Preparation method of pure tantalum standard sample for trace element analysis

Abstract

The present application relates to a kind of preparation methods of pure tantalum standard sample for trace element analysis, belong to the field of chemical standard sample preparation.The design ratio is added in potassium fluotantalate Quantitative aluminum nitrate, calcium nitrate, chromium nitrate, copper nitrate, iron nitrate, manganese nitrate, ammonium molybdate, niobium pentachloride, nickel nitrate, tin tetrachloride, ammonium hexafluorotitanate, ammonium paratungstate, and potassium chloride is added in proportion, after being mixed uniformly, potassium fluotantalate is reduced using sodium heat reduction process, the obtained tantalum metal particles are coarsely crushed by jaw crusher, purified in rotary pickling tank, then high-temperature heat treatment is carried out in vacuum induction furnace, and then hydrogenation, crushing, dehydrogenation, purification, grinding, homogenization treatment and tabletting are carried out to obtain pure tantalum standard sample candidate material.Classical chemical method and instrument method are used to carry out uniformity test, stability test and value determination on each value element in pure tantalum.

Description

TECHNICAL FIELD

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

[0002] Tantalum and tantalum alloy 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, and have been widely used in various industrial fields such as electronics, chemical industry, aerospace and weapon equipment. Pure tantalum material (purity ≥ 4N) has excellent processing plasticity, and its mechanical properties are very sensitive to temperature and strain rate, and is one of important raw materials for preparing high-performance capacitors for integrated circuits. In recent years, with the rapid development of electronic information industry, the scale and integration level of integrated circuits are higher and higher, and higher requirements are put forward for the purity of pure tantalum material used for manufacturing capacitor sealing shells. Therefore, accurate determination of the content of impurity elements in pure tantalum plays a very important supporting role in quality control of pure tantalum and its downstream products.

[0003] At present, the main standards for analyzing and testing 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 by inductively coupled plasma mass spectrometry" and YS / T 899-2013 "High-purity tantalum chemical analysis method Determination of trace impurity elements by glow discharge mass spectrometry", but there is a lack of pure tantalum standard samples in the analysis and testing process, which cannot guarantee the effectiveness and reliability of the measurement results, especially for the glow discharge mass spectrometry, there is no corresponding standard sample and no reliable traceability, and only semi-quantitative results can be provided. According to the search report provided by the Nonferrous Industry Science and Technology Search Center, there is no report on pure tantalum standard samples at present. SUMMARY

[0004] In view of the above technical problems, the application provides a preparation method of a pure tantalum standard sample for trace element analysis, which can prepare a pure tantalum standard sample with regular shape, good uniformity, high stability, accurate value and sufficient characteristic value for reference. Not only does it fill the blank of pure tantalum standard samples, but also it can be used for 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 the quality level.

[0005] A preparation method of a pure tantalum standard sample for trace element analysis, comprising the following steps:

[0006] (1) According to the design of the pure tantalum standard sample composition, the potassium tantalate fluoride, 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 sequentially placed in a reaction kettle, which is then placed in a heating furnace;

[0007] (2) The reaction kettle in step (1) is stirred with a blender while 105% to 125% of metallic sodium is injected into the reaction kettle;

[0008] (3) The heating furnace in step (2) is heated, and the temperature is maintained at 900°C±50°C for 2h±0.5h, so that the substances added in step (1) undergo a redox reaction to obtain coarse metallic tantalum particles;

[0009] (4) The coarse metallic tantalum particles obtained in step (3) are coarsely crushed to small pieces below 3cm by a jaw crusher;

[0010] (5) The metallic tantalum small pieces obtained in step (4) are subjected to purification treatment in a rotary acid pickling tank with a mixed solution of nitric acid and hydrofluoric acid (volume ratio of nitric acid:hydrofluoric acid:water is 2-6:0.5-2:15-30) to obtain flaky tantalum powder.

[0011] (6) The flaky tantalum powder obtained in step (5) is placed in a vacuum induction furnace and subjected to high-temperature heat treatment at 800°C to 1000°C, so that the tantalum powder exhibits a sponge shape;

[0012] (7) The sponge-shaped tantalum powder obtained in step (6) is subjected to heat treatment in a resistance hydrogenation furnace at 400°C±50°C for 2h±0.5h to obtain hydrogenated tantalum powder;

[0013] (8) The hydrogenated tantalum powder obtained in step (7) is placed in a resistance well-type dehydrogenation furnace and subjected to dehydrogenation treatment in an argon protective atmosphere by adding 1% to 3% of metallic magnesium to obtain tantalum powder;

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

[0015] (10) The tantalum powder obtained in step (9) is subjected to drying treatment to obtain high-quality tantalum powder with a loose bulk density of 3.0g / cm 3 ;

[0016] (11) The tantalum powder obtained in step (10) is subjected to grinding treatment and then passed through a 0.075mm (200 mesh) standard sieve;

[0017] (12) The tantalum powder obtained in step (11) is subjected to homogenization treatment in a universal mixer for 150h±30h to obtain tantalum powder standard sample candidate material;

[0018] (13) Accurately weigh 10 g ± 1.0 g of the tantalum powder standard sample candidate obtained in step (12) and place it in a corresponding mold to press into a round block sample under 400 MPa ± 20 MPa on a tablet press, thereby obtaining the pure tantalum standard sample for analysis.

[0019] (14) For the round block sample obtained in step (13), the obtained pure tantalum standard sample is evaluated for homogeneity and stability of the chemical standard sample composition and the sample composition is valued according to the provisions of GB / T 15000 “Guidelines for Standard Sample Work” and YS / T 409-2012 “Technical Specifications for Standard Samples for Non-ferrous Metal Product Analysis”.

[0020] The standard sample prepared in the above manner can be applied as a standard sample in testing impurity elements in a pure tantalum sample.

[0021] The standard sample is sealed in a clean and dust-free PE bag, wrapped in an aluminum plastic film vacuum package, and placed in a wooden packaging box lined with a sponge pad. The standard sample should be stored in the dark at room temperature and normal pressure, and effective measures should be taken to prevent it from being shaken violently during transportation.

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

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

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

[0025] In step (4), the small pieces are preferably coarsely crushed to less than 2.5 cm by a jaw crusher;

[0026] In step (5), the purity of the acid is superior grade

[0027] Advantages

[0028] The present application uses potassium fluotantalate as a raw material, adds trace element compounds, and uses sodium heat reduction process to prepare pure tantalum precursor powder, and the obtained pure tantalum standard sample for trace element analysis has sufficient homogeneity and stability, has a long storage time, fills the blank of pure tantalum standard samples in the domestic and foreign markets, provides a basis for the accuracy of experimental results, can also be used for instrument verification and method verification in the laboratory, makes the pure tantalum test quantifiable and traceable, and brings considerable economic benefits to research and development units. The preparation of the standard sample meets the requirements of GB / T 15000 “Guidelines for Standard Sample Work” and YS / T 409 “Technical Specifications for Standard Samples for Non-ferrous Metal Product Analysis”. DETAILED DESCRIPTION

[0029] The preparation method of the pure tantalum standard sample for component analysis of the application can be used for trace element analysis, and specifically comprises the following steps:

[0030] (1) Put 20.0 kg-25.0 kg of potassium fluotantalate, 10.0 kg-15.0 kg of potassium chloride, 0.01 g-0.1 g of aluminum nitrate, 0.01 g-0.1 g of calcium nitrate, 0.1 g-2.0 g of chromium nitrate, 0.01 g-0.1 g of copper nitrate, 0.1 g-2.0 g of iron nitrate, 0.01 g-0.1 g of manganese nitrate, 0.001 g-0.01 g of ammonium molybdate, 0.02 g-0.3 g of niobium pentachloride, 0.1 g-2.0 g of nickel nitrate, 0.01 g-0.1 g of tin tetrachloride, 0.01 g-0.1 g of ammonium hexafluorotitanate, and 0.01 g-0.1 g of ammonium paratungstate into a reaction kettle in sequence, and put the reaction kettle into a heating furnace;

[0031] (2) Inject sodium metal into the reaction kettle in step (1) by using a stirrer, and inject 6.0 kg-9.5 kg of sodium according to the reaction formula K2TaF7+5Na=Ta+5NaF+2KF;

[0032] (3) Heat the heating furnace in which the sample has been added in step (2) at 900℃±50℃ for 2h±0.5h, so that the substances in step (1) are reduced to obtain coarse tantalum metal particles;

[0033] (4) Coarsely crush the coarse tantalum metal particles obtained in step (3) by using a jaw crusher to obtain small pieces below 3 cm;

[0034] (5) Put the small pieces of tantalum metal obtained in step (4) into a rotary acid washing tank, and use an aqueous solution with a volume ratio of nitric acid:hydrofluoric acid:water being 2-6:0.5-2:15-30 to perform purification treatment, so as to obtain flaky tantalum powder.

[0035] (6) Put the flaky tantalum powder obtained in step (5) into a vacuum induction furnace to perform high-temperature heat treatment at 800℃-1000℃, so that the tantalum powder presents a sponge shape;

[0036] (7) Put the sponge-shaped tantalum powder obtained in step (6) into a resistance hydrogenation furnace to perform heat preservation at 400℃±50℃ for 2h±0.5h, so as to obtain hydrogenated tantalum powder;

[0037] (8) Mix the hydrogenated tantalum powder obtained in step (7) with 0.09 kg-0.4 kg of magnesium metal powder uniformly, and put them into a resistance well-type dehydrogenation furnace to perform dehydrogenation treatment under an argon protective atmosphere at 600℃-1000℃ for 2h-3h, so as to obtain tantalum powder;

[0038] (9) The tantalum powder obtained in step (8) is further purified 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 tantalum powder having a loose bulk density of 3.0 g / cm 3 high-quality tantalum powder;

[0040] (11) The high-quality tantalum powder obtained in step (10) is ground and then passed through a 0.075 mm (200 mesh) standard sieve;

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

[0042] (13) Each sample is accurately weighed at 10 g±1.0 g and placed in a corresponding mold, and then pressed into a circular block sample at 400 MPa±20 MPa on a tablet press, thereby obtaining an analytical pure tantalum standard sample.

[0043] (14) Standard sample composition uniformity test: The tablet sample obtained in step (13) is used to determine the sample element content according to GB / T 15000 “Standard Sample Work Guidelines” and YS / T 409-2012 “Technical Specifications for Standard Samples for Non-ferrous Metal Product Analysis”, and the chemical standard sample composition uniformity test is performed, and the data are analyzed and statistically processed using the single-factor variance method.

[0044] Among them, the chemical standard sample composition stability test: the standard sample whose composition has passed the uniformity test in step (14) is subjected to a stability tracking experiment according to GB / T 15000 “Standard Sample Work Guidelines” and YS / T 409-2012 “Technical Specifications for Standard Samples for Non-ferrous Metal Product Analysis”, and multiple stability experiments are performed within 10 months according to the principle of dense first and sparse later, and the stability test results are analyzed using the trend analysis method, and if there is no significant change in the characteristic values of each element within the storage time, the sample is stable;

[0045] Chemical standard sample composition value setting: the pure tantalum standard sample whose composition has passed the uniformity test in step (14) is subjected to value setting according to GB / T 15000 “Standard Sample Work Guidelines” and YS / T 409-2012 “Technical Specifications for Standard Samples for Non-ferrous Metal Product Analysis”, and the standard sample developed is subjected to value setting in a collaborative manner by multiple parties to obtain the element content and uncertainty of the pure tantalum standard sample.

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

[0047] Example 1​

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

[0049] Step (2), 8.0 kg of metallic sodium was injected into the reaction kettle using a blender;

[0050] Step (3), the heating furnace was heated to 900℃, and the temperature was kept for 2 h to obtain coarse metallic tantalum particles;

[0051] Step (4), the coarse metallic tantalum particles were coarsely crushed to small pieces below 3 cm using a jaw crusher;

[0052] Step (5), the metallic tantalum small pieces were put into a rotary pickling tank, and a water solution with a volume ratio of 4:1:20 of nitric acid and hydrofluoric acid was used for purification treatment to obtain flaky tantalum powder.

[0053] Step (6), the flaky tantalum powder was put into a 900℃ vacuum induction furnace for high-temperature heat treatment, so that the tantalum powder showed a sponge shape;

[0054] Step (7), the sponge-shaped tantalum powder was kept at 400℃ in a resistance hydrogenation furnace for 2 h to obtain hydrogenated tantalum powder;

[0055] Step (8), the hydrogenated tantalum powder was mixed with 0.24 kg of metallic magnesium powder, and was kept at 800℃ for 2 h for dehydrogenation treatment to obtain tantalum powder;

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

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

[0058] Step (11), after grinding treatment, the high-quality tantalum powder was passed through a standard sieve with a mesh size of 0.075 mm (200 mesh);

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

[0060] Step (13), 10.5 g of the tantalum powder standard sample candidate material was accurately weighed and placed in a mold, and was pressed into a The round block sample is made into an analysis pure tantalum standard sample.

[0061] The tantalum powder standard sample obtained in the above example is used to perform the following tests:

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

[0063] 15 standard samples are drawn according to the random number table, and the chemical standard sample composition homogeneity is checked, each sample is measured for 3 times, and the single factor variance analysis method (F test method) is used to statistically analyze the homogeneity test results. The homogeneity test result statistics are shown in Table 1.

[0064] Table 1 Homogeneity test result statistics of the pure tantalum standard sample

[0065]

[0066] From the statistical results in Table 1, the F 0.05(14,30) of 14 impurity elements of Al, Ca, Cr, Cu, Fe, K, Mn, Mo, Na, Nb, Ni, Sn, Ti and W is less than 2.04, indicating that the above elements are uniformly distributed in the standard sample; according to the condition that F α <F in YS / T 409-2012, the non-uniformity variance is calculated and included in the uncertainty of the characteristic value of the standard sample.

[0067] 2. Stability test

[0068] Three samples are randomly drawn each time, each sample is independently measured twice, and the time interval is checked according to the principle of dense first and sparse later. The fixed value method is used as the test method, the average value consistency test method is used as the statistical method of stability, and the calculation formula of the average value consistency test method is as follows: the results are shown in Table 2.

[0069]

[0070] In the formula, t is the statistical quantity; the degree of freedom f = n1+n2-2.

[0071] Table 2 Stability test data

[0072]

[0073] From the results in Table 2, the inventors have performed multiple stability tests, and the statistical value of each element is less than 2.08, that is, the t value test result of each element is less than the critical value t 0.05(10) , which indicates that there is no significant difference between the average values of each measurement, and it can be determined that the characteristic value of the standard sample does not change significantly within the storage time, that is, the standard sample has good stability.

[0074] 3. Value and uncertainty of the standard sample

[0075] The value is determined by 9 qualified laboratories, Grubbs test is used for intra-group and inter-group outlier test, Shapiro-Wilk method is used for normality test of each value data, and Cochran test is used for equal precision test. The arithmetic total average value is used as the standard value of the standard sample, the uncertainty introduced by uniformity and the uncertainty introduced by value are used as the uncertainty of the standard sample, and the calculation results are rounded, and the obtained data are the standard value and uncertainty of the trace analysis pure tantalum standard sample, as shown in Table 3.

[0076] Table 3 Standard value and uncertainty of each element in the pure tantalum standard sample

[0077]

[0078] In Table 3, the standard sample is valued for 14 elements, the standard value of the standard sample is 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 pure tantalum standard sample prepared by the application has accurate and reliable quantity value, is suitable for determination of trace elements in pure tantalum, provides a basis for the accuracy of experimental results, and can also be used for instrument verification and method verification of the laboratory, so that the pure tantalum test can be quantified and traceable, which has great significance and necessity for the production and field analysis and detection capability of pure tantalum in China.

[0079] The technical scheme of the application uses potassium fluorotantalate as a raw material, 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, obtains a precursor in a reaction kettle through reduction purification, and obtains a pure tantalum standard sample by tabletting. The standard sample passes the uniformity test and stability test, and proves to have good uniformity and stability. The characteristic value is determined by multiple collaborative value, the standard value is obtained, and the uncertainty is evaluated by reasonable means. The pure tantalum standard sample developed by the application has sufficient uniformity and stability, fills the blank of the pure tantalum standard sample in the domestic and foreign markets. The standard sample can be used for quality control of GD-MS and ICP-MS testing of trace element content in pure tantalum, improves the accuracy and reliability of the detection results, and can also be used for comparison of test data in the industry, and promotes the development of the industry.

Claims

1. A method for producing a pure tantalum standard sample for trace element analysis, characterized by, It comprises the following steps: (1) According to the design of the pure tantalum standard sample composition, the potassium tantalate fluoride, 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 placed in a reaction kettle in turn, and the reaction kettle is placed in a heating furnace; (2) While stirring with a stirrer, 105%-125% of metallic sodium is injected into the reaction kettle of step (1); (3) The heating furnace of step (2) is heated, and the substance added in step (1) is allowed to undergo a redox reaction at 900℃±50℃ for 2h±0.5h to obtain coarse metal tantalum particles; (4) The coarse metal tantalum particles obtained in step (3) are coarsely crushed to less than 3cm by a jaw crusher; (5) The metal tantalum pieces obtained in step (4) are subjected to purification treatment with a mixture of nitric acid and hydrofluoric acid in a rotary pickling tank to obtain flaky tantalum powder, and the mixture of nitric acid and hydrofluoric acid is an aqueous solution with a volume ratio of nitric acid:hydrofluoric acid:water being 2-6:0.5-2:15-30; (6) The flaky tantalum powder obtained in step (5) is placed in a vacuum induction furnace and subjected to high-temperature heat treatment at 800℃-1000℃ to make the tantalum powder present a sponge shape; (7) The sponge-shaped tantalum powder obtained in step (6) is placed in a resistance hydrogenation furnace and subjected to heat preservation at 400℃±50℃ for 2h±0.5h to obtain hydrogenated tantalum powder; (8) The hydrogenated tantalum powder obtained in step (7) is placed in a resistance well-type dehydrogenation furnace, and 1%-3% of metallic magnesium is added under an argon protective atmosphere for dehydrogenation treatment to obtain tantalum powder; (9) The tantalum powder obtained in step (8) is further purified with a mixture of nitric acid and hydrofluoric acid, and the mixture of nitric acid and hydrofluoric acid is an aqueous solution with a volume ratio of nitric acid:hydrofluoric acid:water being 2-6:0.5-2:40-60; (10) drying the tantalum powder obtained in step (9) to obtain high quality tantalum powder having a bulk density of 3.0 g / cm 3 or more. (11) After the tantalum powder obtained in step (10) is ground, it is passed through a standard sieve with a mesh size of 0.075mm, i.e., 200 mesh; (12) The tantalum powder obtained in step (11) is subjected to homogenization treatment in a universal mixer for 150h±30h to obtain tantalum powder standard sample candidate material; (13) 10g±1.0g of each sample is accurately weighed from the tantalum powder standard sample candidate material of step (12) and placed in a corresponding mold, and a φ20mm×2mm round block sample is pressed at 400MPa±20MPa on a tablet press to obtain an analytical pure tantalum standard sample; (14) For the round block sample obtained in step (13), the uniformity and stability of the chemical standard sample composition of the obtained pure tantalum standard sample are evaluated and the sample composition is valued according to the provisions of GB / T 15000 "Standard Sample Work Guide" and YS / T409-2012 "Technical Specification for Standard Samples of Non-ferrous Metal Products".

2. The production method according to claim 1, characterized by, In the step (1), the pure tantalum standard sample is designed to have a composition of 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.

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

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), Chemical standard sample component uniformity evaluation: the round block sample obtained in the step (13) is used to determine the element content of the sample according to GB / T 15000 "Standard Sample Work Guide" and YS / T 409-2012 "Technical Specification for Standard Sample for Non-ferrous Metal Product Analysis" to perform chemical standard sample component uniformity test.

6. The method of claim 1, wherein, In the step (14), Chemical standard sample component stability evaluation: the standard sample with a component that has passed the uniformity test in the step (14) is used to perform stability tracking experiment according to GB / T 15000 "Standard Sample Work Guide" and YS / T 409-2012 "Technical Specification for Standard Sample for Non-ferrous Metal Product Analysis".

7. The preparation method according to claim 1, characterized in that, In the step (14), Chemical standard sample component value determination: the pure tantalum standard sample with a component that has passed the uniformity test in the step (14) is used to determine the value of the developed standard sample according to GB / T 15000 "Standard Sample Work Guide" and YS / T 409-2012 "Technical Specification for Standard Sample for Non-ferrous Metal Product Analysis" by using the value determination method of multiple cooperation to obtain the element content and uncertainty of the pure tantalum standard sample.

8. Use of the pure tantalum standard sample prepared by the preparation method of any one of claims 1 to 7 in testing impurity elements in a tantalum sample.

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