A method for extracting uranium from a solution system using electron beam irradiation technology

Abstract

The present invention discloses a method for extracting uranium from a solution system using electron beam irradiation technology, comprising the following steps: (1) directly setting aside the uranium solution or blowing excess protective gas into the uranium solution to exhaust air for setting aside; the protective gas is nitrogen or argon; (2) irradiating the uranium solution treated in step (1) under an electron beam at normal temperature and pressure; (3) centrifuging and filtering the irradiated uranium solution to obtain a uranium-containing solid product. The present invention adopts the above-mentioned method for extracting uranium from a solution system using electron beam irradiation technology, and for the first time directly uses high-energy rays to extract uranium from a solution system, without introducing any external material system, avoiding secondary pollution, and being simple to operate. It is suitable for large-scale industrial continuous extraction, and two different uranium extraction paths of oxidation and reduction can be obtained by regulating the solvent composition, which greatly improves the possibility of the method for efficiently extracting uranium in different scenarios. The method is expected to realize the industrial extraction of uranium in a circulating seawater system.

Description

Technical Field

[0001] The invention relates to the technical field of element extraction methods in a solution system, in particular to a method for extracting uranium from a solution system by utilizing electron beam irradiation technology. Background Art

[0002] Uranium is the heaviest radioactive element in nature and an important raw material for the nuclear energy industry. It is used in large quantities in the nuclear industry. During uranium mining, processing, nuclear accidents, and the treatment and disposal of spent fuel, a large amount of uranium-containing wastewater is produced. These wastewaters have complex components, low uranium concentrations, and a large number of coexisting ions. If not properly handled, the radioactive uranium element will migrate and spread to the biosphere through surface runoff and underground seepage, polluting the ecological environment and posing a huge threat to the biosphere, while also causing a waste of uranium resources.

[0003] Previous studies have reported that the heavy metal toxicity of uranium is 6 orders of magnitude higher than its radiotoxicity, and long-term exposure poses a serious threat to human life and health. Uranium is usually present in aqueous solution as uranyl ions (UO2 2+ ) exists in the form of uranium, which easily accumulates in human organs after entering the human body, leading to various brain, kidney and other diseases. Therefore, the treatment of uranium-containing wastewater is imminent.

[0004] At present, a variety of methods have been developed for the extraction of uranium from solution systems, such as chemical precipitation, solvent extraction, membrane treatment, adsorption, etc., but these methods all have the following problems:

[0005] 1. High cost, not conducive to commercialization;

[0006] 2. Slow adsorption kinetics, low adsorption capacity, and easy desorption;

[0007] 3. Poor selectivity and easily interfered by other ions in the solution. Summary of the invention

[0008] The purpose of the present invention is to provide a method for extracting uranium from a solution system using electron beam irradiation technology, so as to solve the problems of high cost, low adsorption capacity and poor selectivity of the above-mentioned uranium extraction method. By introducing high-energy electron beam irradiation technology, the present invention can produce a large number of highly reactive free radicals in a short time from a uranium-containing solution. By changing the composition of the solvent, the oxidation and reduction properties of the obtained free radicals can be easily regulated, thereby realizing the extraction of uranium from the solution through two different pathways of oxidation and reduction. The method is simple and easy to implement, and is expected to solve the needs of efficient and rapid extraction of uranium from specific solution systems in different scenarios (uranium-containing wastewater generated by uranium mining, uranium-containing wastewater in nuclear power plants, seawater, etc.).

[0009] To achieve the above object, the first aspect of the present invention provides a method for extracting uranium from a solution system using electron beam irradiation technology, comprising the following steps:

[0010] (1) The uranium solution is directly kept for use or excess protective gas is blown into the uranium solution to exhaust the air for use; the protective gas is nitrogen or argon;

[0011] (2) irradiating the uranium solution treated in step (1) under an electron beam at room temperature and pressure;

[0012] (3) The irradiated uranium solution is centrifuged and filtered to obtain a uranium-containing solid product.

[0013] Preferably, the concentration of the uranium solution in step (1) is 10 -5 ~10 -3 mol / L.

[0014] Preferably, the solvent in the uranium solution in step (1) is one of a reducing system solution and an oxidizing system solution.

[0015] Preferably, the reducing system solution comprises water and an organic solvent capable of reacting with ·OH to generate reducing free radicals, and the volume ratio of water to the organic solvent is 1-4:1-4.

[0016] Preferably, the reducing system solution includes water and methanol, and the volume ratio of water to methanol is 3:2.

[0017] Preferably, the reducing system solution includes water and ethanol, and the volume ratio of water to ethanol is 3:2.

[0018] Preferably, the oxidation system solution is water.

[0019] Preferably, the electron beam irradiation dose in step (2) is 10 to 110 kGy.

[0020] Preferably, the temperature of the electron beam irradiation in step (2) is 0 to 5°C.

[0021] Preferably, the humidity of the electron beam irradiation in step (2) is 30-80%.

[0022] Preferably, the uranium-containing solid product in step (3) includes uranium-containing compounds such as UO4 compounds and UO2.

[0023] The second aspect of the present invention provides an application of a method for extracting uranium from a solution system using electron beam irradiation technology, wherein the method is applied in extracting uranium from uranium-containing wastewater.

[0024] Preferably, the uranium-containing wastewater includes natural water bodies and non-natural water bodies. Natural water bodies include seawater, salt lake water, river water, and freshwater lake water. Non-natural water bodies are uranium-containing wastewater generated by various human activities.

[0025] A third aspect of the present invention provides an application of a method for extracting uranium from a solution system using electron beam irradiation technology, wherein the method is applied in extracting radioactive elements from wastewater.

[0026] Preferably, the radioactive nuclides include Tc, Ac, Pa, Th, Np, Pu, Am, Cm, etc.

[0027] A fourth aspect of the present invention provides an application of a method for extracting uranium from a solution system using electron beam irradiation technology, wherein the method is applied in extracting non-radioactive elements from wastewater.

[0028] Preferably, the non-radioactive elements include lanthanide elements, Fe, Cu, Ag, Pb, etc.

[0029] Therefore, the present invention adopts a method of extracting uranium from a solution system using electron beam irradiation technology with the above structure, which has the following beneficial effects:

[0030] (1) Compared with the prior art, the method for extracting uranium from a solution system using electron beam irradiation technology provided by the present invention is the first to directly extract uranium from a solution system using high-energy rays without introducing any external material system, thereby avoiding secondary contamination.

[0031] (2) The present invention is simple to operate and is suitable for large-scale industrial continuous extraction.

[0032] (3) The present invention can obtain two different uranium extraction pathways, oxidation and reduction, by regulating the solvent composition, which greatly improves the possibility of this method to efficiently extract uranium in different scenarios. This method is expected to realize the industrial extraction of uranium in a circulating seawater system.

[0033] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 It is the industrial cycle roadmap for uranium extraction by electron beam irradiation;

[0035] Figure 2 It is the removal effect of uranium by uranium solutions with different concentrations and different mixing ratios of deionized water and methanol;

[0036] Figure 3 The uranium concentration is 4.2×10 -4 mol / L, and the removal efficiency of uranium in the solution at different irradiation doses when the ratio of deionized water to methanol was 5:0 and 3:2;

[0037] Figure 4 The uranium concentration is 2.1×10 -4mol / L, and the removal efficiency of uranium in the solution at different irradiation doses when the ratio of deionized water to methanol was 5:0 and 3:2;

[0038] Figure 5 The uranium concentration is 4.2×10 -5 mol / L, and the removal efficiency of uranium in the solution at different irradiation doses when the ratio of deionized water to methanol was 5:0 and 3:2;

[0039] Figure 6 are the scanning electron microscope (SEM) images of the solid products obtained under the two routes A and B;

[0040] Figure 7 This is the uranium content map of the solid products obtained under the two paths A and B based on the SEM-EDS-mapping test;

[0041] Figure 8 It is the Fourier transform infrared spectrum (FT-IR) of the solid products obtained under the two paths A and B;

[0042] Fig. 9 is the X-ray photoelectron spectroscopy (XPS) graph of the solid products obtained under the two paths A and B;

[0043] Fig.10 The uranium concentration under path A is 4.2×10 -5 mol / L、2.1×10 -4 mol / L and 4.2×10 -4 mol / L, the removal efficiency of uranium in the solution under 105 kGy irradiation dose and three different atmospheres;

[0044] Fig.11 The uranium concentration under path B is 4.2×10 -5 mol / L、2.1×10 -4 mol / L and 4.2×10 -4 mol / L, the removal efficiency of uranium in the solution under 105 kGy irradiation dose and three different atmospheres. DETAILED DESCRIPTION

[0045] The present invention will be further described below. It should be noted that this embodiment is based on the technical solution and provides a detailed implementation method and a specific operation process, but the present invention is not limited to this embodiment. Example 1

[0046] A method for extracting uranium from a solution system using electron beam irradiation technology comprises the following steps:

[0047] (1) Preparation of uranium solution

[0048] Weigh five portions of 21.09 mg of uranyl nitrate hexahydrate and add them to 100 mL of a mixed solvent of deionized water / methanol with a volume ratio of 5:0, 4:1, 3:2, 2:3, and 1:4 to prepare 4.2×10 -4 mol / L uranium solution and diluted it to 2.1×10 -4 mol / L and 4.2×10 -5 mol / L, use a pipette to transfer 10 mL of solution into a 20 mL cap bottle, seal it, and blow nitrogen for 30 s to expel the air in the bottle. The oxidation system solution formed by deionized water is recorded as system A, and the reduction system solution formed by water and methanol at a volume ratio of 3:2 is recorded as system B.

[0049] (2) irradiating the uranium solution treated in step (1) under an electron beam at room temperature and pressure;

[0050] The parameters of electron beam irradiation were: dose 105 kGy, temperature 1 °C, and humidity 50%.

[0051] (3) centrifugally filtering the irradiated uranium solution to obtain a uranium-containing solid product;

[0052] The irradiated solution was filtered to obtain a solid precipitate, which was washed three times with deionized water and freeze-dried at -90 °C for 24 h to obtain light yellow (system A) and brown-black (system B) solid products, respectively. Example 2

[0053] A method for extracting uranium from a solution system using electron beam irradiation technology, which differs from Example 1 in that the concentration of the uranium solution is 4.2×10 -4 mol / L (A system or B system), the doses of electron beam irradiation were 15 kGy, 30 kGy, 45 kGy, 75 kGy and 105 kGy respectively. Example 3

[0054] A method for extracting uranium from a solution system using electron beam irradiation technology, which differs from Example 2 in that the concentration of the uranium solution is 2.1×10 -4 mol / L (A system or B system), the doses of electron beam irradiation were 15 kGy, 30 kGy, 45 kGy, 75 kGy and 105 kGy respectively. Example 4

[0055] A method for extracting uranium from a solution system using electron beam irradiation technology, which differs from Example 2 in that the concentration of the uranium solution is 4.2×10 -5mol / L (A system or B system), the doses of electron beam irradiation were 15 kGy, 30 kGy, 45 kGy, 75 kGy and 105 kGy respectively. Example 5

[0056] Figure 1 The uranium extraction process for actual uranium-containing wastewater includes the following steps:

[0057] Step 1: filtering out solid impurities in the original solution to obtain a uranium-containing solution to be irradiated;

[0058] Step 2: irradiating using system A or irradiating using system B;

[0059] Method A: Irradiation reduction method, adding methanol solution to the uranium-containing solution, using electron beam irradiation to generate reducing free radicals to reduce uranyl ions to solid products;

[0060] Method B: using oxidative free radicals generated by irradiation to oxidize uranyl ions into solid products;

[0061] Step 3: Separation

[0062] Place a filter membrane or use other separation methods to block uranium-containing solid products. Multiple parallel channels ensure that the circulation does not stop when the filter membrane is replaced. The solution that passes the test is directly discharged, and the solution that fails the test is recirculated and mixed with the uranium-containing solution for electron beam irradiation again until the solution passes the test and meets the emission standards. Example 6

[0063] A method for extracting uranium from a solution system using electron beam irradiation technology, which is different from Example 2 in that the concentration of the uranium solution is 4.2×10 -4 mol / L, the dose of electron beam irradiation was 30 kGy, and the reduction system solution included water and ethanol in a volume ratio of 3:2. Example 7

[0064] A method for extracting uranium from a solution system using electron beam irradiation technology, which is different from Example 1 in that: no nitrogen is blown into the solution after sealing, and the uranium is directly extracted from the uranium solution in an air atmosphere. Example 8

[0065] A method for extracting uranium from a solution system using electron beam irradiation technology, which is different from Example 1 in that argon gas is blown into the solution after sealing, and the process of extracting uranium is carried out in an argon atmosphere.

[0066] Test Example 1

[0067] The electron beam irradiation effects of Examples 1 to 4 and Example 6 were tested.

[0068] The concentration of the remaining uranium in the solution after irradiation was measured by the following method: the upper layer of the irradiated liquid was first filtered with a 0.1 μm filter membrane, and then the filtered liquid was centrifuged at 8000 r / min for 1 h. The centrifuged solution was diluted and tested by ICP-MS to obtain the precise concentration of the remaining uranium in the solution after irradiation. The irradiation test results are shown in Figures 2 to 5 .

[0069] from Figure 2 It can be seen that the uranium solution of Example 1 has different uranium removal effects under different solvent systems, among which the extraction rate of uranium by method A in the selected sample point solution is as high as over 90%, and the extraction rate of uranium by method B in the selected sample point solution is also as high as over 90%. Figure 3 It can be seen from the figure that the removal rate of uranium in the uranium solution in Example 2 increases with the increase of the irradiation dose under different electron beam irradiation doses. Figure 4 It can be seen from the above that the uranium solution in Example 3 has different uranium element removal effects under different electron beam irradiation doses. Figure 5 It can be seen from the figure that the removal rate of uranium in the uranium solution in Example 4 increases with the increase of the irradiation dose under different electron beam irradiation doses. Fig.10 and Fig.11 It can be seen that the uranium removal rates in Examples 7 and 8 under different atmospheric conditions change. Under the oxidation system A, the uranium removal rates under nitrogen and argon atmospheres are slightly greater than the uranium removal rate under the air atmosphere, and the atmospheric conditions have little effect on the uranium removal effect under the oxidation system; under the reduction system B, the uranium removal rates under nitrogen and argon atmospheres are significantly greater than the uranium removal rate under the air atmosphere.

[0070] The irradiation results of Example 1 and Example 6 are shown in Table 1.

[0071]

[0072] Test Example 2

[0073] The obtained uranium-containing solid product was characterized.

[0074] (1) Scanning electron microscopy and elemental analysis spectrum (SEM-EDS-mapping)

[0075] The solid products obtained by route A (deionized water / methanol = 5:0) and route B (deionized water / methanol = 3:2) were characterized by SEM-EDS. Figure 6As shown in the figure, it is found that the solid surface obtained by path B is smoother than the rough and porous solid surface obtained by path A. The U and O in the EDS spectra of the two paths have good overlap with the morphology map, indicating that the compound is mainly composed of U and O, with U contents of 21.3% and 32.5%, respectively ( Figure 7 ).

[0076] (2) Fourier transform infrared spectroscopy (FT-IR)

[0077] The solid products of route A and route B were characterized by FT-IR. Figure 8 Path A and Path B are at 912 and 908 cm -1 The characteristic peaks at 508 cm-1 and 509 cm-2 are attributed to the asymmetric stretching vibration of OUO in the irradiated solid UO4 and UO2. -1 The characteristic vibration of UO2 appears, proving the existence of UO2 in the B path. In addition, the 3451 and 1621 cm -1 Position and B-path spectra at 3422 and 1642 cm -1 The absorption peaks of 3239 and 1384 cm in the A path spectrum are the stretching vibration and bending vibration of the OH bond in adsorbed water or free water. -1 The absorption peak at the position is the stretching vibration and bending vibration of hydrogen bonding or OH bond in crystal water.

[0078] (3) X-ray photoelectron spectroscopy (XPS)

[0079] In order to further analyze the solid products of path A and path B, XPS characterization was performed to analyze their surface composition and oxidation state, such as Fig. 9 As shown. In the full XPS spectrum, the characteristic peaks of O 1s appear at 532.16 eV and 531.25 eV for path A and characteristic peaks of U 4f appear at 392.43 eV and 382.26 eV and 392.41 eV and 382.27 eV for path B, respectively. This confirms that uranium-containing oxides are produced in both paths. The high-resolution XPS spin-orbit splitting of U 4f in path A is U4f 5 / 2 and U 4f 7 / 2 , corresponding to 392.64 eV and 381.85 eV, respectively. The binding energies at 394.03 eV and 383.33 eV are due to the different valence states of U. The U 4f high-resolution XPS spin-orbit splitting of the B path is U 4f 5 / 2 and U 4f 7 / 2, corresponding to 392.64 eV and 381.85 eV, respectively. Among them, the binding energies at 391.29 eV and 380.49 eV correspond to U(IV), which shows that the solid product under path B is UO2.

[0080] Therefore, the present invention adopts a method of extracting uranium from a solution system using electron beam irradiation technology with the above structure, and for the first time uses high-energy rays to directly realize the extraction of uranium in a solution system, without introducing any external material system, avoiding secondary pollution, and is simple to operate. It is suitable for large-scale industrial continuous extraction, and can obtain two different uranium extraction paths of oxidation and reduction by regulating the solvent composition, which greatly improves the possibility of the method to efficiently extract uranium in different scenarios. The method is expected to realize the industrial extraction of uranium in a circulating seawater system.

[0081] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that they can still modify or replace the technical solution of the present invention with equivalents, and these modifications or equivalent replacements cannot cause the modified technical solution to deviate from the spirit and scope of the technical solution of the present invention.

Claims

1. A method for extracting uranium from a solution system using electron beam irradiation technology, characterized in that : Includes the following steps: (1) Preparation of uranium-containing solution Weigh uranyl nitrate hexahydrate and add it to a reduction system or an oxidation system. The reduction system includes deionized water and methanol in a volume ratio of 3:2, and the oxidation system is deionized water to obtain a uranium-containing solution. The concentration of the uranium-containing solution is 2.1×10 -4 mol / L or 4.2×10 -4 mol / L; (2) Blowing excess nitrogen or argon into the uranium-containing solution and irradiating it with electron beam at a dose of 30 to 110 kGy at room temperature and pressure; After irradiation, the solid product containing uranium is obtained by filtration.

2. A method for extracting uranium from a solution system using electron beam irradiation technology according to claim 1, characterized in that : The temperature of electron beam irradiation in step (2) is 0~5℃.

3. The method for extracting uranium from a solution system using electron beam irradiation technology according to claim 1, characterized in that : The humidity of the electron beam irradiation in step (2) is 30~80%.

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