A high-throughput rapid screening method for radioactive substances in waste textile raw materials

Abstract

The present application relates to the technical field of product quality and safety, in particular to a high-throughput rapid screening method for radioactive substances in waste textile raw materials, comprising the following steps: step one, raw material preselection; step two, raw material pretreatment; step three, radioactive substance detection; step four, radioactive substance measurement and analysis; step five, detection of Sr-90 content in raw materials; and step six, reagent addition. The present application proposes a research on common gamma nuclides and Sr-90 content analysis in textile raw materials, ensures the radioactivity safety of textile raw materials, establishes a method for detecting radioactive substance Sr-90 in waste textile raw material solid waste by using a low-background alpha beta measuring instrument, the average recovery rate of the method is 80%, the average detection limit, and the radioactive detection of waste textile raw materials is studied. The research results show that the content of gamma radioactive nuclides in the selected waste textile raw material samples meets the national limit standard requirements, and reduces the pollution of common radioactive nuclides.

Description

Technical Field

[0001] This invention relates to a screening method, and more particularly to a high-throughput rapid screening method for radioactive substances in waste textile raw materials, belonging to the field of product quality and safety technology. Background Technology

[0002] With the increasing depletion of traditional energy sources and the looming energy crisis and pollution, nuclear energy, as a clean and efficient energy source, is gradually replacing traditional energy. Although the safety requirements for nuclear power plants are now extremely stringent, nuclear leakage accidents can still occur under extreme conditions, such as strong earthquakes. With the construction of a large number of nuclear power units in my country and the Fukushima nuclear accident in 2011, the monitoring of artificial radioactive isotope activity levels has received widespread attention. Accidents at nuclear power plants or other nuclear facilities will release large amounts of fission products into the environment, mainly I-131, Cs-134, Cs-137, and Sr-90. Furthermore, with the vigorous development of the nuclear industry and uranium mining... The scale is gradually expanding. In natural radioactive mining areas, there is a high probability that the activity levels of natural radionuclides such as U-235 and K-40 are significantly higher than in other places. The local environment is contaminated by these natural radionuclides. Textile raw materials grown in these contaminated environments, such as cotton, linen, and animal hair, are very likely to be contaminated by these radionuclides. In fact, due to bioaccumulation, the activity level of a certain nuclide may be significantly increased. After these contaminated textile raw materials are processed into textiles and clothing through weaving, pretreatment and other processes, radioactive substances may remain in them. If humans wear such textiles and clothing, the radioactive substances in them will cause serious harm to human health.

[0003] With economic development, people have higher standards for their clothing, food, housing, and transportation. The detection of harmful substances in textiles has also attracted global attention. However, in the field of textile safety, people are currently only concerned with harmful substances such as formaldehyde, harmful dyes, and heavy metals. There have been no reports on the detection and analysis of radioactive substances that may be present. However, the risk of textile raw material contamination caused by radioactive substances is gradually increasing. Therefore, it is of great significance to carry out this study.

[0004] Therefore, there is an urgent need to improve the screening methods for radioactive materials in order to solve the aforementioned problems. Summary of the Invention

[0005] The purpose of this invention is to provide a high-throughput rapid screening method for radioactive substances in waste textile materials. A study on the analysis of common gamma nuclides and Sr-90 content in textile materials was proposed, aiming to establish a high-throughput rapid screening technology for radioactive substances in waste textile materials to ensure the radioactive safety of textile materials. A method for detecting Sr-90 radioactive substances in solid waste textile materials was established using a low-background αβ meter. The method has an average recovery rate of 80% and an average detection limit. Radioactive detection studies were conducted on waste textile materials. The results show that the contents of gamma radionuclides Cs-137, Cs-134, I-131, K-40, U-235, and Sr-90 in the selected waste textile material samples all meet the national limit standards. The samples measured in this study did not contain common radionuclide contamination.

[0006] To achieve the above objectives, the main technical solutions adopted by the present invention include:

[0007] A high-throughput rapid screening method for radioactive substances in waste textile raw materials includes the following steps;

[0008] Step 1: Raw material pre-selection. Five representative raw materials, namely cotton, linen, silk, wool, and nylon, are selected and treated with different radioactive material detection pretreatment methods before being measured on the instrument.

[0009] Step 2: Raw material pretreatment;

[0010] Step 3: Detection of radioactive substances. The content of radioactive substances such as Cs-137, Cs-134, I-131, K-40, and U-235 in five representative raw materials, namely cotton, linen, silk, wool, and nylon, is measured using a high-purity germanium gamma spectrometer.

[0011] Step 4: Measure and analyze radioactive materials to determine the activity concentration of the nuclides;

[0012] Step 5: Detection of Sr-90 content in raw materials. Strontium is enriched by calcium carbonate co-precipitation. Sr-90 in the sample is adsorbed by DtBuH18C6 crown ether Sr resin. The content of radioactive Sr-90 is measured by a low-background αβ meter.

[0013] Step 6: Add reagents and analyze the Sr-90 content to determine the Sr-90 content in the sample.

[0014] Preferably, the principle in step one is as follows:

[0015] Five representative raw materials—cotton, linen, silk, wool, and nylon—were selected. Different pretreatment methods for radioactive material detection were used to process the materials before measurement. The test results were compared to evaluate and optimize the pretreatment methods.

[0016] Preferably, the instruments in step one include: an analytical balance, a well-type high-purity germanium gamma spectrometer, a standard sample box, and an oven.

[0017] Preferably, step two specifically includes:

[0018] Direct preparation method: After chopping or cutting the sample, pack it into a sample box, compact it, and prepare a suitable sample for gamma spectrum analysis;

[0019] Dry sample preparation method: Crush the sample appropriately, freeze-dry it or place it in a clean enamel dish and dry it in an oven. After drying, crush or grind the sample before loading it for measurement.

[0020] Ash preparation method: Control the temperature, slowly increase the temperature at the beginning of the carbonization stage to prevent ignition. After carbonization is completed, the temperature can be raised to 400℃ more quickly and ashed at this temperature for ten to several tens of hours to make the sample into ash with the least carbon content. Strictly prevent the temperature in the high-temperature furnace from being too high, which may cause sample loss or sintering. After the ashed sample is cooled in the desiccator, it is weighed and placed in the sample box for measurement.

[0021] Preferably, step four, measurement and analysis, specifically includes:

[0022] Sample preparation: Based on the actual testing requirements, the direct preparation method is adopted, and the sample is loaded into the standard sample box for testing.

[0023] On-machine measurement: Place the standard sample box in the center area of ​​the probe of the well-type high-purity germanium gamma spectrometer, maintain the spectrometer's working conditions, and continuously measure for a sufficient time;

[0024] Nuclide identification: Find the peak and determine the peak position, and calculate the corresponding γ energy based on the determined peak position to determine the type of radioactive nuclide measured;

[0025] Determination of nuclide activity concentration: Based on the characteristics of the identified nuclide, the full-energy peak with high gamma-ray emission probability and low interference is selected as the characteristic peak for analyzing the nuclide. The peak area is calculated, and the activity concentration of the corresponding nuclide in the sample is calculated using the passive efficiency scale. The calculation formula is as follows:

[0026] ;

[0027] Where: C—the content of the nuclide in the sample, Bq / kg;

[0028] N—the count rate (cps) of the selected characteristic peak of the nuclide;

[0029] E – Detection efficiency of the gamma-ray total absorption peak at this energy;

[0030] m — the mass of the sample in the sample box (kg);

[0031] a — The decay branching ratio of the selected characteristic peak of the nuclide as measured.

[0032] Preferably, the instruments in step five include: an analytical balance, a low-background αβ measuring instrument, a muffle furnace, a hot plate, a centrifuge, and a vacuum filtration box.

[0033] Preferably, the reagents in step six include;

[0034] Extraction chromatography column: 2 mL pre-packed column (0.65 g DtBuH18C6 resin);

[0035] Nitric acid, ρ is approximately 1.4 g / mL;

[0036] Strontium carrier solution, with a strontium concentration of 5 mg / mL;

[0037] Sodium hydroxide solution, ω(NaOH) = 50%;

[0038] Sodium carbonate saturated solution;

[0039] Precision test paper: pH 0.5~5.0;

[0040] The solvent in the reagent is distilled water or water of equivalent purity.

[0041] Preferably, the measurement and analysis in step six specifically includes:

[0042] Sample preparation: Based on the actual testing requirements, the ash sample preparation method is adopted;

[0043] Strontium preconcentration: Weigh 1g of ash sample, add 1mL of strontium carrier, 5mL of concentrated nitric acid, and 3mL of hydrogen peroxide. Collect the supernatant and discard the insoluble matter.

[0044] Transfer the sample solution to a beaker, adjust the pH to around 2, and then add 0.5 mL of 1.25 mol / L calcium nitrate solution;

[0045] Adjust the pH of the sample solution to 9-10, and add 30 mL of saturated sodium carbonate solution to the beaker;

[0046] After standing, centrifuge, dissolve the precipitate in 5 mL of concentrated nitric acid in a 100 mL beaker, and evaporate to dryness;

[0047] Sr-90 concentration: Dissolve the evaporated residue in 8 mol / L nitric acid and pass it through an extraction column;

[0048] The chromatography column was then washed with 5 mL of 8 mol / L nitric acid and 5 mL of 3 M oxalic acid, respectively, and the washings were discarded.

[0049] Strontium was desorbed using 10 mL of 0.05 mol / L nitric acid. The desorbed solution was collected in a glass beaker and then added dropwise to the central area of ​​the sample pan after evaporation.

[0050] On-machine measurement: After the prepared sample tray is dried, its mass is weighed and placed in a low-background αβ measuring instrument with pre-measured background and efficiency. An argon methane atmosphere is maintained, and the measurement is performed for a sufficient time. The total β count rate is recorded.

[0051] The content of Sr-90 in the sample was calculated;

[0052] Preferably, the calculation of the Sr-90 content in the sample is as follows:

[0053] ;

[0054] In the formula: C—the content of Strontium-90 in the sample, in Bq / kg;

[0055] N t — Sample count rate, in cps;

[0056] N b — Background count rate, in cps;

[0057] G – Ash-to-fresh ratio, in g / kg;

[0058] J0—The net count rate of the Strontium-90 monitoring source measured when calibrating the detection efficiency of the measuring instrument, in cps;

[0059] J—Net count rate of the Strontium-90 monitoring source when measuring the sample, in cps;

[0060] m 灰 —The mass of the ash sample taken, in grams;

[0061] Y—Chemical recovery rate of the sample;

[0062] E – Detection efficiency of Strontium-90;

[0063] Calculation of the method's lower detection limit (MDA):

[0064] ;

[0065] Where: MDA—lower detection limit, in Bq / kg;

[0066] t b — Background measurement time, in seconds.

[0067] This invention has at least the following beneficial effects:

[0068] 1. In response to the current lack of research on the detection of radioactive substances in textile raw materials and the increasing risk of radioactive contamination of textile raw materials, this study proposes a research method for analyzing the content of common γ nuclides and Sr-90 in textile raw materials. The aim is to establish a high-throughput rapid screening technology for radioactive substances in waste textile raw materials to ensure the radioactive safety of textile raw materials.

[0069] 2. A method for detecting radioactive Sr-90 in waste textile raw materials was established using a low-background αβ measuring instrument. The method had an average recovery rate of 80% and an average detection limit. Radioactivity detection studies were conducted on waste textile raw materials. The results showed that the contents of gamma radionuclides Cs-137, Cs-134, I-131, K-40, U-235, and Sr-90 in the selected waste textile raw material samples all met the national limit standards. The samples measured in this study did not contain common radionuclide contamination. Attached Figure Description

[0070] The accompanying drawings, which are included to provide a further understanding of this application and form part of this application, illustrate exemplary embodiments and are used to explain this application, but do not constitute an undue limitation of this application. In the drawings:

[0071] Figure 1 This is a flowchart of the present invention. Detailed Implementation

[0072] The following will describe in detail the implementation of this application with reference to the accompanying drawings and embodiments, so that the implementation process of how this application uses technical means to solve technical problems and achieve technical effects can be fully understood and implemented accordingly.

[0073] like Figure 1 As shown, the high-throughput rapid screening method for radioactive substances in waste textile raw materials provided in this embodiment includes the following steps;

[0074] Step 1: Raw material pre-selection. The selection method is as follows: select five representative raw materials, namely cotton, linen, silk, wool and nylon, process them with different radioactive substance detection pretreatment methods, and then measure them on the instrument. Compare the detection results and evaluate and optimize the pretreatment methods.

[0075] The equipment includes: an analytical balance, a well-type high-purity germanium gamma spectrometer, a standard sample box, and an oven;

[0076] Step 2: Raw material pretreatment, wherein the treatment method is as follows;

[0077] Direct preparation method: After chopping or cutting the sample, pack it into a sample box, compact it, and prepare a suitable sample for gamma spectrum analysis;

[0078] Dry sample preparation method: Crush the sample appropriately, freeze-dry it or place it in a clean enamel dish and dry it in an oven. After drying, crush or grind the sample before loading it for measurement.

[0079] Ash preparation method: Control the temperature, slowly increase the temperature at the beginning of the carbonization stage to prevent ignition. After carbonization is completed, the temperature can be raised to 400℃ more quickly and ashed at this temperature for ten to several tens of hours to make the sample into ash with the least carbon content. Strictly prevent the temperature in the high-temperature furnace from being too high, which may cause sample loss or sintering. After the ashed sample is cooled in the desiccator, it is weighed and placed in the sample box for measurement.

[0080] For the detection of gamma radionuclides, the conventional pretreatment methods are direct preparation, dry sample preparation, and ash sample preparation. The difficulty and time consumption of the operation increase from the three methods. Since all three methods require filling into a standard sample box, and the volume of the standard sample box is fixed (356 cm3 in this work), the amount of sample required varies depending on the state, density, and compaction of the textile raw material being filled, resulting in different detection limits for the radionuclides. Taking Cs-137 as an example, the detection limit of the direct preparation method is about 1 Bq / kg, the detection limit of the dry sample preparation method is about 0.8 Bq / kg, and the detection limit of the ash sample preparation method is about 0.1 Bq / kg.

[0081] For waste textile raw materials, refer to the standards GB 27742-2011 "Activity Concentration of Radionuclides in Materials Exempt from Radiation Protection Supervision" and Appendix A of GB 18871-2002 "Basic Standards for Ionizing Radiation Protection and Radiation Source Safety". Both are applicable to large-batch and small-batch materials respectively. The exempted concentrations of radionuclides measured in this work are shown in Table 1 below. It can be seen that the detection limits meet the requirements of the limit values ​​regardless of the direct preparation method, dry sample preparation method, or ash sample preparation method.

[0082] Table 1: Exemption Concentrations for Some Radionuclides

[0083] In practice, the choice of which method to use depends primarily on the testing requirements. Specifically, the direct preparation method is advantageous because it is fast, non-destructive to the sample, and safe to operate. For example, for more valuable materials such as cotton, silk, and wool, where non-destructive testing is desired, the sample can be folded and placed into a standard sample box for testing, and then folded back after testing. The gray sample preparation method is preferred because of its low detection limit. If it is desirable to detect as much low-level radioactive material as possible in the raw material, this method should be the first choice. In this work, the direct preparation method is selected because its detection limit meets the limit value requirements, and it also offers better testing speed.

[0084] Step 3: Detection of radioactive materials, the principle of which is:

[0085] The contents of gamma-ray radioactive substances Cs-137, Cs-134, I-131, K-40, and U-235 in five representative raw materials, namely cotton, linen, silk, wool, and nylon, were measured using a high-purity germanium gamma-ray spectrometer.

[0086] The equipment includes: an analytical balance, a well-type high-purity germanium gamma spectrometer, a standard sample box, and an oven;

[0087] Step 4: Measure and analyze radioactive materials to determine the activity concentration of the nuclides;

[0088] The measurement and analysis method is as follows:

[0089] Sample preparation: Based on the actual testing requirements, the direct preparation method described above is adopted, and the sample is loaded into a standard sample box for testing.

[0090] On-machine measurement: Place the standard sample box in the center area of ​​the probe of the well-type high-purity germanium gamma spectrometer, maintain the spectrometer's working conditions, and continuously measure for a sufficient time;

[0091] Nuclide identification: Find the peak and determine the peak position, and calculate the corresponding γ energy based on the determined peak position to determine the type of radioactive nuclide measured;

[0092] Determination of nuclide activity concentration: Based on the characteristics of the identified nuclide, the full-energy peak with high gamma-ray emission probability and low interference is selected as the characteristic peak for analyzing the nuclide. The peak area is calculated, and the activity concentration of the corresponding nuclide in the sample is calculated using the passive efficiency scale. The calculation formula is as follows:

[0093] ;

[0094] Where: C—the content of the nuclide in the sample, Bq / kg;

[0095] N—the count rate (cps) of the selected characteristic peak of the nuclide;

[0096] E – Detection efficiency of the gamma-ray total absorption peak at this energy;

[0097] m — the mass of the sample in the sample box (kg);

[0098] a — The decay branching ratio of the selected characteristic peak of the nuclide as measured;

[0099] For radioactive substances Cs-137, Cs-134, I-131, K-40, and U-235 in waste textile raw materials, the characteristic peaks and corresponding decay branching ratios are shown in Table 1 below. Based on the characteristic peaks selected in Table 2, the activity concentration values ​​of radionuclides in the measured samples are determined by the passive efficiency calibration method.

[0100] Table 2: γ-ray radionuclides to be tested and their characteristic peaks and branching ratios

[0101] Fifteen samples of textile raw materials, including cotton, linen, silk, wool, and nylon, were selected and tested for gamma nuclides using the direct preparation method. The results of gamma radioactivity in all samples are shown in Table 2. It can be seen that almost all the tested radionuclides were undetectable. Only a trace amount of K-40 was detected in sample 2, with a result of 11 Bq / kg, which is far less than the exemption concentration of 100,000 Bq / kg for small batches of materials. K-40 is not managed for large batches of materials. It is evident that the selected waste textile raw material samples did not contain the tested radionuclides.

[0102] Step 5: Detection of Sr-90 content in raw materials, the principle of which is as follows:

[0103] Textile raw material samples were ashed and digested. Strontium was enriched using calcium carbonate co-precipitation. Sr-90 in the samples was then adsorbed onto DtBuH18C6 crown ether Sr resin under a strongly acidic atmosphere, quantitatively adsorbing strontium ions to separate strontium from metal ions such as yttrium. The chromatography column was then washed sequentially with 8 mol / L nitric acid, followed by 3 mol / L nitric acid and 0.05 mol / L oxalic acid to remove interference from calcium, barium, other alkaline earth metal ions, and rare earth ions. Finally, strontium was desorbed using 0.05 mol / L nitric acid, and the content of radioactive Sr-90 was measured using a low-background αβ analyzer.

[0104] The instruments and equipment include: analytical balance, low background αβ measuring instrument, muffle furnace, hot plate, centrifuge, and vacuum filtration box;

[0105] All reagents, unless otherwise specified, are of analytical grade; water is distilled water or water of equivalent purity.

[0106] Extraction chromatography column: 2 mL pre-packed column with 0.65 g DtBuH18C6 resin;

[0107] Nitric acid, ρ is approximately 1.4 g / mL;

[0108] Strontium carrier solution, with a strontium concentration of 5 mg / mL;

[0109] Sodium hydroxide solution, ω(NaOH) = 50%;

[0110] Sodium carbonate saturated solution;

[0111] Precision test paper: pH 0.5~5.0;

[0112] Step 6: Add reagents and analyze the Sr-90 content to determine the Sr-90 content in the sample;

[0113] The measurement and analysis method is as follows:

[0114] Sample preparation: The ash sample preparation method described above shall be adopted according to the actual testing requirements;

[0115] Strontium preconcentration: Weigh 1g of ash sample, add 1mL of strontium carrier, 5mL of concentrated nitric acid, and 3mL of hydrogen peroxide. Collect the supernatant and discard the insoluble matter.

[0116] Transfer the sample solution to a beaker, adjust the pH to around 2, and then add 0.5 mL of 1.25 mol / L calcium nitrate solution;

[0117] Adjust the pH of the sample solution to 9-10, and add 30 mL of saturated sodium carbonate solution to the beaker;

[0118] After standing, centrifuge, dissolve the precipitate in 5 mL of concentrated nitric acid in a 100 mL beaker, and evaporate to dryness;

[0119] Sr-90 concentration: Dissolve the above evaporated dry matter in 8 mol / L nitric acid and pass it through an extraction column;

[0120] The chromatography column was then washed with 5 mL of 8 mol / L nitric acid and 5 mL of 3 M oxalic acid, respectively, and the washings were discarded.

[0121] Strontium was desorbed using 10 mL of 0.05 mol / L nitric acid. The desorbed solution was collected in a glass beaker and then added dropwise to the central area of ​​the sample pan after evaporation.

[0122] On-machine measurement: After the prepared sample tray is dried, its mass is weighed and placed in a low-background αβ measuring instrument with pre-measured background and efficiency. An argon methane atmosphere is maintained, and the measurement is performed for a sufficient time. The total β count rate is recorded.

[0123] The content of Sr-90 in the sample was calculated;

[0124] In this embodiment, as Figure 1 As shown, the calculation of the Sr-90 content in the sample is as follows:

[0125] ;

[0126] In the formula: C—the content of Strontium-90 in the sample, in Bq / kg;

[0127] N t — Sample count rate, in cps;

[0128] N b — Background count rate, in cps;

[0129] G – Ash-to-fresh ratio, in g / kg;

[0130] J0—The net count rate of the Strontium-90 monitoring source measured when calibrating the detection efficiency of the measuring instrument, in cps;

[0131] J—Net count rate of the Strontium-90 monitoring source when measuring the sample, in cps;

[0132] m 灰 —The mass of the ash sample taken, in grams;

[0133] Y—Chemical recovery rate of the sample;

[0134] E – Detection efficiency of Strontium-90.

[0135] Calculation of the method's lower detection limit (MDA):

[0136] ;

[0137] Where: MDA—lower detection limit, in Bq / kg;

[0138] t b —Baseline measurement time, in seconds;

[0139] To calculate the recovery rate of the method, three samples of each type of textile raw material (cotton, linen, silk, wool, and nylon) were selected, for a total of 15 samples. 5 mg of strontium carrier was added to each sample. The recovery rate of the samples was calculated by gravimetric method. The results are shown in Table 4. The detection limit of the method was calculated according to the formula. The results are shown in Table 5.

[0140] Table 4. Recovery results of Sr-90 in waste textile raw material samples

[0141] Table 5. Detection limits of Sr-90 in waste textile raw material samples

[0142] As can be seen, the average recovery rate of this method for cotton, linen, silk, wool, and nylon textile raw material samples was 83.1%, indicating that the method can effectively enrich Sr element in textile samples. The average detection limit of this method was 0.93 Bq / kg. Comparing the detection limit of this method with the standard limit, it can be seen that the detection limit of this method is much lower than the standard limit, which can meet the requirements for rapid analysis of Sr-90. Finally, Sr-90 in 15 samples was detected, and the results were all negative, that is, the samples measured in this study did not have radioactive Sr-90 contamination.

[0143] This paper addresses the current lack of research in the field of radioactive substance detection in textile raw materials, as well as the increasing risk of radioactive contamination of textile raw materials. It proposes a study on the analysis of common γ nuclides and Sr-90 content in textile raw materials, aiming to establish a high-throughput rapid screening technology for radioactive substances in waste textile raw materials and ensure the radioactive safety of textile raw materials.

[0144] Based on the properties of the nuclides to be tested, the performance of the detector, and existing domestic and international research on radionuclide analysis methods, a method for pretreatment and extraction of radioactive substances from waste textile materials was established. The direct preparation method is advantageous due to its speed, non-destructive nature, high economic efficiency, and safe operation. The ash sample preparation method is preferred due to its low detection limit. This work established a direct preparation method for detecting gamma radionuclides in waste textile materials using a high-purity germanium gamma spectrometer, with a detection limit of 1 Bq / kg, meeting the radioactive limit requirements of relevant national standards. This work also established a method for detecting Sr-90 radioactive substances in solid waste from waste textile materials using a low-background αβ meter. The method achieved an average recovery rate of 80% and an average detection limit. Radioactive detection studies were conducted on waste textile materials. The results show that the contents of gamma radionuclides Cs-137, Cs-134, I-131, K-40, U-235, and Sr-90 in the selected waste textile material samples all meet the national limit requirements. The samples measured in this study did not exhibit common radionuclide contamination.

[0145] If certain terms are used in the specification and claims to refer to specific components, those skilled in the art will understand that hardware manufacturers may use different names to refer to the same component. This specification and claims do not distinguish components based on differences in name, but rather on differences in function. The term "comprising" as used throughout the specification and claims is an open-ended term and should be interpreted as "comprising but not limited to." "Approximately" means that within an acceptable margin of error, those skilled in the art can solve the technical problem and substantially achieve the technical effect within a certain margin of error.

[0146] It should be noted that the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a product or system comprising a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a product or system. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the product or system that includes that element.

[0147] The foregoing description illustrates and describes several preferred embodiments of the present invention. However, as previously stated, it should be understood that the present invention is not limited to the forms disclosed herein and should not be construed as excluding other embodiments. It can be used in various other combinations, modifications, and environments, and can be altered within the scope of the inventive concept described herein through the foregoing teachings or techniques or knowledge in related fields. Any modifications and variations made by those skilled in the art that do not depart from the spirit and scope of the present invention should be within the protection scope of the appended claims.

Claims

1. A high-throughput rapid screening method for radioactive substances in waste textile raw materials, characterized in that, Includes the following steps; Step 1: Raw material pre-selection. Five representative raw materials, namely cotton, linen, silk, wool, and nylon, are selected and treated with different radioactive material detection pretreatment methods before being measured on the instrument. Step 2: Raw material pretreatment; Step 3: Detection of radioactive substances. The content of radioactive substances Cs-137, Cs-134, I-131, K-40 and U-235 in five representative raw materials, namely cotton, linen, silk, wool and nylon, was measured using a high-purity germanium gamma spectrometer. Step 4: Measure and analyze radioactive materials to determine the activity concentration of the nuclides; Step 5: Detection of Sr-90 content in raw materials. Strontium is enriched by calcium carbonate co-precipitation. Sr-90 in the sample is adsorbed by DtBuH18C6 crown ether Sr resin. The content of radioactive Sr-90 is measured by a low-background αβ meter. Step Six: Add reagents and analyze the Sr-90 content to determine the Sr-90 content in the sample. The measurement and analysis in Step Four specifically includes: (5.1) Sample preparation: Based on the actual testing requirements, the direct preparation method is adopted, and the sample is loaded into the standard sample box for testing; (5.2) On-machine measurement: Place the standard sample box in the center area of ​​the probe of the well-type high-purity germanium gamma spectrometer, maintain the spectrometer working conditions, and continuously measure for a sufficient time; (5.3) Identification of radionuclides: Find the peak and determine the peak position, and calculate the corresponding γ energy based on the determined peak position, thereby determining the type of radionuclide measured; (5.4) Determination of nuclide activity concentration: Based on the characteristics of the identified nuclide, select the full-energy peak with high gamma-ray emission probability and low interference as the characteristic peak for analyzing the nuclide. Calculate the peak area, and calculate the activity concentration of the corresponding nuclide in the sample using the passive efficiency scale. The calculation formula is as follows: ； Where: C—the content of the nuclide in the sample, Bq / kg; N—the count rate (cps) of the selected characteristic peak of the nuclide; E – Detection efficiency of the gamma-ray total absorption peak at this energy; m — the mass of the sample in the sample box (kg); a — The decay branching ratio of the selected characteristic peak of the nuclide as measured.

2. The high-throughput rapid screening method for radioactive substances in waste textile raw materials according to claim 1, characterized in that: The principle in step one is as follows: Five representative raw materials—cotton, linen, silk, wool, and nylon—were selected. Different pretreatment methods for radioactive material detection were used to process the materials before measurement. The test results were compared to evaluate and optimize the pretreatment methods.

3. The high-throughput rapid screening method for radioactive substances in waste textile raw materials according to claim 1, characterized in that: The instruments used in step one include: an analytical balance, a well-type high-purity germanium gamma spectrometer, a standard sample box, and an oven.

4. The high-throughput rapid screening method for radioactive substances in waste textile raw materials according to claim 1, characterized in that: Step two specifically involves: Direct preparation method: After chopping or cutting the sample, pack it into a sample box, compact it, and prepare a suitable sample for gamma spectroscopy analysis; Dry sample preparation method: Crush the sample appropriately, freeze-dry it or put it in a clean enamel tray and dry it in an oven. After drying, crush or grind the sample before loading it for measurement. Ash preparation method: Control the temperature, slowly increase the temperature at the beginning of the carbonization stage to prevent ignition. After carbonization is completed, the temperature can be raised to 400℃ more quickly and ashed at this temperature for ten to several tens of hours to make the sample into ash with the least carbon content. Strictly prevent the temperature in the high-temperature furnace from being too high, which may cause sample loss or sintering. After the ashed sample is cooled in the desiccator, it is weighed and placed in the sample box for measurement.

5. The high-throughput rapid screening method for radioactive substances in waste textile raw materials according to claim 1, characterized in that: The instruments in step five include: an analytical balance, a low-background αβ measuring instrument, a muffle furnace, a hot plate, a centrifuge, and a vacuum filtration box.

6. The high-throughput rapid screening method for radioactive substances in waste textile raw materials according to claim 1, characterized in that: The reagents in step six include: Extraction chromatography column: 2 mL pre-packed column with 0.65 g DtBuH18C6 resin; Nitric acid, ρ is approximately 1.4 g / mL; Strontium carrier solution, with a strontium concentration of 5 mg / mL; Sodium hydroxide solution, ω(NaOH) = 50%; Sodium carbonate saturated solution; Precision test paper: pH 0.5~5.0; The solvent in the reagent is distilled water or water of equivalent purity.

7. The high-throughput rapid screening method for radioactive substances in waste textile raw materials according to claim 4, characterized in that: The measurement and analysis in step six specifically includes: (8.1) Sample preparation: Based on the actual testing requirements, the ash sample preparation method shall be adopted; (8.2) Strontium preconcentration: Weigh 1g of ash sample, add 1mL of strontium carrier, add 5mL of concentrated nitric acid and 3mL of hydrogen peroxide, collect the supernatant and discard the insoluble matter; Transfer the sample solution to a beaker, adjust the pH to around 2, and then add 0.5 mL of 1.25 mol / L calcium nitrate solution; Adjust the pH of the sample solution to 9-10, and add 30 mL of saturated sodium carbonate solution to the beaker; After standing, centrifuge, dissolve the precipitate in 5 mL of concentrated nitric acid in a 100 mL beaker, and evaporate to dryness; (8.3) Sr-90 concentration: Dissolve the evaporated product from (8.2) in 8 mol / L nitric acid and pass it through an extraction column; The chromatography column was then washed with 5 mL of 8 mol / L nitric acid and 5 mL of 3 M oxalic acid, respectively, and the washings were discarded. Strontium was desorbed using 10 mL of 0.05 mol / L nitric acid. The desorbed solution was collected in a glass beaker and then added dropwise to the central area of ​​the sample pan after evaporation. (8.4) Measurement on the instrument: After the prepared sample tray is dried, it is weighed and placed in a low background αβ measuring instrument with pre-measured background and efficiency. The instrument is kept in an argon methane atmosphere and measured for a sufficient time. The total β count rate is recorded. (8.5) Calculate the content of Sr-90 in the sample.

8. The high-throughput rapid screening method for radioactive substances in waste textile raw materials according to claim 7, characterized in that: The calculation of the Sr-90 content in the sample is as follows: ； In the formula: C—the content of Strontium-90 in the sample, in Bq / kg; N t — Sample count rate, in cps; N b — Background count rate, in cps; G – Ash-to-fresh ratio, in g / kg; J0—The net count rate of the Strontium-90 monitoring source measured when calibrating the detection efficiency of the measuring instrument, in cps; J—Net count rate of the Strontium-90 monitoring source when measuring the sample, in cps; m 灰 —The mass of the ash sample taken, in grams; Y—Chemical recovery rate of the sample; E – Detection efficiency of Strontium-90; Calculation of the method's lower detection limit (MDA): ； Where: MDA—lower detection limit, in Bq / kg; t b — Background measurement time, in seconds.

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