JP6428440B2 - Method and apparatus for processing iron group metal ion-containing liquid - Google Patents

Description

  The present invention relates to a processing method and a processing apparatus for an iron group metal ion-containing liquid. Specifically, the ion is extracted from a liquid containing iron group metal ions such as iron (Fe), cobalt (Co), and nickel (Ni). The present invention relates to a removal method and apparatus. The present invention particularly relates to iron group metal ions generated from nuclear power plants such as decontamination waste liquid generated in nuclear power plants and eluents obtained by eluting iron group metal ions from ion exchange resins used in nuclear power plants. It is suitably used for the treatment of waste liquid containing.

  In a nuclear power plant, a large amount of decontamination waste liquid is generated when the radioactive material is chemically removed from the primary cooling system equipment and piping contaminated with the radioactive material and the metal member surface of the system including these. These decontamination waste liquids contain iron group metal ions such as Fe, Co, or Ni, and also contain a lot of radioactive substances such as Co-60 (cobalt 60) and Ni-63 (nickel 63). Usually, the decontamination waste liquid is reused as a decontamination liquid after the ionic components dissolved by the ion exchange resin are removed. For this reason, there exists a problem that the waste of the ion exchange resin containing many radioactive substances generate | occur | produces.

In nuclear power plants, etc., ion exchange resins used to purify cooling water systems containing radioactive materials by directly touching fuel rods such as the reactor water purification system (CUW) and the fuel storage pool water purification system (FPC) Because it absorbs a lot of radioactive material, it is stored as a high dose rate waste in a resin tank installed at the power plant.
Waste containing these radioactive substances is finally kneaded with a solidification aid such as cement and stabilized, and then buried. The cost for disposal is different depending on the amount of radioactive material contained, and the higher the concentration of radioactive material, the higher the cost. For this reason, it is economical to reduce the volume of waste with a high dose rate as much as possible and then use it as a solid waste. Specifically, it is desirable in terms of volume reduction if the radioactive substance can be separated from the ion exchange resin as a solid and can be contained in a shielding container. Waste ion exchange resin from which radioactive materials have been removed is a low-dose rate waste with low disposal costs, and if the radioactive materials can be removed to a level where incineration of the waste ion exchange resin can be achieved, incineration will significantly Volume reduction can be achieved.

  As a method for treating such high-dose waste resin, there are methods of decomposing waste resin by wet oxidation such as Fenton method and supercritical water oxidation as proposed in Patent Document 1 and Patent Document 2. In this case, a large amount of waste liquid with a high dose rate is generated. When the waste liquid with a high dose rate is finally disposed of, it is necessary to stabilize it as a solidified body by a method such as evaporating and concentrating and kneading the concentrated liquid with cement. In this case, since a solidification aid such as cement is newly added, there is a problem that the amount of waste at a high dose rate to be finally disposed increases and the amount of waste cannot be reduced.

  Patent Document 3 discloses a technique in which sulfuric acid is passed through waste resin, ionic radioactive substances are eluted, radioactive substances are separated from the eluent by diffusion dialysis, and sulfuric acid is circulated and reused. Patent Document 4 discloses a waste resin treatment method in which waste resin is immersed in an oxalic acid aqueous solution to dissolve the metal clad on the surface, and metal ions adsorbed on the resin are eluted into the oxalic acid aqueous solution. Yes. In these cases as well, waste liquid containing radioactive substances is generated, but the solidification process is not covered.

  On the other hand, as a method for removing radioactive substances from waste liquid containing ionic radioactive substances, Patent Document 5 discloses that a decontamination solution in which radioactive cations are dissolved is energized while passing through an electrodeposition cell, and the radioactive cations are used. Has been disclosed in which a decontamination solution is regenerated and reused by depositing as a radioactive metal particle on a cathode. At that time, the cathode on which radioactive metal particles are deposited is described as pouring catholyte over the entire cathode to desorb the radioactive metal particles.

  In Patent Document 5, the decontamination solution in which the radioactive cation is dissolved is energized while being directly introduced into the cathode side of the electrodeposition cell, and the radioactive cation is deposited on the cathode as radioactive metal particles. Since the catholyte properties change depending on the decontamination solution, the catholyte cannot be adjusted to a liquid property suitable for electrodeposition. When the decontamination solution is an acidic waste solution, the radioactive metal component deposited on the cathode surface is dissolved again in the acidic waste solution, so that no precipitation occurs or the deposition rate is significantly reduced. In addition, when the waste liquid is neutral or alkaline, a hydroxide precipitate is formed in the vicinity of the cathode surface, and it becomes difficult to recover by depositing radioactive metal on the cathode surface. For this reason, in order to efficiently recover radioactive substances from the waste liquid by the electrodeposition method, it is not preferable to introduce the waste liquid directly into the cathode chamber, and it is important to make the catholyte liquid suitable for electrodeposition. Become.

  In view of this, the inventors of the Japanese Patent Application No. 2013-221322 efficiently used iron group metal ions without being affected by the liquid properties of the iron group metal ion-containing waste liquid in the electrodeposition treatment of the iron group metal ion-containing liquid. In particular, a processing method and a processing apparatus for an iron group metal ion-containing liquid that is deposited and removed from the liquid have been proposed. Specifically, iron group metal ion-containing waste liquid is introduced into the anode chamber of the electrodeposition tank in which the anode chamber with the anode and the cathode chamber with the cathode are separated by a cation exchange membrane, and the catholyte is introduced into the cathode chamber. Then, by applying current between the anode and the cathode, the iron group metal ions in the liquid in the anode chamber are moved into the catholyte in the cathode chamber so that the iron group metal is deposited on the cathode. The iron group metal can be electrodeposited and removed under appropriate electrodeposition conditions without being influenced by the liquid properties of the group metal ion-containing waste liquid.

Japanese Patent Publication No. 61-9599 Japanese Patent No. 3657747 JP 2004-28697 A JP 2013-44588 A Japanese Patent No. 4438898 Japanese Patent Application No. 2013-221322

  As a result of further examination of the processing efficiency according to Japanese Patent Application No. 2013-221322, the present inventors, in this processing method and processing apparatus, although the electrodeposition rate of the iron group metal in the catholyte is relatively rapid, When iron group metal ions are transferred from waste liquid (anolyte) to catholyte, the permeation rate of iron group metal ions through the cation exchange membrane is slow. I found out that

  The present invention further improves the invention of Japanese Patent Application No. 2013-221322, and improves the processing efficiency by increasing the permeation rate of iron group metal ions through the cation exchange membrane, and the processing method and processing of the liquid containing iron group metal ions It is an object to provide an apparatus.

  As a result of intensive studies to solve the above-mentioned problems, the present inventors have used a dialysis tank in which a plurality of cation exchange membranes are arranged, so that cation exchange that allows iron group metal ions to permeate the electrode area. The membrane area of the membrane can be increased. As a result, the permeation rate of the cation exchange membrane in the electrodialysis tank is improved by greatly increasing the amount of iron group metal ions per unit time without increasing the current value. In addition, by separating the electrodialysis tank and the electrodeposition tank, it is possible to set the current density suitable for each of electrodialysis and electrodeposition, simplify the electrodeposition tank, and replace the used electrode As a result, the present invention was completed.

  That is, the gist of the present invention is as follows.

[1] An iron group metal ion-containing solution and an electrodeposition solution containing a ligand that forms a complex with the iron group metal ion are introduced into an electrodialysis tank provided with a plurality of cation exchange membranes. An electrodialysis step of removing iron group metal ions in the iron group metal ion-containing liquid by allowing the iron group metal ions in the metal ion-containing liquid to pass through the cation exchange membrane and transfer to the electrodeposition liquid And introducing an electrodeposition liquid containing iron group metal ions flowing out of the electrodialysis tank into an electrodeposition tank provided with an anode and a cathode, and electrodepositing the iron group metal in the electrodeposition liquid on the cathode An electrodeposition process for removing the iron group metal ions from the electrodeposition liquid, and an electrodeposition liquid circulation process for feeding the electrodeposition liquid from which the iron group metal ions have been removed in the electrodeposition process to the electrodialysis process The processing method of the iron group metal ion containing liquid characterized by these.

[2] The iron group metal ion-containing liquid is an acid decontamination waste liquid having a pH of less than 5 that is generated by decontamination of a nuclear power plant, and after removing the iron group metal ions in the waste liquid in the electrodialysis step, The method for treating an iron group metal ion-containing solution according to [1], wherein the method is reused as a dyeing solution.

[3] The electrodialysis tank includes an anode and a cathode, a first bipolar membrane disposed opposite the anode, a second bipolar membrane disposed opposite the cathode, and the first bipolar membrane. A plurality of cation exchange membranes arranged between the bipolar membrane and the second bipolar membrane, and a third bipolar membrane arranged between the cation exchange membranes, the anode and the first An anode chamber between the bipolar membrane and a cathode chamber between the cathode and the second bipolar membrane, the cation exchange membrane and the bipolar membrane provided on the anode side of the cation exchange membrane; A deionization chamber, and a concentration chamber between the cation exchange membrane and the bipolar membrane provided on the cathode side of the cation exchange membrane, and the iron group metal ion-containing liquid in the deionization chamber And passing the electrodeposition liquid into the concentration chamber. Processing method of an iron group metal ion-containing solution according to [1] or [2] to symptoms.

[4] The electrodialysis tank includes an anode and a cathode, a first hydrogen selective permeable cation exchange membrane disposed opposite to the anode, and a second hydrogen selective permeation disposed opposite to the cathode. Type cation exchange membranes, a plurality of cation exchange membranes arranged between the first hydrogen selective permeable cation exchange membrane and the second hydrogen selective permeable cation exchange membrane, and between the cation exchange membranes And a third hydrogen selective permeable cation exchange membrane disposed between the anode and the first hydrogen selective permeable cation exchange membrane, an anode chamber, the cathode and the second hydrogen selective permeable membrane. Between the cation exchange membrane is a cathode chamber, and between the cation exchange membrane and the hydrogen selective permeable cation exchange membrane provided on the anode side of the cation exchange membrane, a deionization chamber, the cation exchange The hydrogen provided on the cathode side of the membrane and the cation exchange membrane A concentration chamber is formed between the permselective cation exchange membrane, the iron group metal ion-containing liquid is passed through the deionization chamber, and the electrodeposition liquid is passed through the concentration chamber. The processing method of the iron group metal ion containing liquid as described in [1] or [2].

[5] In the electrodeposition tank, an anode chamber having an anode and a cathode chamber having a cathode are partitioned by a cation exchange membrane, and an electrodeposition solution containing the iron group metal ions is passed through the cathode chamber. The method for treating an iron group metal ion-containing liquid according to any one of [1] to [4].

[6] The electrodeposition liquid flowing out from the cathode chamber of the electrodeposition tank is introduced into the electrodialysis tank through an electrodeposition liquid storage tank, and the electrodeposition liquid containing the iron group metal ions flowing out from the electrodialysis tank is The method for treating a liquid containing an iron group metal ion according to [5], wherein the treatment is introduced into a cathode chamber of the electrodeposition tank through an electrodeposition liquid storage tank.

[7] The electrode solution that has passed through the anode chamber and / or the cathode chamber of the electrodialysis tank is passed through the electrode solution storage tank to the anode chamber of the electrodeposition tank, and flows out of the anode chamber of the electrodeposition tank. The method for treating an iron group metal ion-containing solution according to [5] or [6], wherein the anolyte is passed through the electrode solution storage tank to the anode chamber and / or the cathode chamber of the electrodialysis tank. .

[8] An electrodialysis tank having an anode chamber having an anode, a cathode chamber having a cathode, and a plurality of cation exchange membranes provided between the anode and the cathode chamber; An energizing means for energizing between the anode and the cathode; and a means for passing an iron group metal ion-containing liquid through the electrodialysis tank and an electrodeposition liquid containing a ligand that forms a complex with the iron group metal ion. The iron group metal ions in the iron group metal ion-containing liquid are transferred to the electrodeposition liquid through the cation exchange membrane by passing the iron group metal ions in the iron group metal ion-containing liquid. An electrodialysis apparatus, an anode chamber having an anode, a cathode chamber having a cathode, an electrodeposition tank having a cation exchange membrane for partitioning the anode chamber and the cathode chamber, and between the anode and the cathode Energizing means for energizing, and the iron group metal ion flowing out from the electrodialysis tank into the cathode chamber of the electrodeposition tank. A means for passing an electrodeposition solution containing iron, and electrodepositing the iron group metal in the electrodeposition solution containing iron group metal ions on the cathode to form the iron group metal from the electrodeposition solution An iron group metal ion, comprising: an electrodeposition apparatus for removing ions; and means for feeding the electrodeposition liquid from which the iron group metal ions flowing out from the electrodeposition tank have been removed to the electrodialysis tank Processing equipment for contained liquid.

[9] The iron group metal ion-containing liquid is an acidic decontamination waste liquid having a pH of less than 5 generated by decontamination of a nuclear power plant, and the waste liquid from which iron group metal ions have been removed by the electrodialyzer is used as a decontamination liquid. The processing apparatus for an iron group metal ion-containing liquid according to [8], wherein the processing apparatus is reused.

[10] The electrodialysis tank includes an anode and a cathode, a first bipolar membrane disposed opposite the anode, a second bipolar membrane disposed opposite the cathode, and the first bipolar membrane. A plurality of cation exchange membranes arranged between the bipolar membrane and the second bipolar membrane, and a third bipolar membrane arranged between the cation exchange membranes, the anode and the first An anode chamber between the bipolar membrane and a cathode chamber between the cathode and the second bipolar membrane, the cation exchange membrane and the bipolar membrane provided on the anode side of the cation exchange membrane; A deionization chamber, and a concentration chamber between the cation exchange membrane and the bipolar membrane provided on the cathode side of the cation exchange membrane, and the iron group metal ion-containing liquid in the deionization chamber Means for passing the liquid and means for passing the electrodeposition liquid into the concentrating chamber Processor of iron group metal ion-containing solution having the constitution [8] or [9], further comprising.

[11] The electrodialysis tank includes an anode and a cathode, a first hydrogen selective permeation type cation exchange membrane disposed so as to face the anode, and a second hydrogen selective permeation disposed so as to face the cathode. Type cation exchange membranes, a plurality of cation exchange membranes arranged between the first hydrogen selective permeable cation exchange membrane and the second hydrogen selective permeable cation exchange membrane, and between the cation exchange membranes And a third hydrogen selective permeable cation exchange membrane disposed between the anode and the first hydrogen selective permeable cation exchange membrane, an anode chamber, the cathode and the second hydrogen selective permeable cation Between the exchange membrane is a cathode chamber, and between the cation exchange membrane and the hydrogen selective permeable cation exchange membrane provided on the anode side of the cation exchange membrane, a deionization chamber, the cation exchange membrane And the hydrogen provided on the cathode side of the cation exchange membrane A concentration chamber is formed between the permselective cation exchange membrane, means for passing the iron group metal ion-containing liquid into the deionization chamber, and means for passing the electrodeposition liquid into the concentration chamber; The processing apparatus for an iron group metal ion-containing liquid according to [8] or [9], wherein

[12] Further comprising an electrodeposition liquid storage tank, means for introducing the electrodeposition liquid flowing out from the cathode chamber of the electrodeposition tank into the electrodeposition liquid storage tank, and the electrodeposition liquid in the electrodeposition liquid storage tank Means for introducing into the cathode chamber of the tank, means for introducing the electrodeposition liquid flowing out from the concentration chamber of the electrodialysis tank into the electrodeposition liquid storage tank, and the electrodeposition liquid in the electrodeposition liquid storage tank to the electrodialysis tank And an iron group metal ion-containing liquid treatment apparatus as set forth in any one of [8] to [11].

[13] An electrode liquid storage tank is further provided, and means for introducing the anolyte flowing out from the anode chamber of the electrodeposition tank into the electrode liquid storage tank; and the electrode liquid in the electrode liquid storage tank in the anode chamber of the electrodeposition tank Means for introducing, means for introducing the electrode liquid flowing out from the anode chamber and / or cathode chamber of the electrodialysis tank into the electrode liquid storage tank, and the electrode liquid in the electrode liquid storage tank to the anode chamber of the electrodialysis tank and And / or an iron group metal ion-containing liquid treating apparatus as set forth in any one of [8] to [12].

  According to the present invention, the cation exchange membrane permeation rate of the iron group metal ions, which is the rate-determining process, can be increased with respect to the electrode area, and thereby the treatment can be performed without increasing the current value. Speed can be improved. In addition, by separating the electrodialysis tank and the electrodeposition tank, it is possible to set the current density suitable for each of electrodialysis and electrodeposition, simplify the electrodeposition tank configuration, and easily replace the used electrode Will be able to.

It is a systematic diagram of the processing apparatus which shows an example of embodiment of this invention. It is a systematic diagram of the processing apparatus which shows the other example of embodiment of this invention. (A) The figure is a graph which shows a time-dependent change of Co density | concentration of the simulation waste liquid in Examples 1-3 and Comparative Examples 1 and 2, (b) A figure is a graph which shows the time-dependent change of Co density | concentration of the same electrodeposition liquid. is there. (A) The figure is a graph which shows the time-dependent change of Fe density | concentration of the simulation waste liquid in Examples 1-3 and Comparative Examples 1 and 2, (b) The figure is a graph which shows the time-dependent change of Fe density | concentration of the electrodeposition liquid. is there.

  Hereinafter, embodiments of the present invention will be described in detail.

[Processing equipment for iron group metal ion-containing liquid]
First, an embodiment of a processing apparatus for an iron group metal ion-containing liquid according to the present invention will be described with reference to FIGS.
1 and 2 are system diagrams showing an example of an embodiment of a processing apparatus for an iron group metal ion-containing liquid according to the present invention.
In FIGS. 1 and 2, an acidic decontamination waste liquid having a pH of less than 5 (hereinafter simply referred to as “waste acid”) generated in the decontamination process of a nuclear power plant is treated as the iron group metal ion-containing liquid. However, the present invention will be described by exemplifying a case where iron group metal ions are removed in an electrodialysis tank and then reused as a decontamination solution. However, the present invention is not limited to the treatment of this waste acid. .

The processing apparatus for an iron group metal ion-containing liquid in FIG. 1 includes an electrodialysis tank 10 and an electrodeposition tank 20.
First, the electrodialysis tank 10 will be described. In the electrodialysis tank 10, bipolar membranes BP and cation exchange membranes CM are alternately arranged between the anode 11A and the cathode 12A.
A bipolar film (first bipolar film) BP is arranged opposite to the anode 11A, and an anode chamber 11 is formed between the anode 11A and the first bipolar film BP.
A bipolar film BP (second bipolar film) BP is disposed opposite to the cathode 12A, and a cathode chamber 12 is formed between the cathode 12A and the second bipolar film BP.

  A plurality of (three in FIG. 1) cations are provided at a predetermined interval between the first bipolar film BP that partitions the anode chamber 11 and the second bipolar film BP that partitions the cathode chamber 12. The exchange membrane CM is arranged, and the bipolar membrane (third bipolar membrane) BP is arranged at a further interval between the cation exchange membranes CM, whereby a liquid passage chamber is formed.

  The chamber on the anode 11A side of the cation exchange membrane CM is a deionization chamber 13 through which waste acid is passed, and the chamber on the cathode 12A side of the cation exchange membrane CM is in a concentration chamber 14 through which an electrodeposition solution is passed. is there.

  The bipolar membrane BP is an ion exchange membrane having a structure in which a cation exchange membrane layer and an anion exchange membrane layer are bonded to each other, and the anion exchange membrane layer is disposed on the anode 11A side and the cation exchange membrane layer is disposed on the cathode 12A side. Is done. Even if a voltage is applied, the bipolar membrane BP does not transmit cations or anions, and is energized by dissociating water into hydrogen ions and hydroxide ions in the bipolar membrane BP.

  For this reason, in the electrodialysis tank 10 of FIG. 1, the iron group metal ion in the waste acid which distribute | circulates the deionization chamber 13 permeate | transmits the cation exchange membrane CM by applying a voltage between the anode 11A and the cathode 12A. Then, it moves into the electrodeposition liquid flowing through the concentration chamber 14. Thereby, the iron group metal ion in a waste acid is removed. Acid ions (in this case, sulfate ions and hydrogen sulfate ions) in the waste acid are electrically attracted to the anode 11A side. However, since the bipolar membrane BP does not permeate the acid ions, it remains in the waste acid. The later liquid can be reused as an acid liquid.

In FIG. 1, the waste acid introduced into the deionization chamber 13 of the electrodialysis tank 10 through the lines L ₁ , L _1A , L _1B and the line L _1C is removed from the iron group metal ions by electrodialysis in the electrodialysis tank 10. Then, it is returned to the decontamination process through the lines L _2A , L _2B , L _2C and the line L ₂ and reused.

On the other hand, the electrodeposition liquid is conductive from the destination solution storage tank 40 by a pump _{P 1,} line _{L 3} and the line _{L 3A,} L _3B, it is introduced through the _{L 3C} to concentrating compartment 14 of the electrodialysis cell 10. Electrodeposition solutions containing iron group metal ions that have permeated the cation exchange membrane CM from the deionization chamber 13 and moved to the concentration chamber 14 by electrodialysis in the electrodialysis tank 10 are line L _4A , L _4B , L _4C and line L ₄ is returned to the electrodeposition liquid storage tank 40. As described later, since the iron group metal ions are removed from the electrodeposition liquid storage tank 40 in the electrodeposition tank 20, the electrodeposition liquid in the electrodeposition liquid storage tank 40 is electrodeposited from the iron group metal ions. Liquid is delivered.

  An electrode solution containing an electrolyte is circulated in the anode chamber 11 and the cathode chamber 12 of the electrodialysis tank 10. It is necessary to select an electrolyte that does not cause oxidation at the anode 11A, reduction at the cathode 12A, or precipitation at the cathode 12A, and sulfuric acid or an alkali metal salt of sulfuric acid is preferable.

In FIG. 1, an electrode liquid storage tank 30 common to the anolyte in the electrodeposition tank 20 is provided, and the electrode liquid in the electrode liquid storage tank 30 is introduced into the anode chamber 11 of the electrodialysis tank 10 via the line L ₅ by the pump P ₂ . Thereafter, the electrode is introduced into the cathode chamber 12 via the line L ₆ and returned to the electrode liquid storage tank 30 via the line L ₇ , and the electrode liquid in the electrode liquid storage tank 30 is electrodeposited via the line L ₈ by the pump P _3. introduced into the anode compartment 21 of the tank 20, but are formed a circulation path for returning the electrode solution storage tank 30 via line L _9, is not limited in any way to this embodiment, electrode solution for each electrode chamber A storage tank may be provided.

  In the electrodialysis tank 10 of FIG. 1, three cation exchange membranes CM are provided and three deionization chambers 13 are formed. However, the number of cation exchange membranes CM may be two or more, and any three of them. It is not limited to. As the number of cation exchange membranes in the electrodialysis tank increases, the cation exchange membrane area increases and the permeation rate of iron group metal ions increases, but if the number is increased excessively, the resistance of the entire electrodialysis tank increases. As the power consumption increases, the temperature in the electrodialysis tank increases. If the temperature of the electrodialysis tank becomes 40 ° C or higher, the ion exchange membrane may be deteriorated. Therefore, when the temperature of the electrodialysis tank tends to increase, the temperature in the electrodialysis tank should not exceed 40 ° C. It is preferable to cool the waste acid, electrodeposition liquid or electrode liquid as necessary.

  In FIG. 1, the waste acid in the deionization chamber 13 and the electrodeposition solution in the concentration chamber 14 are passed in the same direction, but they may be passed in opposite directions. Moreover, there is no restriction | limiting in particular also about the flowing direction of the electrode liquid of the anode chamber 11 and the cathode chamber 12. FIG.

  In addition, it is preferable to provide an appropriate spacer between the cation exchange membrane CM and the bipolar membrane BP of the electrodialysis tank 10 so as to prevent the membranes from coming into close contact with each other due to membrane deflection or the like. The shape of the spacer is not particularly limited as long as the flow path is secured, and any shape such as a net shape, a honeycomb shape, or a ball shape can be adopted. The material of the spacer is preferably selected according to the properties of the liquid to be passed, and when the above-mentioned waste acid is treated, a material having acid resistance is selected.

Next, the electrodeposition tank 20 will be described.
As the electrodeposition tank, as shown in FIG. 1, a two-chamber electrodeposition tank 20 in which an anode chamber 21 in which an anode 21A is arranged and a cathode chamber 22 in which a cathode 22A is arranged is partitioned by a cation exchange membrane CM. Is preferably used. Containing iron group metals ions electrodeposition solution sent to the electrodialysis cell 10 color electrodeposition solution storage tank 40 is introduced into the cathode chamber 22 of the via line L ₁₀ by the pump P ₄ electrodeposition tank 20. By applying a voltage between the anode 21A and the cathode 22A of the electrodeposition tank 20, the iron group metal ions in the electrodeposition liquid are deposited as an iron group metal on the cathode 22A and are electrodeposited and immobilized.

  As in the electrodialysis tank 10, an electrolytic solution that does not cause oxidation at the anode 21 </ b> A is used as the anolyte in the electrodeposition tank 20. In FIG. 1, the anolyte in the electrodeposition tank 20 and the electrode liquid in the electrodialysis tank 10 are shared, but these may be separated.

  As in the electrodialysis tank 10, the flow direction of the anolyte in the anode chamber 21 and the flow direction of the electrodeposition liquid in the cathode chamber 22 may be the same as shown in FIG. May be.

  In the electrodialysis tank according to the present invention, the ion exchange membrane disposed between the cation exchange membranes does not permeate iron group metal ions (if a membrane through which iron group metal ions permeate is used, the ion exchange membrane permeates the cation exchange membrane. The iron group metal ions that have been transferred to the electrodeposition solution permeate the membrane and return to the waste acid) and do not allow the acid ions to permeate. In the electrodeposition solution or the electrode solution in the anode chamber, and the waste acid cannot be reused as an acid solution). From such a point, not only a bipolar membrane but also a hydrogen selective cation exchange membrane can be used. The hydrogen selective permeation type cation exchange membrane is a cation exchange membrane having a high hydrogen ion transport number (ratio in which the movement of hydrogen ions contributes to the current) and satisfies the above-mentioned required characteristics. As a hydrogen selective permeation type cation exchange membrane, AGC Engineering's Selemion CMF or the like can be adopted as a commercial product.

  FIG. 2 is different from the electrodialysis tank 10 in that a hydrogen selective permeable cation exchange membrane HCM is used instead of the bipolar membrane BP, and other configurations are the same as those in FIG. 2, members having the same functions as those in FIG. 1 are denoted by the same reference numerals.

In the present invention, as shown in FIGS. 1 and 2, since the electrodialysis tank and the electrodeposition tank are provided separately, the dialysis speed of the iron group metal ions in the electrodialysis tank, and the iron group metal in the electrodeposition tank Conditions such as current density can be set so that each of the ion deposition rates of ions is optimized.
The current density of the electrodialysis tank for dialysis of iron group metal ions is 10 to 10 with respect to the cathode area, regardless of whether a bipolar membrane or a hydrogen selective permeation cation exchange membrane is used. it is preferably 400 mA / cm ^2, more preferably 20~200mA / cm ^2.
Moreover, it is preferable that it is 5-200 mA / cm < ² > with respect to a cathode area, and, as for the current density of an electrodeposition tank, it is more preferable that it is 10-150 mA / cm < ² >.

  Further, in the present invention, since the electrodialysis tank and the electrodeposition tank are provided separately, the structure of the electrodeposition tank is simplified, and when replacing the cathode on which the iron group metal is deposited and deposited by electrodeposition In addition, the replacement work can be easily performed without the work being hindered by complicated constituent members.

  As described above, the iron group metal ion-containing liquid treatment apparatus of the present invention having an electrodialysis tank and an electrodeposition tank, when applied to the decontamination process of waste ion exchange resin used in nuclear power plants, As in FIG. 2 of Japanese Patent Application No. 2013-221322, an eluent storage tank that stores an eluent obtained by eluting iron group metal ions from a waste ion exchange resin, and an elution tank that is a packed tower filled with the waste ion exchange resin And an iron group metal ion-containing liquid storage tank that is an acid waste liquid storage tank for storing the acid waste liquid discharged from the elution tank, and the acid effluent from the iron group metal ion-containing liquid storage tank (acid waste liquid storage tank) After passing through the deionization chamber 13 to remove the iron group metal ions, the iron group metal ions can be circulated to the eluent storage tank and reused as the eluent.

[Iron group metal ion-containing liquid]
The iron group metal ion-containing liquid to be treated in the present invention is usually a liquid containing one or more of iron, manganese, cobalt and nickel, particularly one or more of iron, cobalt and nickel. There is no problem even if metals other than iron group metals are included. In particular, the present invention is suitable for treating radioactive iron group metal ion-containing waste liquids generated from nuclear power plants, such as the following (i) and (ii), particularly acid waste liquids having a pH of less than 5 and further having a pH of less than 2. It is suitable, and iron group metal ions can be efficiently removed from these waste liquids, and the treatment liquid can be reused.
(i) Primary decontamination equipment and piping contaminated with radioactive materials at nuclear power plants, and decontamination waste liquid that dissolves radioactive materials from the surfaces of metal members of systems containing them
(ii) Used for purification of cooling water systems containing radioactive materials by directly touching fuel rods such as spent ion exchange resins (reactor water purification system (CUW), fuel storage pool water purification system (FPC)) at nuclear power plants. Ion-exchange resin or ion-exchange resin used to remove radioactive metal ions from the decontamination waste liquid of (i) above, elution acid waste liquid that is acid-eluted to remove radioactive metal ions from the above decontamination waste liquid or The elution acid waste liquid contains radioactive cobalt, which is one of iron group metal ions. According to the present invention, the radioactive cobalt can be stably fixed on the cathode of the electrodeposition tank as a metallic state with a small bulk. There is.

[Electrodeposition liquid]
The electrodeposition liquid used in the present invention contains a ligand that forms a complex with an iron group metal ion in the iron group metal ion-containing liquid (hereinafter sometimes referred to as “complexing agent of the present invention”). If the pH of the electrodeposition solution is too low, re-dissolution of the iron group metal electrodeposited on the cathode of the electrodeposition tank may occur, and the electrodeposition rate may decrease. On the other hand, if the pH is too high, the iron group Metal hydroxide tends to be generated as a suspended substance in the liquid. For this reason, it is preferable to adjust pH suitably with an alkali or an acid as needed so that an electrodeposition liquid may be set to 1-9, especially 2-8.

The complexing agent of the present invention includes dicarboxylic acid having two carboxyl groups in the molecule and a salt thereof (hereinafter sometimes referred to as “dicarboxylic acid (salt)”), and three carboxyl groups in the molecule. Those selected from the tricarboxylic acid and salts thereof (hereinafter sometimes referred to as “tricarboxylic acid (salt)”) are preferable. These may use only 1 type and may mix and use 2 or more types. Dicarboxylic acids (salts) and tricarboxylic acids (salts) suppress the generation of suspended substances during electrodialysis due to their chelating effect, and have an excellent effect in improving the electrodialysis effect.
In contrast, a monocarboxylic acid having one carboxyl group in the molecule has a weak binding force with an iron group metal ion and generates a suspended substance composed of an iron group metal hydroxide in the liquid. There is a problem that the electrode is not uniformly deposited on the cathode during deposition. In addition, when a carboxylic acid having four or more carboxyl groups in the molecule is used, the binding force with the iron group metal ion is too strong, the iron group metal is retained in the liquid, and the rate of electrodeposition is significantly reduced. The problem arises.

  As dicarboxylic acids (salts) and tricarboxylic acids (salts), those represented by the following formula (1) are particularly difficult in that suspended substances are produced, and electrodialysis and electrodeposition proceed quickly. preferable. The dicarboxylic acid (salt) or tricarboxylic acid (salt) represented by the following formula (1) has 1 to 3 carbon atoms between the carboxyl groups in the molecule, and is derived from its shape. Thus, it is presumed that an appropriate binding force can be obtained with the iron group metal ion.

^{_{M 1 OOC- (CHX 1) a}} - (NH) b - (CX 2 X 4) c -CX 3 X 5 -COOM 2
... (1)
(In the formula (1), X ¹ , X ² and X ³ each independently represent H or OH, X ⁴ and X ⁵ each independently represent H, OH or COOM ³ , M ¹ , M ² , M ³ each independently represent H, monovalent alkali metal or ammonium ion, and a, b, and c each independently represent an integer of 0 or 1. However, in Formula (1), X ⁴ and X ⁵ are simultaneously COOM ³ will never be reached.)

Suitable dicarboxylic acids in the present invention, for example, oxalic acid (ethanedioic acid, HOOC-COOH), malonic acid (propanedioic acid, _HOOC-CH 2 -COOH), succinic acid (butanedioic acid, HOOC-CH ₂ -CH ₂ -COOH), glutaric acid (pentanedioic _{acid, HOOC-CH 2 -CH 2 -CH} 2 -COOH), malic acid (2-hydroxybutanedioic _{acid, HOOC-CH 2 -CH (OH} ) -COOH) , Tartaric acid (2,3-dihydroxybutanedioic acid, HOOC—CH (OH) —CH (OH) —COOH), iminodiacetic acid (HOOC—CH ₂ —NH—CH ₂ —COOH), etc. Acid, succinic acid, malic acid, tartaric acid and iminodiacetic acid are particularly preferred. Examples of the tricarboxylic acid include citric acid (HOOC—CH ₂ —COH (COOH) —CH ₂ —COOH), 1,2,3-propanetricarboxylic acid, and citric acid is particularly preferable. In addition, examples of salts of these dicarboxylic acids and tricarboxylic acids include alkali metal salts such as sodium salts and potassium salts, and ammonium salts.

  In the present invention, when the iron group metal ion-containing liquid contains a plurality of types of iron group metal ions, it is preferable that an ammonium salt coexists with dicarboxylic acid (salt) and / or tricarboxylic acid (salt). For example, when an iron group metal ion-containing liquid containing Co and Fe is treated according to the present invention, when no ammonium salt is added, Co is generally faster in electrodeposition than Fe, and the electrodeposition layer of Co An Fe electrodeposition layer is formed on the top, but by adding an ammonium salt, the electrodeposition rates of Co and Fe become substantially equal, and Co and Fe are electrodeposited in an alloy form. When the electrodeposition rates of Co and Fe are different and electrodeposition is performed by separating the Co layer and the Fe layer, the electrodeposition tends to float or peel off due to the difference in the physical properties of Co and Fe, and continuous electrodeposition processing is performed. There is a risk that it will not be possible.

  Any ammonium salt may be used as long as it produces ammonium ions in the liquid. For example, ammonium chloride, ammonium sulfate, ammonium oxalate, and ammonium citrate are preferable. These ammonium salts may be used alone or in combination of two or more. In particular, when ammonium dicarboxylate such as ammonium oxalate or ammonium tricarboxylate such as ammonium citrate is used, the ammonium salt and the complexing agent of the present invention can be used, and suspension due to the chelating effect of dicarboxylic acid or tricarboxylic acid It is possible to obtain the effect of suppressing the generation of substances and the effect of adjusting the electrodeposition rate of Co and Fe with one agent.

  The concentration of the complexing agent of the present invention in the electrodeposition liquid used in the present invention is not particularly limited, but iron group metal ions in the liquid containing iron group metal ions introduced into the deionization chamber of the electrodialysis tank The molar concentration of the complexing agent of the present invention in the electrodeposition liquid introduced into the concentration chamber of the electrodialysis tank is 0.1 to 50 times, particularly 0.5 to 10 times the total molar concentration of As the electrodeposition solution, for example, an aqueous solution having a pH of 1 to 9, preferably pH 2 to 8, containing 0.01 to 20% by weight, preferably 0.1 to 5% by weight of the complexing agent of the present invention is used. . If the amount of the complexing agent of the present invention is too small, the effect of suppressing the generation of suspended matter due to the use of the complexing agent of the present invention cannot be sufficiently obtained, and if too large, the chelating effect becomes too large. As a result, the electrodeposition rate decreases.

  The complexing agent of the present invention is oxidatively decomposed when it comes into contact with the anode of the electrodeposition tank. However, as shown in FIGS. In the electrodeposition tank 20, the anode chamber 21 and the cathode chamber 22 are separated by the cation exchange membrane CM, and the electrodeposition liquid containing the complexing agent of the present invention is in direct contact with the anode. Therefore, the complexing agent of the present invention is not oxidized and wasted. Therefore, in the present invention, the complexing agent of the present invention to be replenished to the electrodeposition solution may be in a very small amount, and the amount of chemicals used can be reduced.

  Moreover, when using ammonium salt, it is preferable to use ammonium salt in the quantity from which the density | concentration in an electrodeposition liquid will be 0.01-20 weight%, Preferably it is 0.1-5 weight%. If the concentration of the ammonium salt is too low, the above effect due to the use of the ammonium salt cannot be sufficiently obtained, and if it is too high, the effect is not improved and the amount of chemicals used increases.

  Hereinafter, the present invention will be described more specifically with reference to Examples and Comparative Examples.

[Examples 1 to 3, Comparative Examples 1 and 2]
<Dialysis experiment>
Using the apparatus shown in FIG. 1 (however, the number of cation exchange membranes is as shown in Table 1), the waste acid (iron rust (α-Fe ₂ O ₃ ) having the composition shown in Table 1 is mixed and adsorbs cobalt. The treatment experiment was carried out using simulated waste liquid (acid waste liquid of pH 1.2, which was eluted from the waste ion exchange resin with sulfuric acid at 90 ° C.). In the experiment, 400 mL of this waste acid was placed in a waste acid storage tank (not shown) and circulated between the electrodialysis tank. 200 mL of the electrodeposition liquid having the composition shown in Table 1 is circulated between the electrodialysis tank and the electrodeposition liquid storage tank, and the treatment effect in the electrodialysis tank is not performed without feeding the electrodeposition liquid to the electrodeposition tank. confirmed. In addition, the liquid temperature at the time of a process was 30 degreeC.

  The dialysis experiment conditions are as shown in Table 1. In dialysis experiment 1, only one cation exchange membrane was placed between the anode chamber and the cathode chamber partitioned by the bipolar membrane. In dialysis experiment II, a cation exchange membrane and a bipolar membrane are alternately arranged in the order of a cation exchange membrane, a bipolar membrane, and a cation exchange membrane between an anode chamber and a cathode chamber separated by a bipolar membrane. An exchange membrane was provided. In dialysis experiment III, cation exchange is performed in the order of cation exchange membrane, bipolar membrane, cation exchange membrane, bipolar membrane, cation exchange membrane, bipolar membrane, and cation exchange membrane between the anode chamber and the cathode chamber separated by the bipolar membrane. Membranes and bipolar membranes were alternately arranged to provide four cation exchange membranes.

The experimental conditions employed in Examples 1 to 3 and Comparative Examples 1 and 2 are as follows.
Comparative Example 1: Dialysis Experiment I (Current = 1.20 A (24.6 mA / cm ² ))
Comparative example 2: Dialysis experiment I (current = 3.05 A (62.5 mA / cm ² ))
Example 1: Dialysis experiment II (current = 3.05 A (62.5 mA / cm ² ))
Example 2: Dialysis Experiment III (Current = 1.20 A (24.6 mA / cm ² ))
Example 3: Dialysis experiment III (current = 3.05 A (62.5 mA / cm ² ))
In Example 3, since most of Co and Fe in the simulated waste liquid moved to the electrodeposition liquid side after 3 hours of energization, the energization was completed in 3 hours.

FIGS. 3A and 3B show the change over time in the Co concentration of the simulated waste liquid and the change over time in the Co concentration of the electrodeposition liquid, respectively. Further, FIGS. 4A and 4B show the temporal change of the Fe concentration of the simulated waste liquid and the temporal change of the Fe concentration of the electrodeposition liquid, respectively.
3 and 4, it can be seen that as the number of cation exchange membranes in the electrodialysis tank is increased, the rate at which Co and Fe in the simulated waste liquid permeate the cation exchange membrane and migrate to the electrodeposition solution side becomes faster. It can also be seen that the current density is increased by increasing the current density from 24.6 mA / cm ² to 62.5 mA / cm ² .

<Electrodeposition experiment>
Electrodeposition treatment was carried out under the conditions shown in Table 2 while circulating the electrodeposition solution after performing the dialysis experiment for 6 hours (3 hours in Example 3) between the electrodeposition solution storage tank and the electrodeposition tank. As a result, any of the electrodeposition liquids could be electrodeposited and removed to a concentration of less than 1 mg / L in the electrodeposition liquid for both Fe and Co by energization for 24 hours. In any experiment, it was confirmed that the cathode surface after the experiment was plated with silver-white metallic iron and cobalt.

DESCRIPTION OF SYMBOLS 10 Electrodialysis tank 11 Anode chamber 11A Anode 12 Cathode chamber 12A Cathode 13 Deionization chamber 14 Concentration chamber 20 Electrodeposition tank 21 Anode chamber 21A Anode 22 Cathode chamber 22A Cathode 30 Electrode liquid storage tank 40 Electrodeposition liquid storage CM Cation exchange membrane BP Bipolar Membrane CHM Hydrogen Permselective Cation Exchange Membrane

Claims (11)

An iron group metal ion-containing solution and an electrodeposition solution containing a ligand that forms a complex with the iron group metal ion are introduced into an electrodialysis tank having a plurality of cation exchange membranes, and the iron group metal ion-containing solution is introduced. An electrodialysis step of removing the iron group metal ions in the iron group metal ion-containing liquid by passing the iron group metal ions in the liquid through the cation exchange membrane and transferring to the electrodeposition liquid;
An electrodeposition liquid containing iron group metal ions flowing out from the electrodialysis tank is introduced into an electrodeposition tank provided with an anode and a cathode, and the iron group metal in the electrodeposition liquid is electrodeposited on the cathode, An electrodeposition step of removing the iron group metal ions from the electrodeposition solution;
The electrodeposition solution to iron group metal ions have been removed by the electrodeposition process possess a transmission Kyusuru electrodeposition circulation step to the electrodialysis step,
The electrodialysis tank is
An anode and a cathode;
A first bipolar membrane disposed opposite the anode;
A second bipolar membrane disposed opposite the cathode;
A plurality of cation exchange membranes arranged without interposing an anion exchange membrane between the first bipolar membrane and the second bipolar membrane;
A third bipolar membrane disposed between the cation exchange membranes;
With
Between the anode and the first bipolar film is an anode chamber, and between the cathode and the second bipolar film is a cathode chamber,
A space between the cation exchange membrane and the bipolar membrane provided on the anode side of the cation exchange membrane is a deionization chamber, and the cation exchange membrane and the bipolar membrane provided on the cathode side of the cation exchange membrane. There is a concentration chamber in between.
A method for treating an iron group metal ion-containing liquid , wherein the iron group metal ion-containing liquid is passed through the deionization chamber and the electrodeposition liquid is passed through the concentration chamber . An iron group metal ion-containing solution and an electrodeposition solution containing a ligand that forms a complex with the iron group metal ion are introduced into an electrodialysis tank having a plurality of cation exchange membranes, and the iron group metal ion-containing solution is introduced. An electrodialysis step of removing the iron group metal ions in the iron group metal ion-containing liquid by passing the iron group metal ions in the liquid through the cation exchange membrane and transferring to the electrodeposition liquid;
An electrodeposition liquid containing iron group metal ions flowing out from the electrodialysis tank is introduced into an electrodeposition tank provided with an anode and a cathode, and the iron group metal in the electrodeposition liquid is electrodeposited on the cathode, An electrodeposition step of removing the iron group metal ions from the electrodeposition solution;
The electrodeposition solution to iron group metal ions have been removed by the electrodeposition process possess a transmission Kyusuru electrodeposition circulation step to the electrodialysis step,
The electrodialysis tank is
An anode and a cathode;
A first hydrogen permselective cation exchange membrane disposed opposite the anode;
A second hydrogen permselective cation exchange membrane disposed opposite the cathode;
A plurality of cation exchange membranes disposed between the first hydrogen selective permeable cation exchange membrane and the second hydrogen selective permeable cation exchange membrane;
A third hydrogen permselective cation exchange membrane disposed between the cation exchange membranes;
With
Between the anode and the first hydrogen selective permeable cation exchange membrane is an anode chamber, and between the cathode and the second hydrogen selective permeable cation exchange membrane is a cathode chamber,
A space between the cation exchange membrane and the hydrogen selective permeable cation exchange membrane provided on the anode side of the cation exchange membrane is provided on the cathode side of the cation exchange membrane and the cation exchange membrane. A concentration chamber is formed between the hydrogen selective permeation type cation exchange membrane,
A method for treating an iron group metal ion-containing liquid , wherein the iron group metal ion-containing liquid is passed through the deionization chamber and the electrodeposition liquid is passed through the concentration chamber . The iron group metal ion-containing liquid is an acid decontamination waste liquid having a pH of less than 5 that is generated by decontamination of a nuclear power plant, and after removing iron group metal ions in the waste liquid in the electrodialysis step, the decontamination liquid is used. The method for treating a liquid containing an iron group metal ion according to claim 1 or 2 , wherein the liquid is reused. The electrodeposition tank is
2. An anode chamber having an anode and a cathode chamber having a cathode are partitioned by a cation exchange membrane, and an electrodeposition solution containing the iron group metal ions is passed through the cathode chamber. The processing method of the iron group metal ion containing liquid of any one of thru | or 3 . The electrodeposition liquid flowing out from the cathode chamber of the electrodeposition tank is introduced into the electrodialysis tank through the electrodeposition liquid storage tank, and the electrodeposition liquid containing the iron group metal ions flowing out from the electrodialysis tank is the electrodeposition liquid. The method for treating an iron group metal ion-containing liquid according to claim 4 , wherein the treatment is performed through a storage tank and introduced into the cathode chamber of the electrodeposition tank. The electrode liquid that has passed through the anode chamber and / or the cathode chamber of the electrodialysis tank is passed through the electrode liquid storage tank to the anode chamber of the electrodeposition tank, and the anolyte that has flowed out of the anode chamber of the electrodeposition tank is 6. The method for treating an iron group metal ion-containing solution according to claim 4 or 5 , wherein the solution is passed through the electrode solution storage tank to the anode chamber and / or the cathode chamber of the electrodialysis tank. An electrodialysis tank having an anode chamber with an anode, a cathode chamber with a cathode, and a plurality of cation exchange membranes provided between the anode and the cathode chamber, and an anode and a cathode of the electrodialysis tank Energizing means for energizing in between, means for passing an iron group metal ion-containing liquid in the electrodialysis tank, and an electrodeposition liquid containing a ligand that forms a complex with the iron group metal ion, The iron group metal ions in the iron group metal ion-containing liquid are removed by passing the iron group metal ions in the iron group metal ion-containing liquid through the cation exchange membrane and transferring to the electrodeposition liquid. An electrodialyzer;
An electrodepositing chamber having an anode chamber having an anode, a cathode chamber having a cathode, a cation exchange membrane separating the anode chamber and the cathode chamber, energizing means for energizing the anode and the cathode, Means for passing the electrodeposition liquid containing the iron group metal ions flowing out from the electrodialysis tank to the cathode chamber of the electrodeposition tank, and the iron group metals in the electrodeposition liquid containing the iron group metal ions An electrodeposition apparatus for electrodepositing on the cathode to remove the iron group metal ions from the electrodeposition liquid;
Means for feeding the electrodeposition liquid from which the iron group metal ions flowing out of the electrodeposition tank have been removed to the electrodialysis tank ;
The electrodialysis tank is
An anode and a cathode;
A first bipolar membrane disposed opposite the anode;
A second bipolar membrane disposed opposite the cathode;
A plurality of cation exchange membranes arranged without interposing an anion exchange membrane between the first bipolar membrane and the second bipolar membrane;
A third bipolar membrane disposed between the cation exchange membranes;
With
Between the anode and the first bipolar film is an anode chamber, and between the cathode and the second bipolar film is a cathode chamber,
A space between the cation exchange membrane and the bipolar membrane provided on the anode side of the cation exchange membrane is a deionization chamber, and the cation exchange membrane and the bipolar membrane provided on the cathode side of the cation exchange membrane. There is a concentration chamber in between.
Means for passing the iron group metal ion-containing liquid through the deionization chamber;
Processor of iron group metal ion-containing solution, characterized in Rukoto to have a means for passing fluid the electrodeposition solution in the concentrating compartment. An electrodialysis tank having an anode chamber with an anode, a cathode chamber with a cathode, and a plurality of cation exchange membranes provided between the anode and the cathode chamber, and an anode and a cathode of the electrodialysis tank Energizing means for energizing in between, means for passing an iron group metal ion-containing liquid in the electrodialysis tank, and an electrodeposition liquid containing a ligand that forms a complex with the iron group metal ion, The iron group metal ions in the iron group metal ion-containing liquid are removed by passing the iron group metal ions in the iron group metal ion-containing liquid through the cation exchange membrane and transferring to the electrodeposition liquid. An electrodialyzer;
An electrodepositing chamber having an anode chamber having an anode, a cathode chamber having a cathode, a cation exchange membrane separating the anode chamber and the cathode chamber, energizing means for energizing the anode and the cathode, Means for passing the electrodeposition liquid containing the iron group metal ions flowing out from the electrodialysis tank to the cathode chamber of the electrodeposition tank, and the iron group metals in the electrodeposition liquid containing the iron group metal ions An electrodeposition apparatus for electrodepositing on the cathode to remove the iron group metal ions from the electrodeposition liquid;
Means for feeding the electrodeposition liquid from which the iron group metal ions flowing out of the electrodeposition tank have been removed to the electrodialysis tank ;
The electrodialysis tank is
An anode and a cathode;
A first hydrogen permselective cation exchange membrane disposed opposite the anode;
A second hydrogen permselective cation exchange membrane disposed opposite the cathode;
A plurality of cation exchange membranes disposed between the first hydrogen selective permeable cation exchange membrane and the second hydrogen selective permeable cation exchange membrane;
A third hydrogen permselective cation exchange membrane disposed between the cation exchange membranes;
With
Between the anode and the first hydrogen selective permeable cation exchange membrane is an anode chamber, and between the cathode and the second hydrogen selective permeable cation exchange membrane is a cathode chamber,
A space between the cation exchange membrane and the hydrogen selective permeable cation exchange membrane provided on the anode side of the cation exchange membrane is provided on the cathode side of the cation exchange membrane and the cation exchange membrane. A concentration chamber is formed between the hydrogen selective permeation type cation exchange membrane,
Means for passing the iron group metal ion-containing liquid through the deionization chamber;
Processor of iron group metal ion-containing solution, characterized in Rukoto to have a means for passing fluid the electrodeposition solution in the concentrating compartment. The iron group metal ion-containing liquid is an acidic decontamination waste liquid having a pH of less than 5 generated by decontamination of a nuclear power plant, and the waste liquid from which iron group metal ions have been removed by the electrodialyzer is reused as a decontamination liquid. The processing apparatus of the iron group metal ion containing liquid of Claim 7 or 8 characterized by the above-mentioned. And a means for introducing the electrodeposition liquid flowing out from the cathode chamber of the electrodeposition tank into the electrodeposition liquid storage tank, and the electrodeposition liquid in the electrodeposition liquid storage tank for supplying the electrodeposition liquid in the electrodeposition tank. Means for introducing into the chamber; means for introducing the electrodeposition liquid flowing out from the concentration chamber of the electrodialysis tank into the electrodeposition liquid storage tank; and the electrodeposition liquid in the electrodeposition liquid storage tank for the concentration chamber of the electrodialysis tank processor of iron group metal ion-containing solution according to any one of claims 7 to 9, characterized in that it has means for introducing into. A means for introducing the anolyte flowing out from the anode chamber of the electrodeposition tank into the electrode liquid storage tank; and a means for introducing the electrode liquid in the electrode liquid tank into the anode chamber of the electrodeposition tank. And means for introducing the electrode liquid flowing out from the anode chamber and / or cathode chamber of the electrodialysis tank into the electrode liquid storage tank; and the electrode liquid in the electrode liquid storage tank as the anode chamber and / or cathode of the electrodialysis tank The treatment apparatus for an iron group metal ion-containing liquid according to any one of claims 7 to 10 , further comprising means for introducing the chamber into the chamber.

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