Preparation method of pure tantalum standard sample for trace element analysis

Abstract

The invention relates to a preparation method of a pure tantalum standard sample for trace element analysis, and belongs to the field of chemical standard sample preparation. The preparation method comprises the following steps: quantitatively adding aluminum nitrate, calcium nitrate, chromic nitrate, copper nitrate, ferric nitrate, manganous nitrate, ammonium molybdate, niobium pentachloride, nickel nitrate, stannic chloride, ammonium hexafluorotitanate and ammonium paratungstate into potassium fluotantalate according to a design ratio, adding potassium chloride according to a ratio, uniformly mixing, and reducing potassium fluotantalate by adopting a sodium thermal reduction process to obtain a potassium fluotantalate solution; the obtained metal tantalum particles are coarsely crushed by a jaw crusher, purified in a rotary pickling tank, then subjected to high-temperature heat treatment in a vacuum induction furnace, and subjected to hydrogenation, crushing, dehydrogenation, purification, grinding, homogenization treatment and tabletting to obtain a pure tantalum standard sample candidate material. A classical chemical method and an instrument method are adopted to carry out uniformity test, stability test and valuing on each valued element in pure tantalum.

Description

Technical Field

[0001] The invention belongs to the field of chemical standard sample preparation, and relates to a method for preparing a pure tantalum standard sample for trace element analysis. Background Art

[0002] Tantalum and tantalum alloys have excellent properties such as high density, high melting point, corrosion resistance, excellent high temperature strength, good processing characteristics and low plastic / brittle transition temperature. They have been widely used in various industrial fields such as electronics, chemical industry, aerospace, weapon equipment, etc. Pure tantalum materials (purity ≥ 4N) have excellent processing plasticity, and their mechanical properties are very sensitive to temperature and strain rate. They are one of the important raw materials for the preparation of high-performance capacitors for integrated circuits. In recent years, with the rapid development of the electronic information industry, the scale and integration of integrated circuits have become increasingly higher, and higher requirements have been placed on the purity of pure tantalum materials used to manufacture capacitor sealed housings. Therefore, the accurate determination of the content of impurity elements in pure tantalum plays a very important supporting role in the quality control of pure tantalum and its downstream products.

[0003] At present, the main analytical method standards for determining the content of impurity elements in pure tantalum / high-purity tantalum in China are YS / T 898-2013 "High-purity tantalum chemical analysis method - determination of trace impurity elements - inductively coupled plasma mass spectrometry" and YS / T 899-2013 "High-purity tantalum chemical analysis method - determination of trace impurity elements - glow discharge mass spectrometry". However, there is a lack of standard samples of pure tantalum in the analytical test process, and the validity and reliability of the measurement results cannot be guaranteed, especially for glow discharge mass spectrometry, which has no corresponding standard samples and no reliable traceability, and can only provide semi-quantitative results. According to the search report provided by the Nonferrous Industry Science and Technology Search Center, there is currently no report on standard samples of pure tantalum. Summary of the invention

[0004] In view of the above-mentioned technical problems, the present invention provides a method for preparing a pure tantalum standard sample for trace element analysis, by which a pure tantalum standard sample with regular shape, good uniformity, high stability and accurate fixed value can be prepared, and at the same time, sufficient characteristic values ​​can be provided for reference. It not only fills the gap of pure tantalum standard samples, but also can be used for the correction of trace element determination results in pure tantalum / high-purity tantalum, equipment verification and method verification, and plays a supporting role in guiding the research and development and production of pure tantalum materials and controlling their quality level.

[0005] A method for preparing a pure tantalum standard sample for trace element analysis comprises the following steps:

[0006] (1) According to the composition of the pure tantalum standard sample, a proportion is designed, potassium fluorotantalate, potassium chloride, aluminum nitrate, calcium nitrate, chromium nitrate, copper nitrate, iron nitrate, manganese nitrate, ammonium molybdate, niobium pentachloride, nickel nitrate, tin tetrachloride, ammonium hexafluorotitanate, and ammonium paratungstate are weighed, and the weighed quantities are placed in a reaction kettle in sequence, and the reaction kettle is placed in a heating furnace;

[0007] (2) injecting 105% to 125% of metallic sodium into the reaction kettle of step (1) while stirring using a stirrer;

[0008] (3) heating the heating furnace in step (2) at 900° C.±50° C. for 2 h±0.5 h to cause the substance added in step (1) to undergo an oxidation-reduction reaction to obtain crude tantalum metal particles;

[0009] (4) crushing the crude tantalum metal particles obtained in step (3) into small pieces less than 3 cm by a jaw crusher;

[0010] (5) The small pieces of tantalum metal obtained in step (4) are purified in a rotary pickling tank using an aqueous solution of a mixture of nitric acid and hydrofluoric acid (the volume ratio of nitric acid: hydrofluoric acid: water is 2-6:0.5-2:15-30) to obtain flaky tantalum powder.

[0011] (6) placing the tantalum powder flakes obtained in step (5) into a vacuum induction furnace for high temperature heat treatment at 800° C. to 1000° C., so that the tantalum powder presents a sponge shape;

[0012] (7) keeping the sponge-like tantalum powder obtained in step (6) in a resistance hydrogenation furnace at 400° C.±50° C. for 2 h±0.5 h to obtain tantalum hydride powder;

[0013] (8) placing the tantalum hydride powder obtained in step (7) into a resistance pit dehydrogenation furnace, adding 1% to 3% by mass of metallic magnesium in an argon protective atmosphere for dehydrogenation treatment to obtain tantalum powder;

[0014] (9) further purifying the tantalum powder obtained in step (8) with a mixture of nitric acid and hydrofluoric acid (the volume ratio of nitric acid: hydrofluoric acid: water is 2-6: 0.5-2: 40-60);

[0015] (10) Dry the tantalum powder obtained in step (9) to obtain a bulk density of 3.0 g / cm 3 High quality tantalum powder;

[0016] (11) grinding the tantalum powder obtained in step (10) and passing it through a 0.075 mm (200 mesh) standard sieve;

[0017] (12) homogenizing the tantalum powder obtained in step (11) in a universal mixer for 150 h±30 h to obtain a candidate material for a tantalum powder standard sample;

[0018] (13) Accurately weigh the tantalum powder standard sample candidate material obtained in step (12) with 10 g ± 1.0 g of each sample and place it in a corresponding mold, and press it into a tablet press at 400 MPa ± 20 MPa. A round block sample was prepared to obtain a pure tantalum standard sample for analysis.

[0019] (14) For the round block sample obtained in step (13), the uniformity and stability of the chemical standard sample composition of the pure tantalum standard sample obtained above are evaluated and the sample composition is determined in accordance with the provisions of GB / T 15000 "Guidelines for Standard Samples" and YS / T 409-2012 "Technical Specifications for Standard Samples for Analysis of Nonferrous Metal Products".

[0020] The standard sample prepared in the present invention can be used as a standard sample when testing impurity elements in a pure tantalum sample.

[0021] The standard samples are sealed in clean and dust-free PE bags, covered with aluminum plastic film and vacuum packed, and placed in wooden packaging boxes lined with sponge pads. The standard samples should be stored at room temperature and pressure away from light, and effective measures should be taken to prevent violent vibrations during transportation.

[0022] In step (1), the purity of potassium tantalate is greater than 99.95%;

[0023] In step (2), preferably 110% to 120% metallic sodium is injected;

[0024] In step (3), the heating furnace is preferably kept at 900°C ± 40°C for 2h ± 0.3h;

[0025] In step (4), the raw material is preferably coarsely crushed into small pieces of less than 2.5 cm by a jaw crusher;

[0026] In step (5), the acid purity is high purity.

[0027] Beneficial Effects

[0028] The present invention uses potassium fluorotantalate as a raw material, adds trace element compounds and adopts a sodium thermal reduction process to prepare pure tantalum precursor powder. The obtained pure tantalum standard sample for trace element analysis has sufficient uniformity and stability, and has a long shelf life. It fills the gap of pure tantalum standard samples in the domestic and foreign markets, provides a basis for the accuracy of experimental results, and can also be used for laboratory instrument verification and method verification, so that pure tantalum testing can be quantified and traceable, and brings considerable economic benefits to the research and development unit. The preparation of standard samples meets the requirements of GB / T15000 "Standard Sample Working Guidelines" and YS / T 409 "Technical Specifications for Standard Samples for Nonferrous Metal Product Analysis". DETAILED DESCRIPTION

[0029] The method for preparing a pure tantalum standard sample for component analysis of the present invention, wherein the obtained pure tantalum sample can be used for trace element analysis, specifically comprises the following steps:

[0030] (1) 20.0 kg to 25.0 kg of potassium fluorotantalate, 10.0 kg to 15.0 kg of potassium chloride, 0.01 g to 0.1 g of aluminum nitrate, 0.01 g to 0.1 g of calcium nitrate, 0.1 g to 2.0 g of chromium nitrate, 0.01 g to 0.1 g of copper nitrate, 0.1 g to 2.0 g of iron nitrate, 0.01 g to 0.1 g of manganese nitrate, 0.001 g to 0.01 g of ammonium molybdate, 0.02 g to 0.3 g of niobium pentachloride, 0.1 g to 2.0 g of nickel nitrate, 0.01 g to 0.1 g of tin tetrachloride, 0.01 g to 0.1 g of ammonium hexafluorotitanate, and 0.01 g to 0.1 g of ammonium paratungstate are sequentially placed in a reaction kettle, and the reaction kettle is placed in a heating furnace;

[0031] (2) Use a stirrer to inject metallic sodium into the reactor in step (1), according to the reaction formula K 2 Tf 7 +5Na=Ta+5NaF+2KF, inject 6.0kg~9.5kg of sodium;

[0032] (3) heating the heating furnace into which the sample has been added in step (2) at 900° C.±50° C. for 2 h±0.5 h to reduce the substance in step (1) to obtain crude tantalum metal particles;

[0033] (4) crushing the crude tantalum metal particles obtained in step (3) into small pieces less than 3 cm by a jaw crusher;

[0034] (5) The small pieces of tantalum metal obtained in step (4) are placed in a rotary pickling tank and purified using an aqueous solution having a volume ratio of nitric acid: hydrofluoric acid: water of 2-6:0.5-2:15-30 to obtain tantalum flake powder.

[0035] (6) placing the tantalum powder flakes obtained in step (5) into a vacuum induction furnace for heat treatment at a high temperature of 800° C. to 1000° C., so that the tantalum powder becomes sponge-like;

[0036] (7) keeping the sponge-like tantalum powder obtained in step (6) in a resistance hydrogenation furnace at 400° C.±50° C. for 2 h±0.5 h to obtain tantalum hydride powder;

[0037] (8) The tantalum hydride powder obtained in step (7) is mixed evenly with 0.09 kg to 0.4 kg of magnesium powder, placed in a resistance pit dehydrogenation furnace, and kept at 600° C. to 1000° C. for 2 h to 3 h under an argon protective atmosphere to perform a dehydrogenation treatment to obtain tantalum powder;

[0038] (9) further purifying the tantalum powder obtained in step (8) with an aqueous solution having a volume ratio of nitric acid: hydrofluoric acid: water of 2-6: 0.5-2: 40-60;

[0039] (10) The tantalum powder obtained in step (9) is dried to obtain a bulk density of 3.0 g / cm 3 High quality tantalum powder;

[0040] (11) grinding the high-quality tantalum powder obtained in step (10) and passing it through a 0.075 mm (200 mesh) standard sieve;

[0041] (12) homogenizing the tantalum powder obtained in step (11) in a universal mixer for 150 h±30 h to obtain a candidate material for a tantalum powder standard sample;

[0042] (13) 10 g ± 1.0 g of each sample was accurately weighed and placed in the corresponding mold, and pressed into a tablet press at 400 MPa ± 20 MPa. A round block sample is prepared to make a pure tantalum standard sample for analysis.

[0043] (14) Standard sample composition uniformity test: The flake sample obtained in step (13) was subjected to a chemical standard sample composition uniformity test by determining the element content of the sample in accordance with GB / T 15000 "Guidelines for Standard Samples" and YS / T 409-2012 "Technical Specifications for Standard Samples for Analysis of Nonferrous Metal Products". The single factor variance method was used for data analysis and statistics.

[0044] Wherein, the chemical standard sample composition stability test: the standard sample whose composition has passed the uniformity test in step (14) is subjected to stability tracking experiment in accordance with GB / T 15000 "Guidelines for Standard Samples" and YS / T 409-2012 "Technical Specifications for Standard Samples for Analysis of Nonferrous Metal Products". According to the principle of first dense and then sparse, multiple stability experiments are carried out within 10 months, and the stability test results are analyzed by trend analysis method. If the characteristic value of each element does not change significantly during the storage time, the sample is stable;

[0045] Chemical standard sample composition determination: The pure tantalum standard sample that has passed the composition uniformity inspection in step (14) is calibrated according to GB / T 15000 "Guidelines for Standard Samples" and YS / T 409-2012 "Technical Specifications for Standard Samples for Analysis of Nonferrous Metal Products" using a collaborative calibration method to obtain the content and uncertainty of each element in the pure tantalum standard sample.

[0046] The preparation method of the present invention is described in detail below through specific examples.

[0047] Example 1

[0048] Step (1), 20.0 kg potassium fluorotantalate, 13.2 kg potassium chloride, 0.07 g aluminum nitrate, 0.05 g calcium nitrate, 1.2 g chromium nitrate, 0.06 g copper nitrate, 1.4 g iron nitrate, 0.08 g manganese nitrate, 0.007 g ammonium molybdate, 0.18 g niobium pentachloride, 0.1 g nickel nitrate, 0.02 g tin tetrachloride, 0.05 g ammonium hexafluorotitanate, and 0.06 g ammonium paratungstate are sequentially placed in a reaction kettle, and the reaction kettle is placed in a heating furnace;

[0049] Step (2), injecting 8.0 kg of metallic sodium into the reactor using a stirrer;

[0050] Step (3), heating the furnace to 900° C. and keeping the temperature for 2 hours to obtain crude tantalum metal particles;

[0051] Step (4), using a jaw crusher to crush the crude tantalum metal particles into small pieces less than 3 cm;

[0052] Step (5), placing the small tantalum metal pieces into a rotary pickling tank, and purifying them with an aqueous solution of nitric acid and hydrofluoric acid in a volume ratio of 4:1:20 to obtain tantalum flake powder.

[0053] Step (6), placing the flaky tantalum powder in a 900° C. vacuum induction furnace for high temperature heat treatment, so that the tantalum powder presents a sponge shape;

[0054] Step (7), keeping the sponge-like tantalum powder in a resistance hydrogenation furnace at 400° C. for 2 hours to obtain tantalum hydride powder;

[0055] Step (8), mixing tantalum hydride powder with 0.24 kg of magnesium powder, keeping the mixture at 800° C. for 2 h, and performing dehydrogenation treatment to obtain tantalum powder;

[0056] Step (9), further purifying the tantalum powder with a nitric acid and hydrofluoric acid solution in a volume ratio of 4:1:45;

[0057] Step (10), drying the tantalum powder to obtain a bulk density of 3.0 g / cm 3 High quality tantalum powder;

[0058] Step (11), grinding the high-quality tantalum powder and passing it through a 0.075 mm (200 mesh) standard sieve;

[0059] Step (12), homogenizing the filtered tantalum powder in a universal mixer for 170 hours to obtain a tantalum powder standard sample candidate material;

[0060] Step (13), accurately weigh 10.5g of tantalum powder standard sample candidate material and place it in a mold, and press it into a tablet press at 400MPa. A round block sample is prepared to make a pure tantalum standard sample for analysis.

[0061] The standard sample of tantalum powder obtained by the above example was subjected to the following tests:

[0062] 1. Uniformity test of pure tantalum standard sample:

[0063] According to the random number table, 15 standard samples were selected to conduct the uniformity inspection of chemical standard sample components. Each sample was tested 3 times, and the uniformity inspection results were statistically analyzed by single-factor variance analysis (F test method). The statistics of uniformity inspection results are shown in Table 1.

[0064] Table 1 Statistics of uniformity test results of pure tantalum standard samples

[0065]

[0066] From the statistical results in Table 1, it can be seen that the F content of 14 impurity elements including Al, Ca, Cr, Cu, Fe, K, Mn, Mo, Na, Nb, Ni, Sn, Ti and W is 0.05(14,30) <2.04, indicating that the above elements are evenly distributed in the standard sample; refer to F in YS / T 409-2012 <F α In the case of , calculate the inhomogeneity variance and include it in the expanded uncertainty of the standard value of the characteristic quantity.

[0067] 2. Stability test

[0068] Three samples were randomly selected each time, and each sample was measured twice independently. The time intervals were checked for stability using the principle of first dense and then sparse. The fixed value method was used as the test method, and the average consistency test method was used as the statistical method for stability. The calculation formula of the average consistency test method is as follows: The results are shown in Table 2.

[0069]

[0070] Where t is the statistic; degrees of freedom f = n 1 +n 2 -2.

[0071] Table 2 Stability test data

[0072]

[0073] From the results in Table 2, it can be seen that the inventors conducted multiple stability tests, and the statistical values ​​of each element were all below 2.08, that is, the t-value test results of each element were all less than the critical value t 0.05(10) This shows that there is no significant difference between the average values ​​of each measurement. It can be determined that the characteristic value of the standard sample does not change significantly during the storage time, which means that the standard sample has good stability.

[0074] 3. The value and uncertainty of standard samples

[0075] Nine laboratories with relevant qualifications were commissioned to coordinate the determination of values. Grubbs test was used to test for abnormal values ​​within and between groups, Shapiro-Wilk method was used to test the normality of each valued data, and Cochran test was used for precision test. The arithmetic mean was used as the standard value of the standard sample, the uncertainty introduced by uniformity and the uncertainty introduced by the determination were used as the uncertainty of the standard sample, and the calculated results were rounded off. The obtained data are the standard value and uncertainty of the pure tantalum standard sample for trace analysis, see Table 3.

[0076] Table 3 Standard values ​​and uncertainties of each element in pure tantalum standard samples

[0077]

[0078] In the above Table 3, the standard sample has set values ​​for 14 elements in total, and the standard values ​​of the standard samples are all in the range of 0.00004% to 0.0026%, and the expanded uncertainty is in the range of 0.00002 to 0.0002%. It can be seen that the value of the pure tantalum standard sample prepared by the present invention is accurate and reliable, suitable for the determination of trace elements in pure tantalum, and provides a basis for the accuracy of the experimental results. At the same time, it can also be used for laboratory instrument verification and method verification, so that the pure tantalum test can be quantified and traceable, which is of great significance and necessity for my country's pure tantalum production and analysis and detection capabilities in the field.

[0079] The technical solution of the present invention uses potassium fluorotantalate as raw material, and adds aluminum nitrate, calcium nitrate, chromium nitrate, copper nitrate, iron nitrate, manganese nitrate, ammonium molybdate, niobium pentachloride, nickel nitrate, tin tetrachloride, ammonium hexafluorotitanate, and ammonium paratungstate according to the component design requirements. The precursor is obtained by reduction purification in a reactor, and a pure tantalum standard sample is obtained by a tabletting method. The standard sample has been tested for uniformity and stability and has been proved to have good uniformity and stability. The characteristic value is determined by collaboration of multiple companies to obtain the standard value, and the uncertainty is evaluated by reasonable means. The pure tantalum standard sample developed by the present invention has sufficient uniformity and stability, filling the gap in the standard sample of pure tantalum in the domestic and foreign markets. The standard sample can be used for quality control of trace element content in pure tantalum tested by GD-MS and ICP-MS, improves the accuracy and reliability of the test results, and can also be used for comparison of test data within the industry to promote industry development.

Claims

1. A method for preparing a pure tantalum standard sample for trace element analysis, characterized in that: The following steps are involved: (1) According to the composition of the pure tantalum standard sample, a proportion is designed, potassium fluorotantalate, potassium chloride, aluminum nitrate, calcium nitrate, chromium nitrate, copper nitrate, iron nitrate, manganese nitrate, ammonium molybdate, niobium pentachloride, nickel nitrate, tin tetrachloride, ammonium hexafluorotitanate, and ammonium paratungstate are weighed, and then placed in a reaction kettle in sequence, and the reaction kettle is placed in a heating furnace; (2) injecting 105% to 125% of metallic sodium into the reaction kettle of step (1) while stirring with a stirrer; (3) heating the heating furnace of step (2) at 900° C.±50° C. for 2 h±0.5 h, so that the substance added in step (1) undergoes an oxidation-reduction reaction to obtain crude tantalum metal particles; (4) crushing the crude tantalum metal particles obtained in step (3) into small pieces of less than 3 cm using a jaw crusher; (5) The tantalum metal flakes obtained in step (4) are purified in a rotary pickling tank using a mixture of nitric acid and hydrofluoric acid to obtain tantalum flake powder. The mixture of nitric acid and hydrofluoric acid is an aqueous solution with a volume ratio of nitric acid: hydrofluoric acid: water of 2-6:0.5-2:15-30. (6) placing the flaky tantalum powder obtained in step (5) into a vacuum induction furnace and subjecting it to high temperature heat treatment at 800° C. to 1000° C., so that the tantalum powder presents a sponge shape; (7) keeping the sponge-like tantalum powder obtained in step (6) in a resistance hydrogenation furnace at 400° C.±50° C. for 2 h±0.5 h to obtain tantalum hydride powder; (8) placing the tantalum hydride powder obtained in step (7) into a resistance pit dehydrogenation furnace, adding 1% to 3% by mass of metallic magnesium under an argon protective atmosphere for dehydrogenation treatment to obtain tantalum powder; (9) further purifying the tantalum powder obtained in step (8) with a mixture of nitric acid and hydrofluoric acid, wherein the mixture of nitric acid and hydrofluoric acid is an aqueous solution having a volume ratio of nitric acid: hydrofluoric acid: water of 2-6:0.5-2:40-60; (10) The tantalum powder obtained in step (9) is dried to obtain a bulk density of 3.0 g / cm 3 High quality tantalum powder; (11) grinding the tantalum powder obtained in step (10) and passing it through a standard sieve of 0.075 mm (200 mesh); (12) homogenizing the tantalum powder obtained in step (11) in a universal mixer for 150 h±30 h to obtain a candidate material for a tantalum powder standard sample; (13) Accurately weigh the tantalum powder standard sample candidate materials of step (12) with 10 g ± 1.0 g of each sample and place them in a corresponding mold, and press them into a φ20 mm × 2 mm round block sample at 400 MPa ± 20 MPa on a tablet press to obtain a pure tantalum standard sample for analysis; (14) For the round block sample obtained in step (13), in accordance with the provisions of GB / T 15000 "Guidelines for Standard Samples" and YS / T409-2012 "Technical Specifications for Standard Samples for Analysis of Nonferrous Metal Products", the uniformity and stability of the chemical standard sample composition of the pure tantalum standard sample obtained above are evaluated and the sample composition is determined.

2. The preparation method according to claim 1, characterized in that: In the step (1), the designed composition ratio of the pure tantalum standard sample is 20.0kg-25.0kg potassium fluorotantalate, 10.0kg-15.0kg potassium chloride, 0.01g-0.1g aluminum nitrate, 0.01g-0.1g calcium nitrate, 0.1g-2.0g chromium nitrate, 0.01g-0.1g copper nitrate, 0.1g-2.0g iron nitrate, 0.01g-0.1g manganese nitrate, 0.001g-0.01 ammonium molybdate, 0.02g-0.3g niobium pentachloride, 0.1g-2.0 nickel nitrate, 0.01g-0.1g tin tetrachloride, 0.01g-0.1g ammonium hexafluorotitanate, and 0.01g-0.1g ammonium paratungstate.

3. The preparation method according to claim 1, characterized in that: In the step (2), according to the reaction formula K2TaF7+5Na=Ta+5NaF+2KF, 6.0kg to 9.5kg of sodium is injected.

4. The preparation method according to claim 1, characterized in that: In the step (1), the purity of the potassium fluorotantalate is greater than 99.95%.

5. The preparation method according to claim 1, characterized in that: In the step (14), Evaluation of the uniformity of the chemical standard sample composition: The flake sample obtained in step (13) is subjected to a test for the uniformity of the chemical standard sample composition by determining the element content of the sample in accordance with GB / T15000 "Guidelines for Standard Samples" and YS / T 409-2012 "Technical Specifications for Standard Samples for Analysis of Nonferrous Metal Products".

6. The preparation method according to claim 1, characterized in that: In the step (14), Evaluation of chemical standard sample composition stability: The standard samples whose composition has passed the uniformity test in step (14) are subjected to stability tracking experiments in accordance with GB / T 15000 "Guidelines for Standard Samples" and YS / T 409-2012 "Technical Specifications for Standard Samples for Analysis of Nonferrous Metal Products".

7. The preparation method according to claim 1, characterized in that: In the step (14), Chemical standard sample composition determination: The pure tantalum standard sample that has passed the composition uniformity inspection in step (14) is calibrated according to GB / T 15000 "Guidelines for Standard Samples" and YS / T 409-2012 "Technical Specifications for Standard Samples for Analysis of Nonferrous Metal Products" using a collaborative calibration method to obtain the content and uncertainty of each element in the pure tantalum standard sample.

8. An application, using the pure tantalum standard sample prepared according to any one of claims 1 to 7 to analyze impurity elements in a tantalum sample.

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