Method for separating molybdenum and cadmium in irradiation thorium target

Abstract

The invention belongs to the technical field of metal element separation, and relates to a separation method of molybdenum and cadmium in an irradiation thorium target, the separation method comprises the following steps: (1) using a first hydrochloric acid solution to shower an anion resin chromatographic column to obtain a pretreated chromatographic column; (2) pretreating a hydrochloric acid solution for irradiating the thorium target, and passing through the pretreated chromatographic column obtained in the step (1); the pretreatment chromatographic column after sample loading is subjected to first washing with a second hydrochloric acid solution and second washing with a third hydrochloric acid solution or ultrapure water, and the first washing and the second washing have no sequence; and respectively collecting the molybdenum-containing effluent after the first washing and the cadmium-containing effluent after the second washing. According to the invention, rapid and efficient separation of molybdenum and cadmium can be realized, and support is provided for subsequent production of medical-grade molybdenum-99 / technetium-99m and cadmium-115 / indium-115m generators.

Description

Technical Field

[0001] This invention belongs to the field of metal element separation technology, and relates to a method for separating molybdenum and cadmium in an irradiated thorium target. Background Technology

[0002] Uranium-230, with a half-life of approximately 20.8 days, is a promising medical alpha nuclide that could be used for targeted alpha therapy of tumors. Its parent nucleus, protactinium-230, can be produced via spallation reactions using a low-energy accelerator proton irradiation of a thorium target. This production route also generates a large number of fragmented nuclides, among which molybdenum-99 and cadmium-115 have high reaction cross-sections. Furthermore, the spallation reactions used to prepare actinium-225 and radium-223 by irradiating a thorium target with medium- and high-energy proton beams also simultaneously produce large quantities of molybdenum-99 and cadmium-115 medical nuclides.

[0003] Molybdenum-99 is a precursor to the medical radioisotope technetium-99m, which is widely used in nuclear medicine diagnostics such as single-photon emission computed tomography (SPECT). Currently, molybdenum-99 production relies on a limited number of reactors and faces supply instability. Radioisotopes of indium, such as indium-111, indium-113m, and indium-115m, can also be used as medical diagnostic radionuclides in SPECT imaging. Indium-115m is a precursor to cadmium-115 and can be produced using a cadmium-115 / indium-115m generator.

[0004] Accelerator proton irradiation of thorium targets can not only produce medical alpha therapeutic nuclides such as uranium-230, but also precursors for medical diagnostic nuclides technetium-99m and indium-115m, namely molybdenum-99 and cadmium-115. The production of medical-grade molybdenum-99 / technetium-99m and cadmium-115 / indium-115m generators places extremely high demands on the separation process of molybdenum and cadmium in the irradiated thorium target. It requires the rapid and efficient separation of high-specific-activity and high-radioactive-purity molybdenum-99 and cadmium-115 from a large number of fragmented nuclides. However, existing literature lacks records of molybdenum and cadmium extraction and separation processes from irradiated thorium targets.

[0005] In summary, there is an urgent need to provide a method for the rapid and efficient separation of molybdenum and cadmium from irradiated thorium targets, which will support the subsequent production of medical-grade molybdenum-99 / technetium-99m and cadmium-115 / indium-115m generators. Summary of the Invention

[0006] To address the shortcomings of existing technologies, the present invention aims to provide a method for separating molybdenum and cadmium in an irradiated thorium target, which can achieve rapid and efficient separation of molybdenum and cadmium, providing support for the subsequent production of medical-grade molybdenum-99 / technetium-99m and cadmium-115 / indium-115m generators.

[0007] To achieve this objective, the present invention adopts the following technical solution:

[0008] This invention provides a method for separating molybdenum and cadmium in an irradiated thorium target, the method comprising the following steps:

[0009] (1) The anion exchange resin column was rinsed with the first hydrochloric acid solution to obtain a pretreated column;

[0010] (2) The hydrochloric acid solution of the irradiated thorium target is pretreated and then passed through the pretreated chromatographic column obtained in step (1); the pretreated chromatographic column after loading is washed with the second hydrochloric acid solution for the first wash and with the third hydrochloric acid solution or ultrapure water for the second wash. The first wash and the second wash have no order. The molybdenum-containing eluent after the first wash and the cadmium-containing eluent after the second wash are collected respectively.

[0011] The present invention provides a method for separating molybdenum and cadmium in an irradiated thorium target. This method utilizes the difference in affinity between molybdenum and cadmium metal cations and chloride ions. By changing the concentration of hydrochloric acid, the generation of molybdenum and cadmium complexed chloride anions is controlled, allowing molybdenum and cadmium to exist as metal cations or complexed chloride anions, respectively, within a specific hydrochloric acid concentration range. Simultaneously, the strong adsorption effect of anion exchange resin on anions is utilized to achieve selective separation of molybdenum and cadmium. The invention first pretreats the anion exchange resin column, then passes the pretreated hydrochloric acid solution of the irradiated thorium target through the column, washing it with different detergents to elute the molybdenum and cadmium adsorbed by the anion exchange resin. This achieves rapid and efficient separation of molybdenum and cadmium, providing support for the subsequent production of medical-grade molybdenum-99 / technetium-99m and cadmium-115 / indium-115m generators.

[0012] Preferably, the concentration of the first hydrochloric acid solution in step (1) is 3-8 mol / L, for example, it can be 3 mol / L, 4 mol / L, 5 mol / L, 6 mol / L, 7 mol / L or 8 mol / L, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0013] Preferably, in step (1), the volume of the first hydrochloric acid solution is 5-10 times the volume of the anion exchange resin column, for example, it can be 5 times, 6 times, 8 times, 9 times or 10 times, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0014] Preferably, the anion exchange resin packed in the anion exchange column in step (1) includes a strongly basic anion exchange resin.

[0015] Preferably, the strongly basic anion exchange resin includes AG MP-1M anion exchange resin and / or AG 1-X8 anion exchange resin.

[0016] The anion exchange resin packed in the anion exchange column of the present invention can be a strong basic anion exchange resin such as AG MP-1M or AG 1-X8. Strong basic anion exchange resin refers to a class of anion exchange resins containing strong basic functional groups. Those skilled in the art can select the appropriate type of anion exchange resin according to the actual application scenario.

[0017] The anion exchange resin in the anion exchange resin chromatographic column of this invention is packed using a wet packing method with ultrapure water. The volume of the chromatographic column used in this invention is 0.3 mL, but it is not limited to this value. Those skilled in the art can adjust the column volume according to the actual application scenario.

[0018] The present invention does not specifically limit the flow rate of the rinsing in step (1). Those skilled in the art can adjust it according to the actual application scenario. For example, when the volume of the chromatographic column is 0.3 mL, the rinsing flow rate can be 1 mL / min.

[0019] Preferably, the pretreatment in step (2) involves adjusting the concentration of the hydrochloric acid medium in the hydrochloric acid solution of the irradiated thorium target to be the same as the concentration of the first hydrochloric acid solution in step (1).

[0020] It should be noted that the hydrochloric acid solution for irradiated thorium targets described in this invention is obtained by dissolving the irradiated thorium target in hydrochloric acid solution.

[0021] The present invention does not specifically limit the flow rate of the pretreated chromatographic column obtained by step (1) in step (2). Those skilled in the art can adjust it according to the actual application scenario. For example, when the volume of the chromatographic column is 0.3 mL, the flow rate of the pretreated chromatographic column obtained by step (1) can be 1 mL / min.

[0022] Preferably, the concentration of the second hydrochloric acid solution in step (2) is 1-2 mol / L, for example, it can be 1 mol / L, 1.2 mol / L, 1.5 mol / L, 1.8 mol / L or 2 mol / L, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0023] Preferably, in step (2), the volume of the second hydrochloric acid solution is 10-15 times the volume of the anion exchange resin column, for example, it can be 10 times, 11 times, 12 times, 13 times, 14 times or 15 times, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0024] The present invention does not specifically limit the flow rate of the first washing in step (2). Those skilled in the art can adjust it according to the actual application scenario. For example, when the volume of the chromatographic column is 0.3 mL, the flow rate of the first washing can be ≤1 mL / min.

[0025] Preferably, the volume of the third hydrochloric acid solution in step (2) is 10-15 times the volume of the anion exchange resin column, for example, it can be 10 times, 11 times, 12 times, 13 times, 14 times or 15 times, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0026] Preferably, the concentration of the third hydrochloric acid solution in step (2) is <0.01 mol / L, for example, it can be 0.008 mol / L, 0.006 mol / L, 0.005 mol / L, 0.003 mol / L or 0.001 mol / L, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0027] Preferably, the second washing step (2) is performed using ultrapure water.

[0028] In this invention, the second washing can be carried out using either a third hydrochloric acid solution or ultrapure water as the elution solution, with ultrapure water being preferred.

[0029] Preferably, the volume of ultrapure water in step (2) is 10-15 times the volume of the anion exchange resin column, for example, it can be 10 times, 11 times, 12 times, 13 times, 14 times or 15 times, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0030] The ultrapure water refers to pure water with a resistivity ≥18MΩ·cm.

[0031] The present invention does not specifically limit the flow rate of the second washing in step (2). Those skilled in the art can adjust it according to the actual application scenario. For example, when the volume of the chromatographic column is 0.3 mL, the flow rate of the second washing can be ≤1 mL / min.

[0032] Preferably, in step (2), the pre-treated chromatographic column after sample loading is first washed with a second hydrochloric acid solution, and then washed with a third hydrochloric acid solution or ultrapure water.

[0033] In this invention, the preferred technical solution is to first wash and separate molybdenum using a second hydrochloric acid solution on the pretreated chromatographic column after sample loading, and then wash and separate cadmium using a third hydrochloric acid solution or ultrapure water.

[0034] The numerical range described in this invention includes not only the point values ​​listed above, but also any point values ​​within the numerical ranges not listed above. Due to space limitations and for the sake of brevity, this invention will not exhaustively list all the specific point values ​​included in the range.

[0035] Compared with the prior art, the present invention has the following beneficial effects:

[0036] The present invention provides a method for separating molybdenum and cadmium in an irradiated thorium target. This method utilizes the difference in affinity between molybdenum and cadmium metal cations and chloride ions. By changing the concentration of hydrochloric acid, the generation of molybdenum and cadmium complexed chloride anions is controlled, allowing molybdenum and cadmium to exist as metal cations or complexed chloride anions, respectively, within a specific hydrochloric acid concentration range. Simultaneously, the strong adsorption effect of anion exchange resin on anions is utilized to achieve selective separation of molybdenum and cadmium. The invention first pretreats the anion exchange resin column, then passes the pretreated hydrochloric acid solution of the irradiated thorium target through the column, washing it with different detergents to elute the molybdenum and cadmium adsorbed by the anion exchange resin. This achieves rapid and efficient separation of molybdenum and cadmium, providing support for the subsequent production of medical-grade molybdenum-99 / technetium-99m and cadmium-115 / indium-115m generators. Detailed Implementation

[0037] The technical solution of the present invention will be further illustrated below through specific embodiments. Those skilled in the art should understand that the embodiments described are merely illustrative of the present invention and should not be construed as limiting the invention in any way.

[0038] Example 1

[0039] This embodiment provides a method for separating molybdenum and cadmium in an irradiated thorium target, the separation method comprising the following steps:

[0040] (1) At room temperature, AG MP-1M anion exchange resin was packed into a chromatographic column with a volume of 0.3 mL. Then, the AG MP-1M anion exchange resin chromatographic column was rinsed with a first hydrochloric acid solution with a concentration of 5 mol / L at a flow rate of 1 mL / min. The volume of the first hydrochloric acid solution was 8 times the volume of the chromatographic column to obtain a pretreated chromatographic column.

[0041] (2) Adjust the hydrochloric acid medium concentration of the hydrochloric acid solution of the irradiated thorium target to 5 mol / L, and then pass it through the pretreated chromatographic column obtained in step (1) at a flow rate of 1 mL / min; after loading the sample, the pretreated chromatographic column is washed for the first time with a second hydrochloric acid solution of 1.5 mol / L at a flow rate of 1 mL / min, and the volume of the second hydrochloric acid solution is 13 times the volume of the chromatographic column; then wash for the second time with ultrapure water at a flow rate of 1 mL / min, and the volume of ultrapure water is 13 times the volume of the chromatographic column; collect the molybdenum-containing eluent after the first wash and the cadmium-containing eluent after the second wash respectively.

[0042] The recovery rates of molybdenum and cadmium were calculated based on the molybdenum-containing and cadmium-containing effluents obtained in this embodiment. The calculation formula is as follows:

[0043] ;

[0044] Where: Q is the mass of molybdenum (or cadmium) in the sample after separation, in μg; Q0 is the mass of molybdenum (or cadmium) in the sample before separation, in μg.

[0045] The recovery rate of molybdenum can reach about 91%, and the recovery rate of cadmium can reach about 88%, indicating that the separation method provided in this embodiment can simply and efficiently separate molybdenum and cadmium in irradiated thorium targets, and the recovery rate is high.

[0046] Example 2

[0047] This embodiment provides a method for separating molybdenum and cadmium in an irradiated thorium target, the separation method comprising the following steps:

[0048] (1) At room temperature, AG MP-1M anion exchange resin was packed into a chromatographic column with a volume of 0.3 mL. Then, the AG MP-1M anion exchange resin chromatographic column was rinsed with a first hydrochloric acid solution with a concentration of 3 mol / L at a flow rate of 1 mL / min. The volume of the first hydrochloric acid solution was 10 times the volume of the chromatographic column to obtain a pretreated chromatographic column.

[0049] (2) Adjust the hydrochloric acid medium concentration of the hydrochloric acid solution of the irradiated thorium target to 3 mol / L, and then pass it through the pretreated chromatographic column obtained in step (1) at a flow rate of 1 mL / min; after loading the sample, the pretreated chromatographic column is washed for the first time with a second hydrochloric acid solution of 1 mol / L at a flow rate of 1 mL / min, and the volume of the second hydrochloric acid solution is 15 times the volume of the chromatographic column; then wash for the second time with ultrapure water at a flow rate of 1 mL / min, and the volume of ultrapure water is 15 times the volume of the chromatographic column; collect the molybdenum-containing eluent after the first wash and the cadmium-containing eluent after the second wash respectively.

[0050] The recovery rates of molybdenum and cadmium were calculated based on the molybdenum-containing effluent and cadmium-containing effluent obtained in this embodiment. The recovery rate of molybdenum reached approximately 82%, and the recovery rate of cadmium reached approximately 88%. This indicates that the separation method provided in this embodiment can easily and efficiently separate molybdenum and cadmium in irradiated thorium targets, and the recovery rate is high.

[0051] Example 3

[0052] This embodiment provides a method for separating molybdenum and cadmium in an irradiated thorium target, the separation method comprising the following steps:

[0053] (1) At room temperature, AG MP-1M anion exchange resin was packed into a chromatographic column with a volume of 0.3 mL. Then, the AG MP-1M anion exchange resin chromatographic column was rinsed with a first hydrochloric acid solution with a concentration of 8 mol / L at a flow rate of 1 mL / min. The volume of the first hydrochloric acid solution was 5 times the volume of the chromatographic column to obtain a pretreated chromatographic column.

[0054] (2) Adjust the hydrochloric acid medium concentration of the hydrochloric acid solution of the irradiated thorium target to 8 mol / L, and then pass it through the pretreated chromatographic column obtained in step (1) at a flow rate of 1 mL / min; after loading the sample, the pretreated chromatographic column is washed for the first time with a second hydrochloric acid solution of 2 mol / L at a flow rate of 1 mL / min, and the volume of the second hydrochloric acid solution is 10 times the volume of the chromatographic column; then it is washed for the second time with ultrapure water at a flow rate of 1 mL / min, and the volume of ultrapure water is 10 times the volume of the chromatographic column; collect the molybdenum-containing eluent after the first wash and the cadmium-containing eluent after the second wash respectively.

[0055] The recovery rates of molybdenum and cadmium were calculated based on the molybdenum-containing effluent and cadmium-containing effluent obtained in this embodiment. The recovery rate of molybdenum reached approximately 87%, and the recovery rate of cadmium reached approximately 86%. This indicates that the separation method provided in this embodiment can easily and efficiently separate molybdenum and cadmium in irradiated thorium targets, and the recovery rate is high.

[0056] Example 4

[0057] This embodiment provides a method for separating molybdenum and cadmium in an irradiated thorium target. The difference from Embodiment 1 is that the concentration of the first hydrochloric acid solution in step (1) is adjusted to 2 mol / L, and the concentration of the hydrochloric acid medium in the hydrochloric acid solution of the irradiated thorium target in step (2) is adjusted to 2 mol / L. All other aspects are the same as in Embodiment 1.

[0058] In this embodiment, the hydrochloric acid concentration of the hydrochloric acid solution for irradiating the thorium target is less than 3 mol / L, which would prevent molybdenum from achieving 100% column loading under this concentration. Based on the molybdenum-containing and cadmium-containing effluents obtained in this embodiment, the recovery rates of molybdenum and cadmium were calculated, with a molybdenum recovery rate of approximately 67% and a cadmium recovery rate of approximately 91%.

[0059] Example 5

[0060] This embodiment provides a method for separating molybdenum and cadmium in an irradiated thorium target. The difference from Embodiment 1 is that the ultrapure water used in the second washing step (2) is replaced with a third hydrochloric acid solution with a concentration of 0.001 mol / L. All other aspects are the same as in Embodiment 1.

[0061] In this embodiment, the second washing uses a third hydrochloric acid solution with a concentration of 0.001 mol / L. Cadmium can also be efficiently eluted under elution conditions with this hydrochloric acid concentration. Based on the molybdenum-containing effluent and cadmium-containing effluent obtained in this embodiment, the recovery rates of molybdenum and cadmium were calculated, with a molybdenum recovery rate of approximately 91% and a cadmium recovery rate of approximately 88%.

[0062] Example 6

[0063] This embodiment provides a method for separating molybdenum and cadmium in an irradiated thorium target. The difference from Embodiment 1 is that the ultrapure water used in the second washing step (2) is replaced with a third hydrochloric acid solution with a concentration of 0.05 mol / L. All other aspects are the same as in Embodiment 1.

[0064] In this embodiment, the second washing uses a third hydrochloric acid solution with a concentration of 0.05 mol / L. Cadmium cannot be efficiently eluted under elution conditions with this hydrochloric acid concentration. Based on the molybdenum-containing effluent and cadmium-containing effluent obtained in this embodiment, the recovery rates of molybdenum and cadmium were calculated, with a molybdenum recovery rate of approximately 91% and a cadmium recovery rate of less than 5%.

[0065] Example 7

[0066] This embodiment provides a method for separating molybdenum and cadmium in an irradiated thorium target. The difference from Embodiment 1 is that the concentration of the second hydrochloric acid solution in step (2) is adjusted to 0.5 mol / L, while the rest is the same as in Embodiment 1.

[0067] In this embodiment, the concentration of the second hydrochloric acid solution was too low, which resulted in inefficient elution of molybdenum. Based on the molybdenum-containing and cadmium-containing effluents obtained in this embodiment, the recovery rates of molybdenum and cadmium were calculated, with a molybdenum recovery rate of approximately 61% and a cadmium recovery rate of approximately 86%.

[0068] Example 8

[0069] This embodiment provides a method for separating molybdenum and cadmium in an irradiated thorium target. The difference from Embodiment 1 is that the concentration of the second hydrochloric acid solution in step (2) is adjusted to 3 mol / L, while the rest is the same as in Embodiment 1.

[0070] In this embodiment, the concentration of the second hydrochloric acid solution was too high, which prevented efficient elution of molybdenum. Based on the molybdenum-containing and cadmium-containing effluents obtained in this embodiment, the recovery rates of molybdenum and cadmium were calculated, with a molybdenum recovery rate of approximately 7% and a cadmium recovery rate of approximately 89%.

[0071] Example 9

[0072] This embodiment provides a method for separating molybdenum and cadmium in an irradiated thorium target. The difference from Embodiment 1 is that, in step (2), the pre-treatment chromatographic column after sample loading is first washed with ultrapure water at a flow rate of 1 mL / min, and the volume of ultrapure water is 13 times the volume of the chromatographic column; then, it is washed with a second hydrochloric acid solution with a concentration of 1.5 mol / L at a flow rate of 1 mL / min, and the volume of the second hydrochloric acid solution is 13 times the volume of the chromatographic column; then, the cadmium-containing eluent after the first wash and the molybdenum-containing eluent after the second wash are collected respectively.

[0073] In this embodiment, the separation order of molybdenum and cadmium was exchanged, i.e., cadmium was separated first, followed by molybdenum. The recovery rates of molybdenum and cadmium were calculated based on the molybdenum-containing and cadmium-containing eluates obtained in this embodiment, with a molybdenum recovery rate of 94% and a cadmium recovery rate of 90%. Since the column volume used in this comparative example was 0.3 mL, the separation order of exchanging molybdenum and cadmium did not show a significant impact on the final cadmium recovery rate. If a large-volume column, such as a 20 mL column, is used, the separation order of exchanging molybdenum and cadmium may result in cadmium not being eluted efficiently due to the high concentration of residual hydrochloric acid medium in the column.

[0074] Comparative Example 1

[0075] This comparative example provides a method for separating molybdenum and cadmium in an irradiated thorium target. The difference from Example 1 is that step (1) is omitted, while the rest is the same as in Example 1.

[0076] In this comparative example, the AG MP-1M anion exchange resin column was not rinsed, which may have resulted in incomplete adsorption of molybdenum by the anion exchange resin, ultimately affecting the molybdenum recovery rate. Based on the molybdenum-containing and cadmium-containing eluates obtained in this comparative example, the recovery rates of molybdenum and cadmium were calculated, with a molybdenum recovery rate of approximately 95% and a cadmium recovery rate of approximately 87%. Since the column volume used in this comparative example was 0.3 mL, no significant impact was observed on the final molybdenum recovery rate from not rinsing the column. However, if a large-volume column, such as a 20 mL column, is used, failure to rinse the column may result in incomplete adsorption of molybdenum by the anion exchange resin during sample loading, thus affecting the final molybdenum recovery rate.

[0077] In summary, the method for separating molybdenum and cadmium in an irradiated thorium target provided by this invention utilizes the difference in affinity between molybdenum and cadmium metal cations and chloride ions. By changing the concentration of hydrochloric acid medium, the generation of molybdenum and cadmium complexed chloride anions is controlled, allowing molybdenum and cadmium to exist as metal cations or complexed chloride anions, respectively, under specific hydrochloric acid concentration ranges. Simultaneously, the strong adsorption effect of anion exchange resin on anions is utilized to achieve selective separation of molybdenum and cadmium. This invention first pretreats the anion exchange resin column, then passes the pretreated hydrochloric acid solution of the irradiated thorium target through the anion exchange resin column, washing it with different detergents to elute the molybdenum and cadmium adsorbed by the anion exchange resin, thereby achieving rapid and efficient separation of molybdenum and cadmium. This provides support for the subsequent production of medical-grade molybdenum-99 / technetium-99m and cadmium-115 / indium-115m generators.

[0078] The above description is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention fall within the protection and disclosure scope of the present invention.

Claims

1. A method for separating molybdenum and cadmium in an irradiated thorium target, characterized in that, The separation method includes the following steps: (1) The anion exchange resin column was rinsed with the first hydrochloric acid solution to obtain a pretreated column; (2) The hydrochloric acid solution of the irradiated thorium target is pretreated and then passed through the pretreated chromatographic column obtained in step (1); After sample loading, the pre-treatment chromatographic column is first washed with a second hydrochloric acid solution and second washed with a third hydrochloric acid solution or ultrapure water. The first and second washings are not in any particular order. The molybdenum-containing effluent after the first washing and the cadmium-containing effluent after the second washing were collected separately.

2. The separation method according to claim 1, characterized in that, Step (1) The concentration of the first hydrochloric acid solution is 3-8 mol / L.

3. The separation method according to claim 1 or 2, characterized in that, Step (1) The volume of the first hydrochloric acid solution is 5-10 times the volume of the anion exchange resin column.

4. The separation method according to any one of claims 1-3, characterized in that, The anion exchange resin packed in the anion exchange column in step (1) includes a strongly basic anion exchange resin. Preferably, the strongly basic anion exchange resin includes AG MP-1M anion exchange resin and / or AG 1-X8 anion exchange resin.

5. The separation method according to any one of claims 1-4, characterized in that, The pretreatment in step (2) involves adjusting the concentration of the hydrochloric acid medium in the hydrochloric acid solution of the irradiated thorium target to be the same as the concentration of the first hydrochloric acid solution in step (1).

6. The separation method according to any one of claims 1-5, characterized in that, In step (2), the concentration of the second hydrochloric acid solution is 1-2 mol / L.

7. The separation method according to any one of claims 1-6, characterized in that, In step (2), the volume of the second hydrochloric acid solution is 10-15 times the volume of the anion exchange resin column.

8. The separation method according to any one of claims 1-7, characterized in that, The volume of the third hydrochloric acid solution in step (2) is 10-15 times the volume of the anion exchange resin column; Preferably, the concentration of the third hydrochloric acid solution in step (2) is <0.01 mol / L.

9. The separation method according to any one of claims 1-8, characterized in that, Step (2) The second washing is performed using ultrapure water; Preferably, the volume of ultrapure water in step (2) is 10-15 times the volume of the anion exchange resin column.

10. The separation method according to any one of claims 1-9, characterized in that, In step (2), the pre-treated chromatographic column after sample loading is first washed with a second hydrochloric acid solution, and then washed with a third hydrochloric acid solution or ultrapure water.