A method for separating and preparing from spent Sr-90 radioactive sources 90 Y nuclide method

Abstract

The present invention relates to 90 The technical field of Y nuclide separation is specifically related to a method for separating and preparing Y nuclides from waste Sr-90 radioactive sources. 90 The method comprises a pre-treatment process and a separation process, wherein the pre-treatment process sequentially carries out the following steps: 1) separating the Sr-90 radioactive source from the waste Sr-90 radioactive source; 90 Sr is leached with aqua regia to obtain a leachate; 2) heating the leachate to remove NO2; 3) adding iron to the leachate to react; 4) adjusting the pH of the leachate to 12-14, filtering or centrifuging to obtain a clear solution; 5) adjusting the pH of the clear solution to 4-7, and allowing it to stand for more than 14 days to obtain 90 Sr / 90 Y solution. The present invention uses waste Sr-90 radioactive source as raw material, obtains the required Sr-90 raw material by dissolving and removing impurities, and provides a new way for the reuse and production of radioactive waste. 90 Y nuclide provides a new method, and subsequent simple precipitation method can be used to separate more than 99.8% of the purity 90 Y nuclide.

Description

Technical Field

[0001] The present invention relates to 90 The technical field of Y nuclide separation is specifically related to a method for separating and preparing from a waste Sr-90 radioactive source. 90 Y nuclide method. Background Art

[0002] 90 Y nuclide is a pure beta nuclide, T 1 / 2 =64h, emission β - The maximum particle energy is 2.28MeV, decay daughter 90 Zr. 90 Y nuclide has excellent chelating properties and is a very valuable therapeutic radioisotope. The radiopharmaceuticals made from it have broad application prospects in the treatment of liver cancer, bone cancer and other medical fields. It can also be used to prepare markers and tracers.

[0003] 90 There are two main methods for preparing Y nuclides. One is to use (n, γ) or (g, p) nuclear reactions and neutron radiation (such as in a reactor). 89 Y or accelerator shooting 91 Zr production 90 The reaction conditions of this method are very harsh. Another method is to 90 Sr / 90 Y decay equilibrium separation 90 Y nuclide is relatively simple to operate, and commonly used methods include resin adsorption method, solvent extraction method, chromatography method, precipitation method, etc.

[0004] The precipitation method uses the different solubility products Ksp of Y(OH)3 and Sr(OH)2. Y(OH)3 will be precipitated first under low pH conditions and can be filtered. 90 Y nuclide from 90 Sr / 90 Y equilibrium body was separated, such as Rubel Chakravarty et al. used a two-step radiochemical method to separate clinical pharmaceutical grade from alkaline conditions. 90 Y nuclide.

[0005] Currently, the mother nucleus is commonly obtained 90 The source of Sr is spent fuel, etc., and the raw material cost is relatively high. In view of this, the present invention is proposed. Summary of the Invention

[0006] The present invention makes up for the shortcomings of the existing technology and provides a method for separating and preparing a waste Sr-90 radioactive source. 90 The Y nuclide method has realized the reuse of Sr-90 radioactive waste, which has provided a basis for the development and production of 90 Y nuclides provide a new approach.

[0007] In order to achieve the above object, the present invention adopts the following technical solutions:

[0008] A method for separating and preparing from spent Sr-90 radioactive sources 90 The method for the Y nuclide comprises a pretreatment process and a separation process, wherein the pretreatment process sequentially performs the following steps:

[0009] 1) The waste Sr-90 radioactive source 90 Sr is leached with aqua regia to obtain a leachate at room temperature for 1-4 hours;

[0010] 2) heating the leachate to remove NO2;

[0011] 3) adding iron to the leachate to react, wherein the iron is in excess;

[0012] 4) adjusting the pH of the leachate to 12-14, and obtaining a clear solution by filtration or centrifugation;

[0013] 5) Adjust the pH of the clear solution to 4-7 and let it stand for more than 14 days to obtain 90 Sr / 90 Y solution;

[0014] The separation process comprises: 90 Sr / 90 The pH of the Y solution is adjusted to 10-14, and the precipitate is obtained by filtration or centrifugation, and then the precipitate is dissolved with acid to obtain 90 Y nuclide solution.

[0015] Specifically, the use of aqua regia can improve the 90 The leaching rate of Sr; NO2 affects the subsequent reduction of chloroauric acid and increases the subsequent consumption of iron or alkali. Direct addition of alkali for neutralization will also increase by-products such as Na + ions, etc., using heated leachate to remove NO2 can reduce the by-products of subsequent reactions; adding iron to the leachate for reaction can neutralize the acid, and the introduced iron ions will be removed in the subsequent precipitation. If it is NaOH, the introduced Na + The ions cannot be removed, and the second is to reduce the strong oxidizing substances such as chloroauric acid produced during the aqua regia leaching process; adjust the pH of the leachate to 12-14, and remove the impurity ions in the leachate, such as Fe 2+ (Fe 3+ ), Au + 、Ag + ions, and the original balance in the leachate 90 The Y nuclide is also removed by filtration; adjust the pH of the clear solution to 4-7 and let it stand for more than 14 days to make90 Sr and 90 Y reaches equilibrium again and can be used as the raw material for the next separation process.

[0016] The pre-treatment step of the present invention 90 Sr / 90 The Y solution can be any known 90 Sr / 90 Y decay equilibrium separation 90 The method of isolating the Y nuclide is followed by a subsequent separation process (e.g., resin adsorption, solvent extraction, chromatography, precipitation).

[0017] As an example, the waste Sr-90 radioactive source is a waste Sr-90 applicator source sheet prepared by powder metallurgy. The waste Sr-90 applicator source sheet is a major waste Sr-90 radioactive source, which is prepared by powder metallurgy and is mainly a gold-silver body. 90 The Sr active component is mainly below the gold layer of several microns. The method of the present invention is particularly suitable for waste strontium-90 applicator source sheets. Most of the Sr active components can be removed by leaching with aqua regia. 90 Sr nuclides dissolve out.

[0018] Further preferably, the leaching temperature in step 1) is room temperature and the leaching time is 1-4 hours. The present invention has found that if the temperature is too low or the leaching time is too short, the waste strontium-90 applicator source sheet will 90 The leaching effect of Sr nuclides decreased significantly. If the temperature is too high, radioactive aerosols will be easily volatilized, causing the disadvantage of radioactive contamination diffusion. If the time is too long, there will be the disadvantage of excessive dissolution of Ag.

[0019] Preferably, the heating temperature in step 2) is 60-100°C and the heating time is 30-60 minutes. The above temperature and time ensure that most or even all of the NO2 is removed.

[0020] Preferably, the iron in step 3) is in excess.

[0021] Preferably, the reaction temperature in step 3) is room temperature and the reaction time is 48 hours or more. The present invention has found that if the iron reaction time is less than 48 hours, there is a disadvantage that the impurity chloroauric acid is not sufficiently treated.

[0022] Preferably, in step 4), the pH is adjusted by adding sodium carbonate, sodium bicarbonate, potassium carbonate, potassium bicarbonate, alkali metal hydroxide or aqueous ammonia.

[0023] Preferably, the filtration in step 4) uses a 0.1-0.45 μm microporous filter membrane to ensure that impurity ions are completely removed.

[0024] Preferably, the separation process comprises: 90Sr / 90 The pH of the Y solution is adjusted to 10-14, and the precipitate is obtained by filtration or centrifugation, and then the precipitate is dissolved with acid to obtain 90 Y nuclide solution. The present invention preferably adopts precipitation method for separation process, which has the beneficial effects of reducing radioactive waste, saving raw material costs and simple operation compared with other methods. 90 The purity of Y can reach more than 99.8%, which can be used for experimental purposes; further through experimental optimization and increasing the number of filtration times, medical grade 90 Y nuclide.

[0025] The beneficial effects of the present invention are at least:

[0026] The present invention uses waste Sr-90 radioactive source as raw material, obtains the required Sr-90 raw material by dissolving and removing impurities, and provides a new way for the reuse and production of radioactive waste. 90 Y nuclide provides a new method, and the subsequent simple precipitation method can be used to separate the purity of more than 99.8% 90 Y nuclide, greatly saving production costs. DETAILED DESCRIPTION

[0027] The specific implementation methods of the present invention are further described in detail below with reference to specific examples.

[0028] The following examples are only used to illustrate the present invention and are not intended to limit the scope of protection of the present invention.

[0029] Unless otherwise specified, the experimental methods used in the following examples are conventional methods.

[0030] Unless otherwise specified, the materials and reagents used in the following examples can be obtained from commercial sources.

[0031] Example 1

[0032] (1) Raw material preparation

[0033] The experiment took a piece of waste Sr-90 radioactive source about 2cm 2 , cut into small pieces with scissors and put into a 10mL penicillin bottle, add 3mL of concentrated hydrochloric acid and 1mL of concentrated nitric acid in turn, shake evenly, and let it stand for 4h. Transfer the solution out, heat it to 95℃ at a rate of 5℃ per minute, maintain for 30 minutes, and remove NO2 from the solution. Add excess iron to the solution and react for 48h to neutralize the acid while reducing the strongly oxidizing chloroauric acid. Add 10mol / L NaOH solution to the solution to adjust the pH to 14, then filter the solution with a 0.22μm microporous filter membrane to obtain a precipitate, and slowly add HCl to the solution to adjust the pH to 5. After standing for 14 days, it is 90 Sr and 90Y regains equilibrium.

[0034] (2) Separation and filtration

[0035] In balance 90 Sr / 90 Slowly add 1 mol / L NaOH solution to the Y solution to adjust the pH to 11. Use a 10 mL medical syringe to draw up the solution, filter it with a 0.22 μm microporous filter membrane, and then continue to draw up 10 mL of 0.1 mol / L NaOH solution. Slowly clean the filter head at a rate of 1 mL / min, repeat twice, and finally draw up deionized water and filter it twice more.

[0036] (3) Acid leaching

[0037] After the above operations, 90 Y is adsorbed on the filter head as precipitate Y(OH)3, and 5 mL of 0.5 mol / L hydrochloric acid solution is drawn at 1 mL / min to rinse the filter head. 90 Y nuclide solution.

[0038] (4) Nuclear purity inspection

[0039] Sampling and elution 90 Y, the radioactivity of the solution is measured by liquid scintillation method, and the measurement is carried out at a certain interval, that is, the half-life determination method. After 640 hours, the radioactivity is measured, and at this time the radioactive impurities are half of the final activity, which can determine the purity of the radionuclides in the original solution. 90 The purity of Y reaches 99.83% and can be used for experimental purposes.

[0040] Comparative Example 1

[0041] Compared with Example 1, the only difference is that: in the preparation of the raw material, the leachate was not heated to remove NO2, Fe was not used for neutralization, and only NaOH was used for neutralization. The raw material obtained was a light yellow Sr-90 solution, and the Y-90 solution obtained in the subsequent reaction was also light yellow. After testing, it was found to contain oxidizing chloroaurate ions.

[0042] Comparative Example 2

[0043] Compared with Example 1, the only difference is that the raw material preparation process uses concentrated nitric acid to heat and dissolve the spent Sr-90 radioactive source sheets, resulting in only 5% Sr-90. After adding alkali precipitation, a large amount of AgOH flocculent precipitate is obtained, making it impossible to proceed to the next step.

[0044] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A method for separation and preparation from spent Sr-90 radioactive sources 90 The method for the gamma nuclide, characterized in that The method comprises a pre-treatment process and a separation process, wherein the pre-treatment process sequentially performs the following steps: 1) The waste Sr-90 radioactive source 90 Sr is leached with aqua regia to obtain a leachate at room temperature for 1-4 hours; 2) heating the leachate to remove NO2; 3) adding iron to the leachate to react, wherein the iron is in excess; 4) adjusting the pH of the leachate to 12-14, and obtaining a clear solution by filtration or centrifugation; 5) Adjust the pH of the clear solution to 4-7 and let it stand for more than 14 days to obtain 90 Sr / 90 Y solution; The separation process comprises: 90 Sr / 90 The pH of the Y solution is adjusted to 10-14, and the precipitate is obtained by filtration or centrifugation, and then the precipitate is dissolved with acid to obtain 90 Y nuclide solution.

2. The method for separating and preparing the waste Sr-90 radioactive source according to claim 1 90 The method for the gamma nuclide, characterized in that The waste Sr-90 radioactive source is a source piece of a waste Sr-90 applicator prepared by a powder metallurgy process.

3. The method for separating and preparing the radioactive material from the waste Sr-90 radioactive source according to claim 1 or 2. 90 The method for the gamma nuclide, characterized in that Step 2) The heating temperature is 60-100° C. and the heating time is 30-60 min.

4. The method for separating and preparing the radioactive material from a waste Sr-90 radioactive source according to claim 1 or 2. 90 The method for the gamma nuclide, characterized in that Step 3) The reaction temperature is room temperature and the reaction time is more than 48 hours.

5. The method for separating and preparing from a waste Sr-90 radioactive source according to claim 3 90 The method for the gamma nuclide, characterized in that Step 3) The reaction temperature is room temperature and the reaction time is more than 48 hours.

6. The method for separating and preparing from a waste Sr-90 radioactive source according to claim 1 or 2 90 The method for the gamma nuclide, characterized in that Step 4) adjusting the pH by adding sodium carbonate, sodium bicarbonate, potassium carbonate, potassium bicarbonate, alkali metal hydroxide or ammonia water.

7. The method for separating and preparing from a waste Sr-90 radioactive source according to claim 3 90 The method for the gamma nuclide, characterized in that Step 4) adjusting the pH by adding sodium carbonate, sodium bicarbonate, potassium carbonate, potassium bicarbonate, alkali metal hydroxide or ammonia water.

8. The method for separating and preparing from a waste Sr-90 radioactive source according to claim 1 or 2. 90 The method for the gamma nuclide, characterized in that Step 4) The filtration uses a 0.1-0.45 μm microporous filter membrane.

9. The method for separating and preparing from a waste Sr-90 radioactive source according to claim 3 90 The method for the gamma nuclide, characterized in that Step 4) The filtration uses a 0.1-0.45 μm microporous filter membrane.

10. The method for separating and preparing from a waste Sr-90 radioactive source according to claim 4 90 The method for the gamma nuclide, characterized in that Step 4) The filtration uses a 0.1-0.45 μm microporous filter membrane.