An efficient separation method of geological sample Sr-Pb-Nd-Hf-Cu-Fe-Zn element purification

Abstract

The application provides an efficient separation and purification method for geological samples Sr-Pb-Nd-Hf-Cu-Fe-Zn elements, and relates to the technical field of analytical chemistry.The application realizes the separation and purification of Sr-Nd-Pb-Hf-Fe-Cu-Zn multiple isotopes through one-time digestion, avoids the waste of precious resources caused by repeated sampling, and is especially suitable for rare or limited mass geological samples.The application significantly improves the experimental efficiency and reduces the labor and time costs.Through integrated process design, the original multiple independent pretreatment steps are integrated into a single process, greatly reducing the experimental time and operation complexity.The application establishes an integrated pretreatment technology based on the correlation of chemical behaviors among multiple element systems, so that the target elements of different isotopic systems can be selectively separated and efficiently recovered in the same medium.

Description

Technical Field

[0001] This invention relates to the field of analytical chemistry, and more specifically, to a highly efficient method for separating and purifying elements in geological samples of Sr-Pb-Nd-Hf-Cu-Fe-Zn. Background Technology

[0002] In Earth science research, isotope analysis is a key technique for revealing the material composition of magma source regions, crustal evolution pathways, and subsequent element migration processes. Currently, the main isotope systems widely used in scientific research include the radiogenic Sr-Nd-Pb-Hf isotope system and the non-traditional stable isotope Fe-Cu-Zn system. These systems are used to characterize the material origin, evolution process, and subsequent fluid activity of magma source regions, and are of great significance to geological research. For these isotope systems, existing analytical methods typically employ standardized sample pretreatment procedures, including acid digestion, selective adsorption and elution with functional resins, and other key steps to achieve effective separation and enrichment of target elements. However, in specific experimental operations, due to the significant differences in the chemical behavior of elements in different isotope systems—for example, Sr, Nd, Pb, and Hf have similar geochemical properties but exhibit different adsorption characteristics on ion exchange resins; Fe, Cu, and Zn, due to differences in oxidation state and coordination environment, possess unique separation behaviors—existing techniques generally employ independent operation modes. Currently, the most widely used technique in laboratories is based on independent pretreatment processes, which involves separate sample digestion and target element purification for different isotopic systems. Under actual experimental conditions, the same geological sample typically requires 2-5 complete digestion and column chromatography steps after completing multi-system analysis of Sr-Nd-Pb-Hf-Fe-Cu-Zn isotopes. This traditional method does not fully consider the chemical behavior correlations and synergistic effects between different elements, and cannot achieve selective separation and efficient recovery in the same medium. Furthermore, all operations rely on manual laboratory personnel, which carries the risk of data deviation due to operational errors, and often fails to perform comprehensive analysis when dealing with rare samples due to insufficient sample quantity. Therefore, to address the problems and shortcomings of the existing technology, this invention proposes an integrated pretreatment technique based on multi-element systems, which can achieve simultaneous and efficient separation and enrichment of multiple key geochemical elements in the same processing flow.

[0003] This invention addresses the following key technical deficiencies in existing geological sample isotope analysis and testing techniques, and provides corresponding solutions: (1) Significant Sample Waste: In traditional isotope analysis procedures, researchers need to perform pretreatment operations on the same geological sample using different isotope systems such as Sr-Nd-Pb-Hf-Fe-Cu-Zn. Each system requires independent sample digestion, column separation, and target element purification steps, resulting in rare, precious, or hard-to-obtain igneous rocks, meteorites, or deep geological samples (initially only milligrams in quantity) undergoing repeated consumable processing in multiple analysis procedures. This repetitive operation not only significantly reduces the utilization rate of effective samples but may also lead to the loss of key information due to insufficient sample quantity, severely restricting the ability to conduct in-depth research and analysis of rare samples.

[0004] (2) Long experimental cycle and low efficiency: Since each round of isotope analysis requires a complete sample pretreatment process (including acid digestion, resin column separation, target element recovery, etc.), the operation steps are cumbersome and time-consuming, making it difficult to achieve parallel analysis of multiple isotope systems. This inefficient processing mode seriously restricts the research progress and experimental efficiency.

[0005] (3) Increased risk of element loss and contamination: Repeated sample purification processes can easily lead to incomplete recovery or cross-contamination of target elements, affecting the accuracy and precision of isotope ratio measurement, and thus reducing the credibility and reliability of data analysis results.

[0006] (4) Lack of integrated processing solutions: Currently, there is no technical path that can simultaneously accommodate multiple isotope systems and achieve efficient separation and enrichment of multiple target elements after a single pretreatment, making it difficult to meet the modern scientific research needs of "multiple uses of one material, one-time purification, and multi-element analysis". Therefore, this invention aims to solve the core problems of serious sample waste, lengthy experimental procedures, low efficiency, and lack of integrated processing solutions in the existing technology, and to provide an integrated pretreatment method that can effectively save sample resources, shorten the experimental cycle, and achieve efficient one-time separation and purification of key elements Sr-Nd-Pb-Hf-Fe-Cu-Zn. Therefore, an element purification method for efficiently separating Sr-Pb-Nd-Hf-Cu-Fe-Zn in geological samples is proposed. Summary of the Invention

[0007] The purpose of this invention is as follows: Based on the shortcomings of the prior art, this invention aims to provide an integrated pretreatment method suitable for the analysis of multi-isotope systems of geological samples. The specific objectives include: (1) Improving sample utilization: Through a single digestion, the separation and purification of multiple isotopes Sr-Nd-Pb-Hf-Fe-Cu-Zn can be achieved, avoiding the waste of precious resources caused by repeated sampling. This method is particularly suitable for rare or limited-mass geological samples. (2) Shortening the experimental cycle: Significantly improving experimental efficiency and reducing manpower and time costs. Through integrated process design, the pretreatment steps that originally required multiple independent operations are integrated into a single process, greatly reducing experimental time and operational complexity. (3) Achieving multi-element synergistic separation: Establishing an integrated pretreatment technology based on the correlation of chemical behavior between multi-element systems, enabling the target elements of different isotope systems to achieve selective separation and efficient recovery in the same medium.

[0008] To achieve the above-mentioned objectives, this invention provides the following technical solution: a method for efficiently separating and purifying the elements in geological samples Sr-Pb-Nd-Hf-Cu-Fe-Zn, comprising the following steps: S1. Sample pretreatment: Cut the collected geological samples into blocks, remove saw marks with a diamond grinding disc to avoid metal contamination, wash the surface of the sample blocks with pure water, dry at 105℃, and then prevent moisture. Grind the samples to 200 mesh powder using an agate ball mill, or select 40-60 mesh matrix particles under a binocular microscope to obtain pretreated samples. S2. Acid dissolution digestion: After drying the pretreated sample at 105℃, place it in a desiccator. Take 45-55mg of the pretreated sample and place it in a Teflon melting bomb. Add 1ml of freshly prepared aqua regia and 0.5ml of concentrated hydrofluoric acid in sequence. Seal the melting bomb and place it in an oven. Heat at 190℃ for 15h to complete the digestion and obtain a clear solution. Dilute the clear solution with 2% nitric acid to 2000 times the sample mass. S3. Initial determination of elemental concentration: The initial concentrations of Sr, Pb, Nd, Hf, Cu, Fe, and Zn in the diluted test solution were determined using ICP-MS. S4. Solution pretreatment: Based on the elemental concentrations measured in S3 and the injection volume required for MC-ICP-MS isotope testing, calculate and measure the corresponding volume of the solution to be tested, evaporate to dryness, add 1 ml of 9N HCl to dissolve, and prepare the sample solution to be passed through the column. S5. Cu-Fe-Zn elemental separation and purification: A resin column loaded with 1 ml AG-MP-1M resin was used. After washing the column with a specific acid washing process, the sample was loaded, and Cu, Fe, and Zn elemental solutions were eluted stepwise and collected separately. After dilution and reconstitution of each elemental solution, the elemental concentration was tested by ICP-MS and ICP-OES respectively to complete the purification of Cu, Fe, and Zn elements. S6, Sr-Pb elemental separation and purification: A resin column loaded with 2 ml SR-B50-S strontium-specific resin was used to load, rinse, and wash the residual sample solution after Cu-Fe-Zn separation in S5. Sr solution and Pb solution were collected stepwise to complete the purification of Sr and Pb elements. S7. Separation and purification of rare earth elements: Using a resin column loaded with 2 ml of AG-50W-X8 resin, the elution solution A obtained in S6 was loaded, rinsed, and washed on the column. The rare earth element solution was collected and evaporated to dryness and treated with acid dissolution and conversion medium. At the same time, the elution solution B was collected for later use. S8 and Nd element separation and purification: A resin column loaded with 2 ml LN-B50-S resin was used to load, wash and elute the rare earth element solution after S7 treatment, and collect the purified Nd solution to complete the Nd element purification. S9. Hf element separation and purification: A resin column loaded with 2ml LN-B50-S resin was used to load the elution solution B collected in S7, perform stepwise acid washing and elution, and collect the purified Hf solution to complete the Hf element purification. S10. Concentration Calibration and Isotope Testing: After diluting the purified Sr, Pb, Nd, Hf, Cu, Fe, and Zn elemental solutions, the concentration of each element was accurately determined using ICP-MS. Then, the isotope ratios of each element were tested using MC-ICP-MS. The isotope analysis of the sample was completed by combining the data with international standard samples.

[0009] As a preferred technical solution of the present invention, the order of adding anti-aqua regia and concentrated hydrofluoric acid in S2 is fixed. Anti-aqua regia must be added first, followed by concentrated hydrofluoric acid, and anti-aqua regia is prepared and used on-site in the experiment.

[0010] As a preferred technical solution of the present invention, the column washing process for separating Cu-Fe-Zn elements in S5 is as follows: 10 ml of 0.5N HNO3, 5 ml of 1N HCl, and 3 ml of 9N HCl are added sequentially to complete the resin column activation and cleaning; the matrix solution collected after sample loading is evaporated to dryness, and 2 ml of 3N HNO3 is added to dissolve it to obtain an intermediate solution for separating Sr-Nd-Pb-Hf elements.

[0011] As a preferred technical solution of the present invention, the elution, collection and post-processing process of each element in S5 is as follows: Cu solution is collected by elution with 10 ml of 6N HCl; Fe solution is collected by elution with 8 ml of 2N HCl; Zn solution is collected by elution with 2 ml of 0.5N HNO3 added three times each time; Fe solution is directly diluted with ultrapure water and its concentration is tested by ICP-OES; Cu and Zn solutions are evaporated to dryness, reconstituted with dilute acid, and diluted by gradient before their concentration is tested by ICP-MS.

[0012] As a preferred technical solution of the present invention, the column washing process for Sr-Pb element separation in S6 is as follows: 10 ml of 6N HCl, 10 ml of ultrapure water, and 10 ml of 3N HNO3 are added sequentially to clean and activate the resin column; after loading the sample, the column is rinsed three times with 1 ml of 3N HNO3, and the eluent is combined to obtain 5 ml of solution A. After multiple acid washes, the Sr solution is collected by elution with 5 ml of ultrapure water, and the Pb solution is collected by elution with 10 ml of 6N HCl.

[0013] As a preferred technical solution of the present invention, the column washing process for rare earth element separation in S7 is as follows: 10 ml of 6N HCl, 10 ml of 2.5N HCl, 10 ml of ultrapure water, and 3 ml of 3N HNO3 are added sequentially to wash and activate the resin column; after loading solution A, it is rinsed three times with 1 ml of 3NHNO3, and the eluents are combined to obtain 8 ml of solution B. After removing impurities by acid washing with 2.5N HCl, the rare earth element solution is collected by elution with 10 ml of 6N HCl. After evaporating the solution to dryness, it is dissolved in 1 ml of 0.25N HCl for later use.

[0014] As a preferred technical solution of the present invention, the pretreatment process of the resin column for Nd element separation in S8 is as follows: the LN-B50-S resin column is washed and activated sequentially with 4 ml 6N HCl, 4 ml ultrapure water, and 4 ml 0.25N HCl; after loading the rare earth element solution, it is rinsed three times with 4 ml 0.25N HCl to remove impurities, and then eluted twice with 4 ml 0.25N HCl each time, and the purified Nd solution is collected.

[0015] As a preferred technical solution of the present invention, the pretreatment process of the resin column for Hf element separation in S9 is as follows: the LN-B50-S resin column is cleaned and activated sequentially with 2.5 ml 2N HF, 10 ml 6N HCl, 10 ml ultrapure water, and 3 ml 3N HNO3; after loading solution B, the column is first rinsed 5 times with a mixture of 10 ml 4N HCl and 0.08N HF, then rinsed 5 times with a mixture of 10 ml 6N HCl and 0.08N HF to remove impurities, and finally eluted with 2.5 ml 2N HF to collect and purify the Hf solution.

[0016] As a preferred technical solution of the present invention, after a single sample digestion, the method uses a multi-stage ion exchange column for stepwise separation to achieve simultaneous purification of seven elements: Sr, Pb, Nd, Hf, Cu, Fe, and Zn. The recovery rates of Sr, Nd, Pb, and Hf are ≥95%, and the recovery rates of Cu, Fe, and Zn are ≥90%.

[0017] As a preferred technical solution of the present invention, the geological samples include igneous rocks, deep mantle materials, lunar rocks, deep-sea sediments, and rare and precious geological samples such as Martian meteorites. The overall experimental cycle is shortened by more than 60% compared with the traditional multi-batch digestion and separation process.

[0018] Compared with existing technologies, the beneficial effects of this invention are as follows: This invention achieves an integrated pretreatment process, significantly reducing sample consumption and experimental time. This invention is the first to propose and verify a technical path for multiple separation operations based on the same sample solution. By optimizing the sequential connection of ion exchange columns and the elution program design, after one sample digestion, only multiple column passes and stepwise elution processes are required to achieve efficient separation and independent enrichment of seven key elements: Sr, Nd, Pb, Hf, Fe, Cu, and Zn. This approach completely avoids the repeated sample digestion and pretreatment operations for different isotopic systems in traditional methods, significantly reducing the amount of valuable geological samples (such as igneous rocks, meteorites, and deep mantle materials) used in experiments, significantly improving sample utilization, and shortening the overall experimental cycle by more than 60%.

[0019] This invention constructs a multi-target element synergistic separation and elution process that balances high recovery rates with low cross-contamination risk. The invention designs an ion exchange column system with sequential segmentation functionality, employing a specific resin type to achieve selective separation and purification of different element groups. This method ensures that the recoveries of Sr, Nd, Pb, and Hf are all >95%, while the recoveries of Fe, Cu, and Zn are also consistently maintained above 90%. Furthermore, it effectively suppresses mutual interference and cross-contamination among the target elements, significantly improving the accuracy of subsequent isotope ratio measurements.

[0020] This invention establishes an integrated pretreatment method compatible with multi-isotope system analysis, supporting an experimental process of "one-time digestion and multi-stage purification": This invention proposes a highly versatile pretreatment process that is not only applicable to conventional geological samples, but can also be extended to multi-isotope joint analysis scenarios of rare samples (such as lunar rocks, deep-sea sediments, Martian meteorites, etc.), breaking through the limitations of the "one column, one element" approach in existing technologies and achieving a technological breakthrough. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the overall process of the present invention; Figure 2 This is a schematic diagram of the target element separation and purification process provided by the present invention; Figure 3 A schematic diagram of the one-column method for separating Cu-Fe-Zn elements provided by this invention; Figure 4 This is a schematic diagram of the single-column method for separating Sr-Pb elements provided by the present invention. Figure 5A schematic diagram of the process for separating REE elements and separating Nd elements provided by the present invention; Figure 6 This is a schematic diagram of the process for separating Hf elements provided by the present invention. Detailed Implementation

[0022] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0023] Therefore, the following detailed description of the embodiments of the present invention is not intended to limit the scope of the claimed invention, but merely illustrates some embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention. It should be noted that, in the absence of conflict, the embodiments and features and technical solutions in the embodiments of the present invention can be combined with each other. It should be noted that similar reference numerals and letters in the following figures indicate similar items; therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0024] Example 1: A highly efficient method for separating and purifying elements in geological samples Sr-Pb-Nd-Hf-Cu-Fe-Zn. The separation and purification method provided by this invention can effectively save the amount of sample consumed, which is of great significance for rare and precious samples. This analytical testing method has the characteristics of high accuracy and high analytical precision.

[0025] (1) Sample pretreatment (grinding or matrix selection): First, cut the collected samples for geochemical analysis into blocks, and use a diamond grinding wheel to remove saw marks (to prevent metal contamination that may occur during the cutting process). Then, wash the surface of the sample blocks with pure water, put them in a clean paper bag, and place them in an oven at 105°C to dry. After removing the dried samples from the oven, take care to prevent moisture, and then use an agate ball mill to grind the sample blocks into 200-mesh powder; or select 40-60 mesh matrix particles under a binocular microscope for later use.

[0026] (2) Acid dissolution digestion: Before digestion, take an appropriate amount of geological sample and put it into a clean paper bag. Place it in an oven and dry it at 105℃. After taking it out, put it directly into a desiccator. Weigh ~50mg of the geological sample to be analyzed into a Teflon melting bomb. Add 1ml of aqua regia (prepared and used immediately) and 0.5ml of concentrated hydrofluoric acid to the sample (the order of adding aqua regia and concentrated hydrofluoric acid cannot be reversed). Put the melting bomb into a stainless steel sleeve, tighten the cap, and put it into an oven. Set the oven to 190℃ and heat for 15 hours. After complete digestion using the acid dissolution method, a clear solution is obtained. Dilute the clear solution with 2% nitric acid to 2000 times the sample mass.

[0027] (3) Element concentration test: The element concentration of the unknown sample solution was analyzed using inductively coupled plasma mass spectrometry (ICP-MS).

[0028] (4) Evaporation of solution: Based on the Sr-Nd-Pb-Hf-Fe-Cu-Zn element content tested in step (3) and the sample injection volume required for the isotope ratio test by the multi-receiver inductively coupled plasma mass spectrometer (MC-ICP-MS), calculate the solution volume of the unknown sample to be evaporated. After evaporating the required volume of the test solution, add 1 ml of 9N HCl to dissolve the sample to obtain the sample solution to be passed through the column.

[0029] (5) One-column Cu-Fe-Zn elemental separation and purification process: 1) Column washing: Prepare resin column tubes loaded with 1ml of AG-MP-1M resin corresponding to the sample number and place them on the elemental separation column rack. Add 10ml of 0.5N HNO3 → 5ml of 1N HCl → 3ml of 9N HCl to wash the column respectively; 2) Sample loading: Add the sample solution to be separated in step (3) to the resin tube, collect the dripping solution (containing all matrix elements), evaporate to dryness and add 2ml of 3N HNO3 to dissolve, to obtain the solution of Sr-Nd-Pb-Hf elements to be separated; 3) Cu solution collection: Add 10ml of 6N HCl to the resin tube and collect the dripping Cu solution using a sample collection cup; 4) Fe solution collection: Add 8ml of 2N HCl and collect the Fe solution using a 15ml plastic vial; 5) Zn solution collection: Add 2ml of 0.5NHNO3 in 3 portions and collect the Zn solution using a sample collection cup; 6) Column washing: Add 5ml of 0.5N HNO3 to the resin tube and collect the Zn solution using a sample collection cup. Wash the column with 0.5N HNO3 → 5ml 1N HCl → 5ml Milli-Q H2O, and collect the resin tube. The collected Fe solution has a high concentration, so dilute it with a certain amount of Milli-Q H2O. The Cu and Zn solutions need to be evaporated to dryness and then dissolved in dilute acid. Extract a certain volume of the treated Cu and Zn solutions, dilute them with Milli-Q H2O, and use ICP-MS to test the concentration of the corresponding elements in the diluted solutions. Calculate the element concentration of the sample after column chromatography. Extract a fixed volume of the diluted Fe solution, dilute it again with Milli-Q H2O, and use inductively coupled plasma optical emission spectrometry (ICP-OES) to test the Fe element concentration in the solution. Calculate the Fe element concentration of the sample after column chromatography. Collect the column-passed sample solutions of known concentrations to determine their isotopic composition.

[0030] (6) Single-column method for Sr-Pb elemental separation and purification: 1) Column washing: Prepare SR-B50-S (strontium-specific resin) resin column tubes with 2ml of sample volume and place them on the resin rack. Add 10ml 6N HCl → 10ml Milli-Q-H2O → 10ml 3N HNO3 to wash the column respectively; 2) Sample loading: Add 2ml 3N HNO3 solution containing the sample from step (5-2) dropwise into the resin tube; 3) Rinsing: Add 1ml 3N HNO3 dropwise to each resin column in sequence, repeat 3 times, and collect the 5ml rinsing solution dripped from the above two steps using a sample collection cup, and label it as solution A; 4) Column washing: Add 5ml 3N HNO3 dropwise, repeat 3 times; 5) Sr solution collection: Add 5ml Milli-Q H2O dropwise, and collect the Sr solution using a sample collection cup; 6) Pb solution collection: Add 10ml 6N HCl → 10ml Milli-Q-H2O → 10ml 3N HNO3 dropwise. 7) Column washing: Add 10 ml of 6N HCl → 10 ml of Milli-Q-H2O to wash the column, and store the resin tube. After evaporating the collected Pb solution to dryness, dissolve it in a certain concentration of dilute acid.

[0031] (7) Rare Earth (REEs) element separation and purification process: 1) Column washing: Prepare AG-50W-X8 resin column tubes with 2ml of sample and place them on the resin rack. Add 10ml 6N HCl → 10ml 2.5N HCl → 10ml Milli-Q → 3ml 3N HNO3 to wash the column respectively; 2) Sample loading: Add solution A containing the sample from step (6-2) to the resin tube; 3) Rinsing: Add 1ml 3N HNO3 to each resin column in sequence, repeat 3 times, and use a sample collection cup to collect 8ml of rinsing solution from the above two steps and label it as solution B; 4) Column washing: Add 5ml 2.5N HCl, repeat 3 times; 5) REEs solution collection: Add 10ml 6N HCl and use a sample collection cup to collect the REEs solution; 6) Column washing: Add 10ml 6N HCl → 10ml Milli-Q to wash the column and put away the resin tube. The collected REEs solution was evaporated to dryness, and then dissolved in 1 ml of 0.25N HCl for later use.

[0032] (8) Nd element separation and purification process: 1) Column washing: Prepare the corresponding number of LN-B50-S resin column tubes loaded with 2ml of sample and place them on the resin rack. Add 4ml of 6N HCl → 4ml of Milli-Q → 4ml of 0.25N HCl to wash the column respectively; 2) Sample loading: Add the REEs solution that has been evaporated and converted in step (7) to the resin tube; 3) Column washing: Add 4ml of 0.25N HCl and repeat 3 times; 4) Nd solution collection: Add 4ml of 0.25N HCl and repeat 2 times. Use a 15ml plastic bottle to collect the Nd solution; 5) Column washing: Add 4ml of 6N HCl → 4ml of Milli-Q to wash the column. Put away the resin tube.

[0033] (9) Hf element separation and purification process: 1) Column washing: Prepare the corresponding number of LN-B50-S resin column tubes loaded with 2ml of sample and place them on the resin rack. Add 2.5ml 2N HF → 10ml 6N HCl → 10ml Milli-Q → 3ml 3NHNO3 to wash the column respectively; 2) Sample loading: Add the B solution containing the sample from step (7-3) to the resin tube; 3) Column washing: Add 10ml 4NHCl + 0.08N HF, repeat 5 times, then add 10ml 6N HCl + 0.08N HF, repeat 5 times; 4) Hf solution collection: Add 2.5ml 2N HF and collect the Hf solution using a sample collection cup; 5) Column washing: Add 2ml 2N HF → 10ml 6N HCl → 10ml Milli-Q to wash the column and put away the resin tube.

[0034] (10) Confirmation of Sr-Nd-Pb-Hf solution concentration: Extract the Sr and Pb elemental solutions collected in step (5), the Nd elemental solution collected in step (6), and the Hf elemental solution collected in step (7) from the same sample into the same injection tube, add a certain volume of Milli-Q for dilution, use ICP-MS to test the corresponding elemental concentrations after dilution, and back-calculate the elemental concentrations of the sample after column chromatography. Collect the column-coated sample solutions of known concentrations to test their isotopic composition. By step (9), the experimenter has obtained Sr-Nd-Pb-Hf-Cu-Fe-Zn elemental solutions of the same sample with known concentrations.

[0035] (11) MC-ICP-MS test of Sr-Nd-Pb-Hf-Cu-Fe-Zn isotope ratio: The sample after column chromatography was diluted and tested using MC-ICP-MS. The test values ​​of international standard samples were compared and the Sr-Nd-Pb-Hf-Cu-Fe-Zn isotope ratio of unknown samples were finally summarized.

[0036] Example 2: A highly efficient method for separating and purifying elements in geological samples Sr-Pb-Nd-Hf-Cu-Fe-Zn, comprising the following steps: S1. Sample pretreatment: Cut the collected geological samples into blocks, remove saw marks with a diamond grinding disc to avoid metal contamination, wash the surface of the sample blocks with pure water, dry at 105℃, and then prevent moisture. Grind the samples to 200 mesh powder using an agate ball mill, or select 40-60 mesh matrix particles under a binocular microscope to obtain pretreated samples. S2. Acid dissolution digestion: After drying the pretreated sample at 105℃, place it in a desiccator. Take 45-55mg of the pretreated sample and place it in a Teflon melting bomb. Add 1ml of freshly prepared aqua regia and 0.5ml of concentrated hydrofluoric acid in sequence. Seal the melting bomb and place it in an oven. Heat at 190℃ for 15h to complete the digestion and obtain a clear solution. Dilute the clear solution with 2% nitric acid to 2000 times the sample mass. S3. Initial determination of elemental concentration: The initial concentrations of Sr, Pb, Nd, Hf, Cu, Fe, and Zn in the diluted test solution were determined using ICP-MS. S4. Solution pretreatment: Based on the elemental concentrations measured in S3 and the injection volume required for MC-ICP-MS isotope testing, calculate and measure the corresponding volume of the solution to be tested, evaporate to dryness, add 1 ml of 9N HCl to dissolve, and prepare the sample solution to be passed through the column. S5. Cu-Fe-Zn elemental separation and purification: A resin column loaded with 1 ml AG-MP-1M resin was used. After washing the column with a specific acid washing process, the sample was loaded, and Cu, Fe, and Zn elemental solutions were eluted stepwise and collected separately. After dilution and reconstitution of each elemental solution, the elemental concentration was tested by ICP-MS and ICP-OES respectively to complete the purification of Cu, Fe, and Zn elements. S6, Sr-Pb elemental separation and purification: A resin column loaded with 2 ml SR-B50-S strontium-specific resin was used to load, rinse, and wash the residual sample solution after Cu-Fe-Zn separation in S5. Sr solution and Pb solution were collected stepwise to complete the purification of Sr and Pb elements. S7. Separation and purification of rare earth elements: Using a resin column loaded with 2 ml of AG-50W-X8 resin, the elution solution A obtained in S6 was loaded, rinsed, and washed on the column. The rare earth element solution was collected and evaporated to dryness and treated with acid dissolution and conversion medium. At the same time, the elution solution B was collected for later use. S8 and Nd element separation and purification: A resin column loaded with 2 ml LN-B50-S resin was used to load, wash and elute the rare earth element solution after S7 treatment, and collect the purified Nd solution to complete the Nd element purification. S9. Hf element separation and purification: A resin column loaded with 2ml LN-B50-S resin was used to load the elution solution B collected in S7, perform stepwise acid washing and elution, and collect the purified Hf solution to complete the Hf element purification. S10. Concentration Calibration and Isotope Testing: After diluting the purified Sr, Pb, Nd, Hf, Cu, Fe, and Zn elemental solutions, the concentration of each element was accurately determined using ICP-MS. Then, the isotope ratios of each element were tested using MC-ICP-MS. The isotope analysis of the sample was completed by combining the data with international standard samples.

[0037] In S2, the order of adding anti-aqua regia and concentrated hydrofluoric acid is fixed. Anti-aqua regia must be added first, followed by concentrated hydrofluoric acid, and anti-aqua regia must be prepared on-site for use in the experiment.

[0038] The column washing procedure for separating Cu-Fe-Zn elements in S5 is as follows: 10 ml of 0.5N HNO3, 5 ml of 1N HCl, and 3 ml of 9N HCl are added sequentially to activate and clean the resin column; the matrix solution collected after sample loading is evaporated to dryness, and 2 ml of 3N HNO3 is added to dissolve it, obtaining an intermediate solution for separating Sr-Nd-Pb-Hf elements.

[0039] The elution, collection, and post-processing procedures for each element in S5 are as follows: Cu solution is collected by elution with 10 ml of 6N HCl; Fe solution is collected by elution with 8 ml of 2N HCl; Zn solution is collected by elution with 2 ml of 0.5N HNO3 added three times each time; Fe solution is directly diluted with ultrapure water and its concentration is tested by ICP-OES; Cu and Zn solutions are evaporated to dryness, reconstituted with dilute acid, and diluted in a gradient before their concentration is tested by ICP-MS.

[0040] The column washing procedure for Sr-Pb elemental separation in S6 is as follows: 10 ml of 6N HCl, 10 ml of ultrapure water, and 10 ml of 3NHNO3 are added sequentially to wash and activate the resin column; after sample loading, the column is rinsed three times with 1 ml of 3N HNO3, and the eluent is combined to obtain 5 ml of solution A. After multiple acid washes, the Sr solution is collected by elution with 5 ml of ultrapure water, and the Pb solution is collected by elution with 10 ml of 6N HCl.

[0041] The column washing procedure for rare earth element separation in S7 is as follows: 10 ml of 6N HCl, 10 ml of 2.5N HCl, 10 ml of ultrapure water, and 3 ml of 3N HNO3 are added sequentially to wash and activate the resin column; after loading solution A, the column is rinsed three times with 1 ml of 3N HNO3, and the eluents are combined to obtain 8 ml of solution B. After removing impurities by acid washing with 2.5N HCl, the rare earth element solution is collected by elution with 10 ml of 6N HCl. This solution is then evaporated to dryness and dissolved in 1 ml of 0.25N HCl for later use.

[0042] The pretreatment process for Nd element separation in S8 resin column is as follows: the LN-B50-S resin column is washed and activated sequentially with 4 ml 6N HCl, 4 ml ultrapure water, and 4 ml 0.25N HCl; after loading the rare earth element solution, it is rinsed three times with 4 ml 0.25N HCl to remove impurities, and then eluted twice with 4 ml 0.25N HCl each time, and the purified Nd solution is collected.

[0043] The pretreatment process for Hf element separation in S9 resin column is as follows: LN-B50-S resin column is cleaned and activated sequentially with 2.5 ml 2N HF, 10 ml 6N HCl, 10 ml ultrapure water, and 3 ml 3N HNO3; after loading solution B, the column is first rinsed 5 times with a mixture of 10 ml 4N HCl and 0.08N HF to remove impurities, then rinsed 5 times with a mixture of 10 ml 6N HCl and 0.08N HF, and finally eluted with 2.5 ml 2N HF to collect and purify the Hf solution.

[0044] The method involves stepwise separation of seven elements—Sr, Pb, Nd, Hf, Cu, Fe, and Zn—after a single sample digestion, using a multi-stage ion exchange column. The recovery rates of Sr, Nd, Pb, and Hf are ≥95%, while the recovery rates of Cu, Fe, and Zn are ≥90%.

[0045] Geological samples include igneous rocks, deep mantle materials, lunar rocks, deep-sea sediments, and rare and precious Martian meteorites. The overall experimental cycle is shortened by more than 60% compared to the traditional multi-batch digestion and separation process.

[0046] The above embodiments are only used to illustrate the present invention and are not intended to limit the technical solutions described herein. Although the present invention has been described in detail with reference to the above embodiments, the present invention is not limited to the specific embodiments described above. Therefore, any modifications or equivalent substitutions to the present invention, as well as all technical solutions and improvements that do not depart from the spirit and scope of the invention, are covered within the scope of the claims of the present invention.

Claims

1. A highly efficient method for separating and purifying elements in geological samples of Sr-Pb-Nd-Hf-Cu-Fe-Zn, characterized in that, Includes the following steps: S1. Sample pretreatment: Cut the collected geological samples into blocks, remove saw marks with a diamond grinding disc to avoid metal contamination, wash the surface of the sample blocks with pure water, dry at 105℃, and then prevent moisture. Grind the samples to 200 mesh powder using an agate ball mill, or select 40-60 mesh matrix particles under a binocular microscope to obtain pretreated samples. S2. Acid dissolution digestion: After drying the pretreated sample at 105℃, place it in a desiccator. Take 45-55mg of the pretreated sample and place it in a Teflon melting bomb. Add 1ml of freshly prepared aqua regia and 0.5ml of concentrated hydrofluoric acid in sequence. Seal the melting bomb and place it in an oven. Heat at 190℃ for 15h to complete the digestion and obtain a clear solution. Dilute the clear solution with 2% nitric acid to 2000 times the sample mass. S3. Initial determination of elemental concentration: The initial concentrations of Sr, Pb, Nd, Hf, Cu, Fe, and Zn in the diluted test solution were determined using ICP-MS. S4. Solution pretreatment: Based on the elemental concentrations measured in S3 and the injection volume required for MC-ICP-MS isotope testing, calculate and measure the corresponding volume of the solution to be tested, evaporate to dryness, add 1 ml of 9N HCl to dissolve, and prepare the sample solution to be passed through the column. S5. Cu-Fe-Zn elemental separation and purification: A resin column loaded with 1 ml AG-MP-1M resin was used. After washing the column with a specific acid washing process, the sample was loaded, and Cu, Fe, and Zn elemental solutions were eluted stepwise and collected separately. After dilution and reconstitution of each elemental solution, the elemental concentration was tested by ICP-MS and ICP-OES respectively to complete the purification of Cu, Fe, and Zn elements. S6, Sr-Pb elemental separation and purification: A resin column loaded with 2 ml SR-B50-S strontium-specific resin was used to load, rinse, and wash the residual sample solution after Cu-Fe-Zn separation in S5. Sr solution and Pb solution were collected stepwise to complete the purification of Sr and Pb elements. S7. Separation and purification of rare earth elements: Using a resin column loaded with 2 ml of AG-50W-X8 resin, the elution solution A obtained in S6 was loaded, rinsed, and washed on the column. The rare earth element solution was collected and evaporated to dryness and treated with acid dissolution and conversion medium. At the same time, the elution solution B was collected for later use. S8 and Nd element separation and purification: A resin column loaded with 2 ml LN-B50-S resin was used to load, wash and elute the rare earth element solution after S7 treatment, and collect the purified Nd solution to complete the Nd element purification. S9. Hf element separation and purification: A resin column loaded with 2ml LN-B50-S resin was used to load the elution solution B collected in S7, perform stepwise acid washing and elution, and collect the purified Hf solution to complete the Hf element purification. S10. Concentration Calibration and Isotope Testing: After diluting the purified Sr, Pb, Nd, Hf, Cu, Fe, and Zn elemental solutions, the concentration of each element was accurately determined using ICP-MS. Then, the isotope ratios of each element were tested using MC-ICP-MS. The isotope analysis of the sample was completed by combining the data with international standard samples.

2. The method for efficient elemental purification of Sr-Pb-Nd-Hf-Cu-Fe-Zn geological samples according to claim 1, characterized in that, In S2, the order of adding anti-aqua regia and concentrated hydrofluoric acid is fixed. Anti-aqua regia must be added first, followed by concentrated hydrofluoric acid, and anti-aqua regia must be prepared on-site for use in the experiment.

3. The method for efficient separation and elemental purification of geological samples Sr-Pb-Nd-Hf-Cu-Fe-Zn according to claim 1, characterized in that, The column washing procedure for separating Cu-Fe-Zn elements in S5 is as follows: 10 ml of 0.5 N HNO3, 5 ml of 1 N HCl, and 3 ml of 9 N HCl are added sequentially to activate and clean the resin column; the matrix solution collected after sample loading is evaporated to dryness, and 2 ml of 3 N HNO3 is added to dissolve it, obtaining an intermediate solution for separating Sr-Nd-Pb-Hf elements.

4. The method for efficient elemental purification of Sr-Pb-Nd-Hf-Cu-Fe-Zn geological samples according to claim 1, characterized in that, The elution, collection, and post-processing procedures for each element in S5 are as follows: Cu solution is collected by elution with 10 ml of 6N HCl; Fe solution is collected by elution with 8 ml of 2N HCl; Zn solution is collected by elution with 2 ml of 0.5N HNO3 added three times each time; Fe solution is directly diluted with ultrapure water and its concentration is tested by ICP-OES; Cu and Zn solutions are evaporated to dryness, reconstituted with dilute acid, and diluted in a gradient before their concentration is tested by ICP-MS.

5. The method for efficient elemental purification of Sr-Pb-Nd-Hf-Cu-Fe-Zn geological samples according to claim 1, characterized in that, The column washing procedure for Sr-Pb elemental separation in S6 is as follows: 10 ml of 6N HCl, 10 ml of ultrapure water, and 10 ml of 3N HNO3 are added sequentially to wash and activate the resin column; after sample loading, the column is rinsed three times with 1 ml of 3N HNO3, and the eluent is combined to obtain 5 ml of solution A. After multiple acid washes, the Sr solution is collected by elution with 5 ml of ultrapure water, and the Pb solution is collected by elution with 10 ml of 6N HCl.

6. The method for efficient elemental purification of Sr-Pb-Nd-Hf-Cu-Fe-Zn geological samples according to claim 1, characterized in that, The column washing procedure for rare earth element separation in S7 is as follows: 10 ml of 6N HCl, 10 ml of 2.5N HCl, 10 ml of ultrapure water, and 3 ml of 3N HNO3 are added sequentially to wash and activate the resin column; after loading solution A, the column is rinsed three times with 1 ml of 3N HNO3, and the eluents are combined to obtain 8 ml of solution B. After removing impurities by acid washing with 2.5N HCl, the rare earth element solution is collected by elution with 10 ml of 6N HCl. This solution is then evaporated to dryness and dissolved in 1 ml of 0.25N HCl for later use.

7. The method for efficient separation and elemental purification of geological samples Sr-Pb-Nd-Hf-Cu-Fe-Zn according to claim 1, characterized in that, The pretreatment process for Nd element separation in S8 resin column is as follows: the LN-B50-S resin column is cleaned and activated sequentially with 4 ml 6N HCl, 4 ml ultrapure water, and 4 ml 0.25N HCl; after loading the rare earth element solution, it is rinsed three times with 4 ml 0.25N HCl to remove impurities, and then eluted twice with 4 ml 0.25N HCl each time, and the purified Nd solution is collected.

8. The method for efficient elemental purification of Sr-Pb-Nd-Hf-Cu-Fe-Zn geological samples according to claim 1, characterized in that, The pretreatment process for Hf element separation in S9 resin column is as follows: LN-B50-S resin column is cleaned and activated sequentially with 2.5 ml 2N HF, 10 ml 6N HCl, 10 ml ultrapure water, and 3 ml 3N HNO3; after loading solution B, it is first rinsed 5 times with a mixture of 10 ml 4N HCl and 0.08N HF to remove impurities, then rinsed 5 times with a mixture of 10 ml 6N HCl and 0.08N HF, and finally eluted with 2.5 ml 2N HF to collect and purify the Hf solution.

9. The method for efficient elemental purification of Sr-Pb-Nd-Hf-Cu-Fe-Zn geological samples according to claim 1, characterized in that, The method describes a single sample digestion followed by stepwise separation using multi-stage ion exchange columns to simultaneously purify seven elements: Sr, Pb, Nd, Hf, Cu, Fe, and Zn. The recovery rates of Sr, Nd, Pb, and Hf are ≥95%, while the recovery rates of Cu, Fe, and Zn are ≥90%.

10. The method for efficient elemental purification of Sr-Pb-Nd-Hf-Cu-Fe-Zn geological samples according to claim 1, characterized in that, The geological samples include igneous rocks, deep mantle materials, lunar rocks, deep-sea sediments, and rare and precious Martian meteorites. The overall experimental cycle is shortened by more than 60% compared to the traditional multi-batch digestion and separation process.

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