An experimental method for studying uranium migration in uranium-rich rocks in a reducing environment

Abstract

The present invention proposes an experimental method for studying the migration of uranium in uranium-rich rocks in a reducing environment, and belongs to the technical field of uranium source research in uranium mines. The present invention crushes the uranium-rich rock and mixes it with a sodium carbonate aqueous solution, places it in an autoclave, and puts the autoclave into an anaerobic incubator, opens the lid of the autoclave, evacuates the anaerobic incubator and fills it with nitrogen, covers the autoclave lid, then takes the autoclave out of the anaerobic incubator, heats or cools the autoclave to fully react after reaching the experimental temperature; places the autoclave to room temperature and then moves it to an anaerobic incubator, pours the sample into a polytetrafluoroethylene centrifuge tube in a nitrogen-filled environment, then takes out the polytetrafluoroethylene centrifuge tube, centrifuges, takes the supernatant, and extracts uranium; finally, detects the uranium content in the supernatant to determine the migration of uranium. This method is simple and efficient, confirms the possibility of the deep source of uranium sources in sandstone-type uranium deposits, and clarifies the migration of uranium in a reducing environment and its influencing factors.

Description

Technical Field

[0001] The invention belongs to the technical field of uranium source research in uranium ore, and in particular relates to an experimental method for studying uranium migration of uranium-rich rocks in a reducing environment. Background Art

[0002] The source of uranium materials in sandstone-type uranium deposits in sedimentary basins is mostly the erosion source area around the basin. The uranium materials migrate into the basin with oxygen-containing water, and are reduced, precipitated, and mineralized in the redox transition zone, forming typical interlayer oxidation zone sandstone-type uranium deposits. The latest research has found that uranium crystals, calcium carbonate, and oil and gas inclusions in the sandstone-type uranium ore clusters in the northern Ordos Basin have a symbiotic relationship, indicating that they were formed at the same time. The uniform temperature of the oil and gas inclusions is about 150°C, and it represents a reducing environment, indicating that the uranium source migrated from deep in a reducing environment with high-temperature hydrothermal fluids. This conclusion is inconsistent with the traditional view that uranium materials can only migrate in an oxidizing environment and precipitate in a reducing environment.

[0003] The existing technology uses a thermal simulation closed system experimental device - HAC-1034 continuous mechanical stirring autoclave to study the migration effect of the mixture of hydrocarbons and water produced by uranium-rich source rocks in the process of hydrocarbon generation under a reducing environment on the uranium element in the source rocks (see Figure 1 ), however, the experimental device has the following two disadvantages: 1) Before the reaction, nitrogen is introduced into the autoclave from one end, and air and nitrogen are removed from the other end, in the hope that the autoclave will eventually be a reducing environment filled with nitrogen and without air. However, this operation is not carried out in a closed system, and a large amount of air may remain or be injected; 2) After the reaction is completed, the sample is taken out and poured into a centrifuge tube for centrifugation. The sample is directly in contact with the air, and the oxygen in the air may have changed the distribution of uranium in the solution and the solid. The final test result may not be the actual experimental result. It can be seen that the device in the prior art does not completely realize the extraction of uranium from uranium-rich rocks in a reducing environment.

[0004] To this end, the present invention proposes an experimental method for studying uranium migration in uranium-rich rocks in a reducing environment. Summary of the invention

[0005] In order to solve the above technical problems, the present invention proposes an experimental method for studying uranium migration in uranium-rich rocks in a reducing environment.

[0006] To achieve the above object, the present invention provides the following technical solutions:

[0007] The present invention proposes an experimental method for studying uranium migration in uranium-rich rocks in a reducing environment, comprising the following steps:

[0008] The uranium-rich rock is crushed and mixed with a sodium carbonate solution, and then placed in an autoclave, and the autoclave is placed in an anaerobic incubator. The lid of the autoclave is opened, the anaerobic incubator is vacuumed and filled with nitrogen, and the lid of the autoclave is closed. Then, the autoclave is taken out of the anaerobic incubator, and the autoclave is heated or cooled to reach the experimental temperature for sufficient reaction; the autoclave is placed at room temperature and then moved to the anaerobic incubator, and the sample is poured into a polytetrafluoroethylene centrifuge tube in a nitrogen-filled environment, and then the polytetrafluoroethylene centrifuge tube is taken out, centrifuged, and the supernatant is taken to achieve uranium extraction; finally, the uranium content in the supernatant is detected to determine the migration of uranium.

[0009] Furthermore, the liquid-to-solid ratio of the sodium carbonate aqueous solution to the uranium-rich rock is (1-7):1 (mL:g).

[0010] Furthermore, the liquid-to-solid ratio of the sodium carbonate aqueous solution to the uranium-rich rock is 7:1 (mL:g).

[0011] Furthermore, the concentration of the sodium carbonate solution is 0-20% (mass concentration, the same below), and is not 0.

[0012] Furthermore, the concentration of the sodium carbonate solution is 10%.

[0013] In organic matter, even in a low pH and reducing environment, about 70% of uranium still presents a +6 oxidized state, existing in the form of minerals, adsorption or complexes, indicating that organic matter does not directly reduce uranium. Taking +6 uranium as an example, when carbonate ions exist in aqueous solution, it can be complexed with carbonate ions and then migrated. The principle is as follows:

[0014] UO 2 2+ +2CO 3 2- →UO 2 (CO 3 ) 2 2-

[0015] Furthermore, when the experimental temperature is 60-150°C, it is achieved through a heating box, that is, the autoclave is taken out of the anaerobic incubator and placed in a heating box to be heated to 60-150°C; when the experimental temperature is 4-60°C, it is achieved through a shaker, that is, the autoclave is taken out of the anaerobic incubator and placed on a shaker, and the shaker temperature is set to 4-60°C; the reaction time is 0.5h-15h.

[0016] Furthermore, the reaction temperature is 150° C. and the reaction time is 5 h.

[0017] Furthermore, the centrifugal speed is 9500 rpm and the time is 10 min.

[0018] Furthermore, an experimental method for studying uranium migration in uranium-rich rocks in a reducing environment specifically comprises the following steps:

[0019] ① Take 3g of uranium-enriched powder sample, 2.1g of sodium carbonate and 21mL of ultrapure water and put them into the autoclave liner;

[0020] ②Put the autoclave with the sample into the sampling chamber of the anaerobic incubator, evacuate and fill it with high-purity nitrogen several times, so that the sampling chamber of the anaerobic incubator is filled with high-purity nitrogen at one atmosphere pressure, open the door of the operating chamber of the anaerobic incubator with gloves, put the autoclave into the operating chamber of the anaerobic incubator, open the lid of the autoclave and the polytetrafluoroethylene liner (lined in the autoclave), let the solution expose the surface, evacuate the operating chamber 10 times, and fill it with high-purity nitrogen to ensure that the operating chamber of the anaerobic incubator is full of nitrogen and oxygen-free, cover the polytetrafluoroethylene liner and the lid of the autoclave, and take out the autoclave according to the operation;

[0021] ③Put part of the autoclave into the heating box, set the temperature to 60-150℃, take out the autoclave after heating for a certain period of time, and put the other part of the samples involving the temperature point below 60℃ (4℃-60℃) into the shaker;

[0022] ④ Place the autoclave to room temperature after the reaction;

[0023] ⑤ Place the autoclave and polytetrafluoroethylene centrifuge tube at room temperature into the sampling chamber of the anaerobic incubator, vacuum and fill with high-purity nitrogen several times, so that the sampling chamber of the anaerobic incubator is filled with high-purity nitrogen at one atmosphere, open the door of the operating room of the anaerobic incubator with gloves, place the autoclave and polytetrafluoroethylene centrifuge tube into the operating room of the anaerobic incubator, vacuum and fill with high-purity nitrogen 10 times, ensure that the operating room of the anaerobic incubator is full of nitrogen and oxygen-free, pour the sample in the autoclave into the polytetrafluoroethylene centrifuge tube, cover the cap of the polytetrafluoroethylene centrifuge tube, and take out the polytetrafluoroethylene centrifuge tube according to the operation;

[0024] ⑥ Place the polytetrafluoroethylene centrifuge tube in a centrifuge and centrifuge at 9500 rpm for 10 min;

[0025] ⑦ Take out the supernatant in the polytetrafluoroethylene centrifuge tube into a clean glass bottle and determine the uranium content of the supernatant.

[0026] Compared with the prior art, the present invention has the following advantages and technical effects:

[0027] The present invention uses an anaerobic incubator, an autoclave and a polytetrafluoroethylene centrifuge tube during operation, so that the autoclave and the polytetrafluoroethylene centrifuge tube are always kept in a reducing environment filled with high-purity nitrogen, thereby realizing the extraction of uranium from uranium-rich rocks in a reducing environment. The method is simple and efficient, confirms the possibility of the deep source of uranium sources in sandstone-type uranium deposits, and clarifies the migration of uranium in a reducing environment and its influencing factors. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] The drawings constituting a part of the present application are used to provide a further understanding of the present application. The illustrative embodiments and descriptions of the present application are used to explain the present application and do not constitute an improper limitation on the present application. In the drawings:

[0029] Figure 1 It is a schematic diagram of the extraction of uranium from uranium-rich hydrocarbon source rocks by a thermal simulation closed system experimental device in the prior art;

[0030] Figure 2 A flow chart of the present invention for extracting uranium from uranium-rich rocks in a reducing environment;

[0031] Figure 3 The results of the effect of heating time on the extraction rate of uranium from uranium-rich rocks in Example 1 are shown in Figure 1. The blue line represents a reducing environment, and the orange line represents an oxidizing environment.

[0032] Figure 4 The results of the change of heating temperature in Example 2 on the extraction rate of uranium in uranium-rich rock;

[0033] Figure 5 The results of the change of sodium carbonate concentration in Example 3 on the extraction rate of uranium in uranium-rich rock;

[0034] Figure 6 The results of the change in the liquid-to-solid ratio in Example 4 show the effect of the extraction rate of uranium in uranium-rich rock. DETAILED DESCRIPTION

[0035] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as limiting the present invention, but should be understood as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0036] It should be understood that the terms described in the present invention are only for describing special embodiments and are not intended to limit the present invention. In addition, for the numerical range in the present invention, it should be understood that each intermediate value between the upper and lower limits of the scope is also specifically disclosed. Each smaller range between the intermediate value in any stated value or stated range and any other stated value or intermediate value in the described range is also included in the present invention. The upper and lower limits of these smaller ranges can be independently included or excluded in the scope.

[0037] Unless otherwise indicated, all technical and scientific terms used herein have the same meanings as those generally understood by those skilled in the art. Although the present invention describes only preferred methods and materials, any methods and materials similar or equivalent to those described herein may also be used in the implementation or testing of the present invention. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and / or materials associated with the documents. In the event of a conflict with any incorporated document, the content of this specification shall prevail.

[0038] It will be apparent to those skilled in the art that various modifications and variations may be made to the specific embodiments of the present invention description without departing from the scope or spirit of the present invention. Other embodiments derived from the present invention description will be apparent to those skilled in the art. The present invention description and examples are exemplary only.

[0039] The words “include,” “including,” “have,” “contain,” etc. used in this document are open-ended terms, meaning including but not limited to.

[0040] The embodiment of the present invention provides an experimental method for studying uranium migration in uranium-rich rocks in a reducing environment, comprising the following steps:

[0041] The uranium-rich rock is crushed and mixed with a sodium carbonate solution, and then placed in an autoclave, and the autoclave is placed in an anaerobic incubator. The lid of the autoclave is opened, the anaerobic incubator is vacuumed and filled with nitrogen, and the lid of the autoclave is closed. Then, the autoclave is taken out of the anaerobic incubator, and the autoclave is heated or cooled to reach the experimental temperature for sufficient reaction; the autoclave is placed at room temperature and then moved to the anaerobic incubator, and the sample is poured into a polytetrafluoroethylene centrifuge tube in a nitrogen-filled environment, and then the polytetrafluoroethylene centrifuge tube is taken out, centrifuged, and the supernatant is taken to achieve uranium extraction; finally, the uranium content in the supernatant is detected to determine the migration of uranium.

[0042] The present invention uses an anaerobic incubator, an autoclave and a polytetrafluoroethylene centrifuge tube during operation, so that the autoclave and the polytetrafluoroethylene centrifuge tube are always kept in a reducing environment filled with high-purity nitrogen, thereby realizing the extraction of uranium from uranium-rich rocks in a reducing environment.

[0043] In some embodiments of the present invention, the liquid-to-solid ratio of the sodium carbonate aqueous solution to the uranium-rich rock is (1-7):1 (mL:g).

[0044] In a preferred embodiment of the present invention, the liquid-to-solid ratio of the sodium carbonate aqueous solution to the uranium-rich rock is 7:1 (mL:g).

[0045] In a preferred embodiment of the present invention, the concentration of the sodium carbonate solution is 0-20% (mass concentration), and is not zero.

[0046] In organic matter, even in a low pH and reducing environment, about 70% of uranium still presents a +6 oxidized state, existing in the form of minerals, adsorption or complexes, indicating that organic matter does not directly reduce uranium. Taking +6 uranium as an example, when carbonate ions exist in aqueous solution, it can be complexed with carbonate ions and then migrated. The principle is as follows:

[0047] UO 2 2+ +2CO 3 2- →UO 2 (CO 3 ) 2 2-

[0048] When the experimental temperature is 60-150°C, it is achieved through a heating box, that is, the autoclave is taken out of the anaerobic incubator and placed in a heating box to be heated to 60-150°C; when the experimental temperature is 4-60°C, it is achieved through a shaker, that is, the autoclave is taken out of the anaerobic incubator and placed on a shaker, and the shaker temperature is set to 4-60°C; the reaction time is 0.5h-15h.

[0049] In a preferred embodiment of the present invention, the centrifugal speed is 9500 rpm and the time is 10 min.

[0050] In a preferred embodiment of the present invention, an experimental method for studying uranium migration in a uranium-rich rock in a reducing environment specifically comprises the following steps, as shown in the flow chart: Figure 2 :

[0051] ① Take 3g of uranium-enriched powder sample, 2.1g of sodium carbonate and 21mL of ultrapure water and put them into the autoclave liner;

[0052] ②Put the autoclave with the sample into the sampling chamber of the anaerobic incubator, evacuate and fill it with high-purity nitrogen several times, so that the sampling chamber of the anaerobic incubator is filled with high-purity nitrogen at one atmosphere pressure, open the door of the operating chamber of the anaerobic incubator with gloves, put the autoclave into the operating chamber of the anaerobic incubator, open the lid of the autoclave and the polytetrafluoroethylene liner, let the solution be exposed on the surface, evacuate and fill it with high-purity nitrogen 10 times, ensure that the operating chamber of the anaerobic incubator is full of nitrogen and oxygen-free, cover the polytetrafluoroethylene liner and the autoclave lid, and take out the autoclave according to the operation;

[0053] ③Put part of the autoclave into the heating box, set the temperature to 60-150℃, take out the autoclave after heating for a certain period of time, and put the other part of the samples involving the temperature point below 60℃ (4℃-60℃) into the shaker;

[0054] ④ Place the autoclave to room temperature after the reaction;

[0055] ⑤ Place the autoclave and polytetrafluoroethylene centrifuge tube at room temperature into the sampling chamber of the anaerobic incubator, vacuum and fill with high-purity nitrogen several times, so that the sampling chamber of the anaerobic incubator is filled with high-purity nitrogen at one atmosphere, open the door of the operating room of the anaerobic incubator with gloves, place the autoclave and polytetrafluoroethylene centrifuge tube into the operating room of the anaerobic incubator, vacuum and fill with high-purity nitrogen 10 times, ensure that the operating room of the anaerobic incubator is full of nitrogen and oxygen-free, pour the sample in the autoclave into the polytetrafluoroethylene centrifuge tube, cover the cap of the polytetrafluoroethylene centrifuge tube, and take out the polytetrafluoroethylene centrifuge tube according to the operation;

[0056] ⑥ Place the polytetrafluoroethylene centrifuge tube in a centrifuge and centrifuge at 9500 rpm for 10 min;

[0057] ⑦ Take out the supernatant in the polytetrafluoroethylene centrifuge tube into a clean glass bottle and determine the uranium content of the supernatant.

[0058] The embodiment of the present invention uses an oxygen content detector (Xima AS8900) to detect the oxygen content in the anaerobic incubator operating room, and the content is lower than the detection limit of 0.1%, ensuring the reducing environment in the autoclave and the polytetrafluoroethylene centrifuge tube.

[0059] The uranium-enriched samples used in the embodiments of the present invention are two sandstone-type mudstone samples (sample No. 35 and sample No. 93), and the basic parameters of uranium valence and content are shown in Table 1.

[0060] Table 1 Basic parameters of uranium valence and content in two uranium-rich mudstone samples used in the examples

[0061] Sample No. Hexavalent uranium content μg / g (percentage) Quaternary uranium content μg / g (percentage) 35 368(75％) 121(25％) 93 446(67％) 213(33％)

[0062] The uranium-enriched sample is crushed by a sample crusher to a particle size of ≤200 mesh.

[0063] The technical solution of the present invention is further illustrated by the following embodiments.

[0064] Example 1 (Study on the Variation of Uranium Extraction Rate in Uranium-Rich Rock (Sample No. 93) over Time)

[0065] An experimental method for studying uranium migration in uranium-rich rocks in a reducing environment comprises the following steps:

[0066] Take 3g of uranium-enriched powder sample (obtained by grinding uranium-enriched rock to 200 mesh), 2.1g of sodium carbonate and 21mL of ultrapure water into the liner of an autoclave (sodium carbonate concentration 10%, liquid-to-solid ratio 7:1), and put them into the autoclave (prepare 11 sets of samples);

[0067] Place the autoclave containing the sample into the sampling chamber of the anaerobic incubator, evacuate and fill with high-purity nitrogen several times, so that the sampling chamber of the anaerobic incubator is filled with high-purity nitrogen at one atmosphere pressure, open the door of the operating chamber of the anaerobic incubator through gloves, place the autoclave into the operating chamber of the anaerobic incubator, open the lid of the autoclave and the polytetrafluoroethylene liner, let the solution be exposed on the surface, evacuate and fill with high-purity nitrogen for 10 times, ensure that the operating chamber of the anaerobic incubator is full of nitrogen and is an oxygen-free environment, cover the polytetrafluoroethylene liner and the autoclave lid, and take out the autoclave according to the operation;

[0068] Place the autoclave in a heating box, set the temperature to 150°C, heat for 0.5 h, 1 h, 1.5 h, 2 h, 3 h, 4 h, 5 h, 7.5 h, 10 h, 12 h and 15 h, respectively, and take out the autoclave;

[0069] Let the autoclave stand at room temperature;

[0070] Place the autoclave and polytetrafluoroethylene centrifuge tube at room temperature into the sampling chamber of the anaerobic incubator, evacuate and fill with high-purity nitrogen several times, so that the sampling chamber of the anaerobic incubator is filled with high-purity nitrogen at one atmosphere pressure, open the door of the operating chamber of the anaerobic incubator with gloves, place the polytetrafluoroethylene centrifuge tube into the operating chamber of the anaerobic incubator, open the lid of the polytetrafluoroethylene centrifuge tube, let the solution be exposed on the surface, evacuate and fill with high-purity nitrogen for 10 times, ensure that the operating chamber of the anaerobic incubator is full of nitrogen and is an oxygen-free environment, cover the lid of the polytetrafluoroethylene centrifuge tube, and take out the polytetrafluoroethylene centrifuge tube according to the operation;

[0071] Place the polytetrafluoroethylene centrifuge tube in a centrifuge and centrifuge at 9500 rpm for 10 min;

[0072] The supernatant in the polytetrafluoroethylene centrifuge tube was taken out into a clean glass bottle, and the uranium content of the 11 groups of supernatants was determined.

[0073] In addition, the experimental method under an oxidative environment was used for comparison, i.e., the use of an anaerobic incubator was omitted and the samples were processed directly in the air.

[0074] The variation of uranium extraction rate with time in uranium-rich rock (sample 93) is shown in Figure 3 (The dotted line represents the content of +6 uranium, the same below), Figure 3It can be seen that even in a reducing environment, uranium is easier to extract at a temperature of 150°C than at 40°C in an oxidizing environment, which shows that heating is beneficial to the extraction of uranium. For uranium from deep sources, as long as the hydrothermal fluid contains carbonate ions and the temperature is high, uranium can be extracted, which also confirms the possibility of deep sources of uranium materials in a reducing environment. Whether in an oxidizing environment or a reducing environment, the uranium extraction rate gradually increases with time, and basically reaches a stable state after 4 hours. In a reducing environment, the extraction is basically complete after a reaction time of 3 hours.

[0075] Example 2 (Study on the variation of uranium extraction rate of uranium-rich rock (sample No. 35) under reducing environment with temperature)

[0076] On the basis of Example 1, the uranium-enriched powder sample was changed to sample No. 35, and the liquid-to-solid ratio was fixed at 7:1, the sodium carbonate concentration was 10%, the reduction time was 3 h, and the reaction temperature was changed to 0°C, 25°C, 50°C, 75°C, 85°C, 100°C, 110°C, and 125°C, respectively.

[0077] The variation of uranium extraction rate with temperature in uranium-rich rock (sample 35) is shown in Figure 4 ,Depend on Figure 4 It can be seen that as the temperature decreases, the uranium extraction rate decreases.

[0078] Example 3 (Study on the variation of uranium extraction rate of uranium-rich rock (sample No. 93) under reducing environment with sodium carbonate concentration)

[0079] Based on Example 1, the reaction temperature was fixed at 150°C, the sodium carbonate concentration was 10%, the reduction reaction time was 5h, and the sodium carbonate concentration was changed to 0%, 0.24%, 0.48%, 2.5%, 5%, 7.5%, 10%, 12.5%, 15%, and 20%.

[0080] The extraction rate of uranium from uranium-rich rock (sample 93) varies with the concentration of sodium carbonate. Figure 5 ,Depend on Figure 5 It can be seen that under a 150°C reducing environment, as the concentration of carbonate ions increases, the extraction rate of uranium in uranium-rich rocks gradually increases, and when the concentration is 0%, almost no uranium is extracted, indicating that the presence of carbonate ions (or other ions that can be complexed with it) in aqueous solution is a prerequisite for uranium migration. Therefore, the major premise for the extraction and migration of uranium in uranium-rich rocks in the erosion source area is that the surface runoff water contains carbonate ions, which means that the atmospheric carbon dioxide content must be very high. This research result breaks the conventional conclusion that oxygen-containing water can extract uranium. This conclusion improves the migration mechanism of uranium in the erosion source area under the surface environment.

[0081] Example 4 (Study on the Variation of Uranium Extraction Rate in Uranium-Rich Rock (Sample No. 93) with Liquid-Solid Ratio)

[0082] On the basis of Example 1, the reaction temperature was fixed at 150° C., the reaction time was 5 h, the sodium carbonate concentration was 10%, and the liquid-solid ratio was changed to 1:1, 3:1, 5:1, and 7:1 respectively.

[0083] The extraction rate of uranium from uranium-rich rock (sample 93) varies with the liquid-solid ratio. Figure 6 ,Depend on Figure 6 It can be seen that as the liquid-to-solid ratio decreases, the uranium extraction rate decreases.

[0084] It can be seen from Examples 1-4 that reducing, high-temperature deep hydrothermal fluids can extract uranium from uranium-rich rocks and migrate them. As uranium migrates from deep to shallow, the temperature decreases, the carbonate ion concentration decreases due to precipitation, and the liquid-solid ratio decreases, all of which lead to a decrease in the ability of the hydrothermal fluid to extract uranium, causing uranium to precipitate and precipitate into minerals. The carbonate ions therein combine with calcium ions to form calcium carbonate, ultimately forming a phenomenon in which uranium ore and calcium carbonate crystals coexist with oil and gas inclusions.

[0085] Comparative Example 1

[0086] The method is the same as that of Example 1, except that the mass of the sodium carbonate solution is replaced by pure water, and uranium is extracted under a reducing / oxidizing environment. The extraction results are shown in Table 2.

[0087] Table 2 Extraction of uranium from uranium-rich rocks by pure water

[0088]

[0089] As can be seen from Table 2, when there are no carbonate ions in the solution, most of the +6 uranium will not migrate with oxygen-containing water even in an oxidizing environment, and only 5.7% of the water-soluble uranium will migrate with water, proving that the presence of carbonate ions is a prerequisite for uranium extraction and migration. The major premise for the extraction and migration of uranium in uranium-rich rocks in the erosion source area is that the surface runoff water contains carbonate ions, which means that the atmospheric carbon dioxide content must be very high. This research result breaks the conventional conclusion that oxygen-containing water can extract uranium. In addition, in a reducing environment, only 1.2% of the uranium migrates with water. The ability of aqueous solutions to extract uranium from uranium-rich rocks in reducing and oxidizing environments is quite different, indicating that the use of anaerobic incubators can ensure the degree of redox in the system. In addition, a slight change in the variables can change the final uranium extraction rate. The above can all show that this experimental process can be used to study the extraction of uranium from uranium-rich rocks by solutions under a reducing environment.

[0090] In summary, the method of the present invention shows that reduced, high-temperature deep hydrothermal fluids can extract uranium from uranium-rich rocks and migrate. As uranium migrates from deep to shallow, the temperature decreases, the concentration of carbonate ions decreases due to precipitation, and the liquid-solid ratio decreases, all of which will lead to a decrease in uranium solubility and precipitation of minerals. At the same time, it is confirmed that the existence of carbonate ions is a prerequisite for uranium extraction and migration. The major prerequisite for the extraction and migration of uranium from uranium-rich rocks in the erosion source area is that the surface runoff water contains carbonate ions, which means that the atmospheric carbon dioxide content must be very high. This research result of the present invention breaks the conventional conclusion that oxygen-containing water can extract uranium.

[0091] The above are only preferred specific implementations of the present application, but the protection scope of the present application is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed in the present application should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.

Claims

1. An experimental method for studying uranium migration in uranium-rich rocks in a reducing environment, characterized in that: The following steps are involved: The uranium-rich rock is crushed and mixed with a sodium carbonate aqueous solution, and then placed in an autoclave, and the autoclave is placed in an anaerobic incubator. The lid of the autoclave is opened, the anaerobic incubator is vacuumed and filled with nitrogen, and the lid of the autoclave is closed. Then, the autoclave is taken out of the anaerobic incubator, and the autoclave is heated or cooled to reach the experimental temperature for sufficient reaction; the autoclave is placed at room temperature and then moved to the anaerobic incubator, and the sample is poured into a polytetrafluoroethylene centrifuge tube in a nitrogen-filled environment, and then the polytetrafluoroethylene centrifuge tube is taken out, centrifuged, and the supernatant is taken to achieve uranium extraction; finally, the uranium content in the supernatant is detected to determine the migration of uranium.

2. The experimental method for studying uranium migration in uranium-rich rocks in a reducing environment according to claim 1, characterized in that: The liquid-to-solid ratio of the sodium carbonate aqueous solution to the uranium-rich rock is (1-7):1 (mL:g).

3. The experimental method for studying uranium migration in uranium-rich rocks in a reducing environment according to claim 2, characterized in that: The liquid-to-solid ratio of the sodium carbonate aqueous solution to the uranium-rich rock is 7:1 (mL:g).

4. The experimental method for studying uranium migration in uranium-rich rocks in a reducing environment according to claim 1, characterized in that: The concentration of the sodium carbonate aqueous solution is 0-20%, and is not 0.

5. The experimental method for studying uranium migration in uranium-rich rocks in a reducing environment according to claim 4, characterized in that: The concentration of the sodium carbonate aqueous solution is 10%.

6. The experimental method for studying uranium migration in uranium-rich rocks in a reducing environment according to claim 1, characterized in that: The experimental temperature is 4°C-150°C, and the time for full reaction after reaching the experimental temperature is 0.5h-15h.

7. The experimental method for studying uranium migration in uranium-rich rocks in a reducing environment according to claim 6, characterized in that: The experimental temperature is 150° C., and the time for full reaction after reaching the experimental temperature is 5 hours.

8. The experimental method for studying uranium migration in uranium-rich rocks in a reducing environment according to claim 1, characterized in that: The centrifugal speed is 9500 rpm and the time is 10 min.

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