Method for measuring content of zirconium in high-purity hafnium

Abstract

The invention relates to a method for measuring the content of zirconium in high-purity hafnium, and belongs to the technical field of chemical detection. The method comprises the following steps: firstly, accurately determining the zirconium content in a series of hafnium matrix internal control samples by utilizing inductively coupled plasma emission spectrometry to obtain traceable constant value concentration data, so as to establish a solid standard series with known concentration for subsequent analysis; and then, taking the hafnium matrix internal control samples after value determination as calibration substances, determining the signal intensity ratio of zirconium to hafnium in glow discharge mass spectrometry, and constructing an exclusive matrix-matched calibration curve by taking the value determination concentration as a reference. This curve establishes a deterministic relationship between the signal response and the true concentration under the instrument condition. And finally, analyzing a to-be-detected high-purity hafnium sample under the same condition, and substituting the obtained signal intensity ratio into the calibration curve to calculate the accurate zirconium content.

Description

Technical Field

[0001] This application relates to the field of chemical detection technology, and in particular to a method for determining the zirconium content in high-purity hafnium. Background Technology

[0002] Hafnium, as an important rare metal, plays an irreplaceable role in fields such as nuclear industry (reactor control rods), aerospace (high-temperature alloys), and electronic information (semiconductor targets) due to its excellent properties such as high melting point (2227℃), strong corrosion resistance, and large neutron absorption cross section. Nuclear-grade high-purity hafnium typically requires a purity of over 99.99%, and its impurity content directly determines the material's safety and performance stability. Zirconium and hafnium belong to the same group of elements and have very similar chemical properties, and are highly associated in minerals. Therefore, even after complex separation and purification processes, trace amounts of zirconium impurities inevitably remain in high-purity hafnium products. However, zirconium's thermal neutron absorption cross section is several orders of magnitude lower than that of hafnium, and the presence of zirconium significantly weakens the material's neutron absorption efficiency. To ensure the performance of nuclear-grade hafnium materials, the extremely low zirconium impurity content must be accurately measured.

[0003] Currently, the determination of zirconium content in high-purity hafnium mainly relies on two technical solutions, but each has its limitations: Inductively coupled plasma optical emission spectrometry (ICP-OES) is a common method for quantitative elemental analysis in laboratories, but for high-purity hafnium with a purity higher than 99.99%, the zirconium content is close to or below the detection limit of conventional ICP-OES methods, leading to a deterioration in the instrument's signal-to-noise ratio and a significant decrease in the accuracy and repeatability of the measurement results, making it difficult to meet the stringent requirements for monitoring trace impurities in nuclear-grade materials. Glow discharge mass spectrometry (GDMS) is a direct solid-state sample introduction technique with outstanding advantages such as extremely high sensitivity (detection limits down to the ng / g level), relatively small matrix effects, and no need for complex chemical pretreatment, making it very suitable for trace impurity analysis in high-purity materials. However, although GDMS has high sensitivity, it is hampered by calibration and traceability problems, making it difficult to guarantee quantitative accuracy. Summary of the Invention

[0004] This application provides a method for determining the zirconium content in high-purity hafnium to solve the following technical problem: how to accurately, stably and traceably quantify trace zirconium in a high-purity hafnium matrix. This application provides a method for determining the zirconium content in high-purity hafnium, the method comprising: Inductively coupled plasma atomic emission spectrometry (ICP-AES) was used to analyze at least three hafnium-based internal control samples with gradient zirconium content to accurately determine the zirconium content in the hafnium-based internal control samples and obtain the fixed zirconium concentration of each hafnium-based internal control sample. The hafnium matrix internal control sample and the high-purity hafnium sample to be tested, which have been determined, are subjected to solid sample preparation processing to obtain samples suitable for glow discharge mass spectrometry analysis. Under the set instrument parameters, glow discharge mass spectrometry was performed on the hafnium-based internal control sample to obtain the signal intensity ratio of zirconium to hafnium in the hafnium-based internal control sample. A calibration curve is constructed with the fixed zirconium concentration of each of the hafnium-based internal control samples as the ordinate and the signal intensity ratio of zirconium to hafnium in the corresponding hafnium-based internal control samples as the abscissa. The signal intensity ratio of zirconium to hafnium in the high-purity hafnium sample to be tested was determined, and the signal intensity ratio of zirconium to hafnium in the high-purity hafnium sample to be tested was substituted into the calibration curve to obtain the zirconium content in the high-purity hafnium sample to be tested.

[0005] Optionally, the step of performing inductively coupled plasma atomic emission spectrometry (ICP-AES) analysis on at least three hafnium-based internal control samples with gradient zirconium content to accurately determine the zirconium content in the hafnium-based internal control samples and obtain a fixed zirconium concentration for each of the hafnium-based internal control samples includes: The hafnium matrix internal control sample was subjected to acid digestion to completely convert the solid sample into a solution to obtain the sample test solution; The sample test liquid was subjected to inductively coupled plasma atomic emission spectrometry (ICP-AES). Each of the hafnium matrix internal control samples was measured in parallel multiple times to obtain the average zirconium concentration. The average zirconium concentration was used as the fixed zirconium concentration.

[0006] Optionally, the digestion solution used in the acid dissolution and digestion treatment is a mixture of hydrofluoric acid and nitric acid; the mass fraction of the hydrofluoric acid is 48% to 50%, the mass fraction of the nitric acid is 70% to 72%, and the volume ratio of the hydrofluoric acid to the nitric acid is (2 to 10):(1 to 4).

[0007] Optionally, the number of measurements for each hafnium matrix internal control sample is 3 to 10; the relative standard deviation of the multiple measurements is ≤10%.

[0008] Optionally, the solid sample preparation process includes: machining and shaping, surface polishing, acid washing, ultrasonic cleaning, drying, and pre-sputtering.

[0009] Optionally, the machining process involves machining the hafnium matrix internal control sample and the high-purity hafnium sample to be tested into cylinders with a diameter of 15 mm to 30 mm and a thickness of 10 mm to 20 mm.

[0010] Optionally, the pickling treatment uses a nitric acid aqueous solution, wherein the volume ratio of nitric acid to water in the nitric acid aqueous solution is (1-4):(5-10); and the pickling treatment time is 5 min to 15 min.

[0011] Optionally, the instrument parameters set include: using a resolution mode with a quality resolution of not less than 4000 for signal acquisition.

[0012] Optionally, under the set instrument parameters, the discharge conditions for the glow discharge mass spectrometry measurement are: discharge voltage 800V~1200V, discharge current 1mA~3mA.

[0013] Optionally, the glow discharge mass spectrometry measurement is selected from... 90 Zr was selected as the analytical isotope of zirconium. 180 Hf is used as an internal standard isotope of hafnium.

[0014] The technical solutions provided in this application have the following advantages compared with the prior art: This application provides a method for determining the zirconium content in high-purity hafnium. The method includes: performing inductively coupled plasma atomic emission spectrometry (ICP-AES) analysis on at least three hafnium-based internal control samples with gradient zirconium content to accurately determine the zirconium content in the hafnium-based internal control samples, obtaining a fixed zirconium concentration for each hafnium-based internal control sample; preparing solid samples from the determined hafnium-based internal control samples and the high-purity hafnium sample to be tested to obtain samples suitable for glow discharge mass spectrometry analysis; and setting instrument parameters... In this process, glow discharge mass spectrometry was performed on the hafnium-based internal control samples to obtain the signal intensity ratio of zirconium to hafnium in the hafnium-based internal control samples. A calibration curve was constructed with the fixed zirconium concentration of each hafnium-based internal control sample as the ordinate and the corresponding signal intensity ratio of zirconium to hafnium in the hafnium-based internal control samples as the abscissa. The signal intensity ratio of zirconium to hafnium in the high-purity hafnium sample to be tested was measured, and the signal intensity ratio of zirconium to hafnium in the high-purity hafnium sample to be tested was substituted into the calibration curve to obtain the zirconium content in the high-purity hafnium sample to be tested. This application utilizes the mature and highly accurate quantitative advantages of inductively coupled plasma optical emission spectrometry (ICP-OES) in solution systems to precisely determine the zirconium content of a series of hafnium-based internal control samples with the same matrix as the test sample (all hafnium matrix) and with a gradient distribution of zirconium content. This step establishes a series of physical standards with known and measurable concentrations for subsequent solid analysis, thus laying the foundation for accuracy throughout the analytical system. Secondly, a standardized solid sample preparation process is designed to ensure that the pre-defined hafnium matrix internal control samples and the high-purity hafnium sample to be analyzed are highly consistent in physical shape, size, and surface condition. Then, the pre-defined hafnium matrix internal control samples are used as calibrators for direct solid analysis using glow discharge mass spectrometry (GDMS). By measuring the signal intensity ratio of zirconium to hafnium in these calibrators and using the known pre-defined zirconium concentration as a benchmark, a calibration curve specific to the hafnium matrix and excluding matrix effects is established. This curve establishes a definite mathematical relationship between the zirconium signal response and its true concentration under specific instrument conditions. Finally, the high-purity hafnium sample to be analyzed under the same glow discharge mass spectrometry conditions is used to obtain the signal intensity ratio, which is then substituted into the aforementioned calibration curve for calculation to obtain the accurate zirconium content. Because glow discharge mass spectrometry (GFMS) inherently possesses extremely high elemental sensitivity, this method can detect even very low concentrations of zirconium. Furthermore, the calibration curve constructed based on a matrix-matched internal control sample ensures high accuracy in the signal-to-concentration conversion process. Thus, the accurate quantitative capability of ICP-OES, through the hafnium matrix internal control sample as a material carrier and the mathematical relationship of the calibration curve, is fully and reliably transferred and empowered by the high-sensitivity detection of GDMS, achieving a fusion of the advantages of both technologies. Attached Figure Description

[0015] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application.

[0016] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 This is a schematic flowchart illustrating a method for determining the zirconium content in high-purity hafnium, provided in an embodiment of this application. Detailed Implementation

[0018] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0019] The range descriptions used herein, such as numerical ranges and proportional ranges, include all possible sub-ranges and single numerical values ​​within that range. For example, the range descriptions of "1 to 6" or "1~6" cover all sub-ranges (such as 1 to 3, 2 to 5, etc.) and single numbers (such as 1, 2, 3, 4, 5, 6) between 1 and 6. Unless otherwise specified, the terms "including" and "contains" as used herein mean "including but not limited to"; relational terms such as "first" and "second" are used only to distinguish different entities or operations and do not imply an actual order or relationship; "and / or" indicates that multiple situations can exist individually or simultaneously; expressions such as "at least one," "multiple," and "at least one" refer to any combination of the corresponding objects, including combinations of single or multiple objects. The proportional relationships mentioned herein, such as mass ratios and molar ratios, should be understood as the correspondence between the first and second terms of a proportional formula, according to the order of description. The raw materials, reagents, instruments, and equipment used herein can all be obtained through commercial purchase or prepared using existing methods.

[0020] Figure 1 This is a schematic flowchart illustrating a method for determining the zirconium content in high-purity hafnium, provided in an embodiment of this application.

[0021] Please see Figure 1 This application provides a method for determining the zirconium content in high-purity hafnium, the method comprising: S1. At least three hafnium-based internal control samples with gradient zirconium content are analyzed by inductively coupled plasma atomic emission spectrometry to accurately determine the zirconium content in the hafnium-based internal control samples and obtain the fixed zirconium concentration of each hafnium-based internal control sample. S2. The hafnium matrix internal control sample and the high-purity hafnium sample to be tested, which have been determined, are subjected to solid sample preparation processing to obtain a sample suitable for glow discharge mass spectrometry analysis. S3. Under the set instrument parameters, perform glow discharge mass spectrometry on the hafnium-based internal control sample to obtain the signal intensity ratio of zirconium to hafnium in the hafnium-based internal control sample; S4. Construct a calibration curve with the fixed zirconium concentration of each of the hafnium-based internal control samples as the ordinate and the signal intensity ratio of zirconium to hafnium in the corresponding hafnium-based internal control samples as the abscissa. S5. Measure the signal intensity ratio of zirconium to hafnium in the high-purity hafnium sample to be tested, and substitute the signal intensity ratio of zirconium to hafnium in the high-purity hafnium sample to be tested into the calibration curve to obtain the zirconium content in the high-purity hafnium sample to be tested.

[0022] In some embodiments, the step of performing inductively coupled plasma atomic emission spectrometry (ICP-AES) analysis on at least three hafnium-based internal control samples with gradient zirconium content to accurately determine the zirconium content in the hafnium-based internal control samples and obtain a fixed zirconium concentration for each of the hafnium-based internal control samples includes: The hafnium matrix internal control sample was subjected to acid digestion to completely convert the solid sample into a solution to obtain the sample test solution; The sample test liquid was subjected to inductively coupled plasma atomic emission spectrometry (ICP-AES). Each of the hafnium matrix internal control samples was measured in parallel multiple times to obtain the average zirconium concentration. The average zirconium concentration was used as the fixed zirconium concentration.

[0023] ICP-OES determination of zirconium concentration in a hafnium matrix control sample involves two sub-steps: first, acid digestion to convert the solid sample into a solution; and second, ICP-OES measurement, obtaining the average value from multiple parallel measurements as the determined concentration. Acid digestion is a necessary prerequisite because ICP-OES is a solution analysis technique and can only analyze liquid samples. Completely converting the solid metal sample into a solution is fundamental to all subsequent analyses. The ICP-OES measurement section involves multiple parallel measurements for each sample, with the average value taken. This follows analytical chemistry principles, increasing the number of measurements to reduce random errors and improve the precision and robustness of the results. The resulting average zirconium concentration measurement is more representative of the true zirconium concentration of the sample than a single measurement, thus ensuring the data quality of the determined zirconium concentration.

[0024] In some embodiments, the digestion solution used in the acid dissolution and digestion treatment is a mixture of hydrofluoric acid and nitric acid; the mass fraction of the hydrofluoric acid is 48% to 50%, the mass fraction of the nitric acid is 70% to 72%, and the volume ratio of the hydrofluoric acid to the nitric acid is (2 to 10):(1 to 4).

[0025] High-purity hafnium is chemically stable and difficult to dissolve by conventional acids. Hydrofluoric acid is the only inorganic acid that can effectively dissolve metallic hafnium and its oxides. In the embodiments of this application, the mass fraction of hydrofluoric acid is 48%–50%, and the mass fraction of nitric acid is 70%–72%. Hydrofluoric acid and nitric acid work synergistically. The strong oxidizing property of nitric acid promotes the removal of the surface passivation film, while hydrofluoric acid forms a soluble complex with hafnium. This ensures that all hafnium matrix control samples are completely and thoroughly converted into solution form, which is a fundamental prerequisite for subsequent solution analysis.

[0026] Dissolving metallic hafnium is a violently exothermic process. Limiting the volume ratio of hydrofluoric acid (48%–50% by mass) to nitric acid (70%–72% by mass) within the range of (2–10):(1–4) effectively controls the intensity of the reaction, preventing sample loss, boiling over, or the generation of large amounts of toxic nitrogen oxides due to excessively vigorous reaction, thus ensuring operational safety and sample integrity. All hafnium matrix control samples were dissolved under this uniform acid medium and ratio, providing a highly consistent solution matrix environment for subsequent inductively coupled plasma atomic emission spectrometry (ICP-AES) measurements using the standard addition method. Matrix consistency is fundamental to ensuring that the standard addition method effectively counteracts matrix effects, thereby obtaining accurate values ​​for zirconium concentration.

[0027] In some embodiments, the number of measurements for each hafnium matrix control sample is 3 to 10; the relative standard deviation of the multiple measurements is ≤10%.

[0028] The number of measurements was set to 3 to 10 to ensure a sufficient sample size for calculating the average zirconium concentration. This range effectively reduces the influence of random errors in statistical analysis, making the final calculated zirconium concentration statistically representative and stable, and providing a solid data foundation for the subsequent construction of a reliable calibration curve.

[0029] A relative standard deviation of ≤10% across multiple measurements sets a clear upper limit for precision in parallel measurements of each hafnium-based internal control sample. This indicator is a core parameter for evaluating the magnitude of random errors in the measurement process and judging the degree of data centrality. Meeting the requirement of a relative standard deviation of ≤10% across multiple measurements means that repeated measurements of the same hafnium-based internal control sample have high repeatability and consistency, thereby ensuring the reliability of the average zirconium concentration measurement itself.

[0030] In some embodiments, the solid sample preparation process includes: machining and shaping, surface polishing, acid washing, ultrasonic cleaning, drying, and pre-sputtering.

[0031] The purpose of machining and forming is to process the irregularly shaped original hafnium matrix internal control sample and the high-purity hafnium sample to be tested into a solid sample with specific size and shape. This provides the geometric basis for all subsequent surface treatments and ensures that the sample can be adapted and stably installed on the sample holder of the glow discharge mass spectrometer.

[0032] Surface polishing is applied to the surface of a mechanically processed solid sample to remove macroscopic scratches and processing marks, resulting in a preliminary smooth and flat surface. This creates conditions for subsequent more refined chemical cleaning and helps the plasma to be uniformly sputtered on the sample surface during subsequent glow discharge.

[0033] Pickling is applied to the surface of the polished sample. The chemical action of nitric acid aqueous solution is used to dissolve and remove the oxide layer, metallic contaminants and some organic impurities that may have been embedded or generated on the surface during the polishing process, thereby achieving chemical purification of the surface.

[0034] In this embodiment, ultrasonic cleaning is applied to samples that have been acid-washed. By utilizing the cavitation effect generated by ultrasound in ultrapure water and anhydrous ethanol, residual acid, particulate matter, and oily contaminants attached to the sample surface and micropores are physically peeled off and washed away, achieving deep cleaning.

[0035] The drying process is applied to the wet sample after ultrasonic cleaning. Its purpose is to thoroughly remove moisture and organic solvents from the sample surface and any adsorbed substances. This prevents the introduction of water vapor when the sample is subsequently loaded into the vacuum chamber of the glow discharge mass spectrometer, thus avoiding a decrease in vacuum and potential analytical interference.

[0036] Pre-sputtering is the final step after the sample is loaded into the instrument and before formal data acquisition. Its purpose is to bombard the dried sample surface with plasma for a short period under specific discharge conditions. Pre-sputtering can further remove any potentially thin adsorbed or contaminant layers, exposing the bulk material of the sample. This results in a stable, clean, and representative surface for analysis, ensuring that the subsequent zirconium to hafnium signal intensity ratio accurately reflects the bulk composition of the material. In this embodiment, the discharge conditions for pre-sputtering are: discharge voltage 800 V–1200 V, discharge current 1 mA–3 mA, and pre-sputtering time 10 min–40 min.

[0037] This solid sample preparation process creates an ideal analytical interface for subsequent glow discharge mass spectrometry measurements. Without such a systematic processing procedure, direct analysis of the raw sample would severely affect signal stability and accuracy due to issues such as surface contamination, oxide layers, and geometric differences.

[0038] In some embodiments, the machining process involves machining the hafnium matrix internal control sample and the high-purity hafnium sample to be tested into cylinders with a diameter of 15 mm to 30 mm and a thickness of 10 mm to 20 mm.

[0039] Processing samples into cylinders with a diameter of 15mm–30mm and a thickness of 10mm–20mm directly ensures that these samples can be reliably loaded, fixed, and form a stable and repeatable physical contact with the instrument's discharge anode. Inconsistent sample sizes lead to inconsistencies in loading position and contact pressure each time, affecting discharge stability and ultimately affecting fluctuations in the desired signal intensity ratio. Furthermore, uniform size ensures the physical consistency between the hafnium matrix internal control sample and the high-purity hafnium sample to be tested, a prerequisite for comparative analysis. The core of this method lies in calibrating the instrument using the known concentration of the hafnium matrix internal control sample and the measured signal intensity ratio, and then analyzing the unknown sample. If the two types of samples differ significantly in shape, size, and mass, their physical behaviors during discharge, such as heat conduction and sputtering rate, may differ. This systematic error introduced by differences in physical morphology directly affects the validity of the calibration curve and the accuracy of the test sample results. Therefore, processing the samples into cylinders of uniform size eliminates an important potential variable at the physical level, ensuring that the differences in the signals measured later mainly reflect differences in chemical composition (i.e., zirconium content) rather than differences in physical morphology.

[0040] In some embodiments, the pickling treatment uses a nitric acid aqueous solution, wherein the volume ratio of nitric acid to water in the nitric acid aqueous solution is (1-4):(5-10); and the pickling treatment time is 5 min to 15 min.

[0041] Solid sample surfaces that have undergone machining and surface polishing may retain residual metal particles, adsorbed impurities, and potentially thin oxide layers. Immersion in a nitric acid aqueous solution within a specified concentration range for 5 to 15 minutes can effectively dissolve and remove these surface contaminants by utilizing the oxidizing and acidic properties of nitric acid. Simultaneously, this relatively mild concentration and limited treatment time prevent excessive erosion of the solid sample matrix due to excessively high acid concentration or prolonged reaction time, thus maintaining the stability and consistency of the sample's surface morphology.

[0042] In some implementations, the instrument parameters set include: using a resolution mode with a quality resolution of not less than 4000 for signal acquisition.

[0043] When analyzing high-purity hafnium samples, the target isotope to be analyzed (such as...) 90 The zirconium (Zr) signal may be interfered with by signals from ions or polyatomic ions with very similar mass numbers from the matrix itself or other trace impurities. By employing a resolution mode with a mass resolution (Δm / m) of not less than 4000, the target ion peak can be effectively separated from these potential interfering ion peaks, thereby ensuring that the final zirconium signal intensity is purely derived from the target isotope.

[0044] In some embodiments, under the set instrument parameters, the discharge conditions for the glow discharge mass spectrometry measurement are: discharge voltage 800V~1200V, discharge current 1mA~3mA.

[0045] A discharge voltage of 800V to 1200V provides a sufficiently high electric field strength to ensure reliable initiation and maintenance of glow discharge on the sample (cathode) surface. A discharge current of 1mA to 3mA controls the plasma density and energy. This moderate current range ensures sufficient ion current for effective sputtering of the sample surface, generating a stable ion current signal for analysis, while avoiding localized overheating of the sample, excessively fast or uneven sputtering rates, or even discharge mode instability caused by excessive current.

[0046] In some embodiments, the glow discharge mass spectrometry measurement is selected 90 Zr was selected as the analytical isotope of zirconium. 180 Hf is used as an internal standard isotope of hafnium.

[0047] choose 90 Using Zr as an analytical isotope of zirconium is beneficial for obtaining stable and less interfering zirconium characteristic signals; the main isotopes of the matrix element hafnium... 180 Designating Hf as the internal standard isotope means that during the measurement process, the signal intensity of zirconium will always be correlated and compared with the signal intensity of hafnium generated at the same time and the same sample point. This measurement method based on the ratio of isotopic signal intensities can effectively correct signal drift caused by factors such as instrument fluctuations and minor differences in sample surface conditions, thereby ensuring the stability of the calibration curve constructed by the "fixed zirconium concentration" and the "signal intensity ratio", and ultimately improving the accuracy and reproducibility of zirconium content in the high-purity hafnium sample to be tested.

[0048] The present application is further illustrated below with reference to specific embodiments. Experimental methods in the following embodiments that do not specify specific conditions are generally determined according to national / industry standards; if there is no corresponding national / industry standard, they are performed according to general international standards, conventional conditions, or conditions recommended by the manufacturer.

[0049] Example 1 1. Preparation of Hafnium Matrix Internal Control Samples and Determination by Inductively Coupled Plasma Emission Spectroscopy Sample preparation: Five known zirconium content control samples A, B, C, D and E with gradient distribution (mass fractions of approximately 0.02%, 0.04%, 0.1%, 0.2% and 0.5% respectively) in blocky hafnium matrix were selected. Sufficient quantities of each sample were prepared and a portion of each sample was made into shavings.

[0050] Acid digestion treatment: Accurately weigh 0.1000 g of each of the flaky samples A, B, C, D, and E, and place them in 50 mL polytetrafluoroethylene beakers. Add 8 mL of a 4:2 (v / v) mixed acid solution of hydrofluoric acid and nitric acid to each beaker. Digest at low temperature on a hot plate until the solution is completely clear and transparent.

[0051] Preparation of sample test solutions: Cool the completely digested solution to room temperature, transfer it to a 100 mL volumetric flask, wash the beaker several times with ultrapure water and combine the washings, finally dilute to the mark with ultrapure water, shake well, and obtain the corresponding sample test solutions A1, B1, C1, D1, and E1. Simultaneously prepare reagent blank solutions without samples.

[0052] Inductively Coupled Plasma Atomic Emission Spectrometry (ICP-AES): The zirconium content of sample solutions A1, B1, C1, D1, and E1 was determined using an ICP-AES spectrometer equipped with a standard sample introduction system and the standard addition method. Each sample solution was measured in parallel six times. The results are shown in Table 1.

[0053] Table 1. Results of inductively coupled plasma emission spectroscopy (%)

[0054] Fixed value results: The average zirconium concentration from six parallel measurements of each sample was calculated and used as the fixed zirconium concentration for the control sample within the hafnium matrix. The fixed zirconium concentrations for samples A, B, C, D, and E are as follows: C A = 0.020%, C B =0.041%, C C = 0.122%, C D =0.234%, C E =0.554%. The relative standard deviation (RSD) of all parallel determinations was less than 5%, meeting the requirement of ≤10%.

[0055] 2. Solid sample preparation and treatment Machining and forming process: The remaining solid parts of the hafnium matrix internal control samples A, B, C, D, and E that have been determined and have been set, as well as the high-purity hafnium sample X to be tested, are respectively machined into cylinders with a diameter of about 20 mm and a thickness of about 15 mm on a lathe.

[0056] Surface polishing: Use 180-grit silicon carbide wet sandpaper to polish the test end face of each cylindrical sample under running water until the surface is smooth and free of obvious macroscopic scratches.

[0057] Acid washing treatment: Immerse the polished sample in a nitric acid aqueous solution with a volume ratio of 1:5 for 10 minutes.

[0058] Ultrasonic cleaning: Remove the acid-washed sample and place it sequentially into beakers containing ultrapure water and anhydrous ethanol, and ultrasonically clean each for 10 minutes. Repeat this ultrapure water-anhydrous ethanol cleaning cycle 3 times.

[0059] Drying treatment: Place the cleaned sample in a vacuum drying oven at 60°C for 30 minutes, then remove it and place it in a desiccator to cool to room temperature.

[0060] Pre-sputtering treatment: The dried sample was loaded into the sample holder of the glow discharge mass spectrometer. The discharge voltage was set to 1000 V and the discharge current to 2 mA. Each sample was pre-sputtered for 20 minutes to further remove any residual contaminants on the surface and stabilize the surface condition.

[0061] 3. Glow discharge mass spectrometry determination Instrument parameter settings: Medium resolution mode, quality resolution set to 4000. Discharge conditions set: discharge voltage 1000 V, discharge current 2 mA. Select... 90 Zr was selected as the analytical isotope of zirconium. 180 Hf was used as an internal standard isotope.

[0062] Signal intensity ratio determination of hafnium-based internal control samples: Under set parameters, glow discharge mass spectrometry was performed on prepared hafnium-based internal control samples A, B, C, D, and E. Data were collected for each sample after signal stabilization and recorded. 90 Zr and 180 The signal intensity ratio of Hf is converted to the signal intensity ratio of Zr to Hf based on its abundance (I Zr / I Hf Each sample was measured three times, and the average value was taken. The results are shown in Table 2.

[0063] Calibration curve construction: using a fixed zirconium concentration (Ci) of three hafnium matrix control samples. A C B CC C D C E Using the vertical axis (Y), the average signal intensity ratio of zirconium to hafnium (I) is used as the ordinate. Zr / I Hf A, (I) Zr / I Hf B, (I) Zr / I Hf )C, (I Zr / I Hf )D,(I Zr / I Hf Using X as the abscissa (E), a linear fit is performed to obtain the calibration curve equation: Y = 1.0167 × X, with a correlation coefficient R. 2 = 0.9999.

[0064] Table 2. Signal strength ratio of Zr to Hf (%)

[0065] 4. Test Samples and Results Measurement of the test sample: Under identical glow discharge mass spectrometry conditions, the high-purity hafnium sample X, prepared using the same solid sample method, was measured. The measurements were repeated three times to obtain the average signal intensity ratio (Iz) of zirconium to hafnium. Zr / I Hf X = 0.0062%.

[0066] Zirconium content calculation: (I) Zr / I Hf Substituting X = 0.0061% into the constructed calibration curve equation Y = 1.0167×X, the zirconium content of the high-purity hafnium sample X to be tested is calculated to be 0.0062%.

[0067] External reproducibility validation: For 10 consecutive days, sample X was reprepared daily according to step 2 and GDMS was performed once a day (3 measurements per day, averaged). The mean value of the 10 measurements was 0.0060%, and the relative standard deviation was 3.2%, indicating that the method has good long-term stability and reproducibility.

[0068] Table 3. External reproducibility test of samples (%)

[0069] Example 2 1. Preparation of Hafnium Matrix Internal Control Samples and Determination by Inductively Coupled Plasma Emission Spectroscopy Sample preparation: Five known zirconium content control samples A, B, C, D and E with gradient distribution (mass fractions of approximately 0.02%, 0.04%, 0.1%, 0.2% and 0.5% respectively) in blocky hafnium matrix were selected. Sufficient quantities of each sample were prepared and a portion of each sample was made into shavings.

[0070] Acid digestion treatment: Accurately weigh 0.1000 g of each of the flaky samples A, B, C, D, and E, and place them in 50 mL polytetrafluoroethylene beakers. Add 8 mL of a 4:2 (v / v) mixed acid solution of hydrofluoric acid and nitric acid to each beaker. Digest at low temperature on a hot plate until the solution is completely clear and transparent.

[0071] Preparation of sample test solutions: Cool the completely digested solution to room temperature, transfer it to a 100 mL volumetric flask, wash the beaker several times with ultrapure water and combine the washings, finally dilute to the mark with ultrapure water, shake well, and obtain the corresponding sample test solutions A1, B1, C1, D1, and E1. Simultaneously prepare reagent blank solutions without samples.

[0072] Inductively Coupled Plasma Atomic Emission Spectrometry (ICP-AES): The zirconium content of sample solutions A1, B1, C1, D1, and E1 was determined using an ICP-AES spectrometer equipped with a standard sample introduction system and the standard addition method. Each sample solution was measured in parallel six times. The results are shown in Table 4.

[0073] Table 4. Results of Inductively Coupled Plasma Emission Spectroscopy Assay (%)

[0074] Fixed value results: The average zirconium concentration from six parallel measurements of each sample was calculated and used as the fixed zirconium concentration for the control sample within the hafnium matrix. The fixed zirconium concentrations for samples A, B, C, D, and E are as follows: C A = 0.020%, C B =0.041%, C C = 0.122%, C D =0.234%, C E =0.554%. The relative standard deviation (RSD) of all parallel determinations was less than 5%, meeting the requirement of ≤10%.

[0075] 2. Solid sample preparation and treatment Machining and forming process: The remaining solid parts of the hafnium matrix internal control samples A, B, C, D, and E that have been determined and have been set, as well as the high-purity hafnium sample X to be tested, are respectively machined into cylinders with a diameter of about 20 mm and a thickness of about 15 mm on a lathe.

[0076] Surface polishing: Use 180-grit silicon carbide wet sandpaper to polish the test end face of each cylindrical sample under running water until the surface is smooth and free of obvious macroscopic scratches.

[0077] Acid washing treatment: Immerse the polished sample in a nitric acid aqueous solution with a volume ratio of 1:5 for 10 minutes.

[0078] Ultrasonic cleaning: Remove the acid-washed sample and place it sequentially into beakers containing ultrapure water and anhydrous ethanol, and ultrasonically clean each for 10 minutes. Repeat this ultrapure water-anhydrous ethanol cleaning cycle 3 times.

[0079] Drying treatment: Place the cleaned sample in a vacuum drying oven at 60°C for 30 minutes, then remove it and place it in a desiccator to cool to room temperature.

[0080] Pre-sputtering treatment: The dried sample was loaded into the sample holder of the glow discharge mass spectrometer. The discharge voltage was set to 1000V and the discharge current to 2 mA. Each sample was pre-sputtered for 20 minutes to further remove any residual contaminants on the surface and stabilize the surface condition.

[0081] 3. Glow discharge mass spectrometry determination Instrument parameter settings: Medium resolution mode, quality resolution set to 4000. Discharge conditions set: discharge voltage 1200 V, discharge current 1.5 mA. 90 Zr was selected as the analytical isotope of zirconium. 180 Hf was used as an internal standard isotope.

[0082] Signal intensity ratio determination of hafnium-based internal control samples: Under set parameters, glow discharge mass spectrometry was performed on prepared hafnium-based internal control samples A, B, C, D, and E. Data were collected for each sample after signal stabilization and recorded. 90 Zr and 180 The signal intensity ratio of Hf is converted to the signal intensity ratio of Zr to Hf based on its abundance (I Zr / I Hf Each sample was measured three times, and the average value was taken. The results are shown in Table 5.

[0083] Calibration curve construction: using a fixed zirconium concentration (Ci) of three hafnium matrix control samples. A C B C C C D C E Using the vertical axis (Y), the average signal intensity ratio of zirconium to hafnium (I) is used as the ordinate. Zr / I Hf A, (I) Zr / I Hf B, (I)Zr / I Hf )C, (I Zr / I Hf )D,(I Zr / I Hf Using X as the abscissa (E), a linear fit is performed to obtain the calibration curve equation: Y = 1.0139 × X, with a correlation coefficient R. 2 = 0.9999.

[0084] Table 5. Signal strength ratio of Zr to Hf (%)

[0085] 4. Test Samples and Results Measurement of the test sample: Under identical glow discharge mass spectrometry conditions, the high-purity hafnium sample X, prepared using the same solid sample method, was measured. The measurements were repeated three times to obtain the average signal intensity ratio (Iz) of zirconium to hafnium. Zr / I Hf X = 0.0061%.

[0086] Zirconium content calculation: (I) Zr / I Hf Substituting X = 0.0061% into the constructed calibration curve equation Y = 1.0139×X, the zirconium content of the high-purity hafnium sample X to be tested is calculated to be 0.0062%.

[0087] External reproducibility validation: For 10 consecutive days, sample X was reprepared daily according to step 2 and GDMS was performed once a day (3 measurements per day, averaged). The mean of the 10 measurements was 0.0062%, and the relative standard deviation was 5.6%, indicating that the method has good long-term stability and reproducibility.

[0088] Table 6. External reproducibility test of samples (%)

[0089] Example 3 1. Preparation of Hafnium Matrix Internal Control Samples and Determination by Inductively Coupled Plasma Emission Spectroscopy Sample preparation: Five known zirconium content control samples A, B, C, D and E with gradient distribution (mass fractions of approximately 0.02%, 0.04%, 0.1%, 0.2% and 0.5% respectively) in blocky hafnium matrix were selected. Sufficient quantities of each sample were prepared and a portion of each sample was made into shavings.

[0090] Acid digestion treatment: Accurately weigh 0.1000 g of each of the flaky samples A, B, C, D, and E, and place them in 50 mL polytetrafluoroethylene beakers. Add 8 mL of a 4:2 (v / v) mixed acid solution of hydrofluoric acid and nitric acid to each beaker. Digest at low temperature on a hot plate until the solution is completely clear and transparent.

[0091] Preparation of sample test solutions: Cool the completely digested solution to room temperature, transfer it to a 100 mL volumetric flask, wash the beaker several times with ultrapure water and combine the washings, finally dilute to the mark with ultrapure water, shake well, and obtain the corresponding sample test solutions A1, B1, C1, D1, and E1. Simultaneously prepare reagent blank solutions without samples.

[0092] Inductively Coupled Plasma Atomic Emission Spectrometry (ICP-AES): The zirconium content of sample solutions A1, B1, C1, D1, and E1 was determined using an ICP-AES spectrometer equipped with a standard sample introduction system and the standard addition method. Each sample solution was measured in parallel six times. The results are shown in Table 7.

[0093] Table 7. Results of Inductively Coupled Plasma Emission Spectroscopy Assay (%)

[0094] Fixed value results: The average zirconium concentration from six parallel measurements of each sample was calculated and used as the fixed zirconium concentration for the hafnium matrix internal control sample. The fixed zirconium concentrations for samples A, B, and C are as follows: C A = 0.020%, C B =0.041%, C C = 0.122%, C D =0.234%, C E =0.554%. The relative standard deviation (RSD) of all parallel determinations was less than 5%, meeting the requirement of ≤10%.

[0095] 2. Solid sample preparation and treatment Machining and forming process: The remaining solid parts of the hafnium matrix internal control samples A, B, C, D, and E that have been determined and have been set, as well as the high-purity hafnium sample X to be tested, are respectively machined into cylinders with a diameter of about 20 mm and a thickness of about 15 mm on a lathe.

[0096] Surface polishing: Use 180-grit silicon carbide wet sandpaper to polish the test end face of each cylindrical sample under running water until the surface is smooth and free of obvious macroscopic scratches.

[0097] Acid washing treatment: Immerse the polished sample in a nitric acid aqueous solution with a volume ratio of 1:5 for 10 minutes.

[0098] Ultrasonic cleaning: Remove the acid-washed sample and place it sequentially into beakers containing ultrapure water and anhydrous ethanol, and ultrasonically clean each for 10 minutes. Repeat this ultrapure water-anhydrous ethanol cleaning cycle 3 times.

[0099] Drying treatment: Place the cleaned sample in a vacuum drying oven at 60°C for 30 minutes, then remove it and place it in a desiccator to cool to room temperature.

[0100] Pre-sputtering treatment: The dried sample was loaded into the sample holder of the glow discharge mass spectrometer. The discharge voltage was set to 900V and the discharge current to 2.5 mA. Each sample was pre-sputtered for 20 minutes to further remove any residual contaminants on the surface and stabilize the surface condition.

[0101] 3. Glow discharge mass spectrometry determination Instrument parameter settings: Medium resolution mode, quality resolution set to 4000. Discharge conditions set: discharge voltage 1000 V, discharge current 2 mA. Select... 90 Zr was selected as the analytical isotope of zirconium. 180 Hf was used as an internal standard isotope.

[0102] Signal intensity ratio determination of hafnium-based internal control samples: Under set parameters, glow discharge mass spectrometry was performed on prepared hafnium-based internal control samples A, B, C, D, and E. Data were collected for each sample after signal stabilization and recorded. 90 Zr and 180 The signal intensity ratio of Hf is converted to the signal intensity ratio of Zr to Hf based on its abundance (I Zr / I Hf Each sample was measured three times, and the average value was taken. The results are shown in Table 8.

[0103] Calibration curve construction: using a fixed zirconium concentration (Ci) of three hafnium matrix control samples. A C B C C C D C E Using the vertical axis (Y), the average signal intensity ratio of zirconium to hafnium (I) is used as the ordinate. Zr / I Hf A, (I) Zr / I Hf B, (I) Zr / I Hf )C, (I Zr / I Hf )D,(I Zr / I Hf Using X as the abscissa (E), a linear fit is performed to obtain the calibration curve equation: Y = 1.0112 × X, with a correlation coefficient R. 2= 0.9999.

[0104] Table 8. Signal strength ratio of Zr to Hf (%)

[0105] 4. Test Samples and Results Measurement of the test sample: Under identical glow discharge mass spectrometry conditions, the high-purity hafnium sample X, prepared using the same solid sample method, was measured. The measurements were repeated three times to obtain the average signal intensity ratio (Iz) of zirconium to hafnium. Zr / I Hf X = 0.0059%.

[0106] Zirconium content calculation: (I) Zr / I Hf Substituting X = 0.0059% into the constructed calibration curve equation Y = 1.0112×X, the zirconium content of the high-purity hafnium sample X to be tested is calculated to be 0.0060%.

[0107] External reproducibility validation: For 10 consecutive days, sample X was reprepared daily according to step 2 and GDMS was performed once a day (3 measurements per day, averaged). The mean of the 10 measurements was 0.0061%, and the relative standard deviation was 7.0%, indicating that the method has good long-term stability and reproducibility.

[0108] Table 9. External reproducibility test of samples (%)

[0109] Furthermore, one or more technical solutions in the embodiments of the present invention have at least the following technical effects or advantages: Breakthrough in sensitivity: The detection limit is lower than that of existing ICP-OES methods, which can meet the requirements for the determination of trace zirconium in 99.99% high-purity hafnium.

[0110] Improved analytical efficiency: After fixing the calibration curve, quantitative analysis can be achieved simply by measuring the sample.

[0111] Simple to operate: After fixing the calibration curve, the sample test only requires simple mechanical processing and polishing, without the need to dissolve the sample.

[0112] Improved accuracy and stability: The accuracy of the method was improved by plotting glow discharge mass spectrometry calibration curves using internal control materials, and the stability of the test was enhanced by optimizing instrument parameters.

[0113] The above description is merely a specific embodiment of this application, enabling those skilled in the art to understand or implement this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features claimed in this application.

Claims

1. A method for determining the zirconium content in high-purity hafnium, characterized in that, The method includes: Inductively coupled plasma atomic emission spectrometry (ICP-AES) was used to analyze at least three hafnium-based internal control samples with gradient zirconium content to accurately determine the zirconium content in the hafnium-based internal control samples and obtain the fixed zirconium concentration of each hafnium-based internal control sample. The hafnium matrix internal control sample and the high-purity hafnium sample to be tested, which have been determined, are subjected to solid sample preparation processing to obtain samples suitable for glow discharge mass spectrometry analysis. Under the set instrument parameters, glow discharge mass spectrometry was performed on the hafnium-based internal control sample to obtain the signal intensity ratio of zirconium to hafnium in the hafnium-based internal control sample. A calibration curve is constructed with the fixed zirconium concentration of each of the hafnium-based internal control samples as the ordinate and the signal intensity ratio of zirconium to hafnium in the corresponding hafnium-based internal control samples as the abscissa. The signal intensity ratio of zirconium to hafnium in the high-purity hafnium sample to be tested was determined, and the signal intensity ratio of zirconium to hafnium in the high-purity hafnium sample to be tested was substituted into the calibration curve to obtain the zirconium content in the high-purity hafnium sample to be tested.

2. The method according to claim 1, characterized in that, The step of performing inductively coupled plasma atomic emission spectrometry (ICP-AES) analysis on at least three hafnium-based internal control samples with gradient zirconium content to accurately determine the zirconium content in the hafnium-based internal control samples and obtain a fixed zirconium concentration for each of the hafnium-based internal control samples includes: The hafnium matrix internal control sample was subjected to acid digestion to completely convert the solid sample into a solution to obtain the sample test solution; The sample test liquid was subjected to inductively coupled plasma atomic emission spectrometry (ICP-AES). Each of the hafnium matrix internal control samples was measured in parallel multiple times to obtain the average zirconium concentration. The average zirconium concentration was used as the fixed zirconium concentration.

3. The method according to claim 2, characterized in that, The digestion solution used in the acid dissolution and digestion treatment is a mixture of hydrofluoric acid and nitric acid; the mass fraction of the hydrofluoric acid is 48% to 50%, the mass fraction of the nitric acid is 70% to 72%, and the volume ratio of the hydrofluoric acid to the nitric acid is (2 to 10): (1 to 4).

4. The method according to claim 2, characterized in that, The number of measurements for each hafnium matrix internal control sample is 3 to 10; the relative standard deviation of the multiple measurements is ≤10%.

5. The method according to claim 1, characterized in that, The solid sample preparation process includes: machining and shaping, surface polishing, acid washing, ultrasonic cleaning, drying, and pre-sputtering.

6. The method according to claim 5, characterized in that, The machining process involves shaping the hafnium matrix internal control sample and the high-purity hafnium sample to be tested into cylinders with a diameter of 15 mm to 30 mm and a thickness of 10 mm to 20 mm.

7. The method according to claim 5, characterized in that, The pickling treatment uses a nitric acid aqueous solution, in which the volume ratio of nitric acid to water is (1-4):(5-10); the pickling treatment time is 5 min to 15 min.

8. The method according to claim 1, characterized in that, The instrument parameters set include: using a resolution mode with a quality resolution of not less than 4000 for signal acquisition.

9. The method according to claim 8, characterized in that, Under the set instrument parameters, the discharge conditions for the glow discharge mass spectrometry measurement are: discharge voltage 800V~1200V, discharge current 1mA~3mA.

10. The method according to claim 1, characterized in that, The glow discharge mass spectrometry measurement was selected 90 Zr was selected as the analytical isotope of zirconium. 180 Hf is used as an internal standard isotope of hafnium.

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