system sections, the transporting module being configured to maintain the temperature of the electrode module close to the temperature of the molten salt , and to maintain an inert gas atmosphere. 2. The method of electrolytic recovery of solid raw materials using the system according to claim 1, comprising the stage at which install the electrode module containing at least one electrode, in the loading section, solid materials are loaded into the electrode module, the electrode module is heated in the heating section, the product is restored in the electrolysis section, and the recovered product is cooled in the cooling section, the electrode module is moved between the sections in the transporting module, and between the heating, electrolysis and cooling sections, the temperature of the electrode module is maintained close to the temperature of the molten salt and an inert atmosphere is maintained in the transporting module. 3. The method according to claim 2, in which the electrode module is moved from the position for loading raw materials in the transport module. 4. The method according to claim 2 or 3, in which the electrode module is heated to a predetermined temperature before being injected into the interaction with the electrolysis section. 5. The method according to claim 4, in which the electrode module is heated in an inert atmosphere in the transport module. - 12 029746 6. The method according to claim 4, in which the electrode module moves from the transport module to the heating section for heating to a predetermined temperature. 7. The method according to claim 6, in which the electrode module is moved from the loading section in the transport module, lowered into the heating section, heated to a predetermined temperature, and rises back into the transport module to move to the electrolysis section. 8. A method according to any one of claims 3 to 7, in which the electrode module is sealed in the transport chamber by closing the gate, which is preferably a slide gate valve. 9. A method according to any one of claims 2 to 8, in which the opening of the electrolysis section is closed by the opening shutter, and preferably the opening shutter is a gate valve opened to allow the electrode module to pass to the electrolysis section. 10. The method according to any one of claims 2 to 9, in which the step of moving the electrode module from the electrolysis section is carried out after electrolysis to extract the recovered raw materials. 11. The method according to claim 2, wherein after moving from the electrolysis section the electrode module cools in an inert atmosphere in the transport module. 12. The method according to claim 2, wherein the electrode module is moved to the cooling section for cooling to a predetermined temperature. 13. The method of claim 12, wherein the electrode module is moved to the cooling section in the transport module, lowered to the cooling section, cooled to a predetermined temperature, and rises back to the transport module to move from the cooling section. 14. The method according to any of PP-13, in which the electrode module is additionally moved to the washing station for leaching salt from the recovered raw materials. 15. The method according to any of PP-14, in which the electrode module is additionally moved to the discharge section for unloading the recovered raw materials. 16. The method according to any one of claims 2 to 15, in which the solid raw material is loaded into removable trays separately from the electrode module, and then the removable trays are connected to the electrode module to load the raw material into the electronic module. 17. A method according to any one of claims 2 to 16, wherein said solid raw material is loaded in such a way that it is in contact with the cathode structure of the electrode module. 18. The method according to any one of claims 2-17, in which the electrode module includes one or more bipolar electrodes, and the raw material is loaded in contact with the cathode surface of each bipolar electrode. 19. The method according to any one of claims 2 to 18, which is performed using the electrodeoxidation of solid raw materials. 130 43 42 46 40 41 45 44 ten 50