JP2005003603A - Wet processing method and apparatus of uranium waste - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method and an apparatus for wet processing of uranium waste that generates a small amount of secondary waste and has small medicine expenses. <P>SOLUTION: In the wet processing method, various types of uranium are separated and recovered from the uranium waste, where uranium, transuranic or a radioactive nuclide element, or various types of compound uranium are adhered. The wet processing method comprises a solution process S1 for generating solution by dissolving the uranium waste with a mask agent; a precipitation process S2 for precipitating various kinds of uranium from the solution; a trace of uranium elimination process S3 for eliminating a trace of various kinds of uranium remaining in the solution after eliminating deposits by using a uranium adsorption resin; a mask agent recovery process S8 for returning the mask agent used in the precipitation process to the dissolution process after recovering from the solution; and a residual fluorine elimination process S5 for eliminating fluorine or a fluorine compound remaining in the solution by using the fluorine adsorption resin. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention uses a certain kind of solution from wastes to which uranium, transuranium elements, radionuclides or their compounds (referred to as uranium for convenience) attached, which are generated from uranium handling facilities or facilities that transfer between uranium handling facilities, are attached. The present invention relates to a wet processing method and apparatus for uranium waste for separating and recovering uranium.
[0002]
[Prior art]
Brick, diatomaceous earth, ore scrap, sludge, chemical trap material (NaF), sediments mainly composed of CaF ₂ generated from uranium handling facilities or facilities that transfer between uranium handling facilities, Al There is a method developed by the Nuclear Fuel Cycle Development Organization as a wet processing method for separating and recovering uranium, transuranium element, or radionuclide from waste such as ₂ O ₃ and UF ₄ (see Non-Patent Document 1 below).
[0003]
As shown in FIG. 9, this method includes a dissolution step S1 for dissolving uranium waste, a precipitation step S2 for precipitating and recovering uranium from the solution, and a small amount of uranium remaining in the solution after the precipitation is removed from the resin. A small amount of uranium removing step S3 to be removed using, a fluorine fixing step S4 for precipitating and collecting fluorine in the solution, and a residual fluorine removing step S5 to remove a trace amount of fluorine remaining in the solution after the precipitation removal using a resin. And a uranium adsorption resin regeneration step S6 that regenerates and reuses the resin used in the trace uranium removal step S3, and a fluorine adsorption resin regeneration step S7 that regenerates and reuses the resin used in the residual fluorine removal step S5. Has been.
[0004]
[Non-Patent Document 1]
Nuclear Fuel Cycle Development Organization report number: JNC ZJ6400 2001-012, JNC TJ6400 2002-004
[0005]
[Problems to be solved by the invention]
In the conventional wet processing method for uranium waste as described above, a mask agent is added in the dissolution step S1 in order to increase the purity of uranium obtained in the uranium precipitation step S2. For example, in order to prevent fluorine from being mixed into the uranium precipitate, a substance that forms a stable complex with fluorine, such as an aluminum compound or a boron compound, is added as a masking agent. These masking agents are precipitated and collected together with CaF ₂ in the fluorine fixing step S4, and a large amount of secondary waste more than uranium waste is generated. Therefore, there is a problem that the processing cost of the secondary waste is increased, and the chemical cost is increased because a masking agent is newly added for each processing batch.
[0006]
The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a wet processing method and apparatus for uranium waste with a small amount of secondary waste and low chemical costs.
[0007]
[Means for Solving the Problems]
In order to achieve the above object, the invention according to claim 1 is a wet processing method for separating and recovering uranium from uranium wastes to which uranium, a transuranium element, a radionuclide, or uranium as a compound thereof is attached. Dissolving waste to produce a solution; adding a masking agent to the solution to precipitate uranium; and removing a small amount of uranium remaining in the solution after removing the uranium adsorption resin Using a fluorine adsorption resin to remove a trace amount of uranium that is removed by using, a mask agent collecting step that recovers the mask agent used in the precipitation step from the solution and returns it to the dissolution step, and a fluorine or fluorine compound remaining in the solution It is set as the structure provided with the residual fluorine removal process to remove.
[0008]
The invention of claim 2 regenerates the uranium adsorption resin used in the trace uranium removal process and returns it to the trace uranium removal process, and regenerates the fluorine adsorption resin used in the residual fluorine removal process. And a fluorine adsorption resin regeneration step for returning to the residual fluorine removal step.
[0009]
According to a third aspect of the invention, there is provided a fluorine fixing step for precipitating and collecting fluorine or a fluorine compound in the solution between the trace uranium removing step and the mask agent collecting step.
[0010]
According to a fourth aspect of the present invention, the mask agent is a substance that prevents a fluorine component from being mixed into a uranium precipitate generated in the precipitation step with respect to a uranium waste having a fluorine component.
[0011]
According to a fifth aspect of the present invention, the mask agent is an aluminum compound, and the aluminum compound is separated and recovered from the secondary waste generated by the mask agent recovery step and reused.
[0012]
According to a sixth aspect of the present invention, the mask agent is aluminum chloride.
The invention of claim 7 is configured such that the mask agent recovery step is performed by electrodialysis.
[0013]
In the invention of claim 8, the electrodialysis uses an electrolytic cell separated into a cathode chamber and an anode chamber by an anion exchange membrane, and introduces a solution containing a masking agent into the cathode chamber and energizes the cathode chamber. Thus, the mask agent is recovered and the acid in the solution is recovered in the anode chamber.
[0014]
In a ninth aspect of the invention, a solution containing an aluminum compound as the masking agent is introduced into the cathode chamber and electrodialyzed to recover the aluminum component as aluminate in the cathode chamber.
[0015]
The invention according to claim 10 is configured to reuse the recovered aluminate as it is or as a mask agent by converting the form so as to become aluminum ions when dissolved.
[0016]
According to an eleventh aspect of the present invention, the acid recovered in the anode chamber is reused as a solution in the dissolution step.
In a twelfth aspect of the present invention, when the uranium waste contains calcium fluoride as a main component, the fluorine fixing step and the mask agent recovery step are simultaneously performed by electrodialysis.
[0017]
The invention of claim 13 is characterized in that the mask agent recovery step comprises a mask agent dissolution step for dissolving only the mask agent, and a secondary waste separation step for separating solid components from the solution in which the mask agent is dissolved. The configuration is as follows.
[0018]
According to a fourteenth aspect of the present invention, there is provided a wet processing apparatus for separating and recovering the uranium waste from the uranium waste to which uranium, which is an element or compound of uranium, super uranium, or a radionuclide, is attached. A dissolution apparatus that produces uranium, a precipitation apparatus that precipitates uranium by adding a masking agent to the solution, and a small amount of uranium removal that removes a small amount of uranium remaining in the solution after precipitation removal using a uranium adsorption resin Apparatus, mask agent recovery device for recovering the mask agent from the solution, residual fluorine removal device for removing fluorine or fluorine compounds remaining in the solution using a fluorine adsorption resin, and uranium used in the trace uranium removal device Uranium adsorbing resin regeneration device for regenerating adsorbing resin and fluorine adsorbing resin regeneration device for regenerating fluorine adsorbing resin used in the residual fluorine removing device A configuration that is equipped with a.
According to a fifteenth aspect of the present invention, the mask agent recovery device includes an electrodialysis device.
[0019]
DETAILED DESCRIPTION OF THE INVENTION
A first embodiment of the present invention will be described with reference to FIGS.
As shown in FIG. 1, the wet processing method for uranium waste according to the present embodiment includes a dissolution step S1 for dissolving uranium waste together with a masking agent, a precipitation step S2 for precipitating and recovering uranium from the solution, and precipitation removal. A trace uranium removal step S3 for removing a trace amount of uranium remaining in the solution using a uranium adsorption resin, a fluorine fixing step S4 for precipitating and collecting fluorine in the solution, and a mask agent for collecting the mask agent from the solution Recovery step S8, residual fluorine removal step S5 for removing a trace amount of fluorine remaining in the solution after precipitation removal using a fluorine adsorption resin, and uranium adsorption resin for regenerating the uranium adsorption resin used in the trace amount uranium removal step S3 The process comprises a regeneration step S6 and a fluorine adsorption resin regeneration step S7 for regenerating the fluorine adsorption resin used in the residual fluorine removal step S5.
[0020]
In the method of the present embodiment, a mask agent recovery step S8 is added after the fluorine fixing step S4 as compared with the conventional method. Further, the acid solution obtained by removing the fluorine in the solution after the mask agent recovery in the residual fluorine removing step S5 is reused in the dissolving step S1. However, when this acid solution is not reused in the dissolution step S1, the acid solution is discharged through the neutralization step S9 after the residual fluorine removal step S5. Further, it is possible in the case of uranium waste mainly composed of CaF ₂ will be omitted fluorine fixing step S4, to implement the masking agent recovery step S8 after traces of uranium removal process S3.
[0021]
Dissolution process S1, precipitation process S2, trace uranium removal process S3, fluorine fixing process S4, mask agent recovery process S8, residual fluorine removal process S5, uranium adsorption resin regeneration process S6, fluorine adsorption resin regeneration process S7 and neutralization process S9 are , Respectively, using a dissolution apparatus, a precipitation apparatus, a trace uranium removal apparatus, a fluorine fixing apparatus, a mask agent recovery apparatus, a residual fluorine removal apparatus, a uranium adsorption resin regeneration apparatus, a fluorine adsorption resin regeneration apparatus, and a neutralization apparatus. These devices may be connected to each other by piping or may be independent.
[0022]
In the present embodiment, the mask agent recovered in the mask agent recovery step S8 is added to the solution in the dissolution step S1 and reused. By doing so, the amount of secondary waste generated can be reduced. Electrodialysis is used as a method for recovering the masking agent. Electrodialysis using an anion exchange membrane is performed on the solution containing the mask agent, so that the mask agent component is concentrated in the cathode chamber and the acid component is concentrated in the anode chamber, which can be recovered and reused. Is possible.
[0023]
As another mask agent recovery method, by adding a pH-controlled acid solution to secondary waste, only the mask agent component can be dissolved and recovered from the difference in solubility between CaF ₂ and the mask agent component. it can. That is, a weakly acidic solution is added to the secondary waste generated after the fluorine fixing step S4 to dissolve only the mask agent. The solution in which the solid component that has not been dissolved and the masking agent are dissolved is subjected to solid-liquid separation, and the solution is reused in the dissolving step. This method adds a mask agent dissolution step and secondary waste separation step to the conventional wet processing method, and reuses the solution in which the mask agent is dissolved in the dissolution step to reduce the amount of secondary waste generated. Can be made.
[0024]
As a condition for the masking agent, a substance that forms a complex with fluoride ions, has a high solubility in water, and does not inhibit the solubility of uranium waste, a substance that exhibits an acidic solution is desirable. Those satisfying these conditions are aluminum compounds and boron compounds. However, when the recovered uranium precipitate is used as uranium fuel as a yellow cake, boron has a large neutron absorption cross section, so the possibility of boron mixing into uranium should be avoided. not appropriate. In addition, since the drainage standards for boron became stricter due to the revision of the Enforcement Ordinance for Water Pollution Prevention Act in June 2001, the use of boron compounds as masking agents complicates post-processing. Therefore, an aluminum compound is appropriate as the mask agent. In order to prevent complication of chemical treatment, it is desirable to reduce the number of chemical species present in the system. In the conventional wet processing method, a solution for dissolving uranium waste is assumed to be hydrochloric acid. Therefore, it is desirable to use aluminum chloride that satisfies the above requirements and does not increase chemical species with respect to hydrochloric acid-based treatment.
[0025]
By separating, recovering, and reusing the aluminum component from the secondary waste generated from the aluminum compound, the amount of secondary waste generated can be reduced. Since the recovered aluminum component is added as a masking agent in the dissolving step S1, it is not necessary to add a new aluminum compound for each batch.
[0026]
When the aluminum compound added as a masking agent is aluminum chloride, aluminum hydroxide produced from the aluminum chloride becomes secondary waste. Therefore, the amount of secondary waste generated can be reduced by separating, recovering and reusing the aluminum component from aluminum hydroxide.
[0027]
2, in the processing of uranium wastes mainly composed of CaF _2, showing the generated amount of aluminum hydroxide which occurs as a secondary waste in the case of using aluminum chloride as a mask material. Assuming that the amount of aluminum hydroxide generated in the conventional wet processing method is 100, it becomes 0.05 when the method of this embodiment is used, and the method of this embodiment is a secondary waste Al ( OH) ₃ generation amount can be reduced to 1/2000 of the conventional method. Note that aluminum hydroxide, which is a secondary waste, is generated for each batch in the conventional method, whereas only the final batch is generated in the method of the present embodiment.
[0028]
In the present embodiment, the treatment is performed by electrodialysis instead of newly adding and treating the mask agent for recovery. By doing in this way, generation | occurrence | production of the tertiary waste by masking agent collection process S8 addition can be suppressed.
[0029]
When an aluminum compound is used as a mask agent, an aqueous solution containing a precipitate of Al (OH) ₃ and CaF ₂ is generated by the fluorine fixing step S4. By performing electrodialysis on this aqueous solution, Al (OH) ₃ is dissolved as an aluminate in the solution, and CaF ₂ remains in a precipitated state, so that Al (OH) ₃ and CaF ₂ are separated. be able to.
[0030]
In an apparatus for performing electrodialysis for masking agent recovery, the inside of the electrolytic cell is separated into a cathode chamber and an anode chamber by an anion exchange membrane. By introducing a solution containing a mask agent component into the cathode chamber and performing electrodialysis, the mask agent component is recovered in the cathode chamber and the acid is recovered in the anode chamber. The aluminum component is recovered as aluminate.
[0031]
The electrodialysis will be described with reference to FIG. The solution containing the precipitate after the fluorine fixing step S4 (containing CaF ₂ , Al (OH) ₃ , Na ⁺ , Cl ⁻ , F ^−, etc.) is put into the cathode chamber. However, the components of the solution when the uranium waste is mainly CaF ₂ and the fluorine fixing step S4 is not performed are Ca ²⁺ , Al ³⁺ , Na ⁺ , Cl ⁻ , F ⁻ and the like. Electricity is applied with the anode chamber side electrode as the anode and the cathode chamber side electrode as the cathode.
When energized, the following reaction occurs at the cathode.
2H ₂ O + 2e = H ₂ ↑ + 2OH ⁻ (1)
[0032]
The pH of the cathode chamber side solution rises by the reaction of the formula (1). In the neutral pH range, both calcium and aluminum precipitate as calcium fluoride (CaF ₂ ) and aluminum hydroxide [Al (OH) ₃ ], but if the solution becomes a strong alkali as the electrolysis progresses, it is an amphoteric electrolyte. Aluminum hydroxide is redissolved as aluminate ions or the like (AlO ₂ ⁻ , Al (OH) ₆ ^{3 −} ) and separated from calcium precipitates.
On the other hand, the following reaction occurs at the anode.
2H ₂ O = 4H ⁺ + O ₂ ↑ + 4e (2)
[0033]
As a result of the reaction of formula (2), hydrogen ions are generated in the anode chamber solution, and the anions (Cl ⁻ , F ⁻ ) in the cathode chamber solution flow into the anode chamber through the anion exchange membrane. The anode chamber solution is a solution containing hydrochloric acid and hydrofluoric acid.
[0034]
FIG. 4 shows a solution (Ca ²⁺ , Al ³⁺ , Na ⁺ , Cl ⁻ , F ⁻⁾ after the uranium precipitation step S2 of uranium waste mainly composed of CaF ₂ using the electrodialyzer shown in FIG. The results of electrodialysis are included. As the main structure of the electrodialyzer, an electrolytic cell is made of acrylic, an electrode is a stainless steel plate coated with Pt, and an anion exchange membrane is an ion exchange membrane Aciplex A-201 manufactured by Asahi Kasei, which is a general commercial product. However, since this constituent material is a laboratory scale device, in an actual plant, it is necessary to reconsider in consideration of mechanical strength, cost, and the like. As the electrolysis progressed, the Ca concentration in the solution on the cathode chamber side decreased and the precipitate was removed, whereas the Al concentration was almost constant and held in the solution. From this, it can be seen that aluminum and calcium can be separated by this electrodialysis, and aluminum as a masking agent can be recovered.
[0035]
As described above, the aluminum component is recovered as an aluminate, but the recovered aluminate is reused as a mask agent in the form as it is. Alternatively, the recovered aluminate is converted and reused as a masking agent so that the recovered masking agent becomes aluminum ions when dissolved.
[0036]
A masking agent such as an aluminum compound prevents fluorine from being mixed into the uranium precipitate generated in the uranium precipitation step S2, and improves the solubility of the fluoride-based uranium waste by forming a complex with fluorine. Further, when the aqueous solution of the masking agent is acidic, the solubility of uranium waste is further improved due to the dissolution effect by the acid. On the other hand, the aqueous solution of aluminate recovered by electrodialysis is alkaline. When uranium waste is dissolved with a strong acid such as hydrochloric acid, addition of aluminate obtained by electrodialysis does not significantly increase the pH of the solution, so it does not inhibit the solubility of the waste. In the case of dissolving with a weak acid, the pH is increased by the addition of aluminate, which may inhibit the solubility. In such a case, it is necessary to convert the aluminate to a compound such as aluminum chloride that becomes aluminum ions when dissolved.
[0037]
FIG. 5 shows the influence of the aluminate solution recovered in the mask agent recovery step S8 on the solubility of calcium fluoride, which is a simulated substance of uranium waste. From the figure, it can be seen that aluminate improves the solubility of calcium fluoride in the same manner as aluminum chloride AlCl ₃ which has been studied for use as a mask agent. For this reason, the aluminum recovered in the masking agent recovery step S8 can be used as an auxiliary for improving the solubility of the fluorine compound waste even when it is reused in its chemical form.
[0038]
6 (a) and 6 (b) show the precipitation rate of fluorine when uranium is precipitated by adding hydrogen peroxide to a solution obtained by dissolving uranium waste containing CaF ₂ as a main component in hydrochloric acid. At this time, in order to prevent precipitation of fluorine, aluminum chloride and sodium aluminate as an aluminate were added to this solution as a masking agent. The horizontal axis represents the elapsed time from the addition of hydrogen peroxide, and the vertical axis represents the supernatant F-concentration and F-precipitation rate. From the figure, it can be seen that sodium aluminate has a function of preventing the precipitation of fluorine in the same manner as aluminum chloride AlCl ₃ which has been conventionally considered to be used as a mask agent. Therefore, the aluminum recovered in the mask agent recovery step S8 can be used in the same chemical form as a mask agent for preventing fluorine precipitation when uranium in the solution is precipitated from the uranium waste solution. It is.
[0039]
The aluminate recovered in the masking agent recovery step S8 can be converted to aluminum chloride by adding hydrochloric acid. The mask agent after conversion acts as aluminum ions in an acidic aqueous solution. The reaction formula for converting the aluminate to aluminum chloride is as follows.
NaAlO ₂ + 4HCl → AlCl ₃ + NaCl + 2H ₂ O (3)
[0040]
If uranium waste mainly composed of CaF _2, it can be implemented in the mask material recovery step S8 after trace uranium removal process S3. A conventional treatment method includes a fluorine fixing step for precipitating and collecting fluorine in a solution. If uranium waste mainly composed of CaF _2, fluorine and calcium in solution after trace uranium removal by electrodialysis performed by the mask material recovery step, because the pH of the cathode chamber side solution is increased, as CaF ₂ Precipitate. Therefore, since the fluorine fixation can be performed together with the mask agent recovery by electrodialysis, the fluorine fixation step included in the conventional wet processing can be eliminated and the process can be simplified simultaneously with the reduction of the secondary waste.
[0041]
As a result of electrodialysis for mask agent recovery, an acid solution is recovered in the anode chamber, so fluorine may be removed from this solution and reused as an acid for dissolving uranium waste in the dissolution step S1. .
[0042]
Next, a second embodiment of the present invention will be described with reference to FIGS.
As shown in FIG. 7, the wet processing method for uranium waste in this embodiment includes a dissolution step S1 for dissolving uranium waste together with a mask agent, a precipitation step S2 for precipitating and recovering uranium from the solution, and precipitation removal. A trace uranium removal step S3 for removing a trace amount of uranium remaining in the later solution using a uranium adsorption resin, a fluorine fixation step S4 for precipitating and collecting fluorine in the solution, and a secondary generated after the fluorine fixation step S4 Mask agent dissolution step S10 for dissolving the waste with the acid used in the dissolution step S1, secondary waste separation step S11 for separating the dissolution residue from the solution in which the mask agent is dissolved by filtration or the like, and after removing the precipitate A residual fluorine removing step S5 for removing a trace amount of fluorine remaining in the solution of the uranium using a fluorine adsorption resin, and a uranium absorption for regenerating the uranium adsorption resin used in the trace uranium removal step S3 The resin regeneration step S6, and a fluorine adsorption resin regeneration step S7 of reproducing a fluorine adsorption resin used in residual fluorine removal step S5.
[0043]
Dissolution step S1, precipitation step S2, trace uranium removal step S3, fluorine fixation step S4, mask agent dissolution step S10, secondary waste separation step S11, residual fluorine removal step S5, uranium adsorption resin regeneration step S6 and fluorine adsorption resin regeneration Step S7 is performed by a dissolution device, a precipitation device, a trace uranium removal device, a fluorine fixing device, a mask agent dissolution device, a secondary waste separation device, a residual fluorine removal device, a uranium adsorption resin regeneration device, and a fluorine adsorption resin regeneration device, respectively. . These devices may be connected to each other by piping or may be independent.
[0044]
The second embodiment is a wet processing method in which only the aluminum component in the secondary waste is dissolved by using a dilute acid solution used in the dissolving step S1 for masking agent recovery. The solution in which only the aluminum component is dissolved is separated from the solid component that has not been dissolved, the pH of this solution is adjusted, and the solution is reused as the solution in the uranium waste dissolution step S1. In this method, since the mask agent is recovered using the acid used in the uranium waste dissolution step, it is possible to suppress generation of tertiary waste due to the addition of the mask agent dissolution step S10 and the secondary waste separation step S11. it can.
[0045]
FIG. 8 shows the dissolution rate of CaF ₂ when pure CaF ₂ is dissolved in a solution having a pH of 0.2 or 1.7. It can be seen that the dissolution rate of CaF ₂ decreases as the pH of the solution increases. On the other hand, there is a test result that aluminum hydroxide does not precipitate when the solution pH is about 4 or less for a solution containing aluminum at a high concentration.
[0046]
Therefore, when secondary waste mixed with CaF ₂ and Al (OH) ₃ after fluorine fixation is dissolved using a weakly acidic solution, only Al (OH) ₃ is dissolved, and CaF ₂ is not dissolved. In the present embodiment, this solution is subjected to solid-liquid separation by filtration or the like to separate the aluminum component and CaF ₂ . Since the form of aluminum in the solution in which the aluminum component is dissolved is aluminum ions, it can be reused as a mask agent. By adjusting the pH of this solution to the optimum pH used in the dissolution step S1, it becomes a solution containing a mask agent used in the uranium waste dissolution step S1, and the mask agent can be reused. The solid-liquid separated CaF ₂ can be effectively used as an aggregate or the like when solidifying the waste with cement.
[0047]
【The invention's effect】
ADVANTAGE OF THE INVENTION According to this invention, the amount of secondary waste generation amount can be provided, and the wet processing method and apparatus of the uranium waste with cheap chemical | medical agent cost can be provided.
[Brief description of the drawings]
FIG. 1 is a flowchart showing a wet processing method for uranium waste according to a first embodiment of the present invention.
FIG. 2 is a graph showing a comparison of the amount of secondary waste generated by the conventional processing method and the processing method of the first embodiment of the present invention.
FIG. 3 is a diagram showing an electrodialysis apparatus used in the wet processing method for uranium waste according to the first embodiment of the present invention and an operation of the apparatus.
FIG. 4 is a graph showing a separation state of Al (OH) ₃ and CaF ₂ by electrodialysis in the wet processing method for uranium waste according to the first embodiment of the present invention.
FIG. 5 is a graph showing the solubility of CaF ₂ by aluminate and aluminum chloride recovered by electrodialysis in the wet processing method for uranium waste according to the first embodiment of the present invention.
FIG. 6 shows a state of separation of fluorine in uranium precipitation by aluminate and aluminum chloride recovered by electrodialysis in the wet processing method for uranium waste according to the first embodiment of the present invention, and (a) shows a supernatant liquid. FIG. 4 is a graph showing a change with time in fluorine ion concentration, and FIG.
FIG. 7 is a flowchart showing a wet processing method for uranium waste according to the second embodiment of the present invention.
FIG. 8 is a graph showing the effect of the wet processing method for uranium waste according to the second embodiment of the present invention, showing the difference in CaF ₂ dissolution rate depending on pH.
FIG. 9 is a flowchart showing a conventional wet processing method for uranium waste.

Claims (15)

In a wet processing method for separating and recovering uranium from uranium waste to which uranium, transuranium element, radionuclide, or uranium, which is a compound thereof, is attached, the uranium waste is dissolved together with a mask agent to form a solution. A precipitation step for precipitating uranium from the solution, a trace uranium removal step for removing a small amount of uranium remaining in the solution after the precipitation removal using a uranium adsorption resin, and a mask used in the precipitation step A uranium comprising: a masking agent recovery step for recovering the agent from the solution and returning it to the dissolution step; and a residual fluorine removing step for removing fluorine or fluorine compounds remaining in the solution using a fluorine adsorption resin. Waste treatment method. The uranium adsorption resin regeneration step for regenerating the uranium adsorption resin used in the trace uranium removal step and returning it to the trace uranium removal step, and the fluorine for regenerating the fluorine adsorption resin used in the residual fluorine removal step and returning to the residual fluorine removal step The method for wet treatment of uranium waste according to claim 1, further comprising an adsorption resin regeneration step. 2. The wet processing method for uranium waste according to claim 1, further comprising a fluorine fixing step of precipitating and recovering fluorine or a fluorine compound in the solution between the trace uranium removal step and the mask agent recovery step. . 2. The uranium waste according to claim 1, wherein the mask agent is a substance that prevents a fluorine component from being mixed into a uranium precipitate generated in the precipitation step with respect to a uranium waste having a fluorine component. Wet processing method. 2. The wet processing method for uranium waste according to claim 1, wherein the mask agent is an aluminum compound, and the aluminum compound is separated, recovered and reused from the secondary waste generated in the mask agent recovery step. . 2. The wet processing method for uranium waste according to claim 1, wherein the mask agent is aluminum chloride. 2. The method for wet treatment of uranium waste according to claim 1, wherein the mask agent recovery step is performed by electrodialysis. The electrodialysis uses an electrolytic cell separated into a cathode chamber and an anode chamber by an anion exchange membrane, introduces a solution containing the mask agent into the cathode chamber and energizes it, thereby recovering the mask agent in the cathode chamber and 8. The method for wet treatment of uranium waste according to claim 7, wherein the acid in the solution is recovered in the chamber. 9. The wet uranium waste according to claim 5 and 8, wherein an aluminum component is recovered as aluminate in the cathode chamber by introducing a solution containing an aluminum compound as the masking agent into the cathode chamber and performing electrodialysis. Processing method. 10. The wet processing method for uranium waste according to claim 9, wherein the recovered aluminate is reused as a masking agent in a form as it is or as a masking agent by converting the form to aluminum ions when dissolved. . 9. The wet processing method for uranium waste according to claim 8, wherein the acid recovered in the anode chamber is reused as a solution in the dissolution step. 4. The wet processing method for uranium waste according to claim 3, wherein when the uranium waste contains calcium fluoride as a main component, the fluorine fixing step and the mask agent recovery step are simultaneously performed by electrodialysis. The mask agent recovery step includes a mask agent dissolution step for dissolving only the mask agent, and a secondary waste separation step for separating a solid component from a solution in which the mask agent is dissolved. Item 4. A wet processing method for uranium waste according to Item 1. In a wet processing apparatus that separates and recovers uranium from uranium waste to which uranium, which is an element or compound of uranium, super uranium, or a radionuclide, adheres, dissolves the uranium waste together with a mask agent to form a solution. An apparatus, a precipitation apparatus for precipitating uranium from the solution, a trace uranium removal apparatus that removes a trace amount of uranium remaining in the solution after the precipitation is removed using a uranium adsorption resin, and the mask agent is recovered from the solution. For recovering the uranium adsorption resin used in the trace uranium removal apparatus, and a residual fluorine removal apparatus for removing fluorine or fluorine compounds remaining in the solution using the fluorine adsorption resin. And a fluorine adsorption resin regeneration device for regenerating the fluorine adsorption resin used in the residual fluorine removal device. Wet-processing apparatus of uranium waste and butterflies. 15. The wet processing apparatus for uranium waste according to claim 14, wherein the mask agent recovery apparatus includes an electrodialysis apparatus.

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