Molten salt electrolytic apparatus and method for producing titanium-based electrodeposits

Abstract

To provide a molten salt electrolytic device capable of continuing electrolysis over a relatively long time with a certain level of small electric power, and a method for manufacturing a titanium-based electrocrystallization product.SOLUTION: A molten salt electrolytic device 1 comprises: an electrolysis tank 2 used in electrorefining for obtaining a refined titanium-based material with higher purity from a conductive rough titanium-based material having Ti, Al, and O and provided with a cathode 53 opposite to an anode 52 containing a molten salt bath Bm and a rough titanium-based material therein; a conductive member 7 provided through an opening 2c of the electrolysis tank 2 and electrically connecting the anode and the cathode; an electrode holding member 3 or 4 provided through the opening 2c of the electrolysis tank 2, holding the anode or the cathode, and capable of moving the anode and the cathode in an opposed posture in a direction in which they are separated from each other; a lid body 5 arranged covering the opening 2c of the electrolysis tank 2 and having a hole part 5a allowing the movement of the electrode holding member 4 formed thereon; and a slide block plate 6 provided with respect to the lid body 5 and sliding together with the electrode holding member 4 while blocking the hole part 5a.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] This invention relates to a molten salt electrolytic apparatus used in electrolytic refining to obtain a refined titanium-based material from a crude titanium-based material by electrolysis using a molten salt bath, and to a method for producing a titanium-based electrodeposit. [Background technology]

[0002] Metallic titanium and titanium alloys are generally manufactured using methods based on the Kroll process, which is suitable for mass production. However, this method requires the chlorination of titanium ore, the subsequent reduction of titanium tetrachloride with metallic magnesium, as well as the crushing of sponge titanium ingots and the electrolysis of the magnesium chloride produced by reduction. Because it involves numerous batch processes, it cannot be said to be an efficient and low-cost way to manufacture metallic titanium.

[0003] In contrast, electrolytic refining using molten salt electrolysis may allow for easier production of titanium than the Chlor method.

[0004] As an example of this type of technology, Patent Document 1 describes a method for extracting titanium products from titanium ore, characterized by comprising the following steps: a step of mixing a chemical blend containing titanium ore and a reducing agent, wherein the ratio of the titanium ore to the reducing agent corresponds to a mass ratio of titanium oxide component in the titanium ore to the reducing metal in the reducing agent of 0.9 to 2.4; a step of heating the chemical blend to start an extraction reaction, wherein the chemical blend is heated at a rate of increase of 1°C to 50°C / min; and the chemical blend is heated at a reaction temperature of 1500 to 1800°C for a time between 5 minutes and 30 minutes. The steps include: maintaining the chemical blend at a certain temperature; cooling the chemical blend to a temperature lower than 1670°C; and separating the titanium product from the residual slag; and including the steps of: placing the titanium product into a reaction vessel having an anode, a cathode, and an electrolyte; heating the reaction vessel to a temperature of 600°C to 900°C to produce a molten mixture, applying an electrical differential between the anode and the cathode to deposit titanium ions on the cathode; and ending the electrical differential and cooling the molten mixture to produce a refined titanium product, wherein the surface area of ​​the refined titanium product is at least 0.1 m². 2 It states that it is " / g". [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] Special Publication No. 2015-507696 [Overview of the project] [Problems that the invention aims to solve]

[0006] In electrolytic refining using molten salt electrolysis, a crude titanium-based material containing Ti, Al, and O and having conductivity is used as the anode, and a voltage is applied between the anode and cathode in a molten salt bath inside an electrolytic cell with its opening covered by a lid. As a result, the crude titanium-based material at the anode dissolves, and a refined titanium-based material with a higher purity than the crude titanium-based material is deposited at the cathode, thereby producing a titanium-based electrodeposited material.

[0007] In this process, the anode and cathode may both be plate-shaped objects placed opposite each other. In this case, from the viewpoint of reducing the effect of electrical resistance and thus lowering power consumption, it is preferable to position the anode and cathode relatively close together so as to shorten the distance between them. On the other hand, as electrolysis continues, the refined titanium-based material deposited on the cathode gradually grows. Therefore, if the anode and cathode are positioned close together beforehand and electrolysis is performed, a short circuit may occur in a short period of time due to contact between the refined titanium-based material growing on the cathode and the anode, potentially making it impossible to continue molten salt electrolysis.

[0008] The object of this invention is to provide a molten salt electrolytic apparatus that can continue electrolysis for a relatively long period of time with a relatively small amount of power, and a method for producing titanium-based electrodeposits. [Means for solving the problem]

[0009] The molten salt electrolytic apparatus of this invention is a molten salt electrolytic apparatus used for electrolytic refining to obtain a purified titanium-based material of higher purity than the crude titanium-based material from a crude titanium-based material containing Ti, Al, and O and having conductivity, by electrolysis using a molten salt bath, and comprises an electrolytic cell containing the molten salt bath, and an electrolytic cell containing a plate-shaped anode containing the crude titanium-based material as an electrode, and a plate-shaped cathode positioned opposite the anode to deposit the purified titanium-based material, and a current-carrying member provided from the outside to the inside through the opening of the electrolytic cell, electrically connecting the anode and the cathode to a power source, and from the outside to the inside through the opening of the electrolytic cell : An electrode holding member for an anode and a cathode, which is provided extending across the electrolytic cell and holding the anode or cathode, respectively, on its internal side, wherein the electrode holding member for an anode and / or cathode is movable in a direction that separates the anode and the cathode from each other in an opposing position; a lid positioned to cover the opening of the electrolytic cell, with a hole formed therein that extends through the inside of the movable electrode holding member to allow the movement of the electrode holding member; and a sliding closing plate provided on the internal or external side of the electrolytic cell relative to the lid, which slides along with the movement of the electrode holding member while closing the hole. In many cases, in a molten salt electrolytic apparatus constructed on an installation surface parallel to a horizontal plane, the "external side" of the electrode holding member provided extending from the external side to the internal side through the opening of the electrolytic cell may correspond to the upper side, and the "internal side" may correspond to the lower side.

[0010] In the molten salt electrolytic apparatus described above, it is preferable that the current-carrying members of the anode and / or cathode, which are held by the movable electrode-holding member, are movable together with the movable electrode-holding member.

[0011] In the molten salt electrolytic apparatus described above, it is preferable that the movable electrode holding member is either an anode or a cathode electrode holding member, and the other anode or cathode electrode holding member is fixed to the lid.

[0012] In this case, it is preferable that a hole is formed in the sliding closure plate at a position offset from the position where the hole is formed in the lid, through which the other electrode holding member extends, and that the other electrode holding member is displaceable inside the hole of the sliding closure plate as the sliding closure plate slides.

[0013] In the molten salt electrolytic apparatus described above, it is preferable that the sliding closure plate is positioned on the outside side of the electrolytic cell relative to the lid.

[0014] In the molten salt electrolytic apparatus described above, it is preferable that the electrode holding member is rod-shaped, and that multiple rod-shaped electrode holding members are provided for each electrode.

[0015] The above-described molten salt electrolysis apparatus preferably includes a temperature controller provided inside the electrolytic cell for adjusting the temperature of the inside of the electrolytic cell, the molten salt bath, the refined titanium-based material, and / or the electrodes.

[0016] The temperature controller is a heat exchanger, and it is preferable that it is laid inside the electrolytic cell at the bottom, below the electrodes, in the region where the refined titanium-based material grows. In a molten salt electrolytic apparatus constructed on a mounting surface parallel to the horizontal plane, the above-mentioned "bottom side" generally corresponds to the lower side or downward side.

[0017] Preferably, the temperature controller is capable of adjusting the anode and cathode sides to different temperatures.

[0018] The electrolytic cell preferably has a molten salt supply port and a molten salt discharge port that can be connected to a molten salt storage tank.

[0019] Preferably, the electrolytic cell and / or lid have a vent that can be connected to a vacuum device.

[0020] When there is no molten salt bath inside the electrolytic cell, the above molten salt electrolysis apparatus can be disposed between the anode and the cathode, and preferably includes a heat insulating plate that suppresses heat transfer between the anode and the cathode.

[0021] The method for producing a titanium-based electrodeposit of this invention is a method for producing a titanium-based electrodeposit by electrolytic purification using any of the above molten salt electrolysis apparatuses, and by electrolysis using the molten salt bath inside the electrolytic cell, the purified titanium-based material is deposited on the cathode, and during the electrolysis, it includes an electrolysis step of separating the anode and the cathode from each other in a facing posture.

[0022] The above method for producing a titanium-based electrodeposit preferably includes a molten salt discharge step of discharging the molten salt from the inside of the electrolytic cell through a molten salt discharge port connected to a molten salt storage tank after the electrolysis step, to expose the purified titanium-based material from the molten salt bath.

[0023] The above method for producing a titanium-based electrodeposit preferably includes a residue separation step of discharging the gas inside the electrolytic cell from a vent connected to a decompression device while heating the purified titanium-based material on the cathode using a temperature regulator provided inside the electrolytic cell after the molten salt discharge step, to separate the residue of the molten salt from the purified titanium-based material.

[0024] In this case, it is preferable to dispose a heat insulating plate that suppresses heat transfer between the anode and the cathode between the anode and the cathode, and perform the residue separation step.

Effect of the Invention

[0025] According to this invention, electrolysis can be continued for a relatively long time with a certain degree of low power.

Brief Description of the Drawings

[0026] [Figure 1] It is a cross-sectional view along the depth direction of the molten salt bath showing the molten salt electrolysis apparatus of one embodiment of this invention. [Figure 2]This is a horizontal cross-sectional view along the line II-II in Figure 1. [Figure 3] This is a cross-sectional view similar to that in Figure 1, showing the molten salt electrolysis apparatus with the anode and cathode separated. [Figure 4] This is a horizontal cross-sectional view along the line IV-IV in Figure 3. [Figure 5] This is a horizontal cross-sectional view along the VV line in Figure 1. [Figure 6] This is a cross-sectional view along the depth direction of the molten salt bath, showing a molten salt electrolysis apparatus of another embodiment. [Figure 7] This is a cross-sectional view along the depth direction of the molten salt bath, showing another embodiment of a molten salt electrolytic apparatus. [Figure 8] This is a cross-sectional view along the line VIII-VIII in Figure 7. [Figure 9] This is a horizontal cross-sectional view along the line IX-IX in Figure 7. [Figure 10] This is a cross-sectional view similar to that in Figure 7, showing the molten salt electrolysis apparatus with the anode separated from the cathode. [Figure 11] This is a horizontal cross-sectional view along the line XI-XI in Figure 10. [Figure 12] This is a horizontal cross-sectional view along the line XII-XII in Figure 10. [Figure 13] This is a cross-sectional view similar to Figure 1, showing how molten salt is supplied to the inside of the electrolytic cell to create a molten salt bath before the electrolysis process is carried out in the molten salt electrolytic apparatus shown in Figure 1. [Figure 14] This is a cross-sectional view similar to Figure 1, showing the molten salt discharge process that can be performed after the electrolysis process in the molten salt electrolytic apparatus of Figure 1. [Figure 15] Figure 14 is a cross-sectional view similar to Figure 1, showing the residue separation process that can be performed after the molten salt discharge process. [Modes for carrying out the invention]

[0027] Embodiments of this invention will be described in detail below with reference to the drawings.

[0028] (Molten salt electrolysis apparatus) The molten salt electrolytic apparatus 1 illustrated in Figure 1 is used for electrolytic refining to obtain refined titanium-based material from crude titanium-based material by electrolysis using the anode 52 and cathode 53 of electrode 51 in a molten salt bath Bm.

[0029] The crude titanium-based material contains Ti (titanium), Al (aluminum), and O (oxygen) and is electrically conductive. It is incorporated into the anode 52 as part or all of the anode 52. In electrolytic refining, as shown in Figure 1, a voltage is applied between the anode 52 and the cathode 53 while at least a portion of each of the anode 52 and cathode 53 is immersed in the molten salt bath Bm. This causes the crude titanium-based material in the anode 52 to dissolve, removing at least some of the impurities Al and O, and depositing a refined titanium-based material with a higher purity than the crude titanium-based material on the cathode 53. This makes it possible to produce titanium-based electrodeposits such as titanium alloys containing a certain amount of metallic titanium or aluminum as the refined titanium-based material. Details of the manufacturing method of titanium-based electrodeposits, including electrolytic refining, will be described later.

[0030] The illustrated molten salt electrolytic apparatus 1 comprises an electrolytic cell 2 containing a molten salt bath Bm for storing molten salt, and the anode 52 and cathode 53 of the electrodes 51 described above. The electrolytic cell 2 is a container made of steel, brick, or the like, and for example, has a cylindrical or rectangular or other cylindrical peripheral wall portion 2a whose inner and outer contour shape of the cross section perpendicular to the depth direction is circular, such as an ellipse, or whose inner and outer contour shape is polygonal, such as a rectangle, a bottom portion 2b that seals the lower side of the peripheral wall portion 2a, and an opening 2c on the upper side of the peripheral wall portion 2a. The inner surface of the brick or steel electrolytic cell 2 may be lined with Ni or the like.

[0031] The electrodes 51 provided inside the electrolytic cell 2 consist of a plate-shaped anode 52 and a plate-shaped cathode 53, positioned opposite each other so that their main surfaces face each other. In this way, during electrolysis, the refined titanium-based material is deposited relatively uniformly on the main surface of the cathode 53, and localized fluctuations in the inter-electrode distance are suppressed, allowing for efficient electrolytic refining at low power.

[0032] Although not shown in the diagram, if multiple cylindrical cathodes are arranged circumferentially inside a cylindrical anode, or if a single cylindrical or cylindrical cathode is arranged concentrically with the anode, the following problems arise, making it inefficient. Specifically, in the former case, the refined titanium-based material deposited on the multiple cathodes concentrates on the cathodes at locations with a short inter-electrode distance on their opposing surfaces. In the latter case, the initial inter-electrode distance is long, which increases the electrical resistance of the molten salt bath and thus the power consumption. Furthermore, as the refined titanium-based material grows on the cathode, the inter-electrode distance decreases, but the surface area increases, leading to an increase in current and thus higher power consumption, making it generally inefficient.

[0033] Preferably, the plate-shaped anode 52 and the plate-shaped cathode 53 each have a polygonal shape such as a rectangle or square when viewed from the front of the main surface. Furthermore, the anode 52 and cathode 53 are not limited to the flat plate shape shown, but can be plate-shaped with bent and / or curved portions in at least a part of them, or their thickness may vary in at least a part of them. Note that "plate-shaped" means a shape in which the dimensions of the main surface (length and width, etc.) are long relative to the thickness, and this includes rectangular parallelepipeds and disc shapes. In addition, to avoid current concentration, shapes with corners at the periphery or corners, such as rectangular parallelepipeds, may be processed by chamfering to eliminate the corners, or by processing to change the thickness at the periphery and in the center, and these are also included in the plate-shaped category.

[0034] When electrolysis is performed using such plate-shaped anodes 52 and cathodes 53, the refined titanium-based material 54 deposited on the main surface of the cathode 53 gradually grows (see Figure 3), and the refined titanium-based material 54 on the cathode 53 approaches the anode 52. When the refined titanium-based material 54 comes into contact with the anode 52, a short circuit occurs, making it impossible to continue electrolysis thereafter. Stopping the electrolysis when the refined titanium-based material 54 and the anode 52 are close enough to cause a short circuit, separating and recovering the refined titanium-based material 54 from the cathode 53, and then restarting the electrolysis requires excessive effort and time, thus reducing productivity.

[0035] On the other hand, if the anode 52 and cathode 53 are positioned far apart beforehand to allow for the growth of the refined titanium-based material 54 on the cathode 53 during electrolysis, the inter-electrode distance between the anode 52 and cathode 53 becomes longer during the initial stages of electrolysis while the refined titanium-based material 54 is growing. In that case, the effect of the electrical resistance due to the molten salt bath Bm becomes greater, resulting in the consumption of enormous amounts of power.

[0036] To address this, the anode 52 and cathode 53 are first positioned relatively close to each other while maintaining their opposing orientation. By positioning the anode 52 and cathode 53 relatively close to each other, power consumption can be reduced by keeping the inter-electrode distance relatively short at the start of electrolysis. Subsequently, by gradually separating the anode 52 and cathode 53 as the refined titanium-based material 54 grows on the cathode 53, electrolysis can be continued for a long period of time without the refined titanium-based material 54 coming into contact with the anode 52. The refined titanium-based material 54 is generated on the cathode 53 and can grow toward the anode 52 while maintaining the dimensions of the main surface of the cathode 53. Since current flows through the refined titanium-based material 54, after the refined titanium-based material 54 is generated on the cathode 53, electrolysis occurs between the anode 52 and the cathode 53 and the refined titanium-based material 54 as the refined titanium-based material 54 grows. In this case, by separating the anode 52 and cathode 53, it is possible to position the anode 52 and the refined titanium-based material 54 in a relatively close proximity. This allows electrolysis to be continued for a long period of time at low power. As a result, a large amount of refined titanium-based material 54 can be obtained in a single electrolysis, greatly increasing productivity.

[0037] To enable separation of the anode 52 and cathode 53 during such electrolysis, the molten salt electrolytic apparatus 1 of this embodiment is equipped with electrode holding members 3 and 4 for the anode 52 and cathode 53, respectively, which hold the anode 52 and cathode 53. At least one of the electrode holding member 3 for the anode 52 and the electrode holding member 4 for the cathode 53 is movable in a direction that separates the anode 52 and cathode 53 from each other in an opposing position.

[0038] The electrode holding members 3 and 4 are each provided through the opening 2c of the electrolytic cell 2, extending from the outside (upper side in Figure 1) to the inside (lower side in Figure 1) of the electrolytic cell 2, and are attached to the upper surface of the anode 52 or cathode 53 on the inside of the electrolytic cell 2, thereby holding the anode 52 or cathode 53. For example, by applying power from a drive source (not shown) installed outside the electrolytic cell 2, the electrode holding member 3 for the anode 52 and / or the electrode holding member 4 for the cathode 53 can move in a direction that separates the anode 52 and / or cathode 53, together with the refined titanium-based material 54 deposited on the cathode 53, while holding the anode 52 and / or cathode 53 inside the electrolytic cell 2. In many cases, the movable electrode holding member 3 for the anode 52 and / or the electrode holding member 4 for the cathode 53 can move not only in the direction of separation between the anode 52 and cathode 53, but also in the direction of approach between the anode 52 and cathode 53. Furthermore, the electrode holding members 3 and / or 4 may be made movable in the vertical direction when removing the electrode 51 or the refined titanium-based material 54 before or after the start or completion of electrolysis. In Figure 1, the molten salt electrolytic apparatus 1 is constructed on an installation surface parallel to the horizontal plane, and in this case, the electrode holding members 3 and 4 are provided through the opening 2c of the electrolytic cell 2, extending from the upper side, which is the outside of the electrolytic cell 2, to the lower side, which is the inside.

[0039] Although both the electrode holding member 3 for the anode 52 and the electrode holding member 4 for the cathode 53 may be made movable in the direction of separation or proximity between the anode 52 and the cathode 53, in this case only the electrode holding member 4 for the cathode 53 is movable.

[0040] Incidentally, during electrolysis, in order to prevent moisture absorption of the molten salt bath Bm and to prevent oxidation of the refined titanium-based material 54 deposited on the cathode 53, the molten salt electrolytic apparatus 1 is provided with a lid 5 that covers the opening 2c of the electrolytic cell 2. The electrode holding member 3 for the anode 52 and the electrode holding member 4 for the cathode 53 are arranged through the opening 2c, and the electrode holding member 4 needs to be movable so as to ensure airtightness inside the electrolytic cell 2 when the lid 5 is closed.

[0041] Therefore, in the illustrated embodiment, a hole 5a is formed in the lid 5, as shown in Figure 2, that penetrates in the thickness direction of the lid 5. The movable electrode holding member 4 is then positioned to extend through the inside of the hole 5a. On top of the lid 5, that is, on the outside side of the electrolytic cell 2 relative to the lid 5, a sliding closure plate 6 is provided, as shown by the dashed line in Figure 2, which closes the hole 5a of the lid 5 and slides on the lid 5 as the electrode holding member 4 moves. When the electrode holding member 4 is moved in the direction of separation between the anode 52 and the cathode 53, the sliding closure plate 6 also slides in the same direction (see Figures 3 and 4). The electrode holding member 4 and the current-carrying member 7 for the cathode 53 extend through the sliding closure plate 6 and are fixed to the sliding closure plate 6.

[0042] As a result, the movement of the electrode holding member 4, which extends both inside and outside the electrolytic cell 2, in the direction of separation or approach of the anode 52 and cathode 53 is permitted by the hole 5a formed in the lid 5. Furthermore, as the electrode holding member 4 moves from the position where it approaches the electrode 51 (Figures 1 and 2) to the position where it separates it (Figures 3 and 4), the hole 5a is covered by the sliding closure plate 6, thus ensuring airtightness inside the electrolytic cell 2. In other words, since the end of the hole 5a is completely covered by the sliding closure plate 6, airtightness inside the electrolytic cell 2 is ensured as described above. This makes it possible to achieve long-term electrolysis while suppressing moisture absorption of the molten salt bath Bm and oxidation of the refined titanium-based material 54.

[0043] The holes 5a shown in Figure 2 are, for example, slit-shaped or groove-shaped holes that penetrate the cover 5 and extend in the direction of movement of the electrode holding member 4 (the direction of separation or approach of the anode 52 and cathode 53, the left-right direction in Figure 2), and are provided for each electrode holding member 4. The ends of the holes 5a can be terminated inside the cover 5 as shown in the figure, or they may be extended to the periphery of the cover 5, although this is not shown in the figure. The shape and dimensions of the holes 5a are not limited to the slit shape shown in the figure, as long as the electrode holding member 4 can be displaced inside them and the movement of the electrode holding member 4 is permitted. Although this is not shown in the figure, for example, it is also conceivable to have one larger hole that can accommodate all the electrode holding members 4 inside. If the holes 5a are elongated slit-shaped as shown in the figure, the electrode holding member 4 may slide and be displaced inside the holes 5a when it moves.

[0044] Furthermore, the lid 5 and the sliding closure plate 6 may be constructed from multiple disassemblable components, taking into consideration the ease of removing the refined titanium-based material 54 from the inside of the electrolytic cell 2 after electrolysis. Although not shown in the illustration, the sliding closure plate may not be a flat, non-deformable plate as shown, but rather a plate that can be deformed into a bellows-type or blind-type shape, similar to the slats of a shutter, and slides by being pulled out, rolled in, or folded as the electrode holding member moves.

[0045] In the embodiment described herein, the sliding closure plate 6 is provided on the outside side of the electrolytic cell 2 (upper side in Figure 1) relative to the lid 5. However, although not shown in the illustration, the sliding closure plate may also be provided on the inside or below side of the electrolytic cell relative to the lid, that is, between the lid and the electrolytic cell. However, in that case, a structure is required to position the sliding closure plate so as to be slidable relative to the electrolytic cell 2. For this reason, from the viewpoint of simplifying the structure, it is preferable to provide the sliding closure plate 6 on the lid 5 as shown in the illustration. Insulation material may be provided in necessary places such as between the lid 5 and the sliding closure plate 6.

[0046] As mentioned above, in this molten salt electrolytic apparatus 1, only the electrode holding member 4 for the cathode 53 is movably positioned relative to the lid 5, while the electrode holding member 3 for the anode 52 is fixedly positioned relative to the lid 5. Specifically, the lid 5 is provided with a through hole 5b that is slightly larger in dimensions than the electrode holding member 3 for the anode 52, and the electrode holding member 3 is fixedly positioned by inserting it into the through hole 5b. On the other hand, although not shown in the figures, the electrode holding member for the cathode may be fixed to the lid and the electrode holding member for the anode may be movable, or both the cathode and anode electrode holding members may be movable. In the molten salt electrolytic apparatus 1, the electrode holding member 4 for the cathode 53 is inserted into a through hole 6a provided in the sliding closure plate 6 and moves together with the sliding closure plate 6. It is preferable to interpose an insulator or a sealing ring between the through holes 5b and 6a and the electrode holding members 3 and 4 and the current-carrying member 7 inserted therein.

[0047] The current-carrying members 7, such as conductors, that electrically connect the anode 52 and cathode 53 to a power source (not shown) outside the electrolytic cell 2, respectively, do not have any particular limitations on their arrangement, as long as they do not obstruct the movement of the electrode holding member 4 for the cathode 53 and the sliding of the sliding closure plate 6. In the illustrated example, each current-carrying member 7 is connected to the upper surface of the anode 52 or cathode 53 together with the electrode holding member 3 or 4, and is arranged to extend to the outside of the electrolytic cell 2 through the through hole 5b or the hole portion 5a and through hole 6a, parallel to the electrode holding member 3 or 4. It is preferable that the current-carrying members 7 of the anode 52 and / or cathode 53, which are held by the movable electrode holding member 4, are movable together with the movable electrode holding member 4. In the illustrated example, the cathode 53 is held by the movable electrode holding member 4, and the current-carrying member 7 that supplies current to the cathode 53 is configured to move together with the electrode holding member 4. The conductive member 7 is positioned so as to ensure insulation from the lid 5, the sliding closure plate 6, and the electrode holding member 4. For example, if the electrode holding member 4 is made of an insulating material such as ceramic, no additional measures are required to ensure insulation from the conductive member 7. However, if it is made of a metallic material such as carbon steel, stainless steel, or heat-resistant steel, such measures are taken. In addition, to avoid contact between the conductive member 7 and the molten salt bath Bm, the upper surfaces of the anode 52 and cathode 53 are positioned above the surface of the molten salt bath Bm.

[0048] The electrode holding members 3 and 4 and the current-carrying member 7 can be in the shape of a plate or other shape, but here they are in the shape of a rod, and as can be seen from Figures 2 and 4, multiple rods, for example three, are provided for each anode 52 and cathode 53 of the electrode 51.

[0049] Incidentally, a temperature controller 8 can be provided inside the electrolytic cell 2 of the molten salt electrolytic apparatus 1 to heat or cool the inside of the electrolytic cell 2, the molten salt bath Bm, the refined titanium-based material 54, and / or the electrode 51, and to adjust their temperatures. In the illustrated embodiment, as shown in Figures 1, 3, and 5, a heat exchanger including piping for flowing a heat transfer medium is laid on the bottom 2b side (lower side or downward side) of the electrode 51 as the temperature controller 8. It is preferable that the temperature controller 8, which is a heat exchanger, is positioned such that its installation area includes the area on the cathode 53 where the refined titanium-based material 54 grows in the direction of movement of the electrode holding member 4 (the direction of separation or approach of the anode 52 and cathode 53). The installation area of ​​the temperature controller 8, which is a heat exchanger, may include the movable area of ​​the electrode holding member 4. Here, the temperature inside the electrolytic cell 2 or the molten salt bath Bm is adjusted by the temperature controller 8 as a heat exchanger, and the temperatures of the refined titanium-based material 54 and the electrode 51 can be adjusted through this.

[0050] As shown in Figure 5, in a plan view of the bottom 2b, the temperature controller 8 is located directly below the anode 52 and has piping for the anode 52 that extends in a direction perpendicular to the direction of movement of the electrode holding member 4 (left-right direction in Figure 5) (up-down direction in Figure 5), and piping for the cathode 53 located below the growth area of ​​the refined titanium-based material 54 and includes a portion that extends in a meandering manner in the direction of movement of the electrode holding member 4 and three portions that extend in a direction perpendicular to the direction of movement of the electrode holding member 4. Regardless of the shape of the piping, it is preferable that the temperature controller 8 be configured to adjust the anode 52 side and the cathode 53 side to different temperatures by providing piping for the anode 52 and piping for the cathode 53 in this manner. This makes it possible to heat only the cathode 53 and the refined titanium-based material 54 by the temperature controller 8 in the residue separation process described later. Furthermore, the temperature controller 8 can also be used for rapid cooling before opening the inside of the electrolytic cell 2 to remove or replace the anode 52, refined titanium-based material 54, cathode 53, etc.

[0051] The electrolytic cell 2 may be provided with a molten salt supply port 9a and a molten salt discharge port 9b. The molten salt supply port 9a is used to supply molten salt into the electrolytic cell 2 as preparation before electrolysis, creating a molten salt bath Bm inside. The molten salt discharge port 9b is used to discharge molten salt from the electrolytic cell 2 after electrolysis is completed, in the molten salt discharge process described later. If the molten salt supply port 9a and the molten salt discharge port 9b are connectable to the molten salt storage tank 61 described later, which is used for storing or transporting molten salt, the transfer of molten salt between the electrolytic cell 2 and the molten salt storage tank 61 will be facilitated (see Figures 13 and 14).

[0052] As shown in the electrolytic cell 2, the molten salt supply port 9a is preferably located at a height above the surface of the molten salt bath Bm, and the molten salt discharge port 9b is preferably located below the surface of the molten salt bath Bm, closer to the bottom 2b. This promotes the flow of the molten salt by its own weight during transfers between the electrolytic cell and the molten salt storage tank 61.

[0053] Furthermore, it is preferable to provide a vent in the electrolytic cell 2. As will be described later, this vent can be connected to the vacuum device 71 and is used to discharge gas from inside the electrolytic cell 2 during the residue separation process (see Figure 15). The vent may be provided separately from the molten salt supply port 9a and molten salt discharge port 9b described above, but in the illustrated example, the molten salt supply port 9a is also used as a vent.

[0054] The molten salt electrolytic apparatus 1 can be provided with an insulating plate 10 to suppress heat transfer between the anode 52 and the cathode 53 (see Figure 15). This insulating plate 10 is positioned between the anode 52 and the cathode 53 when the molten salt bath Bm is not present inside the electrolytic cell 2 during the residue separation process described later. When the refined titanium-based material 54 on the cathode 53 is heated during the residue separation process, the insulating plate 10 suppresses the transfer of heat from the cathode 53 to the anode 52. Preferably, the insulating plate 10 is housed on the peripheral wall 2a side of the electrolytic cell 2, for example, during electrolysis when the molten salt bath Bm is present inside the electrolytic cell 2, and can be moved laterally and positioned between the anode 52 and the cathode 53 when the molten salt bath Bm is not present inside the electrolytic cell 2 and it becomes necessary during the residue separation process or other processes.

[0055] Another embodiment shown in Figure 6 has cathodes 53 arranged on both sides of the anode 52. In this case, it is preferable to provide each of the cathodes 53 on both sides with the aforementioned holes 5a and sliding closure plates 6 so that each cathode 53 can be separated from the anode 52. The other configurations of the molten salt electrolytic apparatus 1 in Figure 6 are substantially the same as those of the embodiments described above, and a further explanation is omitted.

[0056] Figures 7 to 12 show molten salt electrolytic apparatus 1 of yet another embodiment. The molten salt electrolytic apparatus 1 in Figures 7 to 12 has a configuration that is almost the same as that shown in Figures 1 to 5, except that the sliding closure plate 6 is made longer in the direction of movement of the electrode holding member 4, and a slit-shaped hole 6b is provided in the sliding closure plate 6 at a position offset from the formation position of the hole 5a of the lid 5, through which the electrode holding member 3 for the anode 52 is displaced.

[0057] More specifically, as shown in Figures 7 to 12, the sliding closure plate 6 has a slit-shaped or groove-shaped hole 6b that extends in the direction of movement of the electrode holding member 4 for the cathode 53, and penetrates the sliding closure plate 6. The electrode holding member 3 for the anode 52 is positioned to extend through the inside of the hole 6b in the sliding closure plate 6. As the sliding closure plate 6 slides in conjunction with the movement of the electrode holding member 4 for the cathode 53, the electrode holding member 3 for the anode 52 is displaced relative to the sliding closure plate 6 inside the hole 6b. At this time, the electrode holding member 4 for the cathode 53 is displaced by sliding inside the hole 5a provided in the lid 5, similar to the embodiments shown in Figures 1 to 5. As described above, the molten salt electrolytic apparatus 1 shown in Figures 7-12 is configured such that one electrode holding member 4 for the cathode 53 is displaceable inside the hole 5a of the lid 5, and the other electrode holding member 3 for the anode 52 is displaceable inside the hole 6b of the sliding closure plate 6.

[0058] As shown in Figures 8 and 9 and 11 and 12, the hole 6b of the sliding closure plate 6 is formed in a plan view in a direction perpendicular to the direction of movement of the electrode holding member 4, and offset from the position where the hole 5a of the lid 5 is formed. Therefore, even if the sliding closure plate 6 slides relative to the lid 5 and the hole 6b of the sliding closure plate 6 and the hole 5a of the lid 5 come into a positional relationship that overlaps in the direction of movement of the electrode holding member 4, as shown in Figures 11 and 12, the holes 6b and 5a do not overlap in a direction perpendicular to the direction of movement of the electrode holding member 4, thus maintaining the closed state of the hole 5a of the lid 5 by the sliding closure plate 6. At the same time, the hole 6b of the sliding closure plate 6 is also kept closed by the lid 5. As a result, airtightness inside the electrolytic cell 2 can be ensured even when separating the anode 52 and cathode 53.

[0059] In the molten salt electrolytic apparatus 1 shown in Figures 7-12, the travel distance of the electrode holding member 4 can be increased compared to those shown in Figures 1-5. As a result, the molten salt electrolytic apparatus 1 shown in Figures 7-12 can be positioned closer together (i.e., the distance between electrodes can be further reduced) or further apart, which is advantageous in that it can achieve a longer electrolysis duration with lower power consumption and the deposition of a larger amount of purified titanium-based material 54 at the cathode 53.

[0060] The hole 6b of the sliding closure plate 6 is not limited to the slit-shaped or groove-shaped form shown in the figure, as long as the electrode holding member 3 can be displaced inside it. The dimensions and shape of the hole 6b of the sliding closure plate 6 can be changed as appropriate, in the same way as described above for the hole 5a of the lid 5.

[0061] Furthermore, as shown in Figure 10, if the refined titanium-based material 54 grows significantly on one side of the cathode 53, the electrode holding member 4 alone may not be able to support it. To address this, although not shown, a support base may be placed on the bottom 2b of the electrolytic cell 2, below the refined titanium-based material 54, to support the refined titanium-based material 54 from below.

[0062] The molten salt electrolytic apparatus 1 shown in Figures 7-12 has the same configuration as shown in Figures 1-5, and the explanation is the same as described above for Figures 1-5, so it will not be explained further.

[0063] (Method for manufacturing titanium-based electrodeposits) To produce titanium-based electrodeposits, crude titanium-based material is prepared in advance prior to the electrolytic process in which electrolytic purification is carried out using the molten salt electrolytic apparatus 1 described above. The crude titanium-based material can be obtained by the extraction process.

[0064] In the extraction process, a mixture of titanium raw materials, such as titanium ore containing titanium oxides like titanium dioxide (TiO2), and a reducing agent containing aluminum (Al) is heated. A separating agent may also be mixed in at this time. The reaction is complex, but generally, it is thought that a reaction such as 3TiO2 + 4Al → 3Ti + 2Al2O3 occurs. Here, Ti is dissolved in a certain amount of Al and O, which corresponds to the crude titanium-based material. The heating temperature may be 1500°C to 1800°C. After the mixture becomes molten upon heating, the crude titanium-based material (liquid or solid) and slag separate due to the density difference, allowing the crude titanium-based material (Ti in the above reaction equation) to be extracted.

[0065] The titanium raw material used in the extraction process can be any material containing titanium oxide, for example, titanium ore that has undergone upgrade treatment such as leaching or other treatments as needed. The TiO2 content in the titanium ore used as the titanium raw material may be, for example, 50% by mass or more, typically 80% by mass or more, and particularly 90% by mass or more. The separating agent is used to facilitate the formation of slag after heating. Specifically, the separating agent is preferably one or more selected from calcium fluoride, aluminum fluoride, potassium fluoride, magnesium fluoride, calcium chloride, calcium oxide, and sodium fluoride. Among these, calcium fluoride (CaF2) is particularly preferred because it provides excellent separation of crude titanium-based materials from the mixture and has little effect on anything other than the separation. The reducing agent may consist substantially of aluminum (Al) alone, or it may also contain Ca, Na, Mg, Cu, Si, Fe, etc. For example, the mixture may be prepared by adjusting the molar ratio of TiO2:Al:CaF2 to 3:4 to 7:2 to 6.

[0066] The crude titanium-based material obtained in the extraction process contains Ti, Al, and O, and may, for example, have a Ti content of 50% to 80% by mass, an Al content of 1% to 30% by mass, and an O content of 5% to 20% by mass. Typically, the Ti content of the crude titanium-based material may be 60% or more by mass, the Al content 20% or less by mass, and the O content 20% or less by mass. However, in the crude titanium-based material, the Al and O content in Ti may be less than the above-mentioned content and may be present in amounts that can be considered unavoidable impurities. The crude titanium-based material may also contain trace amounts of Al and O.

[0067] Such crude titanium-based materials are electrically conductive and can be included in the anode 52 in the electrolytic process described below for electrolytic refining. The resistivity of the crude titanium-based material measured at room temperature is, for example, 1 × 10⁻⁶. -8 Ω·m ~ 1 × 10 -4 Ω·m, typically 1 × 10⁻⁶ -7 Ω·m~5×10 -5It is Ω·m.

[0068] In the electrolysis process, the molten salt electrolytic apparatus 1 described above is used to dissolve the crude titanium-based material of the anode 52 in the molten salt bath Bm, and electrolytic refining is performed to deposit the refined titanium-based material 54 on the cathode 53.

[0069] Here, the anode 52 is, for example, one that contains the crude titanium-based material obtained in the extraction process described above. For example, the anode 52 has a plate-like outer shape and has a cage-like container with many through holes made of Ni, Ni-based alloy, Hastelloy, or Ni-coated steel, and in this case, the crude titanium-based material can be placed in the cage-like container in granular or powder form. When the anode 52 has a cage-like container, the current-carrying member 7 can be connected to the cage-like container. However, the form of the anode 52 is not limited to this, and for example, it may be a plate-like (rectangular parallelepiped) made from crude titanium-based material by melting and casting, etc. The cathode 53 can be a plate-like material with at least its surface made of Ti, and for example, it can be a titanium plate made entirely of Ti. It is also conceivable to place a bipolar electrode between the anode 52 and the cathode 53, but a bipolar electrode is not required.

[0070] Furthermore, the molten salt bath Bm may be a chloride bath mainly containing metal chlorides, for example, alkali metal chlorides and / or alkaline earth metal chlorides, for example, 70 mol% or more, more preferably 80 mol% or more, or more preferably 90 mol% or more. Such chloride baths are preferred over fluoride baths, bromide baths, and iodide baths because they are less corrosive, have a lower environmental impact, and are less expensive. In particular, when a chloride bath containing magnesium chloride (MgCl2) is used, a purified titanium-based material 54 can be obtained in which not only the O content but also the Al content has been sufficiently reduced. The MgCl2 content in the chloride bath is preferably 30 mol% or more, more preferably 50 mol% or more, more preferably 80 mol% or more, more preferably 85 mol% or more, and especially preferably 90 mol% or more. The chloride bath may contain one or more metal chlorides selected from lithium chloride (LiCl), sodium chloride (NaCl), potassium chloride (KCl), rubidium chloride (RbCl), cesium chloride (CsCl), beryllium chloride (BeCl2), calcium chloride (CaCl2), strontium chloride (SrCl2), and barium chloride (BaCl2) in amounts of, for example, 70 mol% or less, further 50 mol% or less, further 20 mol% or less, further 10 mol% or less, and further 5 mol% or less.

[0071] Furthermore, the molten salt bath Bm may, if necessary, contain lower titanium chlorides with a lower valence of Ti than titanium tetrachloride, specifically titanium dichloride (TiCl2) or titanium trichloride (TiCl3). The titanium ion content in the molten salt bath Bm is preferably 3 mol% or more, more preferably 5 mol% or more, even more preferably 6 mol% or more, and may even be 10 mol% or more, but is preferably 20 mol% or less. The content of metal chlorides and metal ions in the molten salt bath Bm can be measured by ICP emission spectrometry or atomic absorption spectrometry. The titanium ion content is determined as a percentage of the total metal ion content in the molten salt bath Bm.

[0072] Providing the molten salt bath Bm described above inside the electrolytic cell 2 can be achieved by putting a predetermined granular or块状 salt inside the electrolytic cell 2 and heating it to form a molten salt. Alternatively, when molten salt is already obtained, for example, as shown in FIG. 13, the molten salt may be injected into the electrolytic cell 2. Here, a molten salt storage tank 61 storing molten salt inside is connected to the molten salt supply port 9a of the electrolytic cell 2, and a valve (not shown) of the molten salt supply port 9a is opened. Then, since the molten salt supply port 9a is formed above the final bath surface height of the molten salt bath Bm inside the electrolytic cell 2, the molten salt flows from the inside of the molten salt storage tank 61 into the inside of the electrolytic cell 2 by its own weight.

[0073] In the subsequent electrolysis process, electricity is supplied from a power source to the anode 52 and the cathode 53 of the electrode 51 via the current-carrying member 7, and a voltage is applied between the electrodes 51. As a result, titanium ions elute from the crude titanium-based material contained in the anode 52 into the molten salt bath Bm, and the titanium ions are deposited as titanium atoms on the cathode 53 to become a purified titanium-based material 54. During such electrolysis, in accordance with the growth of the purified titanium-based material 54 on the cathode 53, as described above, the electrode holding member 4 is moved while sliding the slide-type closing plate 6, and the anode 52 and the cathode 53 are separated from each other in an opposing posture to adjust the interelectrode distance. Thereby, electrolysis can be carried out for a long time without causing a short circuit, and a large amount of the purified titanium-based material 54 can be deposited on the cathode 53 with less power consumption. The purified titanium-based material 54 deposited on the cathode 53 may correspond to a titanium electrodeposit.

[0074] As conditions for the electrolysis process, for example, the temperature of the molten salt bath Bm is 450°C to 900°C, and the current density at the cathode 53 is 0.01 A / cm 2 ~3 A / cm 2 It may be set as such. The current density is calculated by the formula: Current density (A / cm 2 ) = Current (A) ÷ Electrodeposition area (cm 2This can be calculated by ( ). The electrode 51 can be used to continuously supply current, or it may be used to supply pulsed current, which alternates between periods of current supply and periods of current supply, with periods of current supply being reduced to zero. The maximum voltage between the electrodes 51 may be, for example, 0.2V to 3.5V. During the electrolysis process, it is preferable to maintain an inert atmosphere such as argon inside the electrolytic cell 2.

[0075] After the electrolysis process is completed, a molten salt discharge process can be performed. In the molten salt discharge process, as shown in Figure 14, a molten salt storage tank 61 with enough space to accommodate molten salt (for example, if no molten salt is stored at all) is connected to the molten salt discharge port 9b of the electrolytic cell 2, and a valve (not shown) of the molten salt discharge port 9b is opened. Here, since the molten salt discharge port 9b is formed below the height of the bath surface of the molten salt bath Bm and on the bottom 2b side, opening the valve of the molten salt discharge port 9b causes the molten salt to flow out of the electrolytic cell 2 into the molten salt storage tank 61 by its own weight. This discharges the molten salt from inside the electrolytic cell 2 and exposes the refined titanium-based material 54 from the molten salt bath Bm. In the molten salt discharge process, it is sufficient if almost the entire refined titanium-based material 54 is exposed from the molten salt bath Bm, but the molten salt may be discharged until the molten salt bath Bm is substantially no longer present inside the electrolytic cell 2.

[0076] After the molten salt discharge process, a residue separation process may be performed as shown in Figure 15, if necessary. The purpose of the residue separation process is to remove any residual molten salt that remains attached to the purified titanium-based material 54 on the cathode 53.

[0077] In the residue separation process, for example, a vacuum device 71 is connected to the molten salt supply port 9a, which serves as a vent, and the refined titanium-based material 54 on the cathode 53 is heated to, for example, 850°C to 1000°C while the inside of the electrolytic cell 2 is subjected to a reduced pressure atmosphere such as a vacuum, and the gas inside the electrolytic cell 2 is discharged to the vacuum device 71 side. As a result, the residue of the molten salt evaporates and is discharged to the vacuum device 71 side, separating it from the refined titanium-based material 54. The vacuum device 71 has a container-shaped condenser as shown in the figure, as well as a vacuum pump (not shown), and suction is performed by the vacuum pump as indicated by the white arrow. The condenser of the vacuum device 71 is cooled, and the gas that flows from the electrolytic cell 2 into the condenser is captured there as a solid. In order to suppress the mixing of outside air into the electrolytic cell 2, it is preferable to close the molten salt discharge port 9b with a valve (not shown) or the like.

[0078] For heating the refined titanium-based material 54 on the cathode 53 during the residue separation process, the piping for the cathode 53 of the temperature controller 8 installed inside the electrolytic cell 2 can be used. In this case, the piping on the anode 52 side of the temperature controller 8 can be left unused or used to cool the anode 52. This is to suppress deterioration of components such as the cage-like container of the anode 52 and sintering of any residue of crude titanium-based material that may be contained in the anode 52 due to the heating of the refined titanium-based material 54. Furthermore, if the piping on the anode 52 side is not used, unnecessary energy consumption can be avoided. This also means that only the parts that are deemed to require heating can be heated, enabling energy-saving production. For example, in a cage-like container made of Ni, there is a concern that low-melting-point intermetallic compounds may be generated by reaction with the residue of crude titanium-based material, which may melt during the above heating process, causing the residue to fall from the cage-like container. From this viewpoint, it is preferable to place the aforementioned insulating plate 10 between the anode 52 and the cathode 53, as shown in Figure 15, before starting the residue separation process. This makes it possible to suppress heat transfer from the cathode 53 to the anode 52 when heating the refined titanium-based material 54 on the cathode 53.

[0079] Once the residue separation process is complete, the refined titanium-based material 54 is removed from the electrolytic cell 2 along with the cathode 53. The refined titanium-based material 54 removed from the electrolytic cell 2 may still contain residue of molten salt, so it can be washed with water, pickled, or otherwise cleaned.

[0080] The residue separation step can be omitted. In this case, after the molten salt discharge step, the refined titanium-based material 54 may be removed from inside the electrolytic cell 2 and the above-mentioned cleaning may be performed.

[0081] As described above, a refined titanium-based material 54 can be obtained, and a titanium-based electrodeposit can be manufactured.

[0082] (Titanium-based electrodeposits) The titanium electrodeposit, as the purified titanium-based material 54 obtained by one or more electrolytic processes, has a total content of impurities other than Ti of, for example, 40,000 ppm by mass or less, preferably 5,000 ppm by mass or less, more preferably 2,000 ppm by mass or less, even more preferably 1,000 ppm by mass or less, and particularly preferably 200 ppm by mass or less.

[0083] Titanium-based electrodepositories can be made of metallic titanium, for example, with an Al content of 5 to 20,000 ppm by mass, an O content of 50 to 20,000 ppm by mass, and the remainder consisting of Ti and unavoidable impurities. Alternatively, titanium-based electrodepositories may have an Al content of 5 to 1,000 ppm by mass, an O content of 50 to 1,000 ppm by mass, and the remainder consisting of Ti and unavoidable impurities. It is also possible to manufacture titanium-based electrodepositories made of metallic titanium with a purity of 4N5 or higher, and even higher than 5N5.

[0084] Unavoidable impurities in titanium electrodeposites include those originating from the ore, chloride bath, reducing agent, separating agent, components of electrolytic devices such as electrolytic cells, and those generated when in contact with the atmosphere. Specifically, titanium electrodeposites may contain unavoidable impurities such as a nitrogen (N) content of 0.03% by mass or less, a carbon (C) content of 0.01% by mass or less, an iron (Fe) content of 0.050% by mass or less, a magnesium (Mg) content of 0.02% by mass or less, a nickel (Ni) content of 0.03% by mass or less, a chromium (Cr) content of 0.03% by mass or less, a silicon (Si) content of 0.001% by mass or less, a manganese (Mn) content of 0.05% by mass or less, and a smear cell (Sn) content of 0.01% by mass or less. [Explanation of Symbols]

[0085] 1. Molten salt electrolysis apparatus 2 Electrolytic cell 2a Peripheral wall 2b bottom 2c opening 3, 4 Electrode holding member 5. Lid 5a Hole 5b Through hole 6. Sliding closure plate 6a Through hole 6b Hole 7. Conductive components 8 Temperature controller 9a Molten salt supply port 9b Molten salt outlet 10 Insulation board 51 electrode 52 Anode 53 Cathode 54. Refined Titanium-Based Materials 61 Molten salt storage tank 71 Pressure Reducing Device Bm molten salt bath

Claims

1. This is a molten salt electrolytic apparatus used in electrolytic refining to obtain a purified titanium-based material of higher purity than the crude titanium-based material by electrolysis using a molten salt bath, from a crude titanium-based material containing Ti, Al, and O and having conductivity. An electrolytic cell is provided, inside, with the molten salt bath, and an electrode consisting of a plate-shaped anode containing the crude titanium-based material and a plate-shaped cathode positioned opposite the anode to deposit the refined titanium-based material. A current-carrying member is provided extending from the outside to the inside through the opening of the electrolytic cell, and electrically connects the anode and the cathode to a power source, An electrode holding member for an anode and a cathode is provided extending from the outside to the inside through the opening of the electrolytic cell and holds the anode and the cathode, respectively, on the inside, wherein the electrode holding member for an anode and / or a cathode is movable in a direction that separates the anode and the cathode from each other in an opposing position, A lid is positioned to cover the opening of the electrolytic cell, and has a hole formed therein that allows the movable electrode holding member to extend inward and move. A sliding closure plate is provided on the inside or outside of the electrolytic cell relative to the lid, and slides along with the movement of the electrode holding member while closing the hole. A molten salt electrolytic apparatus equipped with the following features.

2. The molten salt electrolytic apparatus according to claim 1, wherein the anode and / or cathode energizing members, among the energizing members, held by the movable electrode holding member are movable together with the movable electrode holding member.

3. The movable electrode holding member is either the anode or the cathode electrode holding member, The molten salt electrolytic apparatus according to claim 1, wherein the other electrode holding member for the anode or cathode is fixed to the lid.

4. A hole is formed in the sliding closure plate at a position offset from the position where the hole is formed in the lid, through which the other electrode holding member extends. The molten salt electrolytic apparatus according to claim 3, wherein the other electrode holding member is displaceable inside the hole of the sliding closure plate as the sliding closure plate slides.

5. The molten salt electrolytic apparatus according to claim 1, wherein the sliding closure plate is positioned on the outside side of the electrolytic cell relative to the lid.

6. The molten salt electrolytic apparatus according to claim 1, wherein the electrode holding member is rod-shaped, and a plurality of rod-shaped electrode holding members are provided for each electrode.

7. The molten salt electrolysis apparatus according to claim 1, further comprising a temperature controller provided inside the electrolytic cell for adjusting the temperature inside the electrolytic cell, the molten salt bath, the refined titanium-based material, and / or the electrodes.

8. The molten salt electrolytic apparatus according to claim 7, wherein the temperature controller is a heat exchanger and is laid inside the electrolytic cell at a lower position than the electrodes in the region where the refined titanium-based material grows.

9. The molten salt electrolysis apparatus according to claim 7, wherein the temperature controller is capable of adjusting the anode side and the cathode side to different temperatures.

10. The molten salt electrolytic apparatus according to claim 1, wherein the electrolytic cell has a molten salt supply port and a molten salt discharge port that can be connected to a molten salt storage tank.

11. The molten salt electrolytic apparatus according to claim 1, wherein the electrolytic cell and / or lid has a vent that can be connected to a vacuum device.

12. The molten salt electrolytic apparatus according to claim 1, further comprising an insulating plate that can be placed between the anode and the cathode when there is no molten salt bath inside the electrolytic cell, and which suppresses heat transfer between the anode and the cathode.

13. A method for producing a titanium-based electrodeposit by electrolytic refining using a molten salt electrolytic apparatus according to any one of claims 1 to 12, A method for producing a titanium electrodeposited material, comprising: electrolysis using a molten salt bath inside an electrolytic cell to deposit the purified titanium-based material on the cathode; and an electrolytic step during the electrolysis in which the anode and the cathode are separated from each other in an opposing position.

14. A method for producing a titanium electrodeposited material according to claim 13, comprising a molten salt discharge step, after the electrolysis step, in which molten salt is discharged from the inside of the electrolytic cell through a molten salt discharge port connected to a molten salt storage tank, thereby exposing the purified titanium-based material from the molten salt bath.

15. A method for producing a titanium electrodeposited material according to claim 14, further comprising a residue separation step, in which, after the molten salt discharge step, the refined titanium-based material on the cathode is heated using a temperature controller installed inside the electrolytic cell, and the gas inside the electrolytic cell is discharged from a vent connected to a vacuum device, thereby separating the molten salt residue from the refined titanium-based material.

16. A method for producing a titanium electrodeposit according to claim 15, wherein an insulating plate is placed between the anode and the cathode to suppress heat transfer between the anode and the cathode, and the residue separation step is performed.

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