JP2006213972A - Scraping blade in precipitate scraping type electrolyzer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To smoothly scrape-off an objective element precipitated on an electrode, and to prevent the sticking of scraping blades to the precipitate. <P>SOLUTION: The scraping blades 2 in the precipitate scraping type electrolyzer 1 scrape and recover an objective element precipitated on a cylindrical electrode provided in an electrolytic cell at the time of electrolytic refining in the electrolytic cell. The scraping blades 2 are provided around a rotary electrode 4 rotating almost at the center of the cylindrical electrode 5 in a state of being divided into several pieces in the axial direction of the rotary electrode 4, and are tilted with respect to the rotary axis of the rotary electrode 4. In this case, preferably, the blades are tilted upward obliquely in the rotary direction so as to scrape off the precipitated objective element 6 toward the bottom part of the electrolytic cell 3. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a scraping blade in a precipitate scraping type electrolytic apparatus. More specifically, the present invention relates to a structure of a scraping blade used for scraping and collecting a deposited element in a process of depositing and collecting a target element such as metal uranium by electrolysis purification in a solvent salt. Regarding improvements.

  In metal fuel reprocessing using a solvent salt, the target element deposited on the electrode by electrolysis in the solvent salt is recovered through the following electrolytic purification process. That is, in order to separate uranium and transuranium elements (hereinafter, described in the case of uranium) from fission products, a solvent salt such as eutectic lithium chloride-potassium chloride is used as a solvent, and a metal fuel to be reprocessed on the anode Loaded, using a metal such as iron for the cathode, a constant current flows between both electrodes. Thus, the metal element (uranium) loaded on the anode is dissolved as ions in the solvent salt, and the ions in the solvent salt are reduced to metal at the cathode. In such an electrolytic purification step, uranium can be separated from unnecessary elements such as fission products because of the difference in ease of being converted to ions at the anode or the ease of reduction to metal at the cathode.

  Here, in the above-described electrolytic purification process, it is known that uranium precipitates on the cathode and grows in a dendritic shape. Therefore, conventionally, in order to efficiently recover such precipitates, the precipitated uranium is scraped, and the scraped precipitates (uranium) are recovered by a net, a tray, a basket, or the like installed at the lower part of the electrolyzer. Means are being used. Specifically, for example, when electrolytic refining is performed using a cylindrical electrode, electrolysis having a structure in which uranium precipitates grown above a certain level are scraped off by a scraping blade (scraper) that rotates in an electrolytic cell. An apparatus or an electrolytic apparatus having a structure in which uranium deposited on a rotating cathode is scraped off by a fixed scraping blade provided around the apparatus has been proposed and used (see, for example, Patent Document 1).

Japanese Patent Laid-Open No. 10-332880

  However, in the case of an electrolysis apparatus that scrapes uranium precipitates with a blade in this way, since the precipitated uranium is hardened by entraining the solvent salt, the scraping blade interferes with the precipitate (uranium), and in some cases There is a problem that the scraping blade may stick to uranium. In such a state, the scraping blade may stop rotating as a result of interference with the hardened uranium.

  Therefore, an object of the present invention is to provide a scraping blade in a precipitate scraping-type electrolysis apparatus that smoothly scrapes off a target element deposited on an electrode and prevents sticking of the blade.

  In order to achieve this object, the present inventor has conducted various studies. The method of scraping and collecting the target element that precipitates is excellent in that the precipitate can be recovered one after another, but it is structured in that interference may occur and eventually rotation may stop. It was thought that there was a problem above. Considering that, the scraping blades so far have multiple vertical blades arranged on the circumference, and the action of scraping the deposited elements grown on the cathode and pushing it in the rotation direction (circumferential direction) is demonstrated. However, it does not have a structure that positively drops the scraped precipitated elements. For this reason, there is an opinion that scraped deposited elements accumulate between the scraping blade and the electrode, and this interacts with the deposited elements remaining on the cathode surface, and it seems to grow as a roll. As a result, we have gained knowledge to solve these problems.

  The present invention is based on such knowledge, and the invention according to claim 1 scrapes off the target element deposited on the cylindrical electrode provided in the electrolytic cell during electrolytic purification in the electrolytic cell. In the scraping blade in the precipitate scraping-type electrolyzer for recovery by the above, in the state of being divided into a plurality of portions in the axial direction of the rotating electrode around the rotating electrode rotating about the center of the cylindrical electrode, and The rotary electrode is provided so as to be inclined with respect to the rotation axis.

  The scraping blade in the present invention is configured as a so-called inclined blade that is inclined so as to push down or push up precipitates such as uranium in the direction of the rotation axis. For this reason, unlike conventional vertical blades, when scraping, it is possible to generate a component force in the axial direction on the deposit on the electrode, so simply scraping in the rotational direction (circumferential direction) It works like scraping and scraping in an oblique direction. The uranium precipitate scraped off in this way is divided from the electrode surface of the cylindrical electrode and falls to the bottom.

  In addition, if the scraper blade is an integrated scraper as in the past, even if the blade is provided with an inclination, it is possible to secure an opening and a flow path for the target element to pass through the solvent salt, or to perform blade molding. It is considered that the inclination angle was limited to some extent from the viewpoint of ease, but the scraping blade according to the present invention is divided into a plurality of parts in the axial direction, so an opening and a flow path for the distribution of the target element are secured. It is also easy to set the inclination angle of each blade to various angles. Further, in some cases, it is possible to adopt a structure in which the inclination angles of the scraping blades are made different.

  In the above-described invention, it is preferable that the scraping blade is inclined obliquely upward in the rotational direction so as to scrape the deposited target element toward the bottom of the electrolytic cell. The scraping blade in this case acts to scrape off the deposited elements and simultaneously apply a downward component force to scrape it toward the bottom.

  In addition, as described in claim 3, it is also preferable that the axial positions of at least the scraping blades adjacent to each other in the rotation direction out of the scraping blades shifted in the rotation direction are shifted from each other.

  The scraping blade in the precipitate scraping type electrolysis apparatus according to claim 1 constitutes an inclined blade, so that the deposit on the electrode surface is scraped off smoothly and the blade itself is fixed. Can be prevented. In other words, in the case of a conventional scraping blade, the force for transferring the scraped precipitated elements to the recovery section (such as the receiving tray at the bottom of the electrolytic cell) depends on only gravity, and scraping is performed. It is possible to positively apply a force such that the precipitated element scraped off simultaneously with the operation moves to the recovery unit or pushes it up. Therefore, interference with the precipitated elements and blade rotation stop can be effectively suppressed, and as a result, the operation continuation time in one electrolysis is prolonged, and the collection and processing speed of the target element is increased. It becomes possible to plan. In addition, the entire amount of uranium loaded on the anode is dissolved.

  In addition, since the blades are divided in the direction of the rotation axis, and the divided blades are arranged in the vertical direction so as to be arranged vertically, it is not necessary to unnecessarily extend the length of the blade of the scraping blade alone. For this reason, it is not necessary to narrow the opening or the passage required for the target element to pass through the solvent salt during electrolytic purification. In this case, the scraping blade occupies the area of the side surface of the rotating electrode. This increases the flow rate of the solvent salt from the rotating electrode (anode) side to the cylindrical electrode (cathode) side. As a result, an effect of promoting an increase in the flow rate of the target element is also obtained. Furthermore, by adopting the vertically divided inclined blades, it is possible to suppress the growth of the roll-shaped precipitates, and to obtain the effect of facilitating the smooth falling of the precipitates and the collection of fine precipitates.

  In addition, in the case of the present invention in which the scraping blade is inclined, there is also an advantage that the load on the scraping blade itself, the rotating shaft, and further the rotational power source can be reduced. In other words, with a conventional vertical scraping blade, the entire blade may hit the deposits at once. In such a case, the load on the blade and the shaft is greatly fluctuated. In the case of a cutting blade, the blades are sequentially scraped and scraped from the end of the blade, so that the load fluctuation is small and the load on the blade and the shaft can be less than before.

  According to the scraping blade of claim 2, the deposited target element can be scraped downward toward the bottom of the electrolysis apparatus. According to this, in addition to scraping off the deposit smoothly to prevent the blade from sticking, it is possible to effectively collect the scraped-off deposit.

  Furthermore, according to the invention of claim 3, wherein the axial positions of the adjacent scraping blades are shifted from each other, it is possible to scrape deposits on the electrode as a whole scraping blades without omission, By reducing the number of scraping blades required in a certain area and creating a space without scraping blades, it is possible to secure a space necessary for the precipitate to fall. Moreover, it is advantageous to disperse and arrange the plurality of scraping blades in the circumferential direction (rotation direction) as appropriate in this way so as to eliminate unevenness in weight distribution and to prevent uneven rotation.

  Hereinafter, the configuration of the present invention will be described in detail based on embodiments shown in the drawings.

  1 to 2 show an embodiment of the present invention. The scraping blade 2 in the deposit scraping type electrolysis apparatus 1 according to the present embodiment is deposited on a cylindrical electrode (cathode) 5 provided in the electrolytic cell 3 during electrolytic purification in the electrolytic cell 3. In the case of the present embodiment, around the rotating electrode 4 that rotates about the center of the cylindrical electrode 5, the relevant precipitate (target element) 6 is scraped and collected. In other words, the blade is provided with an inclined blade that is divided into a plurality of portions in the axial direction of the rotating electrode 4 and is inclined with respect to the rotating shaft of the rotating electrode 4.

  In the precipitate scraping type electrolysis apparatus 1 provided with such a scraping blade 2, the metal uranium and the like are electrically connected by energizing between the rotating electrode 4 serving as the anode and the cylindrical electrode 5 serving as the cathode. And is deposited on the cylindrical electrode 5. At this time, for example, a collection basket 9 for collecting precipitates, which is continuously scraped off by the rotating scraping blade 2 and is provided at the bottom of the electrolytic cell 3. (See FIG. 1). In this case, the precipitate 6 scraped off from the inner peripheral surface of the cylindrical electrode (cathode) 5 is deposited on the collection basket 9 at the bottom. A metal net (not shown) is stretched on the bottom of the collection basket 9, and an electrode structure (the electrode structure here is a portion of the electrolysis apparatus 1 excluding the electrolytic cell 3 and the solvent salt 7, that is, , The portion composed of the scraping blade 2, the rotating electrode 4, the cylindrical electrode 5 and the like), when the solvent salt 7 is pulled up from the solvent salt 7, the solvent salt 6 is drained through the metal net and is deposited. It is possible to reduce the amount of the solvent salt 7 adhering to the object 6 as much as possible. Hereinafter, after briefly explaining each part of the electrolysis apparatus 1, a description of the scraping blade 2 is added.

  The electrolytic tank 3 is a tank in which, for example, an electrolytic purification process of dry reprocessing of spent nuclear fuel is performed (see FIG. 1). A solvent salt 7 is stored in the electrolytic cell 3, and uranium dissolved in the solvent salt 7 is ionized and precipitated. 1 and 2, the electrolytic cell 3 has a rectangular bottom shape, but this is only an example, and it is needless to say that other shapes may be used. In FIG. 1, hatching is omitted.

  The rotating electrode 4 is a rod-shaped electrode immersed in the center of the solvent salt 7 and functions as an anode in the electrolytic purification process. The upper portion of the rotary electrode 4 is connected to a rotary power source such as a rotary motor (not shown), and is driven counterclockwise by the power source, for example, as shown in FIG.

  The cylindrical electrode 5 is a cylindrical electrode immersed in the solvent salt 7 in the electrolytic cell 3 (see FIG. 1). When the electrolytic purification process is performed in the electrolytic cell 3, the target element (such as uranium) gradually precipitates on the surface of the cylindrical electrode 5 and grows.

  The rotating electrode 4 is provided with an anode basket 8 and a scraping blade 2 that rotate together with the rotating electrode 4. Among these, the anode basket 8 functions to increase the flow of the solvent salt 7 around the rotating electrode (anode) 4. The shape of the anode basket 8 is not particularly limited. For example, in the present embodiment, a rectangular basket is formed, and four baskets are arranged so as to spread around the rotating electrode 4 in four directions. (See FIG. 2). The anode basket 8 is loaded with metal uranium. When the anode basket 8 has a cross shape as in the present embodiment, the flow of the solvent salt 7 around the rotating electrode 4 can be further increased, and further, the amount of uranium loaded on the anode can be increased. It becomes like this.

  The scraping blade 2 is a blade (blade) provided for scraping off the precipitate 6 that has grown to a certain thickness or more on the surface (inner peripheral surface) of the cylindrical electrode 5. For example, the scraping blade 2 of the present embodiment is formed around the rotating electrode (anode) 4, rotates with the rotating electrode 4 during the electrolytic purification process, grows on the cylindrical electrode 5 and exceeds a certain amount. It functions to scrape the deposit 6 and prevent it from being deposited. Here, in the present embodiment, the scraping blade 2 is provided with an inclination in order to prevent the scraped precipitate 6 from staying in the cylindrical electrode 5. Specifically, the scraping blade 2 is inclined obliquely upward in the rotational direction so that the deposited target element can be scraped downward toward the bottom of the electrolytic cell 3. For example, when the rotating electrode 4 and the scraping blade 2 are rotated counterclockwise when viewed from the top as in the present embodiment (see FIG. 2), the shape of the scraping blade 2 viewed from the front or its The cross-sectional shape is a shape inclined from the lower left to the upper right as shown in FIG. 1 (see FIG. 1).

  Moreover, in this embodiment, it is set as the form which divided | segmented the above-mentioned scraping blade 2 to the axial direction, and the number is made into the structure which can be changed suitably as needed. That is, in order to ensure the necessary electrode effective height, the length of the scraping blade 2 may increase depending on the tilt angle, but it is not possible to extend the length of the scraping blade 2 unnecessarily. In electrolytic refining, the opening required for the target element to pass through the solvent salt 7 or its passage may be narrowed, which is not necessarily preferable. Therefore, if necessary, a plurality of short scraping blades 2 can be arranged in the vertical direction to appropriately reduce the installation ratio of the scraping blades 2 occupying the circumferential length (see FIG. 1). The precipitate (target element) 6 dissolves on the rotating electrode (anode) 4 side and dissolves in the solvent salt 7, and what arrives at the cylindrical electrode (cathode) 5 side by the flow of the solvent salt 7 is deposited as a metal. Therefore, from the viewpoint of increasing the flow rate of the solvent salt 7 from the anode side to the cathode side and promoting the flow rate increase of the precipitate (target element) 6, the scraping blade 2 occupying the side area of the rotating electrode 4. It can be said that it is preferable to reduce the ratio. In this manner, when the scraping blade 2 is vertically divided in the direction of the rotation axis and arranged along the axial direction, the scraping blade 2 is disposed on the side surface of the rotating electrode 4 while eliminating a portion where scraping loss occurs. Can be reduced.

  In addition, when a plurality of scraping blades 2 are arranged in the circumferential direction (rotation direction), one region (the region here is a region that is long in the axial direction sandwiched between two bus bars) It is also preferable to widen the installation interval between the scraping blades 2 in), and to shift the height (in other words, the axial position) with respect to the scraping blades 2 in other regions. In such a case, the number of scraping blades 2 required in one region is reduced while allowing the deposit 6 on the cylindrical electrode 5 to be scraped off without omission as a whole of the scraping blade 2. It is possible to secure a space necessary for the deposit 6 to fall by creating a space without any gap. In addition, it is advantageous to disperse and arrange the plurality of scraping blades 2 in the circumferential direction (rotation direction) as described above in order to eliminate unevenness in weight distribution and prevent uneven rotation. . Of course, it is possible to arrange the scraping blades 2 in a row in one area, but it is preferable in that the above-described advantages are obtained when the scrapers 2 are dispersed and arranged as described above.

  Then, the outline | summary of the process by the deposit scraping type | formula electrolysis apparatus 1 mentioned above is demonstrated below. Here, a scene where spent metal fuel is processed in a metal fuel cycle will be briefly described.

  As an object to be processed by the precipitate scraping type electrolysis apparatus 1 of the present embodiment, a used metal fuel that comes out after using a metal fuel (an alloy mainly composed of uranium, plutonium, and zirconium) in a fast reactor is used. Can be mentioned. This is an accumulation of fission products in the above metal fuel, but basically actinide elements such as uranium and plutonium are kept in a metallic state. Further, since the fuel enters the nuclear reactor in a state of being enclosed in a metal cladding tube, the spent fuel is also brought into the shearing process in a state of entering the metal cladding tube together with the fission product.

  In the shearing process, the clad tube containing the spent fuel is cut into round pieces with an interval of several mm to 1 cm together with the fuel inside, and then the anode (in this embodiment, with the sheared clad tube attached). In this case, the rotating electrode 4) is loaded. During electrolysis, in order to keep the anode potential at such a level that the cladding tube and anode structure do not dissolve, basically only actinide elements such as uranium and plutonium and elements that are slightly more soluble than uranium such as zirconium are dissolved. In the fission product, rare earth, alkaline earth, and alkali metal elements, which are more easily dissolved than actinide elements, dissolve in the solvent salt. On the other hand, the noble metal element of the fission product is less soluble than zirconium and is expected to remain on the anode (rotary electrode 4) and be decontaminated during electrolytic purification. In addition, fission products such as rare earths, alkaline earths, and alkali metal elements, which are easily dissolved in the solvent salt, are deposited on the cathode (cylindrical electrode 5 in the case of this embodiment) at the potential at which the actinide element is deposited. Therefore, it basically remains in the solvent salt 7 and can be decontaminated. The recovered material mainly composed of the actinide element deposited at the cathode (cylindrical electrode 5) is separated into the metal salt by distillation separation of the solvent salt 7 adhering in the next cathode deposit treatment step. This is used as a raw material for the production of the next recycled fuel in the fuel production process. The above is a scene of processing spent metal fuel in a metal fuel cycle.

  As described so far, in the electrolysis apparatus 1 according to the present embodiment, when scraping the precipitate 6 such as uranium, the scraping blade 2 that is divided in the axial direction and formed to be inclined is used. By smoothly scraping off the precipitate 6, the interference between the scraping blade 2 and the precipitate 6 can be suppressed, and the rotation of the rotating electrode (anode) 4 can be prevented from stopping. As a result, there is an advantage that effects such as a longer operation continuation time during one electrolysis process and an increase in the recovery / treatment speed of the target element can be obtained.

  The above-described embodiment is an example of a preferred embodiment of the present invention, but is not limited thereto, and various modifications can be made without departing from the gist of the present invention. For example, in the present embodiment, the case where the scraping blade 2 is tilted obliquely upward has been described as a preferred mode when the scraping blade 2 is tilted. On the contrary, the precipitate 6 is pushed upward with rotation. It is also possible to have a simple slope. In such a case, the precipitate 6 such as uranium is subjected to an upward action when it is scraped off by the scraping blade 2, so that it is swept up once and then dropped in the solvent salt 7. However, from the viewpoint of smoothly scraping the deposit 6 and preventing the blade itself from sticking, the effect obtained even when the direction of the inclination is reversed in this way is There is no particular change.

  Further, there are various inclination modes. For example, in the present embodiment, the cross-sectional shape (or the shape when viewed from the front) of the scraping blade 2 is shown as an approximately parallelogram (see FIG. 1). It is only an example, and for example, a curved shape bent in an arc shape or a V-shape (or inverted V-shape) bent and opened in the middle may be used. For example, there is a difference between the case where the cross-sectional shape is a flat shape and the case where the cross-sectional shape is curved or bent, in terms of the scraping ability by the blade, the manner in which the precipitate 6 drops, and the resistance received from the solvent salt 7 during rotation In some cases, it is preferable to appropriately employ the scraping blade 2 having various shapes according to various situations. Further, if a plurality of scraping blades 2 are provided in the axial direction as in the present embodiment, the shape of each scraping blade 2 can be made different.

  Moreover, what was demonstrated in the above-mentioned embodiment is a mode in which the scraping blade 2 rotating in the cylindrical electrode 5 is divided in the axial direction and inclined, but the electrolysis apparatus 1 is opposite to this. Even in the case of this structure, the technique described in this embodiment can be applied. That is, an electrolysis apparatus 1 having a structure in which the cathode is rotated at the center of the electrolytic cell 3 and the deposit on the rotating cathode is scraped off by a scraping blade 2 fixedly installed around the rotating cathode is also used. However, with such a structure, the scraping blade 2 fixedly installed around the rotating cathode can be divided and inclined in the same manner as in the present embodiment to obtain the same effects as the present invention. Is possible.

  In this embodiment, potassium chloride-lithium chloride is exemplified as the phase of the solvent salt 7. For example, potassium chloride-sodium chloride-based solvent salt, cesium chloride-sodium chloride-based solvent salt, potassium chloride-lithium chloride-chloride. Sodium solvent salts, calcium chloride-barium chloride-lithium chloride-sodium chloride solvent salts, calcium chloride-barium chloride-lithium chloride-potassium chloride solvent salts, and the like may be used. Furthermore, it is also possible to apply a solvent such as an aqueous solution instead of using a solvent salt. That is, in the above-mentioned embodiment, since it was considered as “solvent salt” in view of electrolytic purification of uranium, the precipitate scraping type electrolysis apparatus 1 according to the present invention and the scraping blade in the electrolysis apparatus 1 were described. The scope of application of 2 is not limited to the system using “solvent salt”, and in a strict sense, the solvent salt is a kind of solvent, so that a solvent such as an aqueous solution is used. Even a system can be applied.

  In the above-described embodiment, uranium has been described as an example of the precipitate 6. However, this is merely a representative example for explanation, and super uranium is used as a metal element to be scraped and recovered. Needless to say, is also included. Therefore, the present invention is applied not only to the electrolytic purification of uranium but also to the case where adhesion due to interference between the precipitate 6 and the scraping blade 2 becomes a problem in an electrolytic system for depositing and collecting other target elements by the same method. Is of course possible.

The test for confirming the effect which the deposit scraping-off type electrolysis apparatus 1 concerning this embodiment shows is performed. This is described as Example 1 below. The test conditions common to Examples 1 to 3 described below are as follows.
[Test conditions]
・ Bath salt: 4000g, Bottom Cd: 1900g (Electrolytic bath: 170mmφ × 130mmD)
・ Uranium concentration in salt: about 2wt%
・ Anode rotation speed: 100rpm

  In Example 1, 490 g of 5.8 mmφ × about 20 mm uncoated metal uranium was prepared, and the anode basket 8 was loaded almost uniformly at random. Electrolytic current: 20 A, energization amount: equivalent to 465 g-U, anodic dissolution amount: 222 g-U, average treatment rate: 28.4 g-U / h (18.9 g-U / h · liter), and recovered uranium was 64.25 g. The test results are shown in FIG. (1) The electrolysis current at the start of the current electrolysis indicated as “H15Run-1” was increased by about 1.5 times compared to the actual value so far (“H14Run-3” in FIG. 3). From this, it was confirmed that according to the precipitate scraping-off type electrolysis apparatus 1 having the above-described structure, the processing speed is improved. (2) Since fine precipitates 6 that are not in a roll shape were collected, the effect of making the shape of the scraping blade 2 different from the conventional one was confirmed. (3) A large variation in anode potential was observed during electrolysis. As the shape of the scraping blade 2 was made new, no roll was generated, so that the scraping blade 2 was always in contact with the cathode deposit, and the anode (rotary electrode 4) -cathode (cylindrical electrode 5). This was thought to be partly due to an increase in electrical short circuit.

  A test for confirming the improvement in the processing speed of the precipitate scraping-type electrolysis apparatus 1 was performed. In Example 2, 327 g of 5.8 mmφ × about 20 mm uncoated metal uranium was prepared, and each anode basket 8 was loaded almost uniformly at random. The amount of anodic dissolution was 290 g-U, the current efficiency was 53%, the electrolysis current was 15 to 30 A, and the average treatment rate was 34.4 g-U / h (22.9 g-U / h · liter). The treatment speed in the electrolyzer 1 was 8% higher than the past results (however, the rotation of the rotating electrode 4 was stopped when electrolysis was performed up to 546 g-U). In addition, it was confirmed that the continuous processing amount achieved about 290g-U or more, which exceeded the conventional actual value (170g-U).

  A test was conducted to confirm the influence of the cladding tube in the precipitate scraping-type electrolysis apparatus 1 and the effects of reverse electrolysis and reverse rotation. In Example 3, 510 g of 5.8 mmφ × about 20 mm metal uranium (7.0 mm OD × 6.0 mm ID × 22 mm L with SUS304 coating) was prepared, and loaded to each anode basket 8 almost evenly in the horizontal direction. Here, in principle, reverse electrolysis and reverse anode rotation for 5 minutes were performed every 60 minutes of electrolysis. Electrolytic current: 2 to 20A (mostly 15A or more), energization amount: 675g-U equivalent (after reverse electrolysis subtraction), average processing speed: 25.1gU / h (16.7gU / h · liter), but electrolytic current is 15A Before it was reduced below (91% U was electrolyzed), it was 30.3 gU / h (20.2 gU / h · liter). The result of the test is shown in FIG. In FIG. 4, the result of Example 1 is represented as “Run-1”, and the result of Example 3 is represented as “Run-3”. From this result, it was confirmed that the electrolysis current was reduced to about 2/3 compared with Example 1 (uncoated), and it was found that the influence of the surface area reduction by the cladding tube was small. Further, when electrolysis was continued until electrolysis with 3A could not be performed, residual uranium was not observed in the rotating electrode (anode) 4. Moreover, since the current efficiency was improved to 76%, it was confirmed that the effects of reverse electrolysis and reverse rotation appeared.

  Furthermore, the relationship between the electrode occupied volume and the uranium recovery rate is shown in FIG. The result of Example 2 is expressed as “Run-2”, and the result of Example 3 is expressed as “Run-3”. In addition, the test result for the electrolyzer 1 having the conventional structure under the same conditions as in Example 3 is represented as “H14 Run-3”. As a result, it was confirmed that electrolysis could be performed at a speed comparable to Run-2 even before the anode uranium was exhausted, even with a cladding tube. As a supplementary explanation, the “conventional arrangement” in FIG. 5 is a result value in a deposition test on a rod-shaped solid cathode, which means about 9 g-uranium / h · liter. . This value is obtained by dividing the amount of U (g) actually deposited on the electrode by the time (h) required for electrolysis and the electrode occupation volume (twice the approximate volume of the final cathode deposit). It was obtained. The reason why the volume is twice that of the volume is that it is assumed that the volume of the anode is about the same as that of the cathode. On the other hand, in the electrolysis apparatus 1 according to this embodiment, since the rotating electrode (anode) 4 and the cylindrical electrode (cathode) 5 are integrated, the electrode occupation volume is simply immersed in the solvent salt 7. That is the volume of the part. In addition, 2 times and 4 times in FIG. 5 means 2 times and 4 times the above values, which correspond to about 18 g-uranium / h · liter and about 36 g-uranium / h · liter, respectively. .

  As a result of the above examples, the following could be confirmed. (1) By making the structure of the electrolyzer 1 new, it was possible to increase the amount of uranium loaded and further improve the uranium processing speed (up to 22.9 gU / h · liter, compared to the previous results) + 8%). (2) By the improvement of the electrolysis apparatus 1 and the operation method (reverse electrolysis and reverse rotation), finer precipitates 6 that are not in a roll shape were recovered. Moreover, the rotation stop of the rotating electrode 4 due to interference with the precipitate 6 was suppressed, and 510 g of uranium loaded on the rotating electrode 4 was completely dissolved. (3) The test of loading uranium with a cladding tube confirmed that the influence of the decrease in the surface area of anode uranium by the cladding tube on electrolysis was small.

It is a front view of the precipitate scraping type electrolyzer which shows the scraping blade concerning this invention. It is a top view of the deposit scraping-off type electrolysis apparatus shown in FIG. It is a graph which shows the result of Example 1, and represents the comparison of the electrolysis current of the electrolysis apparatus of a conventional structure, and the electrolysis apparatus concerning this invention. It is a graph which shows the result of Example 3, and represents the comparison of the electrolysis electrolysis current by the presence or absence of a cladding tube. It is a graph which shows the relationship between the electrode occupation volume in Example 2 and Example 3, and a uranium recovery rate.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Deposit scraping type electrolysis apparatus 2 Scraping blade 3 Electrolysis tank 4 Rotating electrode (anode)
5 Cylindrical electrode (cathode)
6 Precipitate (Precipitated target element)

Claims (3)

  In the scraping blade in the deposit scraping type electrolysis apparatus for scraping and collecting the target element deposited on the cylindrical electrode provided in the electrolytic tank during the electrolytic purification in the electrolytic tank, It is provided around the rotating electrode that rotates about the center of the cylindrical electrode, in a state of being divided into a plurality of portions in the axial direction of the rotating electrode, and inclined with respect to the rotating axis of the rotating electrode. The scraping blade in the deposit scraping-off type electrolysis apparatus characterized by the above.   The scraping blade in the precipitate scraping-off type electrolysis apparatus according to claim 1, wherein the deposited target element is inclined obliquely upward in the rotational direction so as to scrape off the target element toward the bottom of the electrolytic cell.   3. The precipitate scraping-type electrolyzer according to claim 2, wherein at least axial scraping blades adjacent to each other in the rotational direction out of the scraping blades shifted in the rotational direction are shifted from each other. Scraper blades.

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