Method for screening and separating uranyl ions from strong nitric acid water phase containing uranium, niobium and zirconium

Abstract

The invention belongs to the technical field of nuclear fuel circulation and waste liquid treatment, and particularly relates to a method for screening and separating uranyl ions from a strong nitric acid water phase containing uranium, niobium and zirconium. The preparation method comprises the following steps: step 1, preparing a graphene oxide film by adopting an improved Hummers oxidation method; step 2, preparing a permeation device; step 3, carrying out an ion screening experiment through the permeation device; and 4, sample determination and result calculation. According to the method, the graphene oxide film is developed to serve as a screening and separating material, the screening and separating rule of the graphene oxide film on uranium in a U-Nb-Zr system in a high-acid solution is explored, the related screening and separating technological process is established, and an early-stage technical foundation can be laid for scientific research and production of the related material development process in the future.

Description

Technical Field

[0001] The invention belongs to the technical field of nuclear fuel circulation and waste liquid treatment, and in particular relates to a method for screening and separating uranyl ions from a strong nitric acid aqueous phase containing uranium, niobium and zirconium. Background Art

[0002] During the development, production and analysis of nuclear fuel elements, a type of waste with uranium, niobium and zirconium as the main components will be generated. In order to promote the high-quality and sustainable development of nuclear energy, it is necessary to develop effective technologies to efficiently separate uranium in this system to meet the actual needs of uranium recovery and reuse.

[0003] In order to achieve efficient separation of uranium from uranium niobium zirconium in a strong nitric acid system and meet the actual needs of uranium recovery and reuse in this type of material, it is urgently necessary to provide a method for screening and separating uranyl ions from a strong nitric acid aqueous phase containing uranium niobium zirconium.

[0004] After patent search, no method of using graphene oxide membrane to screen and separate uranium from uranium niobium and zirconium was found in existing patents and literature. Summary of the invention

[0005] The technical problem solved by the present invention is to provide a method for screening and separating uranyl ions from a strong nitric acid aqueous phase containing uranium, niobium and zirconium. By developing a graphene oxide membrane as a screening and separation material, exploring its screening and separation rules for uranium in a U-Nb-Zr system in a high-acid solution, and establishing a related screening and separation process, the preliminary technical foundation can be laid for the scientific research and production of related material development processes in the future.

[0006] The technical solution adopted by the present invention is:

[0007] A method for sieving and separating uranyl ions from a strong nitric acid aqueous phase containing uranium, niobium and zirconium comprises the following steps:

[0008] Step 1, preparing graphene oxide membrane by improved Hummers oxidation method; Step 2, preparing a permeation device; Step 3, conducting ion screening experiment by the permeation device; Step 4, sample measurement and result calculation.

[0009] The step 1 specifically comprises: preparing a graphene oxide nanosheet dispersion using graphite powder by an improved Hummers method, taking a PET nucleopore membrane as a substrate, and obtaining a graphene oxide membrane by vacuum filtration.

[0010] The structure of the graphene oxide membrane is: PET nuclear pore membrane-graphene oxide-PET nuclear pore membrane.

[0011] The graphene oxide membrane has ion screening and separation performance.

[0012] The graphite powder includes 100 mesh, 200 mesh and 325 mesh graphite raw materials.

[0013] The osmosis device is an H-type replaceable membrane osmosis pool, one side of the H-type replaceable membrane osmosis pool is a feed side, and the other side is a receiving side. The feed side and the receiving side are connected at the bottom, and a graphene oxide membrane is provided at the connection.

[0014] The feed side is a nitric acid aqueous solution containing metal ions to be separated; the receiving side is a nitric acid aqueous solution having the same acidity as that of the feed liquid area.

[0015] In the step 3, the mesh size and oxidation time of the graphene oxide raw material are changed to obtain graphene oxide films with different oxidation degrees, and an ion screening experiment is performed; the thickness of the graphene oxide film is changed to perform an ion screening experiment; the acidity of the feed solution is changed to perform an ion screening experiment; the concentration of uranyl ions in the feed solution is changed to perform an ion screening experiment; and the temperature of the feed solution is changed to perform an ion screening experiment.

[0016] The feed liquid is 30mL containing 1000mg / L UO2 2+ 、100mg / L Nb 5+ and 100 mg / L Zr 4+ 3mol / L HNO3 solution.

[0017] In step 4, after 48 hours of permeation, the ratio of the receiving side to the metal ion feed concentration is calculated as the permeability P, and the ratio of each ion distribution ratio is the separation ratio α.

[0018] Beneficial effects of the present invention:

[0019] 1) The present invention provides a method for screening and separating uranyl ions from a strong nitric acid aqueous phase containing uranium, niobium and zirconium. It does not require additional energy input (such as pressurization, electrolysis, etc.), and only relies on the chemical potential driving force to achieve efficient ion diffusion and separation at room temperature and pressure. While saving energy and simplifying equipment, it ensures the safety and controllability of radioactive waste liquid treatment;

[0020] 2) The method provided by the present invention for sieving and separating uranyl ions from a strong nitric acid aqueous phase containing uranium, niobium and zirconium has a simple structure, reduces costs and improves efficiency;

[0021] 3) The present invention provides a method for screening and separating uranyl ions from a strong nitric acid aqueous phase containing uranium, niobium and zirconium. The graphene oxide membrane used can tolerate a wide range of acidity, which greatly enhances the applicability of the method in the field of radioactive waste liquid separation and shows good application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the embodiments of the present invention, the following is a brief description of the drawings required to describe the embodiments of the present invention. Obviously, the drawings described below are only some embodiments recorded in the present invention. For those skilled in the art, other drawings can be obtained based on the following drawings without creative work.

[0023] Figure 1 It is a schematic diagram of the present invention's use of graphene oxide membrane to screen and separate uranium from uranium, niobium and zirconium in a strong nitric acid system.

[0024] Schematic diagram of separation of U from U-Nb-Zr system by graphene oxide membrane DETAILED DESCRIPTION

[0025] The following is a clear and complete description of the technical solutions in the embodiments of the present invention in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0026] In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inside", "outside" and the like are based on the orientations or positional relationships shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance.

[0027] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0028] The present invention provides a method for screening and separating uranyl ions from a strong nitric acid aqueous phase containing uranium, niobium and zirconium, comprising the following steps:

[0029] Step 1: Prepare graphene oxide film using improved Hummers oxidation method

[0030] Graphite powder is used to prepare a graphene oxide nanosheet dispersion by an improved Hummers method, and a PET nucleopore membrane is used as a substrate to obtain a graphene oxide membrane by vacuum filtration; the graphene oxide membrane has ion screening and separation performance;

[0031] The structure of the graphene oxide membrane is: a sandwich structure ion screening membrane of PET nuclear pore membrane-graphene oxide-PET nuclear pore membrane, which is sandwiched in the middle of the H-type cell to form a separation interface.

[0032] The graphite powder includes 100 mesh, 200 mesh and 325 mesh graphite raw materials;

[0033] Step 2: Prepare the infiltration device

[0034] The osmotic device is an H-type replaceable membrane osmotic tank, such as Figure 1 As shown, one side of the H-type replaceable membrane permeation pool is the feed side, and the other side is the receiving side. The feed side and the receiving side are connected at the bottom, and a graphene oxide membrane is provided at the connection. The graphene oxide membrane is first installed, and the permeation device is clamped, and then the feed solution containing mixed metal ions and the blank solution on the receiving side are added to the device in sequence, and stirring is started on both sides of the device at the same time.

[0035] The feed side is a nitric acid aqueous solution containing metal ions to be separated; the receiving side is a nitric acid aqueous solution having the same acidity as that of the feed liquid area.

[0036] Step 3: Conduct ion screening experiment using a permeation device

[0037] Step 301: Prepare a dispersion of graphene oxide nanosheets by using 200-mesh graphite powder through a modified Hummers method, obtain a graphene oxide membrane 200S1 by vacuum filtration, and separate the metal ions. The feed liquid is 30 mL containing 1000 mg / L UO2 2+ 、100mg / L Nb 5+ and 100mg / L Zr 4+ 3mol / LHNO3 solution was used to conduct ion screening experiments. A high acid solution containing mixed metal ions was used on the feed side; a high acid solution without metal ions was used on the receiving side. Under the action of the ion concentration gradient between the feed liquid area and the permeation area, the ions in the feed liquid area continuously diffused to the permeation area.

[0038] Step 302: By changing the mesh size of the graphene oxide raw material and the oxidation time, graphene oxide films with different oxidation degrees are obtained, which are recorded as 100S1, 100S2, 200S1, 200S2, 325S1, and 325S2, and the metal ions are separated. The feed liquid is 30mL containing 1000mg / L UO2 2+ 、100mg / L Nb 5+ and 100 mg / L Zr4+ 3 mol / L HNO3 solution was used for ion screening experiment.

[0039] Step 303, separate the metal ions by changing the thickness of the graphene oxide film. 2.5mL, 5.0mL and 7.0mL of 200S1 graphene oxide nanosheet dispersion were used to prepare graphene oxide films of different thicknesses, which were recorded as 200S1-2.5, 200S1-5.0 and 200S1-7.0, and the corresponding film masses were 1.2mg, 2.4mg and 3.4mg, respectively. The feed liquid was 30mL containing 1000mg / L UO2 2+ 、100mg / L Nb 5+ and 100 mg / L Zr 4+ 3 mol / L HNO3 solution was used for ion screening experiment.

[0040] Step 304: 30 mL of feed liquid containing 1000 mg / L UO2 2+ 、100mg / L Nb 5+ and 100 mg / L Zr 4+ The HNO3 solution was used to change the acidity of nitric acid to pH 3, pH 2, pH 1, 1mol / L, 2mol / L, 3mol / L, 4mol / L, 5mol / L, and 6mol / L, and the ion screening experiment was carried out.

[0041] Step 305: In 30 mL of the feed solution, the concentration of uranyl ions in the feed solution was changed to 1000, 1500, and 2000 mg / L, and the concentration of other ions was fixed at 100 mg / L Nb 5+ and 100mg / L Zr 4+ 3 mol / L HNO3 solution was used for ion screening experiment.

[0042] Step 306: 30 mL of feed liquid containing 1000 mg / L UO2 2+ 、100mg / L Nb 5+ and 100 mg / L Zr 4+ The ion screening experiment was carried out by changing the solution temperature to 25, 30, 35, 40, 50, and 60°C.

[0043] Step 4: Sample measurement and result calculation

[0044] The ratio of the receiving side (permeation zone) to the metal ion feed concentration calculated in step 301 is the permeability P, and the ratio of each ion distribution ratio is the separation ratio α. After 48 hours of permeation, the permeability and separation ratio of each ion are shown in Tables 1 and 2.

[0045] Table 1. 48 h permeability of each ion (%)

[0046]

[0047] Table 2. Separation ratios between various ions and uranium by graphene oxide membrane 200S1

[0048]

[0049] The ratio of the receiving side (permeation zone) to the metal ion feed concentration calculated in step 302 is the permeability P, and the ratio of each ion distribution ratio is the separation ratio α. After 48 hours of permeation, the permeability and separation ratio of each ion are shown in Tables 3 and 4.

[0050] Table 3. 48h permeability of various ions in graphene oxide membranes with different oxidation degrees (%)

[0051]

[0052] Table 4. Separation ratios between various ions and uranium by graphene oxide membranes with different oxidation degrees

[0053]

[0054]

[0055] The ratio of the receiving side (permeation zone) to the metal ion feed concentration calculated in step 303 is the permeability P, and the ratio of each ion distribution ratio is the separation ratio α. After 48 hours of permeation, the permeability and separation ratio of each ion are shown in Tables 5 and 6.

[0056] Table 5. 48h permeability of various ions in graphene oxide membranes of different thicknesses (%)

[0057]

[0058] Table 6. Separation ratios between various ions and uranium by graphene oxide membranes of different thicknesses

[0059]

[0060] The ratio of the receiving side (permeation zone) to the metal ion feed concentration is calculated as the permeability P, and the ratio of each ion distribution ratio is the separation ratio α. After 48 hours of permeation, the permeability and separation ratio of each ion are shown in Tables 7 and 8.

[0061] Table 7. Permeability of various ions in graphene oxide membrane under different acidity nitric acid conditions for 48h (%)

[0062]

[0063] Note: In a solution with a pH of 3, high concentrations of Nb 5+and Zr 4+ As the acidity of the solution continues to decrease, UO2 2+ precipitation.

[0064] Table 8. Separation ratios between various ions and uranium by graphene oxide membranes under different acidity conditions

[0065]

[0066]

[0067] The ratio of the receiving side (permeation zone) to the metal ion feed concentration is calculated as the permeability P, and the ratio of each ion distribution ratio is the separation ratio α. After 48 hours of permeation, the permeability and separation ratio of each ion are shown in Tables 9 and 10.

[0068] Table 9. Permeability of different concentrations of uranyl ions in graphene oxide membranes for 48 h (%)

[0069]

[0070] Table 10. Separation ratios between various ions and uranium under different uranyl ion concentrations using graphene oxide membranes

[0071]

[0072] The ratio of the receiving side (permeation zone) to the metal ion feed concentration is calculated as the permeability P, and the ratio of each ion distribution ratio is the separation ratio α. After 48 hours of permeation, the permeability and separation ratio of each ion are shown in Tables 11 and 12.

[0073] Table 11 Permeability of various ions in graphene oxide membrane at different temperatures for 48h (%)

[0074]

[0075]

[0076] Table 12. Separation ratios between various ions and uranium by graphene oxide membranes under different temperature conditions

[0077]

[0078] For those skilled in the art, although the present invention is not limited to the details of the exemplary embodiments described above, and the present invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the present invention. Therefore, from all points of view, the embodiments should be regarded as exemplary and non-limiting, and the scope of the present invention is limited by the appended claims rather than the above description, and it is intended that all changes falling within the meaning and scope of the equivalent elements of the claims are included in the present invention. Any reference numeral in a claim should not be regarded as limiting the claim involved.

[0079] In addition, it should be understood that although the present invention is described according to implementation modes, not every implementation mode includes only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

Claims

1. A method for separating uranyl ions from a strong nitric acid aqueous phase containing uranium, niobium and zirconium, characterized in that: The steps include: Step 1, preparing graphene oxide membrane by improved Hummers oxidation method; Step 2, preparing a permeation device; Step 3, conducting ion screening experiment by the permeation device; Step 4, sample measurement and result calculation.

2. The method for separating uranyl ions by screening from a strong nitric acid aqueous phase containing uranium, niobium and zirconium according to claim 1, characterized in that: The step 1 specifically comprises: preparing a graphene oxide nanosheet dispersion using graphite powder by an improved Hummers method, taking a PET nucleopore membrane as a substrate, and obtaining a graphene oxide membrane by vacuum filtration.

3. The method for separating uranyl ions by screening from a strong nitric acid aqueous phase containing uranium, niobium and zirconium according to claim 2, characterized in that: The structure of the graphene oxide membrane is: PET nuclear pore membrane-graphene oxide-PET nuclear pore membrane.

4. The method for separating uranyl ions by screening from a strong nitric acid aqueous phase containing uranium, niobium and zirconium according to claim 3, characterized in that: The graphene oxide membrane has ion screening and separation performance.

5. The method for separating uranyl ions by screening from a strong nitric acid aqueous phase containing uranium, niobium and zirconium according to claim 2, characterized in that: The graphite powder includes 100 mesh, 200 mesh and 325 mesh graphite raw materials.

6. The method for separating uranyl ions by screening from a strong nitric acid aqueous phase containing uranium, niobium and zirconium according to claim 1, characterized in that: The osmosis device is an H-type replaceable membrane osmosis pool, one side of the H-type replaceable membrane osmosis pool is a feed side, and the other side is a receiving side. The feed side and the receiving side are connected at the bottom, and a graphene oxide membrane is provided at the connection.

7. The method for separating uranyl ions by screening from a strong nitric acid aqueous phase containing uranium, niobium and zirconium according to claim 6, characterized in that: The feed side is a nitric acid aqueous solution containing metal ions to be separated; the receiving side is a nitric acid aqueous solution having the same acidity as that of the feed liquid area.

8. The method for separating uranyl ions by screening from a strong nitric acid aqueous phase containing uranium, niobium and zirconium according to claim 1, characterized in that: In the step 3, the mesh size and oxidation time of the graphene oxide raw material are changed to obtain graphene oxide films with different oxidation degrees, and an ion screening experiment is performed; the thickness of the graphene oxide film is changed to perform an ion screening experiment; the acidity of the feed solution is changed to perform an ion screening experiment; the concentration of uranyl ions in the feed solution is changed to perform an ion screening experiment; and the temperature of the feed solution is changed to perform an ion screening experiment.

9. The method for separating uranyl ions by screening from a strong nitric acid aqueous phase containing uranium, niobium and zirconium according to claim 8, characterized in that: The feed liquid is 30mL containing 1000mg / L UO2 2+ 、100mg / L Nb 5+ and 100 mg / L Zr 4+ 3mol / L HNO3 solution.

10. The method for separating uranyl ions from a strong nitric acid aqueous phase containing uranium, niobium and zirconium according to claim 1, characterized in that: In step 4, after 48 hours of permeation, the ratio of the receiving side to the metal ion feed concentration is calculated as the permeability P, and the ratio of each ion distribution ratio is the separation ratio α.

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