Uranium reverse extraction system for improving alpha radioactive purification effect

Abstract

The utility model belongs to the technical field of spent fuel aftertreatment, and particularly relates to a uranium reverse extraction system for improving the alpha radioactive purification effect. The system comprises a uranium reverse extraction column, a dirty solvent control tank, a dirty solvent reverse extraction tank, an evaporator and a solvent regeneration system, the input end of the uranium reverse extraction column receives the uranium-containing organic matter, and the output end is connected with the input end of the contaminated solvent control tank and used for reverse extraction of the uranium-containing organic matter to obtain a contaminated solvent; the output end of the dirty solvent control tank is connected with the input end of the dirty solvent reverse extraction tank; and the dirty solvent reverse extraction tank is used for carrying out secondary reverse extraction on the dirty solvent, an obtained uranium-containing water phase is evaporated and concentrated by an evaporator to obtain high-concentration uranium feed liquid, the high-concentration uranium feed liquid is output to the co-decontamination unit, and the dirty solvent subjected to reverse extraction by the dirty solvent reverse extraction tank is output to a solvent regeneration system for reuse treatment. The organic phase feeding tank of the dirty solvent reverse extraction tank is changed into the dirty solvent control tank, so that the operation pressure of the solvent regeneration system can be effectively reduced, and the radioactive index of the generated waste organic phase alpha meets the conveying standard.

Description

Technical Field

[0001] This application belongs to the technical field of spent fuel reprocessing, and specifically relates to a uranium stripping system for improving the purification effect of alpha radioactivity. Background Art

[0002] Compared with similar domestic processes, the stripping effect of the uranium stripping column (IC column) in a certain factory's uranium stripping unit is appropriate, solving the problems of high alpha radioactivity in the aqueous phase effluent of the uranium stripping unit in the previous process, which brings difficulties to removing alpha radioactivity from uranium products in the uranium line, and ensuring the qualification rate of uranium products. However, most of the alpha radioactivity and a small part of uranium (such as uranium in the order of 10 -2 g / L) enter the stripped contaminated solvent (1CW). Under a high-irradiation environment, the quality of the organic phase will decline, affecting the extraction performance of the reusable organic phase. Moreover, when the contaminated solvent enters the caustic scrubber, it will increase the operating pressure of the caustic scrubber in the solvent regeneration system. Utility Model Content

[0003] The purpose of this application is to provide a uranium stripping system for improving the purification effect of alpha radioactivity, solving the problems in the prior art that the alpha radioactivity activity in the stripped contaminated solvent after the uranium stripping column is relatively high, affecting the extraction performance of the reusable organic phase, and when the contaminated solvent enters the caustic scrubber, it will increase the operating pressure of the caustic scrubber in the solvent regeneration system.

[0004] Technical solutions to achieve the purpose of this application:

[0005] The embodiment of this application provides a uranium stripping system for improving the purification effect of alpha radioactivity. The system includes: a uranium stripping column, a contaminated solvent control tank, a contaminated solvent stripping tank, an evaporator, and a solvent regeneration system;

[0006] The input end of the uranium stripping column receives uranium-containing organic matter, and the output end is connected to the input end of the contaminated solvent control tank, for stripping the uranium-containing organic matter to obtain contaminated solvent;

[0007] The output end of the contaminated solvent control tank is connected to the input end of the contaminated solvent stripping tank;

[0008] The contaminated solvent stripping tank is used for secondary stripping of the contaminated solvent. The obtained uranium-containing aqueous phase is evaporated and concentrated by the evaporator to obtain a high-concentration uranium feed solution, which is output to the co-decontamination unit. The contaminated solvent after stripping in the contaminated solvent stripping tank is output to the solvent regeneration system for reuse treatment.

[0009] Optionally, the system further includes: a uranium solution receiving tank;

[0010] The input end of the uranium solution receiving tank is connected to the output end of the evaporator, and the output end of the uranium solution receiving tank is connected to the co-decontamination unit, for temporarily storing the high-concentration uranium feed solution.

[0011] Optionally, the system further includes: a solvent rectification system;

[0012] The solvent regeneration system performs pickling and water washing on the contaminated solvent after back-extraction, outputs the extractant to the co-decontamination unit for reuse, and outputs the waste organic phase to the solvent rectification system.

[0013] Optionally, the ratio of uranium-containing organic matter to aqueous phase input into the contaminated solvent back-extraction tank is 10:1.

[0014] Optionally, the ratio of uranium-containing organic matter to aqueous phase input into the contaminated solvent back-extraction tank is 5:1.

[0015] Optionally, the contaminated solvent back-extraction tank operates under a heating condition.

[0016] Optionally, the contaminated solvent back-extraction tank operates at 71 °C.

[0017] Optionally, the stirring speed of the contaminated solvent back-extraction tank is 350 r / min.

[0018] Optionally, the contaminated solvent back-extraction tank is fed by a two-stage air lift method.

[0019] The beneficial technical effects of the present application are as follows:

[0020] A uranium back-extraction system for improving the purification effect of α radioactivity provided by an embodiment of the present application includes: a uranium back-extraction column, a contaminated solvent control tank, a contaminated solvent back-extraction tank, an evaporator, and a solvent regeneration system; the input end of the uranium back-extraction column receives uranium-containing organic matter, and the output end is connected to the input end of the contaminated solvent control tank for back-extracting the uranium-containing organic matter to obtain a contaminated solvent; the output end of the contaminated solvent control tank is connected to the input end of the contaminated solvent back-extraction tank; the contaminated solvent back-extraction tank is used for performing secondary back-extraction on the contaminated solvent, and the obtained uranium-containing aqueous phase is evaporated and concentrated by the evaporator to obtain a high-concentration uranium feed solution and output it to the co-decontamination unit, and the contaminated solvent after back-extraction by the contaminated solvent back-extraction tank is output to the solvent regeneration system for reuse treatment. In the embodiment of the present application, the organic phase feed tank of the contaminated solvent back-extraction tank is changed to a contaminated solvent control tank, which solves the problem that the original organic phase feed tank of the contaminated solvent back-extraction tank cannot achieve independent feeding, and does not affect the operation of other devices; after the contaminated solvent after secondary back-extraction enters the solvent regeneration system, it can effectively reduce the operating pressure of the solvent regeneration system, ensure the caustic washing purification effect of the solvent regeneration system, and the α radioactivity index of the generated waste organic phase meets the transportation standard and can be transported to the downstream in time, which is beneficial to the stable operation of the large organic phase cycle of the entire system, the α radioactivity content in the waste organic phase meets the design index, and the radioactivity of the downstream plant can be controlled from the source. Description of the Drawings

[0021] Figure 1It is a schematic structural diagram of an existing uranium stripping system;

[0022] Figure 2 It is a schematic structural diagram of a uranium stripping system provided by an embodiment of the present application for improving the purification effect of α radioactivity. Detailed implementation mode

[0023] In order to enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present application. Obviously, the embodiments described below are only a part of the embodiments of the present application, rather than all of them. Based on the embodiments described in the present application, all other embodiments obtained by those skilled in the art without creative efforts are within the scope of protection of the present application.

[0024] For the convenience of understanding, the structure of the existing uranium stripping system will be introduced first below.

[0025] As Figure 1 shown, in the existing uranium stripping system, when the contaminated solvent after stripping in the 1C column is output to the contaminated solvent control tank. When the uranium concentration of the contaminated solvent exceeds the preset value, it is output to the contaminated solvent stripping tank through the emptying tank for stripping. The stripped contaminated solvent is output to the solvent regeneration system, and the uranium-containing aqueous phase feed liquid is output to the uranium purification system; when the uranium concentration of the contaminated solvent does not exceed the preset value, it is output to the solvent regeneration system. The solvent regeneration system performs reuse treatment on the contaminated solvent, and the obtained waste organic phase is output to the solvent distillation system. However, the α radioactivity activity in the contaminated solvent is relatively high, which affects the extraction performance of the reused organic phase, and the contaminated solvent will increase the operating pressure of the alkali washing tank in the solvent regeneration system after entering the alkali washing tank.

[0026] In view of the problem that the relatively high α radioactivity activity in the contaminated solvent affects the extraction performance of the reused organic phase, the embodiment of the present application provides a uranium stripping system for improving the purification effect of α radioactivity. The uranium stripping column and the contaminated solvent stripping tank are operated in series continuously to form a contaminated solvent secondary stripping process, so that the α radioactivity in the contaminated solvent at the outlet of the uranium stripping column is stripped into the aqueous phase twice. Then, the aqueous phase feed liquid generated by the secondary stripping is evaporated and concentrated and then returned to the co-decontamination unit for seasoning and re-extraction. On the premise of ensuring the α radioactivity purification effect, the uranium concentration and α radioactivity concentration of the contaminated solvent are effectively reduced, and the recovery of uranium is realized.

[0027] Based on the above content, in order to clearly and detailedly illustrate the above advantages of the present application, the specific implementation mode of the present application will be described below in conjunction with the accompanying drawings.

[0028] See Figure 1 , this figure is a schematic structural diagram of a uranium stripping system provided by an embodiment of the present application for improving the purification effect of α radioactivity.

[0029] A uranium stripping system for improving the purification effect of α-radioactivity provided by an embodiment of the present application includes: a uranium stripping column 100, a contaminated solvent control tank 200, a contaminated solvent stripping tank 300, an evaporator 400, and a solvent regeneration system 500;

[0030] The input end of the uranium stripping column 100 receives uranium-containing organic matter, and the output end is connected to the input end of the contaminated solvent control tank 200, which is used for stripping the uranium-containing organic matter to obtain contaminated solvent;

[0031] The output end of the contaminated solvent control tank 200 is connected to the input end of the contaminated solvent stripping tank 300;

[0032] The contaminated solvent stripping tank 300 is used for secondary stripping of the contaminated solvent. The obtained uranium-containing aqueous phase is evaporated and concentrated by the evaporator 400, and then the high-concentration uranium feed liquid is output to the co-decontamination unit 600. The contaminated solvent after stripping in the contaminated solvent stripping tank is output to the solvent regeneration system 500 for reuse treatment.

[0033] In the embodiment of the present application, the organic phase feed tank of the contaminated solvent stripping tank 300 is changed to the contaminated solvent control tank 200, which solves the problem that the original organic phase feed tank of the contaminated solvent stripping tank 300 cannot achieve independent feeding, and does not affect the operation of other devices; an aqueous phase transfer path is added, and the aqueous phase generated by the contaminated solvent stripping tank 300 is sent to the evaporator 400 for evaporation and concentration, and is no longer mixed with the uranium-containing aqueous phase feed liquid generated by the uranium stripping column 100 and sent to the solvent regeneration system 500, reducing the operating pressure of the solvent regeneration system 500.

[0034] In one example, the system may further include: a uranium solution receiving tank 700;

[0035] The input end of the uranium solution receiving tank 700 is connected to the output end of the evaporator 400, and the output end of the uranium solution receiving tank 700 is connected to the co-decontamination unit 600, which is used for temporarily storing the high-concentration uranium feed liquid.

[0036] In the embodiment of the present application, the retention path of the aqueous phase output by the contaminated solvent stripping tank 300 is improved. The generated high-concentration uranium feed liquid is temporarily stored in the uranium solution receiving tank 700, and then returned to the co-decontamination unit 600 for seasoning treatment, realizing the recovery of uranium elements, not increasing the treatment pressure of the co-decontamination unit 600, optimizing the overall process of the system, and making the upstream and downstream interface relationships more harmonious.

[0037] In another example, the system may further include: a solvent rectification system 800;

[0038] The solvent regeneration system 500 performs pickling and water washing treatments on the stripped contaminated solvent, obtains the extractant and outputs it to the co-decontamination unit 600 for reuse, and outputs the waste organic phase to the solvent rectification system 800.

[0039] In one example, the ratio of uranium-containing organic matter to the aqueous phase input into the spent solvent back-extraction tank 300 can be 10:1.

[0040] It should be noted that the spent solvent back-extraction tank 300 can be supplied with the aqueous phase by an aqueous phase feed tank, and the aqueous phase can be dilute nitric acid. When the ratio of uranium-containing organic matter to the aqueous phase input into the spent solvent back-extraction tank 300 is 10:1, it is obtained that after the secondary back-extraction of the spent solvent, the uranium concentration drops from 10 -2 g / L to 10 -3 g / L, and the α-radioactivity of the organic phase outlet of the uranium back-extraction column 100 and the α-radioactivity of the organic phase outlet of the spent solvent back-extraction tank decrease by 50%. The secondary back-extraction of the spent solvent at the outlet of the uranium back-extraction column 100 by the spent solvent back-extraction tank 300 can effectively reduce the uranium concentration and α-radioactivity in the spent solvent, and at the same time make the uranium recovery rate of the co-decontamination unit 600 meet the design requirements.

[0041] In another example, the ratio of uranium-containing organic matter to the aqueous phase input into the spent solvent back-extraction tank 300 can be 5:1.

[0042] In some possible implementation manners of the embodiments of the present application, the spent solvent back-extraction tank 300 operates under a heating condition.

[0043] As an example, the spent solvent back-extraction tank 300 operates at 71 °C.

[0044] In some possible implementation manners of the embodiments of the present application, the stirring speed of the spent solvent back-extraction tank is 350 r / min.

[0045] In some possible implementation manners of the embodiments of the present application, the spent solvent back-extraction tank is fed by a two-stage air-lift method to accurately control the flow ratio.

[0046] The uranium back-extraction system for improving the α-radioactivity purification effect provided by the embodiments of the present application not only improves the purification effect of α-radioactivity in the organic phase, but also amplifies the mass transfer effect of the uranium back-extraction unit and improves the uranium product recovery rate. After the secondary back-extraction of the spent solvent enters the caustic scrubbing tank of the solvent regeneration system 500, it can effectively reduce the operating pressure of the caustic scrubbing tank and ensure the caustic scrubbing purification effect of the caustic scrubbing tank; the α-radioactivity index of the generated waste organic phase meets the transportation standard and can be transported to the downstream in time, which is beneficial to the stable operation of the large circulation of the organic phase of the whole system, and the α-radioactivity content in the waste organic phase meets the design index, and the radioactivity of the downstream workshop can be controlled from the source.

[0047] The uranium back-extraction system for improving the α-radioactivity purification effect provided by the embodiments of the present application, after the secondary back-extraction, the aqueous phase is subjected to evaporation and concentration treatment and then returned to the co-decontamination unit for re-extraction, realizing the recovery of uranium elements, without increasing the treatment pressure of the uranium purification system, optimizing the overall process of the system, and making the interface relationship between the upstream and downstream more harmonious.

[0048] The present application has been described in detail above with reference to the accompanying drawings and embodiments. However, the present application is not limited to the above embodiments, and various changes can be made without departing from the gist of the present application within the scope of knowledge possessed by those of ordinary skill in the art. Contents not described in detail in the present application can all adopt the prior art.

Claims

1. A uranium stripping system for improving the purification effect of α radioactivity, characterized in that, The system includes: a uranium stripping column, a contaminated solvent control tank, a contaminated solvent stripping tank, an evaporator, and a solvent regeneration system; The input end of the uranium stripping column receives uranium-containing organic matter, and the output end is connected to the input end of the contaminated solvent control tank, which is used to strip the uranium-containing organic matter to obtain contaminated solvent; The output end of the contaminated solvent control tank is connected to the input end of the contaminated solvent stripping tank; The contaminated solvent stripping tank is used to perform secondary stripping on the contaminated solvent. The uranium-containing aqueous phase obtained is evaporated and concentrated by the evaporator and then high-concentration uranium feed liquid is output to the co-decontamination unit. The contaminated solvent after stripping in the contaminated solvent stripping tank is output to the solvent regeneration system for reuse treatment.

2. The uranium stripping system for improving the purification effect of α radioactivity according to claim 1, wherein The system further includes: a uranium solution receiving tank; The input end of the uranium solution receiving tank is connected to the output end of the evaporator, and the output end of the uranium solution receiving tank is connected to the co-decontamination unit, which is used to temporarily store the high-concentration uranium feed liquid.

3. The uranium stripping system for improving the purification effect of α radioactivity according to claim 1, wherein The system further includes: a solvent rectification system; The solvent regeneration system performs pickling and water washing treatments on the stripped contaminated solvent, obtains an extractant and outputs it to the co-decontamination unit for reuse, and outputs the waste organic phase to the solvent rectification system.

4. The uranium stripping system for improving the purification effect of α radioactivity according to any one of claims 1-3, characterized in that, The contaminated solvent stripping tank operates under a heating condition.

5. The uranium stripping system for improving the purification effect of α radioactivity according to claim 4, characterized in that, The contaminated solvent stripping tank operates at 71 °C.

6. The uranium stripping system for improving the purification effect of α radioactivity according to any one of claims 1-3, characterized in that The stirring speed of the contaminated solvent stripping tank is 350 r / min.

7. The uranium stripping system for improving the purification effect of α radioactivity according to any one of claims 1-3, characterized in that, The contaminated solvent stripping tank uses a two-stage air lift method for feeding.

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