A method for removing organic matter from a fissile molybdenum solution

Abstract

This application relates to a method for removing organic matter from a fission molybdenum solution, belonging to the field of radionuclide separation technology. The method for removing organic matter from a fission molybdenum solution includes: heating the fission molybdenum solution containing organic matter to remove water; subjecting the system after heating and dehydration to a first treatment; wherein the temperature of the heating and dehydration treatment is lower than the carbonization temperature of the organic matter; the first treatment includes: sequentially adding a first nitric acid solution and a sodium nitrite solution, followed by evaporation to dryness. The method for removing organic matter from a fission molybdenum solution provided by this application can efficiently and rapidly remove organic matter from the fission molybdenum solution to achieve purification of the fission molybdenum product. The process is simple, the purification efficiency is high, the amount of secondary waste is small, and it is easy to promote.

Description

Technical Field

[0001] This application relates to the field of radionuclide separation technology, and in particular to a method for removing organic matter from fission molybdenum solution. Background Technology

[0002] Fission molybdenum (T 1 / 2 =66h) is an important medical radionuclide for diagnosis. 99m The parent compound of Tc is mainly obtained from uranium fission products. The process of extracting molybdenum from uranium fission products mainly uses chromatography and solvent extraction to separate molybdenum from uranium and most fission products. Organic substances (extractants or extraction resins, etc.) are required in this process.

[0003] Currently, extracting from uranium fission products 99 The organic compounds used in the Mo process are mainly phosphorus-based extractants (such as tributyl phosphate and di(2-ethylhexyl)phosphoric acid). In actual production, it has been found that these phosphorus-based extractants and other organic compounds remain in the molybdenum fission solution during the separation process, thus affecting the quality of the final product. Therefore, it is necessary to remove the residual organic compounds from the molybdenum fission solution. Summary of the Invention

[0004] The purpose of this application is to provide a method for removing organic matter from fission molybdenum solution, which can efficiently and quickly remove organic matter from fission molybdenum solution to purify fission molybdenum product. The process is simple, the purification efficiency is high, the amount of secondary waste is small, and it is easy to promote.

[0005] This application provides a method for removing organic matter from a fission molybdenum solution. The method includes: heating the fission molybdenum solution containing organic matter to remove water; performing a first treatment on the system after heating to remove water; wherein the temperature of the heating to remove water is lower than the carbonization temperature of the organic matter; the first treatment includes: sequentially adding a first nitric acid solution and a sodium nitrite solution, and then evaporating the solution to dryness.

[0006] The method for removing organic matter from a fission molybdenum solution provided in this application involves adding nitric acid solution after heating and dehydrating the fission molybdenum solution. This process effectively dissolves the solid molybdenum salt and allows for... 99 Mo is oxidized to the stable valence state of MoO4. 2- Then, a sodium nitrite solution is added, where the sodium ions can react with MoO4. 2-The formation of stable sodium molybdate helps reduce molybdenum loss during subsequent evaporation of the solution; the presence of nitrite ions ensures thorough removal of organic matter during evaporation. Therefore, the method for removing organic matter from fission molybdenum solution provided in this application can efficiently and rapidly remove organic matter from fission molybdenum solution to purify fission molybdenum product. The process is simple, highly efficient, produces little secondary waste, and is easy to promote.

[0007] In an optional embodiment of this application, the method for removing organic matter from the fission molybdenum solution includes: after heating and dehydration treatment, performing multiple first treatments on the system after heating and dehydration treatment.

[0008] In the above technical solution, performing multiple first treatments is beneficial to further improve the removal rate of organic matter in the fission molybdenum solution.

[0009] In an optional embodiment of this application, the method for removing organic matter from the fission molybdenum solution further includes: after the first treatment, performing a second treatment on the system after the first treatment; wherein the second treatment includes: heating the system after the first treatment to a molten salt state.

[0010] In the above technical solution, since nitrite ions are introduced in the first treatment process, it is beneficial to further remove residual organic matter during the heating to the molten salt state, thereby improving the removal rate of organic matter in the fission molybdenum solution.

[0011] In an optional embodiment of this application, the second process further includes: cooling the system in the molten salt state, adding a second nitric acid solution to the cooled system, and performing a second heating until the molten salt phase dissolves.

[0012] The above technical solution allows the system to be in a solution state, which is convenient for subsequent use.

[0013] In an optional embodiment of this application, the temperature of the first heating is 300~320°C.

[0014] In the above technical solution, by adjusting the first heating temperature, it is beneficial to further improve the removal rate of organic matter in the fission molybdenum solution.

[0015] Optionally, the first heating time is 8 to 10 minutes.

[0016] In an optional embodiment of this application, the molar concentration of the second nitric acid solution is 0.5~1 mol / L.

[0017] In the above technical solution, by controlling the concentration of the second nitric acid solution, it is beneficial to ensure that the molten salt phase is fully dissolved.

[0018] Optionally, the volume ratio of the second nitric acid solution to the fission molybdenum solution is (0.1~0.2):1.

[0019] In an optional embodiment of this application, the temperature of the second heating is 200~250°C.

[0020] In the above technical solution, by controlling the temperature of the second heating, it is beneficial to fully dissolve the molten salt phase.

[0021] Optionally, the second heating time is 3 to 5 minutes.

[0022] In an optional embodiment of this application, the molar concentration of the first nitric acid solution is 10~12 mol / L, and the mass concentration of the sodium nitrite solution is 0.05~0.2 g / L.

[0023] In the above technical solution, by controlling the concentration of the first nitric acid solution, it is possible to quickly and sufficiently achieve... 99 Mo is oxidized to the stable valence state of MoO4. 2- By adjusting the concentration of sodium nitrite solution, it is beneficial to further improve the removal rate of organic matter in fission molybdenum solution.

[0024] Optionally, the volume ratio of the first nitric acid solution to the fission molybdenum solution is (0.08~0.1):1, and the volume ratio of the sodium nitrite solution to the fission molybdenum solution is (0.015~0.035):1.

[0025] In an optional embodiment of this application, the organic material is a phosphorus-based extractant, and the temperature for evaporating the solution to dryness is 200~250℃.

[0026] In the above technical solution, when the organic matter is a phosphorus extractant, adjusting the temperature of the solution evaporation process accordingly helps to remove the phosphorus extractant quickly and completely during the solution evaporation process.

[0027] Optionally, the solution evaporation time is 10-15 minutes.

[0028] Optionally, phosphorus extractants include diethylhexylphosphoric acid.

[0029] In optional embodiments of this application, the fission molybdenum solution is a neutral solution or an acidic solution.

[0030] Of the above technical solutions, the solution of this application can efficiently remove organic matter from neutral or acidic fission molybdenum solutions and has a wide range of applications. Attached Figure Description

[0031] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0032] Figure 1 A process flow diagram of the method for removing organic matter from fission molybdenum solution provided in this application. Detailed Implementation

[0033] This application provides a method for removing organic matter from a fission molybdenum solution, the method comprising: heating the fission molybdenum solution containing organic matter to remove water; and performing a first treatment on the system after the heating and water removal treatment.

[0034] The temperature of the heating and dehydration treatment is lower than the carbonization temperature of the organic matter; the first treatment includes: sequentially adding a first nitric acid solution and a sodium nitrite solution, and then evaporating the solution to dryness.

[0035] In this application, nitric acid solution refers to a homogeneous mixture formed by mixing nitric acid and water in different proportions. Sodium nitrite solution refers to a homogeneous mixture formed by mixing sodium nitrite and water in different proportions.

[0036] The method for removing organic matter from a fission molybdenum solution provided in this application involves adding nitric acid solution after heating and dehydrating the fission molybdenum solution. This process effectively dissolves the solid molybdenum salt and allows for... 99 Mo is oxidized to the stable valence state of MoO4. 2- Then, a sodium nitrite solution is added, where the sodium ions can react with MoO4. 2- The combination forms stable sodium molybdate, which helps reduce the loss of molybdenum during the subsequent evaporation of the solution; the presence of nitrite ions allows organic matter to be fully removed during the evaporation of the solution.

[0037] Therefore, the method for removing organic matter from fission molybdenum solution provided in this application can efficiently and quickly remove organic matter from fission molybdenum solution. It can be used for the efficient removal of organic matter from fission molybdenum solution with strong acid and strong radiation to achieve the purification of fission molybdenum products. The process is simple, the purification efficiency is high, the amount of secondary waste is small, and it is easy to promote. It is especially suitable for use in large-scale fission molybdenum production lines.

[0038] Figure 1 For a process flow diagram of the method for removing organic matter from fission molybdenum solution provided in this application, please refer to [link / reference needed]. Figure 1 The method for removing organic matter from a fission molybdenum solution provided in this application includes the following steps: S1, heating and dehydrating a fission molybdenum solution containing organic matter; wherein the temperature of the heating and dehydration treatment is lower than the carbonization temperature of the organic matter.

[0039] In some optional embodiments of this application, the temperature for the heating and dehydration treatment is 200~400°C.

[0040] As an example, the temperature for heating and dewatering can be any one of 200°C, 225°C, 250°C, 275°C, 300°C, 325°C, 350°C, 375°C, and 400°C, or a range between any two.

[0041] In some optional embodiments of this application, the heating and dehydration treatment time is 80~150 min.

[0042] As an example, the heating and dehydration treatment time can be any one of 80 min, 90 min, 100 min, 110 min, 120 min, 125 min, 130 min, 140 min and 150 min or a range between any two.

[0043] In some optional embodiments of this application, the organic material is a phosphorus-based extractant.

[0044] As an example, phosphorus extractants include diethylhexylphosphonic acid and tributyl phosphate, etc.

[0045] It should be noted that in other optional embodiments of this application, the organic matter is not limited to phosphorus-based extractants; for example, the organic matter can be n-dodecane, etc.

[0046] As an example, the volume percentage of organic matter in the fission molybdenum solution is ≤3%.

[0047] In some optional embodiments of this application, the fission molybdenum solution is a neutral solution or an acidic solution. The solution of this application can efficiently remove organic matter from neutral or acidic fission molybdenum solutions and has a wide range of applications.

[0048] As an example, the fission molybdenum solution is a nitric acid solution system.

[0049] S2, the system after heating and dehydration is subjected to a first treatment; wherein, the first treatment includes: sequentially adding a first nitric acid solution and a sodium nitrite solution, and then evaporating the solution to dryness.

[0050] In some optional embodiments of this application, the system after heating and dehydration is subjected to multiple first treatments. Performing multiple first treatments is beneficial to further improve the removal rate of organic matter in the fission molybdenum solution.

[0051] In this application, "multiple times" means: more than twice (including twice).

[0052] In some optional embodiments of this application, the solution is evaporated until white crystals appear.

[0053] In some optional embodiments of this application, the molar concentration of the first nitric acid solution is 10~12 mol / L. By controlling the concentration of the first nitric acid solution, the desired concentration can be achieved quickly and sufficiently. 99 Mo is oxidized to the stable valence state of MoO4. 2- .

[0054] As an example, the molar concentration of the first nitric acid solution can be any one of 10 mol / L, 10.5 mol / L, 11 mol / L, 11.5 mol / L, and 12 mol / L, or a range between any two.

[0055] Furthermore, the volume ratio of the first nitric acid solution to the fission molybdenum solution is (0.08~0.1):1.

[0056] As an example, the volume ratio of the first nitric acid solution to the fission molybdenum solution can be any one of 0.08:1, 0.085:1, 0.086:1, 0.09:1, 0.095:1, and 0.1:1, or any range between the two.

[0057] In some optional embodiments of this application, the mass concentration of the sodium nitrite solution is 0.05~0.2 g / L. Adjusting the concentration of the sodium nitrite solution can further improve the removal rate of organic matter from the fission molybdenum solution.

[0058] As an example, the mass concentration of the sodium nitrite solution can be any one of 0.05 g / L, 0.075 g / L, 0.1 g / L, 0.15 g / L, and 0.2 g / L, or a range between any two.

[0059] Furthermore, the volume ratio of sodium nitrite solution to fission molybdenum solution is (0.015~0.035):1.

[0060] As an example, the volume ratio of sodium nitrite solution to fission molybdenum solution can be any one of 0.015:1, 0.017:1, 0.02:1, 0.023:1, 0.024:1, 0.025:1, 0.027:1, 0.029:1, 0.03:1, 0.032:1, and 0.035:1, or any range between the two.

[0061] In some optional embodiments of this application, when the organic matter is a phosphorus-based extractant, the temperature for evaporation of the solution is 200-250°C. When the organic matter is a phosphorus-based extractant, adjusting the temperature for evaporation of the solution accordingly helps to ensure that the phosphorus-based extractant is removed quickly and completely during the evaporation process.

[0062] As an example, when the organic matter is a phosphorus-based extractant, the temperature for evaporating the solution to dryness can be any one of 200°C, 210°C, 225°C, 230°C, 240°C, and 250°C, or a range between any two.

[0063] Furthermore, the solution is evaporated to dryness for 10-15 minutes.

[0064] As an example, the solution evaporation time can be any one of 10 min, 11 min, 12 min, 13 min, 14 min, and 15 min, or a range between any two.

[0065] S3, perform a second treatment on the system after the first treatment; wherein the second treatment includes: heating the system after the first treatment to a molten salt state.

[0066] Because nitrite ions are introduced in the first treatment process, it is beneficial for the further removal of residual organic matter during the heating to the molten salt state, thereby improving the removal rate of organic matter in the fission molybdenum solution.

[0067] As an example, the first heating method can be heating by a heating instrument, such as high-temperature burning. This application does not limit the instrument used for the first heating.

[0068] In some optional embodiments of this application, the system is first heated until it is in a colorless molten salt state.

[0069] In some optional embodiments of this application, the temperature of the first heating is 300~320°C. By adjusting the first heating temperature, it is beneficial to further improve the removal rate of organic matter in the fission molybdenum solution.

[0070] As an example, the temperature of the first heating can be any one of 300°C, 305°C, 310°C, 315°C and 320°C or a range between any two.

[0071] Furthermore, the initial heating time can be 8 to 10 minutes.

[0072] As an example, the first heating time can be any one of 8 min, 8.5 min, 9 min, 9.5 min, and 10 min, or a range between any two.

[0073] In some optional embodiments of this application, the second process further includes: cooling the molten salt system, adding a second nitric acid solution to the cooled system, and then heating it again until the molten salt phase dissolves. This method allows the system to be in a solution state, facilitating subsequent use.

[0074] Furthermore, the molar concentration of the second nitric acid solution is 0.5~1 mol / L. Adjusting the concentration of the second nitric acid solution facilitates the complete dissolution of the molten salt phase.

[0075] As an example, the molar concentration of the second nitric acid solution can be any one of 0.5 mol / L, 0.6 mol / L, 0.7 mol / L, 0.8 mol / L, 0.9 mol / L, and 1 mol / L, or a range between any two.

[0076] Furthermore, the volume ratio of the second nitric acid solution to the fission molybdenum solution is (0.1~0.2):1.

[0077] As an example, the volume ratio of the second nitric acid solution to the fission molybdenum solution can be any one of the following: 0.1:1, 0.12:1, 0.14:1, 0.143:1, 0.15, 0.152:1, 0.16:1, 0.167:1, 0.17:1, 0.18:1, 0.19:1, and 0.2:1, or a range between any two.

[0078] In some optional embodiments of this application, the temperature of the second heating is 200~250°C. By controlling the temperature of the second heating, it is beneficial to ensure that the molten salt phase dissolves completely.

[0079] As an example, the temperature of the second heating can be any one of 200°C, 210°C, 220°C, 225°C, 230°C, 240°C and 250°C or a range between any two.

[0080] Furthermore, the second heating time is 3-5 minutes.

[0081] As an example, the second heating time can be any one of 3 min, 3.5 min, 4 min, 4.5 min and 5 min or a range between any two.

[0082] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions in the embodiments of this application will be clearly and completely described below. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall apply. Reagents or instruments whose manufacturers are not specified are all conventional products that can be purchased commercially.

[0083] Example 1 This embodiment provides a method for removing organic matter from a fission molybdenum solution, the specific steps of which are as follows: (1) Mix 0.1 g of Mo, 1 mL of di(2-ethylhexyl)phosphoric acid, 9 mL of n-dodecane and 1 mol / L nitric acid solution to obtain 300 mL of simulated fission molybdenum solution.

[0084] (2) Transfer the prepared 300mL simulated fission molybdenum solution to a 500mL evaporation flask, place it on a heating plate, set the temperature of the heating plate to 200℃, and heat for 150min to evaporate the water in the simulated fission molybdenum solution.

[0085] (3) After the evaporation flask has cooled to room temperature, add 30 mL of 10 mol / L HNO3 solution and 5 mL of 0.1 g / L NaNO2 solution to the evaporation flask, set the heating plate temperature to 200 °C, and heat for 15 min to obtain white crystals.

[0086] (4) After the evaporation flask has cooled to room temperature, add 30 mL of 10 mol / L HNO3 solution and 5 mL of 0.1 g / L NaNO2 solution to the evaporation flask, set the heating plate temperature to 200 °C, and heat for 15 min to obtain white crystals.

[0087] (5) Continue to raise the temperature of the heating plate to 300°C, and burn the white crystals into a colorless and transparent molten salt, and maintain this state for about 8 minutes.

[0088] (6) After the evaporation flask has cooled to room temperature, add 50 mL of 0.5 mol / L HNO3 to the evaporation flask, set the heating plate temperature to 250 °C, and maintain the solution boiling for about 5 min. Then turn off the heating plate and allow the solution to cool naturally to obtain the purified solution. 99 Mo solution.

[0089] Example 2 This embodiment provides a method for removing organic matter from a fission molybdenum solution, the specific steps of which are as follows: (1) Mix 0.1 g of Mo, 8 mL of di(2-ethylhexyl)phosphoric acid and 2 mol / L nitric acid solution to obtain 330 mL of simulated fission molybdenum solution.

[0090] (2) Transfer the prepared 330mL simulated fission molybdenum solution to a 500mL evaporation flask, place it on a heating plate, set the temperature of the heating plate to 300℃, and heat for 125min to evaporate the water in the simulated fission molybdenum solution.

[0091] (3) After the evaporation flask has cooled to room temperature, add 30 mL of 11 mol / L HNO3 solution and 8 mL of 0.1 g / L NaNO2 solution to the evaporation flask, set the heating plate temperature to 225 °C, and heat for 10 min to obtain white crystals.

[0092] (4) After the evaporation flask has cooled to room temperature, add 30 mL of 11 mol / L HNO3 solution and 8 mL of 0.1 g / L NaNO2 solution to the evaporation flask, set the heating plate temperature to 225 °C, and heat for 12 min to obtain white crystals.

[0093] (5) Continue to raise the temperature of the heating plate to 310°C, and burn the white crystals into a colorless and transparent molten salt, and maintain it for about 10 minutes.

[0094] (6) After the evaporation flask has cooled to room temperature, add 50 mL of 0.8 mol / L HNO3 to the evaporation flask, set the heating plate temperature to 225℃, and maintain the solution boiling for about 5 minutes. Then turn off the heating plate and allow the solution to cool naturally to obtain the purified solution. 99 Mo solution.

[0095] Example 3 This embodiment provides a method for removing organic matter from a fission molybdenum solution, the specific steps of which are as follows: (1) Mix 0.1 g of Mo, 5 mL of di(2-ethylhexyl)phosphoric acid, 6 mL of n-dodecane with 3 mol / L nitric acid solution to obtain 350 mL of simulated fission molybdenum solution.

[0096] (2) Transfer the prepared 350mL simulated fission molybdenum solution to a 500mL evaporation flask, place it on a heating plate, set the temperature of the heating plate to 400℃, and heat for 80min to evaporate the water in the simulated fission molybdenum solution.

[0097] (3) After the evaporation flask has cooled to room temperature, add 30 mL of 12 mol / L HNO3 solution and 8 mL of 0.1 g / L NaNO2 solution to the evaporation flask, set the heating plate temperature to 250 °C, and heat for 10 min to obtain white crystals.

[0098] (4) After the evaporation flask has cooled to room temperature, add 30 mL of 12 mol / L HNO3 solution and 10 mL of 0.1 g / L NaNO2 solution to the evaporation flask, set the heating plate temperature to 250 °C, and heat for 10 min to obtain white crystals.

[0099] (5) Continue to raise the temperature of the heating plate to 320°C, and burn the white crystals into a colorless and transparent molten salt, and maintain it for about 10 minutes.

[0100] (6) After the evaporation flask has cooled to room temperature, add 50 mL of 1 mol / L HNO3 to the evaporation flask, set the temperature of the heating plate to 250℃, and maintain the solution boiling for about 3 minutes. Then turn off the heating plate and allow the solution to cool naturally to obtain the purified solution. 99 Mo solution.

[0101] Example 4 This embodiment provides a method for removing organic matter from a fission molybdenum solution. The only difference between this embodiment and Embodiment 1 is that step (4) is not performed in this embodiment.

[0102] Comparative Example 1 This comparative example provides a method for removing organic matter from a fission molybdenum solution. The only difference between this comparative example and Example 1 is that NaNO2 solution is not added in steps (3) and (4) of this comparative example.

[0103] Comparative Example 2 This comparative example provides a method for removing organic matter from a fission molybdenum solution. The only difference between this comparative example and Example 1 is that the NaNO2 solution in steps (3) and (4) of the example is replaced with NaNO3 solution.

[0104] Experimental Example The total organic carbon (TOC) samples obtained in Examples 1-4 and Comparative Examples 1-2 were analyzed using a total organic carbon (TOC) analyzer. 99 Total carbon content analysis was performed on the Mo solution; the results obtained from Examples 1-4 and Comparative Examples 1-2 were compared. 99 The Mo solution was evaporated to dryness and then carbonized at 500℃ for 10 minutes. The phases after carbonization were compared. The results are shown in Table 1.

[0105] Table 1

[0106] As can be seen from the table, the method obtained using embodiments 1-4 of this application... 99 The total carbon content in the Mo solutions was ≤16 mg / L, and no black substances appeared after carbonization treatment, indicating that the methods in Examples 1-4 can all achieve efficient removal of residual organic matter from fission molybdenum solutions. In contrast, the methods in Comparative Examples 1-2, which did not use NaNO2 solution, yielded... 99 The total carbon content in the Mo solution was ≥2.6 g / L, and black substances appeared after carbonization treatment, indicating that the methods of Comparative Examples 1 and 2 failed to effectively remove residual organic matter in the fission molybdenum solution.

[0107] In summary, the method for removing organic matter from a fission molybdenum solution provided in this application, by adding nitric acid solution after heating and dehydrating the fission molybdenum solution, can fully dissolve the solid molybdenum salt and thus... 99Mo is oxidized to the stable valence state of MoO4. 2- Then, a sodium nitrite solution is added, where the sodium ions can react with MoO4. 2- The formation of stable sodium molybdate helps reduce molybdenum loss during subsequent evaporation of the solution; the presence of nitrite ions ensures thorough removal of organic matter during evaporation. Therefore, the method for removing organic matter from fission molybdenum solution provided in this application can efficiently and rapidly remove organic matter from fission molybdenum solution to purify fission molybdenum product. The process is simple, highly efficient, produces little secondary waste, and is easy to promote.

[0108] The embodiments described above are some, but not all, of the embodiments of this application. The detailed description of the embodiments of this application is not intended to limit the scope of the claimed application, but merely to illustrate selected embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

Claims

1. A method for removing organic matter from a fission molybdenum solution, characterized in that, include: A fission molybdenum solution containing organic matter is subjected to a heating dehydration treatment; wherein the temperature of the heating dehydration treatment is lower than the carbonization temperature of the organic matter; The system after heating and dehydration is subjected to a first treatment; wherein the first treatment includes: sequentially adding a first nitric acid solution and a sodium nitrite solution, and then evaporating the solution to dryness.

2. The method for removing organic matter from a fission molybdenum solution according to claim 1, characterized in that, The method for removing organic matter from the fission molybdenum solution includes: after the heating and dehydration treatment, performing the first treatment multiple times on the system after the heating and dehydration treatment.

3. The method for removing organic matter from a fission molybdenum solution according to claim 1, characterized in that, The method for removing organic matter from the fission molybdenum solution further includes: performing a second treatment on the system after the first treatment; The second process includes heating the system after the first process to a molten salt state.

4. The method for removing organic matter from a fission molybdenum solution according to claim 3, characterized in that, The second process further includes: cooling the molten salt system, adding a second nitric acid solution to the cooled system, and heating it a second time until the molten salt phase dissolves.

5. The method for removing organic matter from a fission molybdenum solution according to claim 3, characterized in that, The temperature of the first heating is 300~320℃; Optionally, the first heating time is 8 to 10 minutes.

6. The method for removing organic matter from a fission molybdenum solution according to claim 4, characterized in that, The molar concentration of the second nitric acid solution is 0.5~1 mol / L; Optionally, the volume ratio of the second nitric acid solution to the fission molybdenum solution is (0.1~0.2):

1.

7. The method for removing organic matter from a fission molybdenum solution according to claim 4, characterized in that, The second heating temperature is 200~250℃; Optionally, the second heating time is 3 to 5 minutes.

8. The method for removing organic matter from a fission molybdenum solution according to any one of claims 1 to 7, characterized in that, The molar concentration of the first nitric acid solution is 10~12 mol / L, and the mass concentration of the sodium nitrite solution is 0.05~0.2 g / L; Optionally, the volume ratio of the first nitric acid solution to the fission molybdenum solution is (0.08~0.1):1, and the volume ratio of the sodium nitrite solution to the fission molybdenum solution is (0.015~0.035):

1.

9. The method for removing organic matter from a fission molybdenum solution according to any one of claims 1 to 7, characterized in that, The organic matter is a phosphorus-based extractant, and the temperature for evaporating the solution to dryness is 200~250℃; Optionally, the solution is evaporated to dryness for 10-15 minutes; Optionally, the phosphorus extractant includes diethylhexylphosphoric acid.

10. The method for removing organic matter from a fission molybdenum solution according to any one of claims 1 to 7, characterized in that, The fission molybdenum solution is a neutral or acidic solution.

Images