Uranyl fluoride and preparation method thereof

Abstract

The invention relates to the technical field of uranium compound metallurgy, in particular to uranyl fluoride and a preparation method thereof. The method comprises the following steps: providing uranium tetrafluoride; uranium tetrafluoride is calcined in an oxygen-containing atmosphere, so that uranyl fluoride is obtained, and the oxygen-containing atmosphere comprises oxygen and ozone. According to the method, one-step direct conversion is achieved, operation is easy, control is easy, automatic and continuous production is achieved, and high-purity uranyl fluoride can be obtained.

Description

Technical Field

[0001] This application relates to the field of uranium compound metallurgy technology, and in particular to a uranyl fluoride and its preparation method. Background Technology

[0002] Uranyl fluoride (UO2F2) is an important uranium compound with wide applications in the nuclear industry. It is a key intermediate in the uranium enrichment process to produce uranium hexafluoride (UF6), and is also a common form used in spent fuel reprocessing and uranium purification and conversion. The stable preparation of high-quality UO2F2 is crucial for ensuring the efficiency and safety of the nuclear fuel cycle.

[0003] Currently, the preparation of uranyl fluoride still faces problems such as complex process conditions and harmful byproducts, resulting in low conversion rates of the obtained uranyl fluoride.

[0004] It should be noted that the above content is not necessarily prior art, nor is it intended to limit the scope of patent protection of this application. Summary of the Invention

[0005] This application provides a uranyl fluoride and a method for preparing the same, in order to solve or alleviate one or more of the technical problems mentioned above.

[0006] A first aspect of this application provides a method for preparing uranyl fluoride, comprising the following steps: Provide uranium tetrafluoride; Uranium tetrafluoride was calcined in an oxygen-containing atmosphere to obtain uranyl fluoride. The oxygen-containing atmosphere includes oxygen and ozone.

[0007] The method in this application uses a mixture of oxygen and ozone (O2 / O3) as an advanced oxidant, which can significantly reduce the temperature of the reaction system and achieve efficient and highly selective conversion of UF4 to UO2F2, thereby obtaining uranyl fluoride (UO2F2) with high purity. Specifically, uranium tetrafluoride is calcined to form uranyl fluoride in a mixed gas atmosphere of oxygen and ozone. Ozone provides a new reaction pathway with lower activation energy for the formation of uranyl fluoride from uranium tetrafluoride, thus significantly reducing the reaction temperature. During the formation of uranyl fluoride, almost no UF6 is generated, thereby reducing the amount of harmful byproducts and simplifying the tail gas treatment of this method. The near absence of UF6 formation during the formation of uranyl fluoride reduces the volatilization loss of UF6, thereby increasing the conversion rate of uranium tetrafluoride to uranyl fluoride, resulting in a higher conversion rate of the obtained uranyl fluoride. The entire reaction process is a gas-solid phase dry process, without introducing any water or other impurity ions. The resulting UO2F2 product has high purity and requires no subsequent complex purification steps. Furthermore, this method is a one-step direct conversion, simple to operate, easy to control, and can be automated and continuously produced, thus resulting in high production efficiency.

[0008] According to an embodiment of this application, in the oxygen-containing atmosphere, the volume of ozone accounts for 5%-15% of the total volume of the oxygen-containing atmosphere.

[0009] According to an embodiment of this application, the calcination treatment of uranium tetrafluoride includes: Uranium tetrafluoride is formed into a layer, the thickness of which is denoted as H mm. The flow rate of the mixed gas formed by oxygen and ozone is denoted as Q mL / min. The relationship between H and Q is as follows: .

[0010] According to an embodiment of this application, the flow rate Q of the mixed gas is 50~200 mL / min.

[0011] According to embodiments of this application, the method for forming the mixed gas includes: Oxygen is used as the gas source, which is obtained through an ozone generator.

[0012] According to an embodiment of this application, the calcination includes a heating stage and a holding stage, wherein the heating rate of the heating stage is 1~10℃ / min; and the temperature of the holding stage is 200~400℃.

[0013] According to an embodiment of this application, the calcination holding time is 2-6 hours.

[0014] According to embodiments of this application, the method further includes a cooling stage. The cooling phase includes a first cooling phase and a second cooling phase. The first cooling stage is carried out in an oxygen-containing atmosphere, and the second cooling stage is carried out in a pure oxygen atmosphere.

[0015] According to an embodiment of this application, the starting temperature of the second cooling stage is 90~120°C.

[0016] A second aspect of the embodiments of this application provides a uranyl fluoride prepared by the method of the first aspect of this application. Attached Figure Description

[0017] In the accompanying drawings, unless otherwise specified, the same reference numerals throughout the various drawings denote the same or similar parts or elements. These drawings are not necessarily drawn to scale. It should be understood that these drawings depict only some embodiments disclosed in this application and should not be construed as limiting the scope of this application.

[0018] Figure 1 This is a flowchart illustrating the preparation process of uranyl fluoride provided in the embodiments of this application. Detailed Implementation

[0019] The embodiments of this application are described in detail below, examples of which are illustrated in the accompanying drawings. In the drawings, for clarity, the dimensions of layers, regions, and elements, as well as their relative dimensions, may be exaggerated. Throughout, the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this application, and should not be construed as limiting this application. It should be noted that, unless otherwise specified, the embodiments and features in the embodiments of this application can be combined with each other.

[0020] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such terms can be used interchangeably where appropriate so that the embodiments of this application described herein can be implemented, for example, in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0021] In this application, when numerical intervals (i.e., numerical ranges) are involved, unless otherwise specified, the distribution of selectable numerical values ​​within the numerical interval is considered continuous, and includes the two endpoints of the numerical interval (i.e., the minimum and maximum values), as well as every numerical value between these two endpoints. Unless otherwise specified, when a numerical interval refers only to integers within that numerical interval, it includes the two endpoint integers of the numerical range, as well as every integer between the two endpoints, which is equivalent to directly listing every integer. When multiple numerical ranges are provided to describe features or characteristics, these numerical ranges can be merged. In other words, unless otherwise specified, the numerical ranges disclosed in this application should be understood to include any and all subranges included therein. The "numerical value" in the numerical interval can be any quantitative value, such as a number, percentage, ratio, etc. The term "numerical interval" can be broadly included to include percentage intervals, ratio intervals, proportion intervals, etc.

[0022] Currently, the high-temperature peroxidation method is commonly used: UF4 is oxidized to higher-valence oxides of uranium (such as U3O8) in the presence of excess oxygen, and then fluorinated to UO2F2 using hydrogen fluoride (HF) gas. This process involves multiple steps, a long process flow, complex equipment, extremely high energy consumption, and stringent requirements for equipment corrosion resistance. Typical reaction temperatures are usually above 800℃. Alternatively, an aqueous solution conversion method can be used: UF4 is first dissolved in a strong oxidizing acid (such as nitric acid, hydrogen peroxide, etc.) to generate uranyl ions (UO2²). + The process involves reacting fluoride ions with fluoride ions to crystallize UO2F2. While this method operates at lower temperatures, it introduces significant amounts of moisture and impurity ions, requiring complex purification, crystallization, and drying steps. This results in a cumbersome process, heavy wastewater treatment burden, and difficulty in guaranteeing product purity. Furthermore, these methods suffer from several drawbacks: high reaction temperatures (traditional solid-phase oxidation requires 800℃ or higher, leading to high energy consumption and demanding reactor materials); low and unstable yields (limitations of reversible reaction equilibrium and the volatilization of UF6 mean the theoretical yield of UO2F2 rarely exceeds 70%, often falling even lower in practice); significant byproduct hazards (UF6 is highly toxic, corrosive, and radioactive, posing a major challenge to sealing and exhaust gas treatment systems, increasing operational risks and environmental costs); and complex processes (both high-temperature peroxidation-refluorination routes and aqueous solutions involve multiple steps and control points, making stable continuous production difficult to achieve).

[0023] Accordingly, a first aspect of the embodiments of this application provides a method for preparing uranyl fluoride. (See reference...) Figure 1 The preparation method includes the following steps: S100: Provides uranium tetrafluoride; S200: Uranium tetrafluoride is calcined in an oxygen-containing atmosphere to obtain uranyl fluoride, wherein the oxygen-containing atmosphere includes oxygen and ozone.

[0024] The method in this application uses a mixture of oxygen and ozone (O2 / O3) as an advanced oxidant, which can significantly reduce the temperature of the reaction system and achieve efficient and highly selective conversion of UF4 to UO2F2, thereby obtaining uranyl fluoride (UO2F2) with high purity. Specifically, uranium tetrafluoride is calcined to form uranyl fluoride in a mixed gas atmosphere of oxygen and ozone. Ozone provides a new reaction pathway with lower activation energy for the formation of uranyl fluoride from uranium tetrafluoride, thus significantly reducing the reaction temperature. During the formation of uranyl fluoride, almost no UF6 is generated, thereby reducing the amount of harmful byproducts and simplifying the tail gas treatment of this method. The near absence of UF6 formation during the formation of uranyl fluoride reduces the volatilization loss of UF6, thereby increasing the conversion rate of uranium tetrafluoride to uranyl fluoride, resulting in a higher conversion rate of the obtained uranyl fluoride. The entire reaction process is a gas-solid phase dry process, without introducing any water or other impurity ions. The resulting UO2F2 product has high purity and requires no subsequent complex purification steps. Furthermore, this method is a one-step direct conversion, simple to operate, easy to control, and can be automated and continuously produced, thus resulting in high production efficiency.

[0025] In some embodiments, uranium tetrafluoride is a dry powder with a particle size range of 50-500 nm. This results in uniform uranium tetrafluoride particles within this particle size range, which is beneficial for the reaction.

[0026] In some embodiments, uranium tetrafluoride is calcined in an oxygen-containing atmosphere to obtain uranyl fluoride, wherein the oxygen-containing atmosphere includes oxygen and ozone. In this process, oxygen (O2) not only acts as a diluent and a carrier of ozone, promoting a safe and stable reaction, but also participates in the oxidation reaction and synergistically works with the reactive oxygen species generated by ozone decomposition to maintain the stable oxidizing properties of the reaction atmosphere. Ozone is an extremely strong oxidant, with a standard redox potential higher than that of oxygen. Under heating conditions, ozone molecules can more effectively provide reactive oxygen atoms, disrupting the crystal structure of UF4 and initiating the oxidation reaction, thereby breaking the thermodynamic equilibrium limitations of the traditional O2 / UF4 reaction system. The intervention of ozone provides a new reaction pathway with a lower activation energy. It allows the oxidation of UF4 to proceed without exceeding the high energy barrier required by the traditional high-temperature pathway, thus enabling the reaction to occur at low temperatures. Furthermore, this process inhibits the formation of UF6 because ozone preferentially reacts with UF4 to produce UO2F2 and fluorine (F2). The generated F2 then rapidly reacts with excess ozone or oxygen in the system to produce intermediates such as oxygen difluoride (OF2), which eventually return to the reaction system. This pathway produces no UF6 at all. Even if a small amount of UF6 is generated, the highly oxidizing ozone environment may further oxidize it back to UO2F2 and F2. Therefore, the generation of harmful UF6 byproducts is reduced. The main reaction equation is: UF4+ O3→ UO2F2+ F2(1) F2 + O3 → F2O + O2(2) Overall reaction: UF4 + O3 → UO2F2 + 1 / 2 O2 (3) Optionally, in an oxygen-containing atmosphere, the volume of ozone accounts for 5%-15% of the total volume of the oxygen-containing atmosphere, for example, 5%, 7%, 9%, 10%, 12%, 15%, etc. Thus, when the contents of ozone and oxygen are within the aforementioned ranges, oxygen participates in the oxidation reaction and synergistically works with the reactive oxygen species produced by the decomposition of ozone to maintain the stable oxidizing properties of the reaction atmosphere.

[0027] Furthermore, preferably, in the oxygen-containing atmosphere, the volume of ozone accounts for 8%-12% of the total volume of the oxygen-containing atmosphere.

[0028] As a specific example, in an oxygen-containing atmosphere, the volume of ozone accounts for 10% of the total volume of the oxygen-containing atmosphere.

[0029] In some embodiments, the gas flow rate of the mixed gas should maintain the reactant bed in a slightly fluidized state or in a state of sufficient dynamic atmosphere exchange to promote effective contact between the reactants and the gas. The calcination treatment of uranium tetrafluoride includes forming a uranium tetrafluoride bed, the thickness of which is denoted as H mm, and the flow rate of the mixed gas formed by oxygen and ozone is denoted as Q mL / min. The relationship between H and Q is as follows: Maintaining the above-mentioned proportional relationship between the flow rate Q of the mixed gas and the bed thickness H is crucial. If Q < 10H, the diffusion dynamics of the gas within the bed are insufficient, resulting in an excessively low ozone concentration in contact with the bottom UF4, leading to incomplete reaction or requiring a significantly extended reaction time. If Q > 40H, the excessively high flow rate will cause powdered uranium tetrafluoride to become airborne or channel, disrupting the homogeneity of the bed and resulting in ineffective waste of ozone. Within the above range, ozone molecules can be ensured to fully penetrate to the bottom of the bed while maintaining a stable gas-solid interface.

[0030] Optionally, during the calcination process, the flow rate Q of the mixed gas formed by oxygen and ozone is 50~200 mL / min, for example, 50 mL / min, 80 mL / min, 100 mL / min, 120 mL / min, 150 mL / min, etc.

[0031] Optionally, H can be set according to the actual situation. For example, it can be 5mm, 10mm, etc.

[0032] In some embodiments, the addition of ozone significantly reduces the reaction temperature; this also reduces energy consumption and lowers the requirements for the reaction equipment. In some alternative examples, the reactor can be made of more economical materials, such as 316L stainless steel or Monel alloy.

[0033] Optionally, the calcination includes a heating stage and a holding stage, with the holding temperature ranging from 200 to 400°C. For example, 200°C, 300°C, 400°C, etc.

[0034] In some embodiments, the heating rate during the heating stage is 1~10℃ / min, such as 1℃ / min, 5℃ / min, 8℃ / min, 10℃ / min, etc. If the heating rate is too high (e.g., greater than 10℃ / min), local heat accumulation in the reaction system will be too rapid, potentially leading to further decomposition or sintering of some UO2F2; if the heating rate is too low (e.g., less than 1℃ / min), the production cycle will be too long, and prolonged exposure to low temperatures will hinder the effective utilization of ozone activation energy.

[0035] It is understandable that during the calcination process, the temperature rises from room temperature to the calcination temperature.

[0036] In some embodiments, the holding time during the calcination process is 2 to 6 hours, such as 2 hours, 3 hours, 4 hours, 5 hours, 6 hours, etc. Thus, if the holding time is too short, the conversion rate will be insufficient, and UF4 will remain in the product; if the holding time is too long, it will not help to further improve the conversion rate, but will instead increase energy consumption and may lead to coarsening of the product grains.

[0037] In some embodiments, the method further includes a cooling stage, wherein the cooling stage comprises a first cooling stage and a second cooling stage, the first cooling stage being carried out in an oxygen-containing atmosphere and the second cooling stage being carried out in a pure oxygen atmosphere. Thus, the first cooling stage being carried out in an oxygen-containing atmosphere helps maintain a strong oxidizing environment within the reaction system, allowing the residual uranium tetrafluoride to continue reacting completely during the cooling process, thereby maximizing the conversion rate and purity of uranyl fluoride; the second cooling stage being carried out in a pure oxygen atmosphere helps to minimize the hygroscopicity of the obtained uranyl fluoride.

[0038] Furthermore, the starting temperature of the second cooling stage is 90~120℃, such as 90℃, 100℃, 110℃, 120℃, etc.

[0039] Understandably, the second cooling stage is stopped at room temperature, which facilitates the extraction of uranyl fluoride. At the same time, the oxygen supply is stopped.

[0040] The method in this application embodiment can suppress the volatilization loss of UF6, making the conversion rate of UF4 to UO2F2 close to the theoretical value.

[0041] Furthermore, the conversion rate of uranyl fluoride is at least 95%.

[0042] In some embodiments, the calcination of uranium tetrafluoride to obtain uranyl fluoride is carried out in a reaction vessel, the outlet of which may be connected to a tail gas absorption bottle containing sodium hydroxide solution.

[0043] Furthermore, ion chromatography analysis can be performed on the tail gas absorption bottle to detect the fluoride content.

[0044] A second aspect of the embodiments of this application provides a uranyl fluoride prepared by the method of the first aspect of this application.

[0045] In some embodiments, the purity of the uranyl fluoride is at least 99.9%. This is because the method provided in this application is a gas-solid phase dry process that introduces almost no impurity ions, resulting in an extremely high purity uranyl fluoride product that requires almost no subsequent complex purification process.

[0046] Exemplary embodiments according to this application will now be described in more detail with reference to the accompanying drawings. It should be understood that these exemplary embodiments may be implemented in many different forms and should not be construed as being limited to the embodiments set forth herein.

[0047] Example 1 S1: Loading Weigh 50.0g of UF4 powder and spread it evenly in a shallow boat made of nickel-based alloy, with the thickness of the material layer controlled at 5mm.

[0048] S2: Device Push the material boat into the isothermal zone of the tubular reactor. Ensure the system is airtight, and connect the reactor outlet to a tail gas absorption bottle containing sodium hydroxide solution.

[0049] S3: Atmosphere Replacement Open the oxygen valve and introduce high-purity oxygen (99.999%) into the reaction tube at a flow rate of 100 mL / min for 10 minutes to purge the air from the tube.

[0050] S4: Generate a mixed atmosphere Start the ozone generator (using pure oxygen as the source gas), adjust its power, and generate an O2 / O3 mixed gas with an ozone volume fraction of 10%. Control the flow rate of the mixed gas to continuously flow into the reaction tube at a rate of 100 mL / min using a mass flow meter.

[0051] S5: Heating reaction The tube furnace was heated to 300°C at a rate of 5°C / min. Timing was started after the set temperature was reached, and the furnace was held at that temperature for 4 hours. During this period, the flow rate of the mixed atmosphere was kept stable.

[0052] S6: Cooling Sampling After the reaction is complete, heating is stopped, and the mixed gas is continued to be introduced until the furnace temperature drops below 100°C, then pure oxygen is switched to purging. After cooling to room temperature, the gas source is turned off, the material boat is removed, and uranyl fluoride is obtained, which is a pale yellow, loose solid powder.

[0053] Example 2 Uranyl fluoride was prepared according to the method described in Example 1, except that: S5: Heating reaction The tube furnace was heated to 250°C at a rate of 5°C / min. Timing was started after the set temperature was reached, and the furnace was held at that temperature for 6 hours. During this period, the flow rate of the mixed atmosphere was kept stable.

[0054] Example 3 Uranyl fluoride was prepared according to the method described in Example 1, except that: S5: Heating reaction The tube furnace was heated to 350°C at a rate of 5°C / min. Timing was started after the set temperature was reached, and the furnace was held at that temperature for 3 hours. During this period, the flow rate of the mixed atmosphere was kept stable.

[0055] Example 4 Uranyl fluoride was prepared according to the method described in Example 1, except that: S4: Generate a mixed atmosphere Start the ozone generator (using pure oxygen as the source gas), adjust its power, and generate an O2 / O3 mixed gas with an ozone volume fraction of 5%. Control the flow rate of the mixed gas to continuously flow into the reaction tube at a rate of 100 mL / min using a mass flow meter.

[0056] Example 5 Uranyl fluoride was prepared according to the method described in Example 1, except that: S4: Generate a mixed atmosphere Start the ozone generator (using pure oxygen as the source gas), adjust its power, and generate an O2 / O3 mixed gas with an ozone volume fraction of 15%. Control the flow rate of the mixed gas to continuously flow into the reaction tube at a rate of 100 mL / min using a mass flow meter.

[0057] Comparative Example 1 Weigh 50.0g of the same batch of UF4 powder and place it in a tube furnace. Under a pure oxygen atmosphere (100 mL / min), raise the furnace temperature to 800℃ and hold for 4 hours.

[0058] Comparative Example 2 Uranyl fluoride was prepared according to the method described in Example 1, except that: S4: Generate a mixed atmosphere Start the ozone generator (using pure oxygen as the source gas), adjust its power, and generate O3 gas with an ozone volume fraction of 100%. Control the flow rate of the mixed gas to continuously flow into the reaction tube at a rate of 100 mL / min using a mass flow meter.

[0059] The tube furnace was heated to 350°C at a rate of 5°C / min. Timing was started after the set temperature was reached, and the furnace was held at that temperature for 30 minutes. During this period, the flow rate of the mixed atmosphere was kept stable.

[0060] The uranyl fluoride obtained from the above embodiments and comparative examples was tested as follows, and the test results are shown in Table 1.

[0061] Conversion rate: Test conditions: The test shall be conducted in a dry laboratory with a temperature of 25±5℃ and a relative humidity (RH) of ≤30% to avoid uranyl fluoride powder absorbing moisture or hydrolyzing during the test.

[0062] Conversion analysis: The concentration of tetravalent uranium (U) in the product was determined by redox titration (or potentiometric titration).4+ The content of uranyl fluoride (UO2F2). Because the uranium in the product uranyl fluoride (UO2F2) is hexavalent (U... 6+ ), while the uranium in the raw material uranium tetrafluoride (UF4) is tetravalent (U... 4 + ), by measuring the residual U in the sample 4+ The degree of completeness of the conversion can be inferred from the content.

[0063] Conversion rate The calculation formula is as follows:

[0064] In the formula: The mass of the product (uranyl fluoride) analyzed from the sample; U in the sample determined by titration 4+ The mass fraction; k is U 4+ The conversion factor to UF4 (i.e., UF4 molecular weight / U atomic weight, approximately equal to 1.32); The mass of uranium tetrafluoride raw material added before the reaction (or the corresponding theoretical input amount).

[0065] Table 1

[0066] According to Table 1, comparing Examples 1-5 with Comparative Examples 1-2, it can be seen that the examples of this application all obtained uranyl fluoride products with high conversion rates and good morphology at low temperatures, while the comparative examples failed to obtain industrial-grade products that met the requirements under conventional high temperatures or extreme atmospheres. This indicates that introducing an appropriate amount of ozone into an oxygen-containing atmosphere can significantly reduce the reaction temperature while breaking the thermodynamic equilibrium, thus achieving efficient conversion.

[0067] A comparison of Examples 1 and 2 shows that the reaction kinetics are relatively slow at 250°C. Although products are eventually formed, extending the reaction time or increasing the ozone concentration is beneficial for further improving the conversion rate. A comparison of Examples 1 and 3 shows that the uranyl fluoride powder obtained at 350°C begins to show slight signs of sintering, indicating that while 350°C is still an effective temperature, 300°C is the optimal process temperature that balances high conversion rate, low energy consumption, and excellent material porosity.

[0068] A comparison of Examples 1 and 4 shows that ozone concentration is a key parameter; too low a concentration leads to insufficient oxidation kinetics, thus limiting the improvement of conversion rate. A comparison of Examples 1 and 5 shows that although increasing the ozone concentration can shorten the reaction time to reach equilibrium, excessively high ozone concentrations pose greater challenges to the sealing of the equipment and operational safety; therefore, a balance must be struck between efficiency and safety.

[0069] Comparing Example 1 and Comparative Example 1, Comparative Example 1 (traditional high-temperature method) used a high-temperature reaction at 800℃. After the experiment, a large amount of white condensate (identified as UF6 hydrolysis products) was found adhering to the inner wall of the reactor, resulting in uranium source loss. Simultaneously, the product severely adhered to the boat and dish at high temperatures, making it difficult to remove. Furthermore, the product contained a large amount of oxide impurities such as U3O8, and a high concentration of fluoride ions was detected in the tail gas absorption bottle. Given the severe material loss, extremely low product purity, and unqualified morphology under these conditions, it was impossible to accurately calculate the effective conversion rate; therefore, it was not included in Table 1 (referred to as " / ").

[0070] Compared to Comparative Example 1, Comparative Example 2 (pure ozone method) experienced extremely violent oxidation in the initial stage of the reaction due to the lack of oxygen as a diluent and heat carrier, leading to localized thermal runaway of the material layer. Furthermore, the high temperature and high concentration of ozone caused severe oxidative corrosion to the reaction equipment. Given that a stable process environment could not be maintained under these conditions, and the product had lost its characterization significance as an industrial product due to overheating, its conversion rate was not statistically analyzed in Table 1 (denoted as " / "). This, in turn, confirms the necessity of using a mixture of oxygen and ozone as the atmosphere in this application.

[0071] It should also be noted that the terms "some embodiments," "other embodiments," and "embodiments" used in this application refer to specific features, structures, or characteristics described in connection with those embodiments, which are included in at least one embodiment described in the general description of this application. The appearance of the same expression in multiple places in the specification does not necessarily refer to the same embodiment. Furthermore, when a specific feature, structure, or characteristic is described in connection with any embodiment, the intention is to suggest that implementing such a feature, structure, or characteristic in conjunction with other embodiments also falls within the scope of this application.

[0072] In the above embodiments, the descriptions of each embodiment have different focuses. For parts not described in detail in a certain embodiment, please refer to the relevant descriptions in other embodiments.

[0073] It should also be noted that the above are merely preferred embodiments of this application and do not limit the scope of patent protection of this application. Any equivalent structural or procedural changes made using the content of this application’s specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the scope of patent protection of this application.

Claims

1. A method for preparing uranyl fluoride, characterized in that, Includes the following steps: Provide uranium tetrafluoride; Uranium tetrafluoride was calcined in an oxygen-containing atmosphere to obtain uranyl fluoride. The oxygen-containing atmosphere includes oxygen and ozone.

2. The preparation method according to claim 1, characterized in that, In the oxygen-containing atmosphere, the volume of ozone accounts for 5%-15% of the total volume of the oxygen-containing atmosphere.

3. The preparation method according to claim 1, characterized in that, The calcination treatment of uranium tetrafluoride includes: Uranium tetrafluoride is formed into a layer, the thickness of which is denoted as H mm. The flow rate of the mixed gas formed by oxygen and ozone is denoted as Q mL / min. The relationship between H and Q is as follows: .

4. The preparation method according to claim 3, characterized in that, The flow rate Q of the mixed gas is 50~200 mL / min.

5. The preparation method according to any one of claims 3 or 4, characterized in that, The mixed gas is formed in the following ways: Oxygen is used as the gas source, which is obtained through an ozone generator.

6. The preparation method according to claim 1, characterized in that, The calcination includes a heating stage and a holding stage. The heating rate during the heating stage is 1~10℃ / min; The temperature during the heat preservation stage is 200~400℃.

7. The preparation method according to claim 6, characterized in that, The calcination holding time is 2-6 hours.

8. The preparation method according to claim 1 or 6, characterized in that, Also includes: During the cooling phase, The cooling phase includes a first cooling phase and a second cooling phase. The first cooling stage is carried out in an oxygen-containing atmosphere, and the second cooling stage is carried out in a pure oxygen atmosphere.

9. The preparation method according to claim 8, characterized in that, The starting temperature of the second cooling stage is 90~120℃.

10. A uranyl fluoride, characterized in that, It is prepared by the method described in any one of claims 1-9.

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