A method for the production of molybdenum-99 by a reactor using a uranyl nitrate solution as a nuclear fuel
The purification of molybdenum-99 under low-temperature conditions through oxidation and digestion methods solves the safety risks of impurity introduction and high-temperature operation in existing technologies, achieving efficient and safe purification of molybdenum-99 that meets pharmacopoeia requirements.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- NUCLEAR POWER INSTITUTE OF CHINA
- Filing Date
- 2023-12-29
- Publication Date
- 2026-06-30
AI Technical Summary
Existing molybdenum-99 purification methods have problems such as introducing new impurities, high temperatures, and high safety risks. In particular, they are inconvenient to operate in hot chambers and have low impurity removal rates.
Molybdenum-99 was oxidized to MoO42- using an oxidant. Subsequently, organic impurities were digested in a microwave digester using a mixture of concentrated nitric acid and hydrogen peroxide. Sodium molybdate was obtained by repeatedly dissolving in nitric acid and treating with alkaline solution to reduce acidity. The use of alkaline solution and the method of reducing acidity through multiple steps avoided the complexity and safety risks of operation in a hot chamber.
It achieves efficient removal of impurities under low-temperature conditions, avoids the introduction of new impurities, meets the purification effect required by the pharmacopoeia, and reduces energy consumption and safety risks.
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Abstract
Description
Technical Field
[0001] This invention relates to the field of radioisotope production technology, specifically to a purification method for producing molybdenum-99 using uranyl nitrate solution as nuclear fuel in a reactor. Background Technology
[0002] Molybdenum-99 ( 99 Mo), with a half-life of 65.9 h, decays into technetium-99m via electron decay. 99m Tc), is 99 Mo- 99m The main raw material for Tc generator. 99m Tc, with its suitable gamma rays (140 keV) and half-life (6.02 h), is widely used in nuclear medicine single-photon emission computed tomography (SPECT), with global annual production... 99m Tc-labeled drugs have been used in nuclear medicine diagnostics more than 40 million times, accounting for more than 80% of all nuclear medicine applications. 99 The traditional method for producing molybdenum (Mo) is uranium target irradiation fission. While the extraction process for Mo using this method is mature and commercially available, it presents challenges such as the difficulty in disposing of high-level radioactive waste. Nuclear reactors using uranyl nitrate or uranyl sulfate aqueous solutions as nuclear fuel are used for… 99 Mo production was a novel concept proposed in the 1990s. The production of uranyl nitrate aqueous solution reactors (referred to as "solution reactors")... 99 At Mo, uranyl nitrate solution serves as both fuel for reactor operation and... 99 Compared with target irradiation, solution-based production of isotopes such as Mo has significant advantages in terms of high neutron utilization, low waste generation, simple process, and low operating cost.
[0003] In patents related to the extraction and separation of Mo and I in solution reactors, the fuel solution from the solution reactor flows through an alumina column and a Mo / I separation column to obtain a crude Mo product. However, alumina detaches to varying degrees in the Mo product, resulting in a high aluminum content, thus requiring further purification. The crude Mo-99 product solution produced in the solution reactor contains some impurities, mainly including detached Al ions, organic matter accumulated during system operation, and incompletely separated I, etc.
[0004] Patent CN99107707 describes a method for purifying Mo using sublimation. This method requires a high-temperature furnace and operates at high temperatures within a heated chamber, posing significant risks. Furthermore, it necessitates the collection of sublimated components at varying temperatures, resulting in a complex apparatus setup. Under high radioactivity conditions, electrical components are easily damaged, leading to low reliability. Therefore, it is difficult to apply this method in heated chambers with high radioactivity.
[0005] Traditional Mo purification methods primarily employ inorganic ion exchange columns. While these methods achieve some purification, the inorganic ion exchanger is prone to shedding during elution, introducing new inorganic ion exchanger impurities into the Mo product and potentially causing adverse effects. In the initial design of the solution stack, Mo purification was attempted using high-temperature sublimation. However, this method requires heating to 1400°C, resulting in high energy consumption, inconvenient high-temperature operation within the heated chamber, and significant safety risks. Summary of the Invention
[0006] This invention addresses the problems of introducing new impurities, high temperatures, and high safety risks in current molybdenum purification methods. It provides a purification method for producing molybdenum-99 using a reactor with uranyl nitrate solution as nuclear fuel. This method obtains the final product without introducing new impurities, has low heating temperature, low energy loss, is easy to operate in a hot chamber, and has a high impurity removal rate. The obtained product meets the requirements of the pharmacopoeia.
[0007] This invention is achieved through the following technical solution:
[0008] A purification method for producing molybdenum-99 in a reactor using uranyl nitrate solution as nuclear fuel includes the following steps:
[0009] Step 1: Add an oxidant to the crude molybdenum-99 produced by the solution reactor to oxidize molybdenum-99 to MoO4. 2- This forms a stable high-valence chemical form, which is then evaporated to dryness.
[0010] Step 2: Add a digestion solution to the distillation residue to digest the impurities. The digestion solution is nitric acid + hydrogen peroxide, and the digestion is carried out in a microwave digester. This decomposes organic impurities into gases, and volatile nuclides also evaporate upon heating, thereby removing organic impurities and volatile nuclides.
[0011] Step 3: Add a dissolving solution to the digested solid to dissolve it, then evaporate it to dryness. Repeat this process three times to remove residual digesting solution such as nitric acid from the product. At this time, nitric acid of decreasing concentration should be used to dissolve the solid to minimize the residue of nitric acid (e.g., 1M for the first time, 0.1M for the second time, and deionized water for the third time). Then evaporate it to dryness to obtain sodium molybdate solid.
[0012] Step 4: Add alkali solution to the evaporated solid to dissolve it, and add hydrochloric acid to adjust the pH of the solution to 7-9 to obtain the molybdenum-99 product solution.
[0013] Furthermore, the oxidant used in step one includes either hydrogen peroxide or nitric acid.
[0014] Furthermore, the concentration of the oxidant is 1% to 30%.
[0015] Furthermore, the dissolving solution mentioned in steps one and three is nitric acid.
[0016] Furthermore, the concentration of the solution is 0.1 mol / L to 1 mol / L.
[0017] Furthermore, the digestion solution added in step two is a mixture of concentrated nitric acid and hydrogen peroxide.
[0018] Furthermore, the volume ratio of concentrated nitric acid to hydrogen peroxide is (2-6):1.
[0019] Furthermore, the alkaline solution mentioned in step four includes sodium hydroxide.
[0020] Furthermore, the concentration of the alkaline solution is 0.5 mol / L to 2 mol / L.
[0021] Furthermore, in step two, a stepped digestion temperature is adopted, with the temperature of the first stage set at 120℃~170℃; and the temperature of the second stage set at 170℃~210℃.
[0022] Preferably, the temperature of the first stage is set to 150°C and the temperature of the second stage is set to 180°C.
[0023] Both the first and second stages of the process take 15 minutes to resolve.
[0024] Digestion requires heating. If the temperature is too high, the reaction becomes too vigorous, resulting in excessive gas production and pressure, which is detrimental to system safety. If the temperature is too low, the digestion reaction takes too long, is inefficient, and may lead to incomplete digestion. Within the temperature range specified in this application, digestion efficiency can be improved while ensuring system safety.
[0025] Compared with the prior art, the present invention has the following advantages and beneficial effects:
[0026] The purification method of the present invention can purify molybdenum-99. Compared with traditional molybdenum purification methods, the present invention does not introduce new impurities, has a low heating temperature, low energy loss, is easy to operate in the hot chamber, has a high impurity removal rate, and the obtained product meets the requirements of the pharmacopoeia. Detailed Implementation
[0027] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are some embodiments of the present invention, but not all embodiments.
[0028] In the following description, numerous specific details are set forth in order to provide a thorough understanding of the invention. However, it will be apparent to those skilled in the art that these specific details are not necessary to practice the invention. In other embodiments, well-known materials or methods have not been specifically described in order to avoid obscuring the invention.
[0029] Throughout this specification, references to “an embodiment,” “an example,” or “an example” mean that a particular feature, structure, or characteristic described in connection with that embodiment or example is included in at least one embodiment of the invention. Therefore, the phrases “an embodiment,” “an example,” “an example,” or “an example” appearing in various places throughout the specification do not necessarily refer to the same embodiment or example. Furthermore, specific features, structures, or characteristics can be combined in one or more embodiments or examples in any suitable combination and / or sub-combination. The term “and / or” as used herein includes any and all combinations of one or more of the associated listed items.
[0030] Therefore, the following detailed description of embodiments of the present invention is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.
[0031] Example 1
[0032] This embodiment provides a purification method for producing molybdenum-99 in a reactor using uranyl nitrate solution as nuclear fuel. The crude Mo-99 product contains the following components: 390 μg Mo, 65.8 μg organic carbon, 600 μg Al, 20 μg I, 1.35 μg Ce, 0.69 μg Ru, and 0.003 μg Sr. The specific purification method is as follows:
[0033] S1: Add 5 mL of 5% hydrogen peroxide to the crude product solution of molybdenum-99 produced by the 20 mL solution pile, stir and react for 5 minutes to oxidize Mo, and then heat the oxidized solution to 120°C to evaporate to dryness.
[0034] S2: Add concentrated nitric acid and hydrogen peroxide to the distillation residue to dissolve the molybdenum solid. The volume ratio of concentrated nitric acid (68%) to hydrogen peroxide (30%) is 4:1. Then digest at 120°C.
[0035] S3: Add 1 mol / L nitric acid to the digested solid to dissolve the molybdenum solid, then evaporate it to dryness at 120℃. Repeat the operation three times to reduce the acid content.
[0036] S4: Add 1 mol / L sodium hydroxide solution to the evaporated solid to dissolve it, and add hydrochloric acid to adjust the pH of the solution to 7-9 to obtain Na2. 99 MoO4 product solution.
[0037] After purification using the above method, the recovery rate of Mo was 93.2%.
[0038] Example 2
[0039] This embodiment provides a purification method for producing molybdenum-99 in a reactor using uranyl nitrate solution as nuclear fuel. The crude Mo-99 product contains the following components: 390 μg Mo, 65.8 μg organic carbon, 600 μg Al, 20 μg I, 1.35 μg Ce, 0.69 μg Ru, and 0.003 μg Sr. The specific purification method is as follows:
[0040] S1: Add 5 mL of 10% hydrogen peroxide to the crude molybdenum-99 product solution produced by the 20 mL solution pile, stir and react for 5 minutes to oxidize Mo, and then heat the oxidized solution to 120°C to evaporate to dryness.
[0041] S2: Add concentrated nitric acid and hydrogen peroxide to the distillation residue to dissolve the molybdenum solid. The volume ratio of concentrated nitric acid (68%) to hydrogen peroxide (30%) is 6:1. Then digest at 120°C.
[0042] S3: Add 1 mol / L nitric acid to the digested solid to dissolve the molybdenum solid, then evaporate it to dryness at 120℃. Repeat the operation three times to reduce the acid content.
[0043] S4: Add 2 mol / L sodium hydroxide solution to the evaporated solid to dissolve it, and add hydrochloric acid to adjust the pH of the solution to 7-9 to obtain Na2. 99 MoO4 product solution.
[0044] After purification using the above method, the recovery rate of Mo was 95.0%.
[0045] Example 3
[0046] This embodiment provides a purification method for producing molybdenum-99 in a reactor using uranyl nitrate solution as nuclear fuel. The crude Mo-99 product contains the following components: 390 μg Mo, 65.8 μg organic carbon, 600 μg Al, 20 μg I, 1.35 μg Ce, 0.69 μg Ru, and 0.003 μg Sr. The specific purification method is as follows:
[0047] S1: Add 5 mL of 1% hydrogen peroxide to the crude molybdenum-99 product solution produced by the 20 mL solution pile, stir and react for 5 minutes to oxidize Mo, and then heat the oxidized solution to 120°C to evaporate to dryness.
[0048] S2: Add concentrated nitric acid and hydrogen peroxide to the distillation residue to dissolve the molybdenum solid. The volume ratio of concentrated nitric acid (68%) to hydrogen peroxide (30%) is 2:1. Then digest at 120°C.
[0049] S3: Add 0.1 mol / L nitric acid to the digested solid to dissolve the molybdenum solid, then evaporate it to dryness at 120°C. Repeat this process three times to reduce the acid content.
[0050] S4: Dissolve the solid by adding 0.5 mol / L sodium hydroxide solution to the evaporated solid, and adjust the pH of the solution to 7-9 by adding hydrochloric acid to obtain Na2. 99 MoO4 product solution.
[0051] After purification using the above method, the recovery rate of Mo was 80.9%.
[0052] Example 4
[0053] This embodiment provides a purification method for producing molybdenum-99 in a reactor using uranyl nitrate solution as nuclear fuel. The crude Mo-99 product contains the following components: 390 μg Mo, 65.8 μg organic carbon, 600 μg Al, 20 μg I, 1.35 μg Ce, 0.69 μg Ru, and 0.003 μg Sr. The difference from Example 1 is that the hydrogen peroxide used in this embodiment has a concentration of 20%, while other technical characteristics are identical to Example 1. The specific purification method is as follows:
[0054] S1: Add 5 mL of 20% hydrogen peroxide to the crude molybdenum-99 product solution produced by the 20 mL solution pile, stir and react for 5 minutes to oxidize Mo, and then heat the oxidized solution to 120°C to evaporate to dryness.
[0055] S2: Add concentrated nitric acid and hydrogen peroxide to the distillation residue to dissolve the molybdenum solid. The volume ratio of concentrated nitric acid (68%) to hydrogen peroxide (30%) is 4:1. Then digest at 120°C.
[0056] S3: Add 1 mol / L nitric acid to the digested solid to dissolve the molybdenum solid, then evaporate it to dryness at 120℃. Repeat the operation three times to reduce the acid content.
[0057] S4: Add 2 mol / L sodium hydroxide solution to the evaporated solid to dissolve it, and add hydrochloric acid to adjust the pH of the solution to 7-9 to obtain Na2. 99 MoO4 product solution.
[0058] After purification using the above method, the recovery rate of Mo was 97.1%.
[0059] Example 5
[0060] This embodiment provides a purification method for producing molybdenum-99 in a reactor using uranyl nitrate solution as nuclear fuel. The crude Mo-99 product contains the following components: 390 μg Mo, 65.8 μg organic carbon, 600 μg Al, 20 μg I, 1.35 μg Ce, 0.69 μg Ru, and 0.003 μg Sr. The difference from Example 1 is that the hydrogen peroxide used in this embodiment has a concentration of 30%, while other technical characteristics are identical to Example 1. The specific purification method is as follows:
[0061] S1: Add 5 mL of 30% hydrogen peroxide to the crude molybdenum-99 product solution produced by the 20 mL solution pile, stir and react for 5 minutes to oxidize Mo, and then heat the oxidized solution to 120℃ to evaporate to dryness.
[0062] S2: Add concentrated nitric acid and hydrogen peroxide to the distillation residue to dissolve the molybdenum solid. The volume ratio of concentrated nitric acid (68%) to hydrogen peroxide (30%) is 4:1. Then digest at 120°C.
[0063] S3: Add 3 mol / L nitric acid to the digested solid to dissolve the molybdenum solid, then evaporate it to dryness at 120℃. Repeat the operation three times to reduce the acid content.
[0064] S4: Add 2 mol / L sodium hydroxide solution to the evaporated solid to dissolve it, and add hydrochloric acid to adjust the pH of the solution to 7-9 to obtain Na2. 99 MoO4 product solution.
[0065] After purification using the above method, the recovery rate of Mo was 97.3%.
[0066] Example 6
[0067] This embodiment provides a purification method for producing molybdenum-99 in a reactor using uranyl nitrate solution as nuclear fuel. The crude Mo-99 product contains the following components: 390 μg Mo, 65.8 μg organic carbon, 600 μg Al, 20 μg I, 1.35 μg Ce, 0.69 μg Ru, and 0.003 μg Sr. The difference from Example 1 is that nitric acid is used as the oxidant in this embodiment; all other technical features are identical to Example 1. The specific purification method is as follows:
[0068] S1: Add 5 mL of 10% nitric acid to the crude molybdenum-99 product solution produced by the 20 mL solution pile, stir for 5 minutes to oxidize Mo, and then heat the oxidized solution to 120°C to evaporate to dryness.
[0069] S2: Add concentrated nitric acid and hydrogen peroxide to the distillation residue to dissolve the molybdenum solid. The volume ratio of concentrated nitric acid (68%) to hydrogen peroxide (30%) is 6:1. Then digest at 120°C.
[0070] S3: Add 1 mol / L nitric acid to the digested solid to dissolve the molybdenum solid, then evaporate it to dryness at 120℃. Repeat the operation three times to reduce the acid content.
[0071] S4: Add 2 mol / L sodium hydroxide solution to the evaporated solid to dissolve it, and add hydrochloric acid to adjust the pH of the solution to 7-9 to obtain Na2. 99 MoO4 product solution.
[0072] After purification using the above method, the recovery rate of Mo was 98.2%.
[0073] The products treated with the purification methods of Examples 1 to 6 were tested, and the test results are shown in Table 1 below.
[0074] Table 1
[0075]
[0076] The table above shows that the recovery rate of Mo is mainly related to the oxidant. Nitric acid has a greater oxidizing effect than hydrogen peroxide. Therefore, nitric acid has the highest recovery rate of Mo when used as the oxidant. The higher the concentration of hydrogen peroxide, the stronger the oxidizing power, and the higher the recovery rate of Mo.
[0077] The content of organic carbon is mainly related to the ratio of digestion solution. The higher the nitric acid content, the lower the organic carbon residue. Since Al is an amphoteric substance, it has a certain removal effect under conditions of oxidation, digestion and acid-base changes.
[0078] This method has a certain removal effect on volatile nuclides such as Ru and I, but no removal effect on non-volatile nuclides such as Ce and Sr.
[0079] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.
Claims
1. A purification method for producing molybdenum-99 in a reactor using uranyl nitrate solution as nuclear fuel, characterized in that, Includes the following steps: Step one: To the Mo-99 initial product solution produced by solution pile, an oxidizing agent is added to oxidize the Mo-99 initial product to MoO4 2- , and then the solution is evaporated to dryness; Step 2: Add digestion solution to the distillation residue to digest the impurities in the initial molybdenum-99 product; Step 3: Add a dissolving solution to the digested solid to dissolve it, then evaporate it to dryness; Step 4: Add alkali solution to the evaporated solid, and after dissolution, obtain molybdenum-99 product solution; The digestion solution added in step two is a mixture of concentrated nitric acid and concentrated hydrogen peroxide, and the volume ratio of the concentrated nitric acid to the hydrogen peroxide is (2~6):
1.
2. The purification method for producing molybdenum-99 in a reactor using uranyl nitrate solution as nuclear fuel according to claim 1, characterized in that, The oxidizing agent used in step one includes either hydrogen peroxide or nitric acid.
3. A purification method for producing molybdenum-99 in a reactor using uranyl nitrate solution as nuclear fuel, as described in claim 1 or 2, characterized in that, The concentration of the oxidant is 1% to 30%.
4. The purification method for producing molybdenum-99 in a reactor using uranyl nitrate solution as nuclear fuel according to claim 1, characterized in that, The dissolving solution mentioned in both Step 1 and Step 3 is nitric acid.
5. A purification method for producing molybdenum-99 in a reactor using uranyl nitrate solution as nuclear fuel, as described in claim 1 or 4, characterized in that... The concentration of the solution is 0.1 mol / L to 1 mol / L.
6. The purification method for producing molybdenum-99 in a reactor using uranyl nitrate solution as nuclear fuel according to claim 1, characterized in that, The alkaline solution mentioned in step four includes any one of sodium hydroxide, potassium hydroxide, and ammonia water.
7. A purification method for producing molybdenum-99 in a reactor using uranyl nitrate solution as nuclear fuel, as described in claim 1 or 6, characterized in that... The concentration of the alkaline solution is 0.5 mol / L to 2 mol / L.
8. The purification method for producing molybdenum-99 in a reactor using uranyl nitrate solution as nuclear fuel according to claim 1, characterized in that, Step two uses a stepped digestion temperature, with the temperature of the first stage set at 120℃~170℃ and the temperature of the second stage set at 170℃~210℃.