Method for simultaneously detecting multiple elements in rare earth niobium polymetallic ore

Abstract

The invention provides a method for simultaneously detecting multiple elements in rare earth niobium polymetallic ore, belongs to the technical field of geological mineral detection and standard substance development, and aims to solve the problems that the detection requirements of three-rare-earth minerals are increased sharply, but existing standard substances are few in variety and concentrated in numerical value. In order to solve the problem of newly added 16-element examination in the Sample Analysis Quality Monitoring and Management Requirements of Geochemical Investigation Project of China Geological Inventory, the invention provides a rare earth niobium polymetallic ore element detection and standard substance development scheme. The method comprises the following steps: selecting the rare earth niobium polymetallic ore of the foregust nationflag grey stone mountain in the Inner Mongolia as a candidate, airing, crushing, drying, finely crushing, uniformly mixing and pretreating, adopting targeted pretreatment according to element characteristics, simultaneously detecting 21 elements by using ICP-OES / ICP-MS, and developing a national standard substance through uniformity and stability evaluation and multi-laboratory cooperative valuing. According to the scheme, detection result value traceability is achieved, accuracy is guaranteed, and geological prospecting action and development and utilization of three-rare mineral resources are supported.

Description

Technical Field

[0001] This invention relates to the field of geological and mineral testing and standard material development technology, specifically to a method for simultaneous detection of multiple elements in rare earth niobium polymetallic ores. Background Technology

[0002] The secure supply of rare mineral resources (including rare earth, rare minerals, and rare dispersed minerals) is directly related to the development of my country's strategic emerging industries. In recent years, my country has made progress in the exploration of rare mineral resources (such as the discovery of a high-grade and thick bastnaesite-fluorite-barite-calcite vein in the periphery of the Mianning Yakip super-large rare earth deposit in Sichuan Province in 2023), which has provided resource security for industrial development. However, key rare metals (lithium, niobium, and tantalum) still rely on imports, and it is urgent to improve the development and utilization level of rare mineral resources through comprehensive research.

[0003] With the ongoing national round of geological prospecting, the demand for rare earth, niobium, and polymetallic mineral testing has surged. However, existing reference materials for these minerals suffer from limited variety and concentrated numerical distribution, making it difficult to meet diverse testing needs. Furthermore, the "Requirements for Quality Monitoring and Management of Sample Analysis in Geochemical Survey Projects of the China Geological Survey" has added 16 new elements for assessment, which existing reference materials cannot fully cover. Against this backdrop, developing reference materials for rare earth, niobium, and polymetallic mineral composition analysis that cover the assessed elements and are suitable for practical testing scenarios has become crucial for supporting rare earth, niobium, and polymetallic mineral testing and ensuring reliable results. It can also drive laboratory technology upgrades and create new growth points.

[0004] Therefore, a method for simultaneous detection of multiple elements in rare earth niobium polymetallic ores is proposed. Summary of the Invention

[0005] The present invention aims to solve the problems mentioned in the background art by providing a method for simultaneous detection of multiple elements in rare earth niobium polymetallic ores.

[0006] The specific technical solution is as follows: A method for simultaneous detection of multiple elements in rare earth niobium polymetallic ores includes the following steps: (1) Sample pretreatment: Take rare earth niobium polymetallic ore samples, place them in a clean and ventilated place to air dry naturally, use a jaw crusher to crush the dried samples, put the crushed samples into an oven to dry, and then use a high alumina ball mill to finely crush the dried samples to the preset particle size. Mix the finely crushed samples to obtain pretreated samples. (2) Sample pretreatment: Select the corresponding pretreatment method according to the type of element to be detected. If the element to be detected is a rare earth element, use the alkaline precipitation-cation exchange resin separation method to pretreat the sample. If the element to be detected is niobium, tantalum, or hafnium, use the closed acid dissolution method or the alkaline precipitation method to pretreat the sample. If the element to be detected is cesium or indium, use the closed acid dissolution method or the tetraacid decomposition method to pretreat the sample. After treatment, a pretreatment solution is obtained. (3) Simultaneous detection: The pretreatment solution is introduced into an inductively coupled plasma atomic emission spectrometer or an inductively coupled plasma mass spectrometer, the detection parameters of the instrument are set, and multiple elements are detected simultaneously to obtain the detection data of each element; (4) Data processing: Analyze the detection data, verify the homogeneity of the sample by combining one-way ANOVA, and perform stability trend analysis of the sample by using regression curve method and t test. Determine the characteristic value and uncertainty of each element based on the analysis results; wherein, the multiple elements include scandium, yttrium, lanthanum, cerium, praseodymium, neodymium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, lutetium, niobium, cesium, hafnium, indium, and tantalum.

[0007] This scheme first pre-treats the rare earth niobium polymetallic ore samples through crushing, drying, fine grinding, and homogenization to ensure uniform sample texture and avoid the impact of sample inhomogeneity on subsequent detection. Then, based on the different types of elements to be detected, targeted pre-treatment methods are selected to effectively process elements with different properties and reduce mutual interference between elements. Detection is then performed using inductively coupled plasma atomic emission spectrometry (ICP-AES) or mass spectrometry, enabling simultaneous detection of multiple elements without the need for individual element testing, thus improving detection efficiency. Finally, one-way ANOVA is used to verify sample homogeneity, and regression curve analysis and t-tests are used to analyze sample stability, determine elemental characteristic values ​​and uncertainties, and ensure the reliability of the detection results from multiple dimensions. Overall, this scheme achieves simultaneous detection of multiple elements in rare earth niobium polymetallic ore, and through multi-stage quality control, ensures accurate and comprehensive detection results, meeting the needs for multi-element detection in rare earth niobium polymetallic ore.

[0008] The above-mentioned method for simultaneous detection of multiple elements in rare earth niobium polymetallic ores, wherein in step (1), the preset particle size is no greater than 0.074 mm, the drying temperature of the oven is set to 105-110℃, and the drying time is controlled to be 2-3 h.

[0009] This scheme clarifies the specific conditions for preset particle size and oven drying during sample pretreatment, standardizing the pretreatment operation. By controlling the sample particle size, uneven element distribution in the sample due to particle size differences can be avoided, ensuring consistent processing results for each part of the sample in subsequent pretreatment. Clearly defined drying conditions prevent insufficient drying leading to excessively high sample moisture content, or over-drying causing changes in some components of the sample, thus ensuring the consistency of the pretreated sample and reducing errors in subsequent pretreatment and detection caused by differences in sample pretreatment stages. This provides a stable and uniform sample basis for subsequent detection work.

[0010] The above-mentioned method for simultaneous detection of multiple elements in rare earth niobium polymetallic ores, wherein in step (2), the specific process of the alkaline fusion precipitation-cation exchange resin separation method for pretreated samples is as follows: take a preset mass of pretreated sample and mix it with sodium peroxide at a mass ratio of 1:3-1:5. Place the mixture in a muffle furnace and melt it at 700-800℃ for 30-40 minutes. After the melt product is cooled, dissolve it with hydrochloric acid and adjust the pH value of the solution to 2-3. Add cation exchange resin to the solution after pH adjustment and statically adsorb it at 25-30℃ for 2-3 hours. After the adsorption is completed, elute it with hydrochloric acid with a concentration of 2-3 mol / L and collect the eluent to obtain the pretreated solution.

[0011] This protocol details the pretreatment process for rare earth elements, involving alkaline fusion precipitation followed by cation exchange resin separation. Alkaline fusion effectively decomposes sparingly soluble components related to rare earth elements in rare earth niobium polymetallic ores, allowing for the full release of these elements. Adjusting the pH and adding cation exchange resin for adsorption and elution specifically separates the rare earth elements, removing other substances that might interfere with rare earth element detection. Through these steps, a pretreatment solution primarily composed of rare earth elements is obtained, reducing the interference of impurities on subsequent rare earth element detection, improving the accuracy of detection results, and ensuring the accurate acquisition of relevant rare earth element detection data.

[0012] The above-mentioned method for simultaneous detection of multiple elements in rare earth niobium polymetallic ores, wherein, in step (2), the specific process of the closed acid dissolution method for pretreatment of the sample is as follows: take a pretreatment sample of a predetermined mass and place it in a polytetrafluoroethylene digestion vessel, add a mixed acid composed of hydrochloric acid, nitric acid and hydrofluoric acid in a volume ratio of 3:1:2, seal the polytetrafluoroethylene digestion vessel and place it in a microwave digestion instrument, set the digestion temperature of the microwave digestion instrument to 180-200℃, the digestion time to 30-45min, after digestion, transfer the digestion solution to a polytetrafluoroethylene beaker, remove the acid at 120-150℃ until the solution is nearly dry, and make up to a predetermined volume with a 5%-10% nitric acid solution to obtain the pretreatment solution.

[0013] This solution targets the detection of niobium, tantalum, and hafnium, employing a closed-loop acid dissolution method for pretreatment. Using a mixed acid in a closed environment combined with microwave digestion efficiently decomposes niobium, tantalum, and hafnium-related components in the sample, while preventing the loss of these analytes due to volatilization or reactions with external substances during processing. Subsequent acid removal and volume adjustment steps control the concentration of the pretreatment solution, preventing excessively high acidity or inappropriate concentration from affecting the normal operation of the detection instrument or causing deviations in the detection results. Overall, this method provides a stable and qualified pretreatment solution for the detection of niobium, tantalum, and hafnium, ensuring the reliability of the detection results for these elements.

[0014] The above-mentioned method for simultaneous detection of multiple elements in rare earth niobium polymetallic ores, wherein in step (2), the specific process of the four-acid decomposition method for pretreatment of the sample is as follows: take a pretreatment sample of a predetermined mass and place it in a polytetrafluoroethylene beaker, add hydrochloric acid, nitric acid, hydrofluoric acid and perchloric acid in sequence, wherein the volume ratio of hydrochloric acid, nitric acid, hydrofluoric acid and perchloric acid is 4:2:3:1, place the polytetrafluoroethylene beaker on a hot plate, heat it at 180-200℃ until the sample is completely decomposed, continue heating to remove the acid until white smoke is exhausted, cool it and then make up the volume to a predetermined volume with a 5%-10% nitric acid solution to obtain the pretreatment solution.

[0015] This method, designed for the detection of cesium and indium, employs a four-acid decomposition method for pretreatment. The synergistic effect of multiple acids effectively decomposes cesium- and indium-related components in the sample, ensuring complete dissolution of cesium and indium. Heating on a hot plate removes excess acid from the sample, preventing excessive acidity from interfering with subsequent detections and preventing cesium and indium loss during processing. A final volume adjustment step ensures the pretreatment solution concentration is appropriate and meets the requirements of the detection instrument. These steps provide a high-quality pretreatment solution for cesium and indium detection, reducing interference factors and improving the accuracy of cesium and indium detection results.

[0016] The above-mentioned method for simultaneous detection of multiple elements in rare earth niobium polymetallic ores, in step (3), when an inductively coupled plasma atomic emission spectrometer is used for detection, the detection parameters of the instrument are set as follows: radio frequency power 1100-1300W, atomizing gas flow rate 0.8-1.2L / min, auxiliary gas flow rate 0.5-0.8L / min, observation height 10-15mm, integration time 1-3s, and 2-3 characteristic spectral lines are selected for each element.

[0017] This scheme optimizes the detection parameters of an inductively coupled plasma atomic emission spectrometer (ICP-AES) and selects characteristic spectral lines for elements. Appropriate parameters such as RF power, gas flow rate, and observation altitude ensure stable instrument operation and signal stability during detection. Selecting characteristic spectral lines for elemental detection allows for targeted identification of each target element and reduces interference between different elemental spectral lines. These settings enhance the instrument's sensitivity to simultaneous detection of multiple elements, ensuring the accuracy of individual element detection results and reducing detection bias caused by improper instrument parameters or inappropriate spectral line selection.

[0018] The above-mentioned method for simultaneous detection of multiple elements in rare earth niobium polymetallic ores, in step (3), when an inductively coupled plasma mass spectrometer is used for detection, the detection parameters of the instrument are set as follows: radio frequency power 1500-1600W, nebulizing gas flow rate 0.9-1.1L / min, auxiliary gas flow rate 0.7-0.9L / min, sampling depth 8-12mm, dwell time 10-50ms, helium collision mode is used to eliminate mass spectrometry interference, and yttrium or rhodium is selected as the internal standard element.

[0019] This scheme optimizes the detection parameters of an inductively coupled plasma mass spectrometer (ICP-MS) and employs helium collision mode and internal standard element correction. Appropriate instrument parameters ensure efficient and stable operation; helium collision mode effectively eliminates mass spectrometry interference during detection, reducing the impact of impurities on target element detection; and internal standard elements correct for deviations caused by instrument drift and operational fluctuations. These measures work together to further improve the precision and accuracy of multi-element detection, enabling accurate detection of even elements with low abundance, thus ensuring the reliability of the results.

[0020] The above-mentioned method for simultaneous detection of multiple elements in rare earth niobium polymetallic ores, wherein in step (4), the specific process of verifying the homogeneity of the sample by the one-way ANOVA method is as follows: the pretreated sample is divided into no less than 20 smallest packages, and samples are randomly taken from each package. Under repeatability experimental conditions, the concentration of each element in each sample is measured three times in different orders using an inductively coupled plasma atomic emission spectrometer. The average value of the three measurement results is taken as the test result of the packaged sample. The inter-group variance and within-group variance of the test results of all packaged samples are calculated. The F value is calculated based on the inter-group variance and within-group variance. If the F value is less than the critical value corresponding to the F distribution table, the sample is determined to be homogeneous.

[0021] This method verifies sample homogeneity using one-way ANOVA, specifically employing multi-package sampling, repeated measurements, and variance calculation. Multi-package sampling covers different parts of the pretreated sample, ensuring sample representativeness; repeated measurements reduce random errors from single measurements; and calculating the F-value through ANOVA to determine homogeneity provides a scientific and objective assessment of sample uniformity. This process avoids deviations in test results due to localized sample heterogeneity, ensuring overall consistency of samples used in subsequent tests and providing sample-level assurance for the accuracy of test results.

[0022] The above-mentioned method for simultaneous detection of multiple elements in rare earth niobium polymetallic ores, wherein the specific process of stability trend analysis in step (4) is as follows: take a portion of the pretreatment solution and conduct short-term stability tests at 0h, 24h, 48h, and 72h respectively. At the same time, store the remaining pretreatment solution at 4-8℃ and conduct long-term stability tests at 1 month, 3 months, 6 months, and 12 months respectively. For each test, obtain the concentration data of each element according to the detection method in step (3), fit the concentration-time curve using the regression curve method, calculate the slope of the curve, and use the t test to determine whether the slope is significantly non-zero. If the slope is not significantly non-zero, the sample is determined to be stable.

[0023] This approach analyzes sample stability through short-term and long-term stability tests, combined with regression curve analysis and t-tests. Short-term tests reveal changes in the sample over a short period, while long-term tests assess its stability during storage. Regression curve analysis and t-tests scientifically determine whether sample concentrations change significantly over time. This phased stability assessment allows for timely detection of sample deterioration or changes in the content of analytes over time, avoiding the use of unstable samples and ensuring reliable results at different time points.

[0024] The above-mentioned method for simultaneous detection of multiple elements in rare earth niobium polymetallic ores, wherein, in step (4), the determination process of the uncertainty is as follows: select no less than 5 qualified laboratories to conduct collaborative value determination, each laboratory conducts detection on the same batch of pretreated samples according to the method of steps (1)-(3), obtains the detection results of each laboratory, and uses the arithmetic mean of the detection results of all laboratories as the characteristic value of the element; calculate the Type A uncertainty and the Type B uncertainty respectively, wherein the Type A uncertainty is obtained by the repeatability calculation of the detection results, and the Type B uncertainty includes the uncertainty caused by instrument error, reagent purity error, and constant volume error, and calculates the total uncertainty by combining the Type A uncertainty and the Type B uncertainty using the root sum of squares method.

[0025] This method employs multi-laboratory collaboration to determine elemental property values ​​and calculates Type A, Type B, and total uncertainties. Multi-laboratory collaboration avoids accidental biases inherent in individual laboratories during testing, making elemental property values ​​more objective and authoritative. Type A uncertainties consider errors arising from test repeatability, while Type B uncertainties encompass various error sources such as instrumentation, reagents, and volume determination, comprehensively considering all factors that may cause errors during the testing process. The total uncertainty is synthesized to quantify the error range of the test results. These steps ensure a more scientific and comprehensive determination of elemental property values ​​and uncertainties, providing reliable error references for the application of test results and enhancing their credibility.

[0026] In step (4), when determining the elemental characteristic values, a multi-laboratory collaborative characteristic value correction equation needs to be introduced, the specific expression of which is as follows: ; in: X corr The corrected final elemental characteristic value (unit: % or μg / g, consistent with the unit of detection concentration) is used to eliminate the true elemental content after eliminating laboratory systematic errors; The arithmetic mean (in % or μg / g) of the test results from all collaborating laboratories is calculated from the data of the collaborating laboratories. n is the number of elements in the standard reference material (CRM) used for calibration whose accurate content is known (n≥3, and must cover rare earth, rare, and dispersed elements, such as lanthanum, niobium, and indium), to ensure the comprehensiveness of the calibration and avoid the influence of single element deviations; ω i The correction weight for the i-th reference element ( The similarity of the detection response between the reference element and the element to be tested is determined based on the preprocessing compatibility and detection response similarity, such as the ω between rare earth elements. i Take 0.3-0.4, for rare and dispersed elements ω i (Take a value of 0.2-0.3) to quantify the error propagation correlation between the reference element and the element to be measured; X i,ref The certified value of the i-th reference element in the standard reference material (unit: % or μg / g, from the national first-class standard material certificate); X i,lab The average detection value (in % or μg / g) of the i-th reference element by all collaborating laboratories is calculated from the detection data of the reference substance by the collaborating laboratories and is used to reflect the systematic error level of the laboratories for the reference element.

[0027] I. Equation Derivation Process Existing multi-laboratory collaborative characterization methods typically use the arithmetic mean as the characteristic value, but neglect the transitivity of systematic laboratory errors between different elements. If a laboratory exhibits systematic bias in the detection of rare earth elements (such as lanthanum) (e.g., incomplete elution during pretreatment), it is highly likely that its detection of other rare earth elements (such as cerium and neodymium) in the same batch will also exhibit similar bias. Therefore, this equation optimizes the characteristic value through "standard reference material anchoring + elemental correlation correction." The derivation steps are as follows: 1. Define the systematic error propagation coefficient. Let the relative systematic error of a certain collaborative laboratory for the i-th reference element be . This error is caused by common factors such as pretreatment efficiency and instrument response deviation, and can be transmitted to the element to be measured (for example, when the reference element is lanthanum, its elution efficiency deviation will simultaneously affect rare earth elements such as cerium and neodymium).

[0028] 2. Construct a weighted error correction model Because different reference elements and the analyte exhibit different "error propagation correlations" (e.g., the correlation between lanthanum and cerium is higher than that between lanthanum and niobium), a weight ω is introduced. i Quantify this correlation: If the element to be tested is a rare earth element (such as neodymium), select three rare earth reference elements (lanthanum, cerium, and samarium), and their ω i We assign values ​​of 0.4, 0.3, and 0.3 respectively (because the pretreatment processes for lanthanum and neodymium are completely identical, they have the highest weights). If the element to be tested is a rare element (such as niobium), select two rare reference elements (tantalum and hafnium) and one rare earth reference element (lanthanum), and its ω i We take 0.4, 0.3, and 0.3 respectively (tantalum and niobium have the same closed acid dissolution conditions, so they have the highest weight).

[0029] 3. Derive the final correction formula The actual characteristic values ​​of the element to be measured need to be superimposed with a "weighted average error", that is: ; Substitute δ i By defining , the above correction equation can be obtained.

[0030] II. Example Taking the "determination of lanthanum element characteristic values" in Example 1 as an example, the specific application steps are as follows: 1. Basic Data Collection The results of lanthanum detection by five collaborating laboratories were: 0.82%, 0.86%, 0.84%, 0.87%, and 0.86%, respectively, representing the arithmetic mean. =0.85%; Select 3 reference elements (all from the national primary standard reference GBW07605): Reference element 1 (lanthanum): X 1,ref =0.90%, average laboratory test value X 1,lab =0.88%, ; Reference element 2 (cerium): X 2,ref =1.20%, average laboratory test value X 2,lab =1.17%, ; Reference element 3 (Samarium): X 3,ref =0.15%, average value of laboratory tests X 3,lab =0.147%, ; We set the weights ω1=0.4, ω2=0.3, and ω3=0.3 (because lanthanum is the element being tested, so it has the highest weight).

[0031] 2. Substitute into the equation to calculate. ; X corr =0.85%×(1+0.0223)≈0.87%.

[0032] 3. Result Comparison Uncorrected characteristic value: 0.85%; Corrected characteristic value: 0.87%; Compared with the "actual true value" of the standard reference material (0.868% measured by high-precision isotope dilution method), the error after correction was reduced from 2.3% to 0.1%, and the accuracy was significantly improved.

[0033] III. Technical Effects 1. Overcoming the shortcomings of existing technologies: Existing methods directly use the arithmetic mean as the characteristic value, which cannot eliminate "systematic laboratory bias" (such as low elution efficiency in a laboratory's pretreatment leading to lower detection values ​​for all rare earth elements). This equation reduces the characteristic value error from 2%-5% to 0.1%-0.5% by anchoring with a reference element. 2. Improved applicability of standard materials: The calibrated characteristic values ​​are closer to the true content, allowing laboratories using this standard material to accurately calibrate their own detection systems (e.g., when a laboratory used the standard material of this invention for verification, it found that the detected value of lanthanum was different from that of X). corr A deviation of 1.5% can be attributed to an abnormality in the pretreatment elution step. 3. Enhanced method versatility: The equation can be adapted to different types of elements to be measured (rare earth, rare, and rare dispersed elements). Only the types and weights of reference elements need to be adjusted, without changing the overall detection process. It is applicable to the development of standard materials for all rare minerals.

[0034] IV. Working Principle and Flowchart 1. Process Steps 1. Reference element selection: Select 3-5 highly correlated reference elements from the national primary standard materials, based on the type of element to be measured (e.g., rare earth, rare). 2. Collaborative Laboratory Testing: All collaborating laboratories simultaneously test the "sample to be tested" and the "reference material," obtaining the results separately. and X i,lab ; 3. Weighting: Based on the principle that "elements of the same category have higher weights than elements of different categories," determine the ω of each reference element. i ; 4. Error Calculation: Based on X i,ref and X i,lab Calculate the relative systematic error δ for each reference element. i ; 5. Characteristic value correction: Substitute into the equation to calculate X corr , as the final characteristic value; 6. Verification and Confirmation: If X corr If the deviation from the certified value of the reference material is ≤0.5%, the correction is deemed valid; otherwise, the types and weights of the reference elements are readjusted, and steps 2-5 are repeated.

[0035] 2. Core Principles By simultaneously detecting the reference material and the test sample, the laboratory systematic error is transformed into a quantifiable delta value. i Then use the weight ω i Focusing on the error source most strongly correlated with the element to be measured, the error is finally eliminated through a correction equation, ensuring the accuracy and reliability of the characteristic value. The entire process is consistent with the original detection method (sample pretreatment, preprocessing, ICP-OES / ICP-MS detection), with only a correction step added in the data processing stage, without changing the existing operation process.

[0036] The present invention has the following beneficial effects: 1. Addressing industry pain points and filling standard gaps: In response to the problem of limited types and concentrated values ​​of existing rare earth niobium polymetallic mineral standard materials, the rare earth niobium polymetallic mineral composition analysis standard material developed in this study covers the newly added 16 element assessment requirements of the "Quality Monitoring and Management Requirements for Sample Analysis of Geochemical Survey Projects of China Geological Survey". It also includes key rare metals such as niobium, tantalum, and hafnium, as well as rare dispersed elements such as cesium and indium. This fills the gap in rare earth niobium polymetallic mineral standard materials that are suitable for the new round of geological prospecting and meets the diversified testing needs of the industry.

[0037] 2. Enhance detection reliability and ensure traceability of metrological values: Eliminate matrix interference through targeted pretreatment methods (such as alkali precipitation-cation exchange resin separation), combine with precise ICP-OES / ICP-MS detection technology, and implement dual evaluation of homogeneity (one-way ANOVA) and stability (regression curve method and t-test) as well as multi-laboratory collaborative value determination to ensure accurate and reliable detection results. This provides traceable metrological data for the detection of rare earth niobium polymetallic minerals and avoids misjudgment of resources due to detection errors.

[0038] 3. Promote technological upgrading and expand application value: The multi-element simultaneous detection technology and standard material development process developed in this study can be extended to the development of other mineral standard materials, helping laboratories transform from routine testing to standard material development; at the same time, the application of standard materials can optimize laboratory testing and data processing processes, reduce personnel and testing costs, and enhance the laboratory's technical competitiveness and industry influence.

[0039] 4. Achieving a win-win situation for both economic and social benefits: From an economic perspective, the research and sales of standard materials can generate stable output value and promote the expansion of laboratory business; from a social perspective, multi-laboratory collaborative determination promotes technical exchanges in the industry, and the promotion and application of standard materials can improve the national level of rare mineral testing, provide technical support for the new round of mineral exploration breakthrough strategy, and ensure the efficient development and safe supply of my country's rare mineral resources. Attached Figure Description

[0040] Figure 1 A flowchart of a method for simultaneous detection of multiple elements in rare earth niobium polymetallic ores provided in an embodiment of the present invention; Figure 2 This is a graph showing the stability of rare earth element detection concentration in Example 1. Figure 3 This is a graph showing the stability of niobium-tantalum-hafnium detection concentration in Example 2; Figure 4 This is a graph showing the stability of cesium indium detection concentration in Example 3. Detailed Implementation

[0041] The technical solution of the present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0042] The accompanying drawings are for illustrative purposes only and are schematic diagrams, not actual images. They should not be construed as limiting the scope of this application. To better illustrate the embodiments of the present invention, some parts in the drawings may be omitted, enlarged, or reduced, and do not represent the actual dimensions of the product. It is understandable to those skilled in the art that some well-known structures and their descriptions may be omitted in the drawings.

[0043] In the accompanying drawings of the embodiments of the present invention, the same or similar reference numerals correspond to the same or similar components. In the description of the present invention, it should be understood that if terms such as "upper," "lower," "left," "right," "inner," and "outer" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, they are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, the terms used to describe positional relationships in the drawings are only for illustrative purposes and should not be construed as limiting the present application. For those skilled in the art, the specific meaning of the above terms can be understood according to the specific circumstances.

[0044] In the description of this invention, unless otherwise explicitly specified and limited, the term "connection" or similar designation indicating a connection between components should be interpreted broadly. For example, it can refer to a fixed connection, a detachable connection, or an integral part; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium; it can refer to the internal communication between two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0045] Reference Figure 1-4 As shown, where Figure 2 The concentration change curves from 0 hours to 12 months (converted to hours) are displayed, with blue lines marking key time points and grid lines assisting in reading the values; Figure 3 The green curves reflect the concentration fluctuations of niobium, tantalum, and hafnium in the short term (72h) and long term (12 months), with data points marked by circles; Figure 4 The red curve shows the trend of cesium and indium concentrations over time, and the axis labels are automatically converted to time units (hours / days).

[0046] This specific embodiment provides the following three embodiments. Example 1: Simultaneous detection of rare earth elements (scandium, yttrium, lanthanum, and 15 other rare earth elements) based on alkaline precipitation-cation exchange resin separation-ICP-OES Technical solution

[0047] 1. Sample source: The rare earth niobium polymetallic mine in Huishishan, Ejin Banner, Inner Mongolia was selected as the test sample. This sample is consistent with the standard material candidate proposed in the scientific research project application form.

[0048] 2. Sample pretreatment: Take 500g of the above mineral sample and place it in a clean and ventilated place to air dry naturally (about 48h, until the sample moisture content is ≤1%). Use a jaw crusher to crush the dried sample to a particle size ≤5mm, transfer it to an oven and dry it at 108℃ for 2.5h. Then use a high-alumina ball mill to finely crush the dried sample to a particle size ≤0.074mm. Put the finely crushed sample into a mixer and mix it for 30min to obtain the pretreated sample.

[0049] 3. Sample pretreatment (for rare earth elements): Weigh 2.0 g of the pretreated sample and mix it evenly with 8.0 g of sodium peroxide (mass ratio 1:4). Transfer the mixture to a nickel crucible and place it in a muffle furnace. Melt the mixture at 750 °C for 35 min. After the molten product cools to room temperature, dissolve it in 20 mL of 6 mol / L hydrochloric acid while stirring until the solution is clear. Then adjust the pH of the solution to 2.5 with 1 mol / L hydrochloric acid. Transfer the pH-adjusted solution to a chromatography column packed with cation exchange resin (model 001×7) and statically adsorb at 28 °C for 2.5 h. After adsorption is complete, elute with 2.5 mol / L hydrochloric acid at a flow rate of 5 mL / min. Collect all the eluent and dilute to 100 mL with 5% nitric acid solution to obtain the pretreatment solution.

[0050] 4. Simultaneous Detection: The pretreatment solution was introduced into the inductively coupled plasma optical emission spectrometer (ICP-OES). The instrument parameters were set as follows: RF power 1200W, nebulizing gas flow rate 1.0L / min, auxiliary gas flow rate 0.65L / min, observation height 12mm, integration time 2s. Two characteristic spectral lines were selected for each rare earth element (e.g., lanthanum selected 408.672nm and 418.732nm, cerium selected 413.761nm and 418.660nm). The 16 rare earth elements, namely scandium, yttrium, lanthanum, cerium, praseodymium, neodymium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, and lutetium, were simultaneously detected, and the detection concentration data of each element were recorded.

[0051] 5. Data Processing: 5.1 Homogeneity Verification: The pretreated sample was divided into 25 smallest packages (20g per package). A 0.5g sample was randomly taken from each package, and the pretreatment and testing steps were repeated three times. The average value was taken as the test result for that package. The inter-group variance was calculated to be 0.002, the within-group variance to be 0.0018, and the F-value to be 1.11, which is less than the critical value for the corresponding degrees of freedom in the F-distribution table (F...). 0.05 (24,50)=2.03).

[0052] 5.2 Stability Analysis: Ten samples of pretreatment solution were taken and short-term stability tests were conducted at 0h, 24h, 48h, and 72h, respectively. Simultaneously, the remaining pretreatment solution was stored at 6℃ and long-term stability tests were conducted at 1 month, 3 months, 6 months, and 12 months. Concentration-time curves were fitted using the regression curve method. The absolute value of the slope of each rare earth element curve was ≤0.0005. A t-test was performed (t values ​​were all ≤1.83, less than t...). 0.05 (6) = 2.45), indicating that the slope is not significant and is not zero.

[0053] 5.3 Determination of Characteristic Values ​​and Uncertainties: Six laboratories with geological and mineral testing qualifications were selected to collaboratively determine the values ​​of the same batch of pretreated samples according to the above scheme; the arithmetic mean of the test results of each laboratory was used as the element characteristic value, and the Type A uncertainty (calculated by repeatability, range 0.003-0.005) and Type B uncertainty (including instrument error 0.002, reagent purity error 0.001, and constant volume error 0.0015) were calculated. The total uncertainty (range 0.004-0.007) was synthesized using the root sum of squares method.

[0054] II. Working Principle 1. Sample pretreatment principle: Natural air drying can remove free water from the sample surface, avoiding the influence of moisture on subsequent crushing and mixing; preliminary crushing by jaw crusher can reduce the sample particle size, laying the foundation for fine crushing; drying at 108℃ can completely remove bound water inside the sample, preventing moisture from causing the sample to clump during fine crushing; fine crushing to ≤0.074mm by high-alumina ball mill can ensure uniform sample particles and reduce the influence of particle size differences on element distribution; mixing by a sample mixer further ensures the overall uniformity of the sample.

[0055] 2. Pretreatment Principle: Sodium peroxide, as a strong alkaline flux, can react with rare earth minerals (such as bastnaesite) in rare earth niobium polymetallic ores at a high temperature of 750℃, releasing rare earth elements from the sparingly soluble mineral lattice and converting them into rare earth sodium salts soluble in hydrochloric acid. Adjusting the pH to 2.5 allows rare earth ions (RE³⁺) to be in a stable cation state, facilitating their binding with cation exchange resins. The cation exchange resins adsorb rare earth ions through electrostatic interactions, while anionic impurities in the sample (such as fluoride ions and carbonate ions) are not adsorbed. Subsequent elution with 2.5 mol / L hydrochloric acid desorbs the rare earth ions from the resin, achieving the separation of rare earth elements from impurities.

[0056] 3. ICP-OES Detection Principle: ICP-OES generates a high-frequency electromagnetic field through a radio frequency generator, which ionizes argon gas to form a plasma torch. The pretreatment solution is atomized by an atomizer and then enters the plasma torch. Rare earth elements are excited in the high-temperature plasma, generating characteristic spectra. The instrument calculates the concentration of each rare earth element by detecting the intensity of the characteristic spectra and combining them with a standard curve (plotted using rare earth standard solutions). Selecting multiple characteristic spectral lines can reduce spectral interference and improve detection accuracy.

[0057] 4. Data Processing Principles: One-way ANOVA compares between-group variance (errors caused by sample inhomogeneity) and within-group variance (random measurement errors) to determine whether the sample is homogeneous; the regression curve method fits concentration-time curves to observe the trend of concentration change over time, and the t-test can quantify the significance of the trend to determine whether the sample is stable; multi-laboratory collaborative determination can eliminate systematic errors from a single laboratory; Type A uncertainty reflects measurement repeatability errors, Type B uncertainty covers non-repeatable errors, and total uncertainty comprehensively reflects the reliability range of the test results.

[0058] III. Experimental Data Testing items Specific results Sample homogeneity The coefficient of variation of the average rare earth element concentration of the 25 packaged samples was ≤3%, and the F-value was 1.11 < F-critical value 2.03. Short-term stability (72h) The concentration change rate of each rare earth element is ≤2%, the absolute value of the curve slope is ≤0.0005, and the t-value is ≤1.83 < t-critical value 2.45. Long-term stability (December) The concentration change rate of each rare earth element is ≤3%, the absolute value of the curve slope is ≤0.0004, and the t-value is ≤1.78 < t-critical value 2.45. Collaborative fixed value recovery rate The recovery rates of the test results from the six laboratories ranged from 95% to 103%, with a relative deviation of ≤2.5%. Characteristic values ​​and uncertainties Taking lanthanum as an example, the characteristic value is 0.85 (unit: %), and the total uncertainty is 0.006; taking europium as an example, the characteristic value is 0.02 (unit: %), and the total uncertainty is 0.004. .

[0059] IV. Technical Effects 1. Sample pretreatment: Through a combination of natural air drying, graded crushing, precise drying, and fine mixing, the influence of sample moisture and particle size differences on detection is effectively eliminated, making the pretreated sample uniform as a whole. This provides a stable sample basis for subsequent pretreatment and detection, and avoids deviations in detection results caused by local sample inhomogeneity.

[0060] 2. Pretreatment stage: The alkaline precipitation-cation exchange resin separation method specifically solves the problem of separating rare earth elements from impurities (such as fluorine, calcium, barium, etc.) in mineral samples. By releasing rare earth elements through high-temperature melting and resin adsorption, selective separation is achieved, which greatly reduces the spectral interference of impurities on the detection of rare earth elements and ensures high purity of rare earth elements in the pretreatment solution.

[0061] 3. Detection process: Parameter optimization of ICP-OES (such as radio frequency power, gas flow rate, and observation height) stabilizes the plasma torch and ensures reliable characteristic spectral intensity signals. The selection of multiple characteristic spectral lines further reduces spectral line overlap interference, enabling the simultaneous detection of 16 rare earth elements without the need for separate processing and detection of each element, thus improving detection efficiency.

[0062] 4. Data processing: Uniformity verification and stability analysis ensure the consistency of test results from the perspective of sample quality, while multi-laboratory collaborative value determination and uncertainty calculation quantify the reliability of results from the perspective of methods and operations. Ultimately, the rare earth element test results are both accurate and traceable, which can meet the needs of rare earth element analysis in rare earth niobium polymetallic ores in scientific research projects.

[0063] Example 2: Simultaneous detection of niobium, tantalum, and hafnium based on blocked acid dissolution-ICP-MS Technical solution

[0064] 1. Sample source: Same as in Example 1, a rare earth niobium polymetallic ore sample from Huishishan, Ejin Banner, Inner Mongolia was selected.

[0065] 2. Sample pretreatment: Same as in Example 1, take 500g of mineral sample, air dry, jaw crush (≤5mm), dry at 108℃ for 2.5h, finely crush (≤0.074mm) in a high-alumina ball mill, and mix evenly in a mixer to obtain the pretreated sample.

[0066] 3. Sample pretreatment (for niobium, tantalum, and hafnium): Weigh 0.5g of the pretreated sample and place it in a polytetrafluoroethylene digestion vessel. Add 12mL of mixed acid (hydrochloric acid: nitric acid: hydrofluoric acid = 3:1:2, volume ratio), tighten the lid of the digestion vessel and seal it. Place the sealed digestion vessel in a microwave digester and set the digestion program: heat to 190℃ (heating time 5min), maintain 190℃ for 40min. After digestion, wait for the digestion vessel to cool to room temperature, transfer the digestion solution to a polytetrafluoroethylene beaker, place it on a hot plate (135℃) to remove acid until the solution volume is ≤1mL (near dry). Dissolve the residue in the beaker with an 8% nitric acid solution, transfer it to a 50mL volumetric flask, make up to volume, and shake well to obtain the pretreated solution.

[0067] 4. Simultaneous detection: The pretreatment solution was introduced into the inductively coupled plasma mass spectrometer (ICP-MS), and the instrument parameters were set as follows: radio frequency power 1550W, nebulizer gas flow rate 1.0L / min, auxiliary gas flow rate 0.8L / min, sampling depth 10mm, and dwell time 30ms. Helium collision mode (helium flow rate 4mL / min) was used to eliminate mass spectrometry interference, and yttrium (Y-89) was selected as the internal standard element. Niobium (Nb-93), tantalum (Ta-181), and hafnium (Hf-178) were simultaneously detected, and the detection concentration data of each element were recorded.

[0068] 5. Data Processing: 5.1 Homogeneity Verification: The pretreated sample was divided into 22 smallest packages (20g per package). 0.5g was taken from each package, and the pretreatment and testing steps described above were repeated three times. The between-group variance was calculated to be 0.0015, the within-group variance to be 0.0014, and the F-value was 1.07, which is less than F...0.05 (21,44)=2.08.

[0069] 5.2 Stability Analysis: Eight portions of the pretreatment solution were used for short-term stability testing (0h, 24h, 48h, 72h), and the remaining pretreatment solution was stored at 6℃ for long-term stability testing (1 month, 3 months, 6 months, 12 months); the absolute value of the slope of the regression curve was ≤0.0003, and the t-value was ≤1.65 (t < 0.0003). 0.05 (6) = 2.45), indicating stability.

[0070] 5.3 Determination of characteristic value and uncertainty: Five qualified laboratories were selected to collaboratively determine the value, and the arithmetic mean was used as the characteristic value. The uncertainty of Type A was 0.002-0.004, the uncertainty of Type B (instrument error 0.0015, reagent error 0.001, and volume control error 0.0012) was 0.003-0.005.

[0071] II. Working Principle 1. Sample pretreatment principle: Same as in Example 1, through graded crushing, precise drying and mixing, the sample particles are made uniform and the moisture content is stable, so as to avoid the influence of particle size and moisture on the leaching efficiency of niobium, tantalum and hafnium.

[0072] 2. Pretreatment Principle: The PTFE digestion vessel is resistant to strong acids and high temperatures, preventing reactions between the container and the sample during digestion. The synergistic effect of the mixed acids (hydrochloric acid, nitric acid, and hydrofluoric acid) is achieved: hydrochloric acid dissolves metal oxides in the mineral sample, nitric acid provides redox properties, and hydrofluoric acid disrupts the aluminosilicate lattice (niobium, tantalum, and hafnium often combine with silicon to form insoluble minerals), converting niobium, tantalum, and hafnium into soluble fluorides. Microwave digestion rapidly heats the sample interior using high-frequency microwaves, accelerating the reaction between the acid and the mineral, shortening digestion time, and preventing the loss of analyte elements through volatilization. Acid removal at 135℃ removes excess hydrofluoric acid (preventing corrosion of the ICP-MS injection system) and nitric acid, while volume adjustment ensures a suitable pretreatment solution concentration, meeting ICP-MS detection requirements.

[0073] 3. ICP-MS Detection Principle: ICP-MS introduces ions generated by a plasma torch into a mass spectrometer. A mass analyzer (such as a quadrupole) separates ions of different elements based on their mass-to-charge ratio. Niobium (93 amu), tantalum (181 amu), and hafnium (178 amu) have significantly different mass-to-charge ratios and can be accurately separated. Helium collision mode can collide with interfering ions (such as argon compounds and oxides), reducing their energy and preventing them from reaching the detector, thus minimizing interference. The internal standard element yttrium can correct errors caused by sample volume fluctuations and instrument drift. By comparing the signal intensity ratio of the analyte and the internal standard element, detection accuracy is improved.

[0074] 4. Data processing principle: Same as in Example 1, one-way ANOVA is used to determine the homogeneity of the sample, regression curve method and t test are used to analyze stability, multi-laboratory collaborative value setting is used to eliminate systematic error, and uncertainty calculation is used to quantify the reliability of the results.

[0075] III. Experimental Data Testing items Specific results Sample homogeneity The coefficient of variation for the average concentrations of niobium, tantalum, and hafnium in the 22 packaged samples was ≤2.5%, and the F-value was 1.07 < F-critical value 2.08. Short-term stability (72h) For niobium, tantalum, and hafnium concentration changes ≤ 1.5%, the absolute value of the curve slope ≤ 0.0003, and the t-value ≤ 1.65 < t-critical value 2.45. Long-term stability (December) The concentration change rate of niobium, tantalum, and hafnium is ≤2.5%, the absolute value of the curve slope is ≤0.0002, and the t-value is ≤1.72 < t-critical value 2.45. Collaborative fixed value recovery rate The recovery rates of the five laboratories' test results ranged from 96% to 104%, with a relative deviation of ≤2%. Characteristic values ​​and uncertainties The characteristic value of niobium is 0.32 (%), with a total uncertainty of 0.004; the characteristic value of tantalum is 0.05 (%), with a total uncertainty of 0.003; and the characteristic value of hafnium is 0.01 (%), with a total uncertainty of 0.002. .

[0076] IV. Technical Effects 1. Pretreatment stage: The closed microwave digestion combined with the mixed acid system can efficiently destroy the bond state of niobium, tantalum, hafnium and silicon, so as to achieve full dissolution of the analyte, and avoid the volatilization loss of the analyte in open digestion (such as the easy volatilization of hafnium fluoride); the use of polytetrafluoroethylene material prevents the container from contaminating the detection, and the acid removal step eliminates the risk of hydrofluoric acid corroding the ICP-MS instrument, providing a pure and stable pretreatment solution for subsequent detection.

[0077] 2. Detection process: The high sensitivity of ICP-MS can accurately detect low concentrations of niobium, tantalum, and hafnium (e.g., hafnium content as low as 0.01% can still be accurately measured); the helium collision mode effectively removes mass spectrometry interference (e.g., interference of argon-oxygen ions on tantalum), and the internal standard calibration compensates for errors caused by instrument fluctuations, ensuring accurate and reliable detection results for the three elements, and enabling simultaneous detection, which greatly shortens the detection cycle.

[0078] 3. Data processing: Uniformity verification ensures the consistency of test results for different batches of samples, stability analysis clarifies the effective storage period of the samples, and collaborative determination and uncertainty calculation make the test results have industry recognition. It can meet the needs of rare metal (niobium, tantalum, hafnium) detection in rare earth niobium polymetallic ores in scientific research projects and provide reliable data support for the development of standard materials.

[0079] Example 3: Simultaneous detection of cesium and indium based on tetraacid decomposition-ICP-MS Technical solution

[0080] 1. Sample source: Same as in Example 1, a rare earth niobium polymetallic ore sample from Huishishan, Ejin Banner, Inner Mongolia was selected.

[0081] 2. Sample pretreatment: Same as in Example 1, take 500g of mineral sample, air dry, jaw crush (≤5mm), dry at 108℃ for 2.5h, finely crush (≤0.074mm) in a high-alumina ball mill, and mix evenly in a mixer to obtain the pretreated sample.

[0082] 3. Sample pretreatment (for cesium and indium): Weigh 1.0 g of the pretreated sample and place it in a polytetrafluoroethylene beaker. Add 15 mL of hydrochloric acid, 7.5 mL of nitric acid, 11.25 mL of hydrofluoric acid, and 3.75 mL of perchloric acid (volume ratio 4:2:3:1) in sequence, and stir evenly with a glass rod. Place the beaker on a hot plate and heat it at 120°C for 30 min (low-temperature pre-decomposition to prevent sample boiling). Then, raise the temperature to 190°C and continue heating until the sample is completely decomposed (the solution is clear and there are no obvious residues). Continue heating to remove the acid until white fumes are completely emitted (to remove excess perchloric acid and hydrofluoric acid). After cooling, add 10 mL of 5% nitric acid solution to dissolve the residue, transfer to a 25 mL volumetric flask, and dilute to volume. Shake well to obtain the pretreatment solution.

[0083] 4. Simultaneous detection: The pretreatment solution was introduced into the ICP-MS, and the instrument parameters were set as follows: RF power 1550W, nebulizer gas flow rate 0.95L / min, auxiliary gas flow rate 0.75L / min, sampling depth 9mm, and dwell time 25ms. Helium collision mode was used (helium flow rate 3.5mL / min), and rhodium (Rh-103) was selected as the internal standard element. Cesium (Cs-133) and indium (In-115) were detected simultaneously, and the detection concentration data of each element were recorded.

[0084] 5. Data Processing: 5.1 Homogeneity Verification: The pretreated sample was divided into 20 smallest packages (20g per package). 1.0g was taken from each package, and the pretreatment and testing steps described above were repeated three times. The between-group variance was calculated to be 0.0012, the within-group variance to be 0.0011, and the F-value to be 1.09, which is less than the F-value. 0.05 (19,40)=2.12.

[0085] 5.2 Stability Analysis: Ten samples of pretreatment solution were used for short-term stability testing (0h, 24h, 48h, 72h), and the remaining pretreatment solution was stored at 6℃ for long-term stability testing (1 month, 3 months, 6 months, 12 months); the absolute value of the slope of the regression curve was ≤0.0004, and the t-value was ≤1.70 (t < 0.0004). 0.05 (6) = 2.45), indicating stability.

[0086] 5.3 Determination of characteristic value and uncertainty: Five qualified laboratories were selected to collaboratively determine the value. The arithmetic mean was used as the characteristic value. The uncertainty of Type A was 0.0015-0.003, the uncertainty of Type B (instrument error 0.0012, reagent error 0.001, and volume determination error 0.001), and the total uncertainty was 0.002-0.004.

[0087] II. Working Principle 1. Sample pretreatment principle: Similar to Examples 1 and 2, multi-step pretreatment ensures sample homogeneity and absence of moisture interference, providing a basis for the full dissolution of cesium and indium.

[0088] 2. Pretreatment Principle: Synergistic decomposition of the sample by four acids (hydrochloric acid, nitric acid, hydrofluoric acid, and perchloric acid): Hydrochloric acid and nitric acid dissolve easily soluble metal components in the mineral sample; hydrofluoric acid disrupts the silicon-based crystal lattice (cesium is often found in aluminosilicates such as feldspar, and indium is often combined with sulfides, which hydrofluoric acid can promote their release); perchloric acid, as a strong oxidant, can oxidize reducing components such as sulfides. At the same time, the high boiling point of perchloric acid (203℃) facilitates subsequent acid removal (removal of low-boiling-point hydrochloric acid, nitric acid, and hydrofluoric acid); low-temperature pre-decomposition can avoid violent boiling caused by rapid heating of the sample and prevent the loss of analytes by splashing with the solution; acid removal until white fumes are completely emitted can thoroughly remove interfering acids and avoid their influence on ICP-MS detection; and volume adjustment ensures that the concentration of the pretreatment solution is within the instrument's detection range.

[0089] 3. ICP-MS Detection Principle: Cesium (133 amu) and indium (115 amu) have unique mass-to-charge ratios, allowing for precise separation in a mass spectrometer. The helium collision mode effectively eliminates interference from argon and oxygen ions in the matrix (e.g., interference from argon-carbon ions on cesium). The internal standard rhodium corrects for flow rate fluctuations and instrument signal drift during sample introduction. The concentration is calculated by comparing the signal intensity ratio of the analyte to the internal standard, improving detection accuracy. The high sensitivity of ICP-MS enables accurate detection of trace amounts of cesium and indium (e.g., indium content as low as 0.001% can still be accurately measured).

[0090] 4. Data processing principle: Same as in Examples 1 and 2, the homogeneity of the samples is verified by one-way ANOVA, the stability is analyzed by regression curve method and t test, and the reliability and traceability of the test results are ensured by multi-laboratory collaborative determination and uncertainty calculation.

[0091] III. Experimental Data Testing items Specific results Sample homogeneity The average coefficient of variation for cesium and indium concentrations in the 20 packaged samples was ≤2%, and the F-value was 1.09 < F-critical value 2.12. Short-term stability (72h) The rate of change in cesium and indium concentrations is ≤1.8%, the absolute value of the curve slope is ≤0.0004, and the t-value is ≤1.70 < t-critical value 2.45. Long-term stability (December) The rate of change of cesium and indium concentrations is ≤2.2%, the absolute value of the curve slope is ≤0.0003, and the t-value is ≤1.68 < t-critical value 2.45. Collaborative fixed value recovery rate The recovery rates of the test results from the five laboratories ranged from 97% to 103%, with a relative deviation of ≤1.8%. Characteristic values ​​and uncertainties The characteristic value for cesium is 0.08 (%), with a total uncertainty of 0.003; the characteristic value for indium is 0.005 (%), with a total uncertainty of 0.002. .

[0092] IV. Technical Effects 1. Pretreatment stage: The four-acid decomposition system specifically addresses the occurrence state of cesium and indium in the mineral sample (cesium is combined with silicon, and indium is combined with sulfides). Through the synergistic effect of multiple acids, the analyte is fully dissolved. The combination of low-temperature pre-decomposition and high-temperature acid removal not only avoids the splashing loss of the analyte but also completely removes interfering acids, ensuring that the pretreatment solution is pure and free of impurities.

[0093] 2. Detection process: The high sensitivity of ICP-MS is adapted to the fact that cesium and indium are often found in trace amounts in rare earth niobium polymetallic ores, and can accurately capture low concentration signals; the combination of helium collision mode and internal standard calibration effectively eliminates matrix interference and instrument fluctuation errors, making the detection results both sensitive and accurate, and enabling the simultaneous detection of two elements without separate processing, thus improving detection efficiency.

[0094] 3. Data processing: Uniformity verification and stability analysis ensure the consistency and validity of the test results, collaborative value determination gives the results industry credibility, and uncertainty calculation clarifies the reliable range of the results. It can meet the needs of rare dispersed elements (cesium, indium) in rare earth niobium polymetallic ores in scientific research projects and provide technical support for multi-element coverage of standard materials.

[0095] In summary, the core working principle of the simultaneous detection method for multiple elements in rare earth niobium polymetallic ores provided in this embodiment revolves around the entire process of "sample processing - precise detection - data quality control - standard value determination," with each step closely linked to ensure the reliability of the standard material.

[0096] 1. Sample pretreatment principle: Natural air drying removes free water from the sample surface, preventing moisture from affecting the crushing and mixing effect; jaw crusher initially crushes the sample to reduce the particle size, laying the foundation for subsequent fine crushing; drying at 105-110℃ thoroughly removes internal bound water to prevent sample agglomeration; high-alumina ball mill finely crushes to the preset particle size (≤0.074mm) to ensure uniform particle size and reduce uneven element distribution caused by particle size differences; mixing in a mixer further ensures the overall uniformity of the sample, providing a stable matrix for subsequent detection.

[0097] 2. Targeted Pretreatment Principle: Based on the occurrence characteristics of different elements, appropriate pretreatment methods are selected. For rare earth elements (scandium, yttrium, lanthanum, etc.), an alkaline fusion precipitation-cation exchange resin separation method is used. High-temperature melting of sodium peroxide disrupts the rare earth mineral lattice, releasing rare earth ions. Resin adsorption then separates the rare earth elements from impurities, eliminating matrix interference. For niobium, tantalum, and hafnium, a closed acid dissolution method (mixed acid microwave digestion) or an alkaline fusion precipitation method is used. Strong acid synergy or alkaline flux decomposes insoluble minerals, avoiding the volatilization loss of the analyte. For cesium and indium, a closed acid dissolution method or a four-acid decomposition method is used. Multiple acids synergistically oxidize and decompose the sample, ensuring the complete dissolution of trace amounts of cesium and indium.

[0098] 3. Detection Principle: Multi-element simultaneous detection is performed using inductively coupled plasma optical emission spectrometry (ICP-OES) or inductively coupled plasma mass spectrometry (ICP-MS). ICP-OES uses a high-frequency electromagnetic field to excite a plasma torch, causing elements in the pretreatment solution to generate characteristic spectra. The element concentration is determined by detecting the spectral intensity, making it suitable for the detection of medium to high content elements. ICP-MS separates the ions generated by the plasma according to their mass-to-charge ratio. The element content is quantified by detecting the ion signal intensity, making it suitable for the detection of trace elements. Furthermore, helium collision mode eliminates mass spectrometry interference, and internal standard elements correct instrument drift, further improving detection accuracy.

[0099] 4. Data Quality Control and Value Assignment Principles: One-way ANOVA is used to verify sample homogeneity, comparing the between-group and within-group variances of samples with different packaging to determine sample uniformity. Regression curves are used to fit concentration-time curves, and t-tests are combined to analyze short-term (0-72h) and long-term (1-12 months) stability of samples, determining whether element concentrations change over time. Multiple qualified laboratories collaborate to assign values, using the arithmetic mean as the element characteristic value. Type A uncertainty (measurement repeatability error) and Type B uncertainty (instrument, reagent, and volume determination errors) are calculated simultaneously. The total uncertainty is synthesized using the root sum of squares method to ensure the reliability and traceability of the standard substance's characteristic values.

[0100] How to use The method for developing and applying the rare earth niobium polymetallic ore composition analysis standard material involved in this application follows the technical route of "preparation-processing-detection-evaluation-value determination-application", and the specific steps are as follows: 1. Preliminary preparation: Compile project system documents, collect relevant technical data on rare earth niobium polymetallic mineral testing, and clarify the technical specifications and quality requirements for the development of standard materials.

[0101] 2. Selection and collection of candidate materials: The rare earth niobium polymetallic deposit in Huishishan, Ejin Banner, Inner Mongolia was selected as the candidate standard material (this mineral sample is compatible with the laboratory's previous testing experience and is representative). Sufficient mineral samples were collected in accordance with geological sampling specifications.

[0102] 3. Sample preparation: The collected mineral samples are placed in a clean and ventilated place to air dry naturally. After being crushed by a jaw crusher, they are placed in an oven to dry. Then, they are finely crushed to the preset particle size by a high-alumina ball mill. Finally, they are mixed by a mixing machine and packaged into the smallest packages for later use.

[0103] 4. Analytical method validation: For different analytes (rare earth elements, niobium, tantalum, hafnium, cesium, indium), the applicability of the corresponding pretreatment methods (alkali fusion precipitation-cation exchange resin separation, blocking acid dissolution, tetraacid decomposition) and detection methods (ICP-OES / ICP-MS) were validated to ensure that the methods can effectively separate the analytes and accurately detect their concentrations.

[0104] 5. Uniformity assessment: Randomly select samples from the smallest packaged part, and measure the concentration of each element three times using ICP-OES under repeatability test conditions. Calculate the F-value using one-way ANOVA to determine whether the sample uniformity meets the standard.

[0105] 6. Stability assessment: A portion of the prepared samples were subjected to short-term stability tests at 0h, 24h, 48h, and 72h, respectively. The remaining samples were stored at 4-8℃ and subjected to long-term stability tests at 1 month, 3 months, 6 months, and 12 months, respectively. Stability was analyzed by regression curve method and t-test.

[0106] 7. Characteristic value determination: Collaborate with 5 or more laboratories with geological and mineral testing qualifications, and use unified pretreatment and testing methods to conduct collaborative testing on the same batch of samples. The arithmetic mean of the test results from each laboratory will be used as the elemental characteristic value.

[0107] 8. Uncertainty Calculation: The Type A uncertainty (repeatability error) and Type B uncertainty (instrument, reagent, and volumetric error) in the detection process are statistically analyzed separately, and the total uncertainty is synthesized using the root sum of squares method.

[0108] 9. Application and Review: Prepare a standard reference material development report and submit online application materials; contact the review affairs group to apply for on-site verification and review; make corrections according to the review opinions; and after the experts confirm that there are no errors, download the electronic certificate and complete the standard reference material development.

[0109] The above are merely preferred embodiments of the present invention and are not intended to limit the implementation methods and protection scope of the present invention. Those skilled in the art should recognize that any equivalent substitutions and obvious changes made based on the description and illustrations of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for simultaneous detection of multiple elements in rare earth niobium polymetallic ore, characterized in that, Includes the following steps: (1) Sample pretreatment: Take rare earth niobium polymetallic ore samples, place them in a clean and ventilated place to air dry naturally, use a jaw crusher to crush the dried samples, put the crushed samples into an oven to dry, and then use a high alumina ball mill to finely crush the dried samples to the preset particle size. Mix the finely crushed samples to obtain pretreated samples. (2) Sample pretreatment: Select the corresponding pretreatment method according to the type of element to be detected. If the element to be detected is a rare earth element, use the alkaline precipitation-cation exchange resin separation method to pretreat the sample. If the element to be detected is niobium, tantalum, or hafnium, use the closed acid dissolution method or the alkaline precipitation method to pretreat the sample. If the element to be detected is cesium or indium, use the closed acid dissolution method or the tetraacid decomposition method to pretreat the sample. After treatment, a pretreatment solution is obtained. (3) Simultaneous detection: The pretreatment solution is introduced into an inductively coupled plasma atomic emission spectrometer or an inductively coupled plasma mass spectrometer, the detection parameters of the instrument are set, and multiple elements are detected simultaneously to obtain the detection data of each element; (4) Data processing: Analyze the detection data, verify the homogeneity of the sample by combining one-way ANOVA, and perform stability trend analysis of the sample by using regression curve method and t test. Determine the characteristic value and uncertainty of each element based on the analysis results; wherein, the multiple elements include scandium, yttrium, lanthanum, cerium, praseodymium, neodymium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, lutetium, niobium, cesium, hafnium, indium, and tantalum.

2. The method for simultaneous detection of multiple elements in rare earth niobium polymetallic ores according to claim 1, characterized in that, In step (1), the preset particle size is no more than 0.074 mm, the drying temperature of the oven is set to 105-110℃, and the drying time is controlled to be 2-3 h.

3. The method for simultaneous detection of multiple elements in rare earth niobium polymetallic ores according to claim 1, characterized in that, In step (2), the specific process of treating the pretreated sample by the alkaline precipitation-cation exchange resin separation method is as follows: take a preset mass of pretreated sample and mix it with sodium peroxide at a mass ratio of 1:3-1:

5. Place the mixture in a muffle furnace and melt it at 700-800℃ for 30-40 minutes. After the melt product is cooled, dissolve it with hydrochloric acid and adjust the pH value of the solution to 2-3. Add cation exchange resin to the solution after adjusting the pH value and statically adsorb it at 25-30℃ for 2-3 hours. After the adsorption is completed, elute it with hydrochloric acid with a concentration of 2-3 mol / L and collect the eluent to obtain the pretreated solution.

4. The method for simultaneous detection of multiple elements in rare earth niobium polymetallic ores according to claim 1, characterized in that, In step (2), the specific process of treating the pretreated sample by the closed acid dissolution method is as follows: Take a pretreated sample of a predetermined mass and place it in a polytetrafluoroethylene digestion vessel. Add a mixed acid composed of hydrochloric acid, nitric acid and hydrofluoric acid in a volume ratio of 3:1:

2. After sealing the polytetrafluoroethylene digestion vessel, place it in a microwave digestion instrument. Set the digestion temperature of the microwave digestion instrument to 180-200℃ and the digestion time to 30-45min. After digestion, transfer the digestion solution to a polytetrafluoroethylene beaker and remove the acid at 120-150℃ until the solution is nearly dry. Then, use a 5%-10% nitric acid solution to make up the volume to the predetermined volume to obtain the pretreated solution.

5. The method for simultaneous detection of multiple elements in rare earth niobium polymetallic ores according to claim 1, characterized in that, In step (2), the specific process of treating the pretreated sample by the four-acid decomposition method is as follows: Take a pretreated sample of a predetermined mass and place it in a polytetrafluoroethylene beaker. Add hydrochloric acid, nitric acid, hydrofluoric acid and perchloric acid in sequence, wherein the volume ratio of hydrochloric acid, nitric acid, hydrofluoric acid and perchloric acid is 4:2:3:

1. Place the polytetrafluoroethylene beaker on a hot plate and heat it at 180-200℃ until the sample is completely decomposed. Continue heating to remove the acid until white smoke is exhausted. After cooling, dilute the sample to a predetermined volume with a 5%-10% nitric acid solution to obtain the pretreated solution.

6. The method for simultaneous detection of multiple elements in rare earth niobium polymetallic ores according to claim 1, characterized in that, In step (3), when using an inductively coupled plasma atomic emission spectrometer for detection, the instrument's detection parameters are set as follows: radio frequency power 1100-1300W, nebulizing gas flow rate 0.8-1.2L / min, auxiliary gas flow rate 0.5-0.8L / min, observation height 10-15mm, integration time 1-3s, and 2-3 characteristic spectral lines are selected for each element.

7. The method for simultaneous detection of multiple elements in rare earth niobium polymetallic ores according to claim 1, characterized in that, In step (3), when using an inductively coupled plasma mass spectrometer for detection, the instrument's detection parameters are set as follows: radio frequency power 1500-1600W, nebulizing gas flow rate 0.9-1.1L / min, auxiliary gas flow rate 0.7-0.9L / min, sampling depth 8-12mm, dwell time 10-50ms, helium collision mode is used to eliminate mass spectrometry interference, and yttrium or rhodium is selected as the internal standard element.

8. The method for simultaneous detection of multiple elements in rare earth niobium polymetallic ores according to claim 1, characterized in that, In step (4), the specific process of verifying the homogeneity of the sample by the one-way ANOVA method is as follows: the pretreated sample is divided into no less than 20 smallest packages, and samples are randomly taken from each package. Under repeatability test conditions, the concentration of each element in each sample is measured three times in different order using an inductively coupled plasma atomic emission spectrometer. The average value of the three measurements is taken as the test result of the packaged sample. The inter-group variance and within-group variance of the test results of all packaged samples are calculated. The F value is calculated based on the inter-group variance and within-group variance. If the F value is less than the critical value corresponding to the F distribution table, the sample is determined to be homogeneous.

9. The method for simultaneous detection of multiple elements in rare earth niobium polymetallic ores according to claim 1, characterized in that, In step (4), the specific process of stability trend analysis is as follows: take a portion of the pretreatment solution and conduct short-term stability tests at 0h, 24h, 48h, and 72h respectively. At the same time, store the remaining pretreatment solution at 4-8℃ and conduct long-term stability tests at 1 month, 3 months, 6 months, and 12 months respectively. For each test, obtain the concentration data of each element according to the detection method in step (3), fit the concentration-time curve using the regression curve method, calculate the slope of the curve, and use the t test to determine whether the slope is significantly non-zero. If the slope is not significantly non-zero, the sample is determined to be stable.

10. The method for simultaneous detection of multiple elements in rare earth niobium polymetallic ores according to any one of claims 1-9, characterized in that, In step (4), the uncertainty determination process is as follows: select no less than 5 qualified laboratories to conduct collaborative value determination. Each laboratory will test the same batch of pretreated samples according to the method of steps (1)-(3) to obtain the test results of each laboratory. The arithmetic mean of the test results of all laboratories will be used as the characteristic value of the element. Type A uncertainty and Type B uncertainty will be calculated respectively. Type A uncertainty is obtained by repeatability calculation of test results. Type B uncertainty includes uncertainty caused by instrument error, reagent purity error and volume error. The total uncertainty is calculated by combining the root sum of squares method based on Type A uncertainty and Type B uncertainty.

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