Separation, purification and source preparation method for analyzing radioactive silver in fission product
By generating AgCl precipitate in nitric acid medium and combining it with ammonia dissolution and organic compound reduction, the problems of complex separation, purification, and source preparation processes and the introduction of impurities in radioactive silver have been solved, realizing a simple and efficient quantitative analysis of radioactive silver.
Patent Information
- Application Number
- CN202511817557.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-04
- Publication Date
- 2026-03-17
AI Technical Summary
In the existing technology, the separation, purification and source preparation methods of radioactive silver are complicated to operate and easily introduce other metal ions, making it difficult to perform accurate gamma measurement and mass spectrometry or atomic emission spectroscopy analysis.
Ag ion solution was added under nitric acid medium to generate AgCl precipitate. After centrifugation and washing, the precipitate was dissolved in ammonia water to form a silver ammonia solution. Then, Ag element was generated by reducing organic compounds. The precipitate was washed with anhydrous ethanol and deionized water, and finally dissolved in nitric acid to prepare a silver solution.
The operation process was simplified, the introduction of other metal ions was avoided, and efficient purification and quantitative measurement of radioactive silver were achieved, with a recovery rate of over 90% and an impurity removal rate of over 10³.
Abstract
Description
TECHNICAL FIELD
[0001] The application belongs to the technical field of radiochemical separation, and particularly relates to a separation and purification method and a source preparation method for analyzing radioactive silver in fission products. BACKGROUND
[0002] The silver ion and chloride ion generate a silver chloride precipitate and a silver mirror reaction is a characteristic reaction of silver, which is widely used in the production and research fields. At present, there are methods for generating a silver chloride precipitate from the reaction of silver ions and chloride ions for Ag separation. However, silver chloride is difficult to dissolve, and it is difficult to carry out accurate gamma measurement, and it is impossible to measure the concentration by mass spectrometry or atomic emission spectrometry.
[0003] Rouser et al. (Separation of the radioisotopes of silver and palladium, Journal of American Chemcal Society, 1951, 74: 2398) dissolved the Pd target irradiated by neutrons with aqua regia, added a carrier, then added excess ammonia water, reduced the solution with ascorbic acid, and obtained Ag element. Sicilio et al. (Separation of radioactive silver-111 from pile-irradiated palladium, Analytical Chemistry, 1956, 28(3): 365-366) used the difference in solubility of Ag in concentrated hydrochloric acid and dilute hydrochloric acid to separate Ag from the Pd target, then dissolved the precipitate with ammonia water, then converted Ag into Ag2O precipitate with sodium hydroxide, and then dissolved it with nitric acid. Alexander et al. (Short-lived isotopes of Pd and Ag of masses 113-117, Physical Review, 1958, 111(1): 228-236) used the same method to first separate Ag fission products from a U target in the form of AgCl, then dissolved it with ammonia water, then reduced Ag with Zn, then dissolved it with nitric acid, and then removed Zn with a chloroform solution of dimethylglyoxime. Although these methods ultimately obtained silver or silver oxide that can be dissolved with nitric acid, they are only used for the separation of silver in a system of silver and palladium ions, and the reaction process is relatively harsh, the operation is relatively complex, and other metal ions are introduced in the process. SUMMARY
[0004] In order to overcome the deficiencies of complex operation and introduction of other metal ions in Ag separation and purification and source preparation, the application provides a separation and purification method and a source preparation method for analyzing radioactive silver in fission products.
[0005] The technical solution adopted by this invention to solve its technical problem is: A method for separating and purifying radioactive silver in fission products, comprising the following steps: Step 1, Preparation of fission product solution Nitric acid is added to the fission products to prepare a fission product solution in nitric acid medium of 1 mol / L to 5 mol / L.
[0006] Step 2, add Ag ion solution A 1 mol / L to 5 mol / L Ag ion solution in nitric acid medium is added to a fission product solution. This yields a fission product solution containing Ag.
[0007] Step 3, add hydrochloric acid When hydrochloric acid is added to a solution containing Ag fission products, AgCl precipitate is formed.
[0008] Step 4: Collect the precipitated AgCl The supernatant was removed by centrifugation to obtain the precipitated AgCl.
[0009] Step 5, washing with AgCl AgCl washing includes adding water, dispersion, and separation.
[0010] Add deionized water to the precipitated AgCl, disperse by ultrasonication, separate by centrifugation, and aspirate the supernatant; repeat the process of adding water, dispersing, and separating until the pH of the supernatant is greater than 6 to obtain neutral AgCl.
[0011] Step 6, Prepare silver ammonia solution Ammonia solution with a concentration of 0.3 mol / L to 0.5 mol / L was added to neutral AgCl and dissolved by sonication to obtain a silver ammonia solution for the analysis of radioactive silver in fission products.
[0012] The above-mentioned separation and purification method produces fission products that are neutron-irradiated fission products of uranium or plutonium.
[0013] In the above separation and purification method, the number of moles of hydrochloric acid added is greater than the number of moles of silver ions in the Ag-containing fission product solution, and the molar concentration of chloride ions in the solution after adding hydrochloric acid is less than 4 mol / L.
[0014] In the above separation and purification method, in step 4, the centrifuge speed is 2000 rpm to 5000 rpm and the time is 10 min.
[0015] In the above separation and purification method, in step 5, the centrifuge speed is 2000 rpm to 5000 rpm and the time is 10 min.
[0016] A source preparation method for the analysis of radioactive silver in fission products, comprising any one of the above-mentioned separation and purification methods, further comprising: Step 7, Extract Ag elemental Adding a reducing organic compound aqueous solution to a silver ammonia solution and maintaining it in a water bath at 20~80℃ for 10min~10h will produce elemental Ag.
[0017] Step 8: Wash and dissolve Ag Ag washing includes washing with anhydrous ethanol and washing with deionized water.
[0018] Anhydrous ethanol washing: Add anhydrous ethanol to a container containing Ag, disperse by ultrasonication, separate by centrifugation, and aspirate the supernatant. Alternatively, wash several times with anhydrous ethanol to obtain Ag washed with anhydrous ethanol.
[0019] Washing with deionized water: Add deionized water and separate the product using a centrifuge, then aspirate the supernatant. Alternatively, wash several times with deionized water to obtain washed Ag.
[0020] The washed Ag was dissolved in concentrated nitric acid and then diluted with deionized water to the required concentration to obtain a nitric acid solution of Ag, which is the source solution used for the analysis of radioactive silver in the fission products.
[0021] In the above-described source preparation method, in step 7, the aqueous solution of the reducing organic compound is an aqueous solution of formaldehyde or acetaldehyde, or a saturated solution of glucose or fructose.
[0022] In the above-described source preparation method, step 8 involves washing with Ag, washing twice with anhydrous ethanol, and washing three times with deionized water. Alternatively, it may involve washing once with anhydrous ethanol and twice with deionized water.
[0023] In the above-described source preparation method, in step 8, Ag is washed and the centrifuge speed is 2000~5000 rpm.
[0024] The beneficial effects of this invention are: A source preparation method for the analysis of radioactive silver in fission products is disclosed. The method is simple to operate, does not introduce other metal ions in the entire process, and can purify radioactive silver multiple times to improve the decontamination level. The final product is a silver nitric acid solution, which is convenient for quantitative measurement of radioactive silver by gamma-ray measurement or mass spectrometry and atomic emission spectrometry.
[0025] A source preparation method for the analysis of radioactive silver in fission products combines two characteristic reactions of silver: the precipitation effect of chloride ions on silver ions and the reduction effect of aldehyde compounds on silver ammonium complex ions. The reaction directly separates radioactive silver from fission products and prepares a liquid measurement source. The method is simple and environmentally friendly, and the entire process does not introduce other metal elements. The prepared measurement source is easy to use for quantitative analysis via gamma measurement and mass spectrometry or atomic emission spectrometry. The Ag recovery rate is approximately 90%, and the radionuclide impurity removal rate is within 10%. 3 above. Detailed Implementation
[0026] The present invention will be further described in detail below with reference to specific embodiments.
[0027] Example 1 A method for the separation, purification, and source preparation of radioactive silver for quantitative analysis of fission products, comprising the following steps: Step 1: Take 3-10 mL of fission product solution in 1-5 mol / L nitric acid medium; Step 2: Add 0.1-5 mL of a solution containing 1-5 mol / L nitric acid and 1-9 mg of Ag ions to the solution in step 1); Step 3: Add hydrochloric acid to the solution in step 2) to react and generate AgCl precipitate; The number of moles of hydrochloric acid added is greater than the number of moles of silver ions in the Ag fission product solution, and the molar concentration of chloride ions in the solution after adding hydrochloric acid is less than 4 mol / L.
[0028] Step 4: Collect the AgCl precipitate produced in step 3); The collection process involves centrifuging at 2000-5000 rpm for 10 minutes and then aspirating the supernatant.
[0029] Step 5: Wash the AgCl collected in step 4) until neutral; The procedure to wash to near neutral is as follows: add 3-8 mL of deionized water to the precipitate collected in step 4), disperse by sonication, centrifuge at 2000-5000 rpm for 10 min, aspirate the supernatant, and measure the pH with pH paper. If it is less than 6, repeat this step until the pH value of the supernatant is greater than 6.
[0030] Step 6: Add ammonia water to the AgCl precipitate from step 5) and sonicate to dissolve it to generate a silver ammonia solution; The ammonia solution has a concentration of 0.3~0.5 mol / L and a volume of 1~12 mL.
[0031] Step 7: Add an aqueous solution of a reducing organic compound to the silver ammonia solution in step 6, and react to produce elemental Ag. The reducing organic compound aqueous solution is a commercially available formaldehyde or acetaldehyde aqueous solution purchased within one month, or a saturated solution of glucose or fructose prepared within one month, with a solution volume of 0.1 mL to 0.5 mL.
[0032] The conditions for the reaction to produce Ag elemental substance are: 20~80℃ water bath for 10 min-10 h.
[0033] Step 8: Collect and wash the Ag produced in step 7), then dissolve it in nitric acid.
[0034] The washing steps are as follows: add 3-8 mL of anhydrous ethanol, disperse by ultrasonication, centrifuge at 2000-5000 rpm, aspirate the supernatant, and wash twice; then add 3-8 mL of deionized water, centrifuge at 2000-5000 rpm, aspirate the supernatant, and wash three times.
[0035] Example 2 In a 1 mol / L nitric acid medium solution containing 5 mL of uranium neutron irradiation fission products, 1 mL of a 1 mol / L nitric acid solution containing 2 mg / mL AgNO3 was added, followed by 1 mL of commercially available concentrated hydrochloric acid. The mixture was centrifuged at 4000 rpm for 10 min, and the supernatant was carefully aspirated to collect the AgCl precipitate. 5 mL of deionized water was added to the precipitate, and the mixture was ultrasonically dispersed. The mixture was centrifuged at 4000 rpm for 10 min, and the supernatant was aspirated. The mixture was washed twice. 1 mL of 1 mol / L ammonia solution was added to the obtained AgCl precipitate, and the mixture was ultrasonically dissolved. 0.1 mL of 40% acetaldehyde aqueous solution was added, and the mixture was incubated in a 60 °C water bath for 6 h. The mixture was centrifuged at 4000 rpm for 10 min, and the supernatant was carefully aspirated to collect the Ag precipitate. 5 mL of anhydrous ethanol was added, and the mixture was ultrasonically dispersed. The mixture was centrifuged at 4000 rpm for 10 min, and the supernatant was aspirated. The mixture was then washed once with anhydrous ethanol. Then, 5 mL of deionized water was added, and the mixture was ultrasonically dispersed. It was then centrifuged at 4000 rpm for 10 min, and the supernatant was aspirated. The mixture was then washed twice with deionized water. Finally, it was dissolved in 0.5 mL of concentrated nitric acid and diluted to 7.5 mL with deionized water. ICP-AES analysis showed a recovery rate of 89%. Gamma detector measurements showed that all radioactive impurities were removed within 10... 3 above.
[0036] Example 3 To a 3 mL solution of plutonium neutron irradiation fission products in 3 mol / L nitric acid medium, add 1 mL of a 3 mol / L nitric acid solution containing 5 mg / mL AgNO3, then add 2 mL of commercially available concentrated hydrochloric acid. Centrifuge at 3000 rpm for 12 min, carefully aspirate the supernatant to collect the AgCl precipitate. Add 3 mL of deionized water to the precipitate, sonicate to disperse, centrifuge at 3000 rpm for 12 min, aspirate the supernatant, and wash twice. Add 2 mL of 7 mol / L ammonia solution to the obtained AgCl precipitate and sonicate until dissolved. Add 0.5 mL of 0.5 g / mL glucose aqueous solution, incubate at 60 ℃ for 6 h, centrifuge at 3000 rpm for 12 min, carefully aspirate the supernatant to collect the Ag precipitate. Add 5 mL of anhydrous ethanol, sonicate to disperse, centrifuge at 3000 rpm for 12 min, aspirate the supernatant, and wash once with anhydrous ethanol. Then, 5 mL of deionized water was added, and the mixture was ultrasonically dispersed. It was then centrifuged at 3000 rpm for 12 min, and the supernatant was aspirated. The mixture was then washed twice with deionized water. Finally, it was dissolved in 0.5 mL of concentrated nitric acid and diluted to 7.5 mL with deionized water. ICP-AES analysis showed a recovery rate of 92%. Gamma detector measurements showed that all radioactive impurities were decontaminated within 10... 3 above.
Claims
1. A separation and purification method for the analysis of radioactive silver in fission products, characterized by, The method comprises the following steps: Step 1, preparation of fission product solution: Add nitric acid to the fission product to prepare a fission product solution with a nitric acid medium of 1 mol / L to 5 mol / L; Step 2, addition of Ag ion solution: Add an Ag ion solution with a nitric acid medium of 1 mol / L to 5 mol / L to the fission product solution with the nitric acid medium; Obtain a fission product solution containing Ag; Step 3, addition of hydrochloric acid: Add hydrochloric acid to the fission product solution containing Ag to generate AgCl precipitate through reaction; Step 4, collection of AgCl precipitate: Separate and treat by using a centrifuge, and then suck out the supernatant to obtain the AgCl precipitate; Step 5, AgCl washing: The AgCl washing comprises water adding, dispersion and separation; Add deionized water to the AgCl precipitate, ultrasonic dispersion, centrifugal separation treatment, and then suck out the supernatant; repeat the water adding, dispersion and separation process until the pH value of the supernatant is greater than 6 to obtain neutral AgCl; Step 6, preparation of silver ammine solution: Add ammonia water with a concentration of 0.3 mol / L to 0.5 mol / L to the neutral AgCl, ultrasonic dissolution, and then obtain the silver ammine solution for analysis of radioactive silver in the fission product.
2. The separation and purification method according to claim 1, characterized by, In the step 1, the fission product is a neutron irradiation fission product of uranium or plutonium.
3. The separation and purification method according to claim 1, characterized by, In the step 3, further comprising: The number of moles of the added hydrochloric acid is greater than the number of moles of silver ions in the fission product solution containing Ag, and the molar concentration of the chloride ions contained in the solution after the addition of the hydrochloric acid is less than 4 mol / L.
4. The separation and purification method according to claim 1, characterized by, In the step 4, the centrifuge rotates at a speed of 2000 rpm to 5000 rpm for 10 min.
5. The separation and purification method according to claim 1, characterized by, In the step 5, the centrifuge rotates at a speed of 2000 rpm to 5000 rpm for 10 min.
6. A method for source preparation for analysis of radioactive silver in fission products, comprising the separation and purification method according to any one of claims 1 to 5, characterized in that, Further comprising: Step 7, extraction of Ag element: Add an aqueous solution of a reducing organic compound to the silver ammine solution, keep in a water bath at 20 to 80 ℃ for 10 min to 10 h, and then generate Ag element; Step 8, Ag washing and dissolution: The Ag washing comprises anhydrous ethanol washing and deionized water washing; The anhydrous ethanol washing comprises the following steps: add anhydrous ethanol to a container containing the Ag element, ultrasonic dispersion, separate and treat by using a centrifuge, and then suck out the supernatant; or wash the Ag element with anhydrous ethanol for several times to obtain Ag washed with anhydrous ethanol; The deionized water washing comprises the following steps: add deionized water, separate and treat by using a centrifuge, and then suck out the supernatant; or wash the Ag element with deionized water for several times to obtain washed Ag; Dissolve the washed Ag with concentrated nitric acid, dilute with deionized water to a required concentration, and then obtain a nitric acid solution of Ag, i.e., a source solution for analysis of radioactive silver in the fission product.
7. The method of claim 6, wherein, In the step 7, the aqueous solution of the reducing organic compound is an aqueous solution of formaldehyde or acetaldehyde, or a saturated solution of prepared glucose or fructose.
8. The method of claim 6, wherein, In the step 8, the Ag washing comprises anhydrous ethanol washing for 2 times and deionized water washing for 3 times; or anhydrous ethanol washing for 1 time and deionized water washing for 2 times.
9. The method of claim 6, wherein, In the step 8, the Ag washing is performed by using a centrifuge rotating at a speed of 2000 rpm to 5000 rpm.