Preparation method of ferronickel standard sample containing high-content harmful elements and standard sample

Abstract

The invention discloses a preparation method of a ferronickel standard sample containing high-content harmful elements and the standard sample. The ferronickel standard sample contains the following chemical elements in percentage: 34.00-36.00% of Ni; fe: 64.00% to 66.00%; the content of As is 0.009%-0.011%; 0.009% to 0.011% of Sb; sn: 0.005% to 0.007%; pb: 0.005% to 0.007%; 0.002% to 0.004% of Bi; c: 0.10% to 0.20%; 0.50% to 0.60% of Si; 0.10% to 0.20% of Mn; 0.010% to 0.020% of P; s: 0.006% to 0.007%; 0.30% to 0.40% of Cr; cu: 0.04% to 0.05%; 0.60% to 0.70% of Co; 0 to 0.0020 percent of N; the balance is unavoidable impurities; the preparation method comprises the steps of standard sample smelting, standard sample preparation, segregation detection, standard sample turning and packaging, sampling detection, uniformity detection, constant value analysis and mathematical statistics. And meanwhile, the types and contents of the added harmful elements can meet the requirements of design and uniformity, and the use requirements of customers and markets are met.

Description

Technical Field

[0001] The invention relates to the technical field of preparation of standard samples of metallurgical materials, and in particular to a method for preparing a nickel-iron standard sample containing a high content of harmful elements and a standard sample. Background Art

[0002] Ferronickel is an alloy with a nickel content of 15% to 80%. It is one of the important raw materials required for the smelting of stainless steel products and a globally scarce strategic resource. Compared with other high-grade nickel raw materials, such as metallic nickel and sintered nickel, ferronickel has the advantage of low cost. At the same time, ferronickel, as a substitute for nickel raw materials, can be directly used in stainless steel smelting. In order to meet the gap in nickel required for the expansion of stainless steel production capacity and reduce production costs, many stainless steel manufacturers at home and abroad have begun to use ferronickel raw materials.

[0003] Harmful elements in steel and alloy materials include arsenic (As), antimony (Sb), tin (Sn), lead (Pb) and bismuth (Bi), which have a great impact on the performance and organizational structure of steel and alloy materials. The metals of the above harmful elements are all low-melting-point metals: the melting point of arsenic (As) is 717°C, and it sublimates at 613°C, which is prone to segregation in steel; the melting point of antimony (Sb) is 630.7°C, which will reduce the strength of steel and increase its brittleness; the melting point of tin (Sn) is 232°C, which will greatly reduce the high-temperature mechanical properties of steel; the melting point of lead (Pb) is 327.5°C, and lead and iron do not produce solid solutions, which are prone to segregation, which will reduce the plasticity and impact resistance of steel. Most of the lead overflows the molten steel as steam during the smelting process, resulting in extremely low lead content in the steel. The melting point of bismuth (Bi) is 271.4℃, and the boiling point is 1560℃. Bismuth is almost insoluble in steel, and most of it will overflow as steam. Therefore, the content of bismuth in steel is extremely small. Bismuth is easy to segregate between the crystals (phases) of steel, causing the brittleness of steel, and reducing the plasticity and high-temperature strength of steel. Due to the presence of harmful elements such as high arsenic, high antimony, high lead, high tin and high bismuth, the difficulty of smelting standard samples is very large, and internal structural defects such as structural defects and structural cracks are very likely to occur, which often leads to the situation of tofu dregs in the standard samples and cannot be used further. Moreover, the harmful element has a high melting point, and even if it is added, it is difficult to ensure the uniformity of the element in the alloy standard sample.

[0004] In the process of steelmaking, harmful elements generally need to be controlled to an upper limit to ensure the performance of steel. For standard samples, it is necessary to deliberately add them so that physical standards with accurate content can be used in analysis and testing to control the analytical quality of the products, so as to provide standard sample users with more information and better meet user needs.

[0005] A standard sample is a material or substance with one or more sufficiently uniform and well-defined characteristic values, which is used to calibrate equipment, evaluate measurement methods, or assign values ​​to materials. As converter slag is a metallurgical waste, its application is increasing year by year, and the inspection of converter slag products requires corresponding standard samples, and the demand is bound to increase. At present, there are very few converter slag standard samples on the market, especially those for determining the values ​​of harmful elements. They can no longer meet the market and customer needs in terms of product quality inspection, calibration of measuring instruments, and evaluation of test methods. Summary of the invention

[0006] In order to solve some or all of the technical problems existing in the above-mentioned prior art, the present invention provides a method for preparing a nickel-iron standard sample containing a high content of harmful elements and a standard sample, which can be used to prepare a nickel-iron standard sample with a high content of harmful elements, and at the same time can ensure that the type and content of the added harmful elements meet the design and uniformity requirements, thereby meeting the usage needs of customers and the market.

[0007] The technical solution of the present invention is as follows:

[0008] In a first aspect, the present invention provides a method for preparing a nickel-iron standard sample containing a high content of harmful elements, which contains the following chemical elements in the following percentages:

[0009] Ni: 34.00%~36.00%; Fe: 64.00%~66.00%; As: 0.009%-0.011%; Sb: 0.009%-0.01 1%; Sn: 0.005%-0.007%; Pb: 0.005%-0.007%; Bi: 0.002%-0.004%; C: 0.10%-0.20 %; Si: 0.50%~0.60%; Mn: 0.10%-0.20%; P: 0.010%-0.020%; S: 0.006%-0.007%; Cr: 0.30%~0.40%; Cu: 0.04%~0.05%; Co: 0.60%-0.70%; N: 0~0.0020%; the rest are unavoidable impurities;

[0010] The preparation method thereof comprises the following steps:

[0011] Standard sample smelting: smelt the nickel-iron raw material containing the preset content of Ni and Fe in a vacuum induction furnace, slowly heat it to 1550℃±50℃ until the nickel-iron raw material is completely melted, stir and mix well and keep warm for 30 minutes, add harmful elements when the temperature drops to 1050℃±50℃ under a protective atmosphere, stir and heat in the furnace and keep warm for 30 minutes, then cast and mold under the furnace bottom to obtain the sample;

[0012] Standard sample preparation: After removing the surface burrs and peeling the obtained sample, a sample with a regular shape is obtained;

[0013] Segregation detection: Use chemical analysis methods to perform segregation detection on the obtained regular-shaped samples, and compare the detection results with the standard uncertainty to obtain samples that pass the initial uniformity inspection;

[0014] Turning and packaging of standard samples: Turn the samples that have passed the initial uniformity inspection, and screen and retain the samples with a size of 0.18mm-0.60mm and a mesh size of 30-80 after grinding. Turn over and mix multiple samples as a group and package them as standard samples;

[0015] Sampling test: Take a number of packaged standard samples as samples, use ICP-MS method to analyze the harmful chemical elements in the samples, and determine the minimum sample weight;

[0016] Uniformity test: Under the same measurement conditions and analysis environment, a small sample weighing and high precision analysis method is used to measure multiple independent data for each of all elements to be tested in the sample, and the variance analysis test method is used to test the uniformity data. If the test is qualified, a standard sample that has passed the uniformity test is obtained;

[0017] Fixed value analysis: The standard samples that have passed the uniformity test are subjected to fixed value analysis using the benchmark analysis method or an accurate and reliable chemical wet analysis method to obtain standard samples that meet the preset standards;

[0018] Mathematical statistics: Perform mathematical statistics on the data obtained from the inspection of standard samples that meet the preset standards to obtain standard samples with chemical elements that meet the target content.

[0019] Furthermore, in the above-mentioned method for preparing a nickel-iron standard sample containing a high content of harmful elements, stability determination and standard sample traceability are also included, wherein:

[0020] The stability determination includes storing a standard sample having a target content of chemical elements for a preset time, and regularly measuring the content of the chemical elements in the standard sample during the preset storage time to determine the stability of the chemical elements in the standard sample;

[0021] The standard sample traceability includes measuring the chemical elements of the standard sample to determine the accuracy of the elements and their contents in the standard sample.

[0022] Furthermore, in the above-mentioned method for preparing a nickel-iron standard sample containing a high content of harmful elements, the prepared standard sample contains at least the following chemical elements in the following percentages:

[0023] Ni: 35±1.5%; Fe: 65±2.5%; As: 0.010±0.002%; Sb: 0.010±0.002%; Sn: 0.006±0.002%; Pb: less than or equal to 0.006±0.002%; Bi: 0.003±0.002%.

[0024] Furthermore, in the above-mentioned method for preparing a nickel-iron standard sample containing a high content of harmful elements, the harmful elements include As, Sb, Sn, Pb and Bi.

[0025] Further, in the above-mentioned method for preparing the nickel-iron standard sample containing high content of harmful elements, the uniformity test using the variance analysis test method includes:

[0026] The variance statistic F value of multiple independent numbers measured for each of all elements packaged in the sample extracted is compared with the critical value of Fα0.05;

[0027] If the variance statistic F value of each element is less than or equal to the critical value of Fα0.05, the uniformity of all elements in the sampled sample meets the requirements;

[0028] If the variance statistic F value of each element is greater than the critical value Fα0.05, the element does not meet the uniformity requirement; then calculate the inhomogeneity variance Sbb of all elements of the sample 2 .

[0029] Furthermore, in the above-mentioned method for preparing standard nickel-iron samples containing high levels of harmful elements, mathematical statistics are performed on standard samples that meet the preset standards, and standard samples that do not meet the preset standards are tested using a variety of test methods including method precision test, normality test, outlier test or equal precision test. If they meet the test standards, they are used as original statistical data of the standard samples for mathematical statistics; if they do not meet the test standards, the non-compliant data are eliminated.

[0030] Furthermore, in the above-mentioned method for preparing a nickel-iron standard sample containing a high content of harmful elements, the standard sample that does not meet the preset standard is tested by a variety of test methods including method precision test, normality test, outlier test or equal precision test, wherein:

[0031] The precision test of the method includes: comparing all the data of all elements in the standard samples that do not meet the preset standards with 1.3 times of the indoor precision r or the allowable difference, reviewing and judging whether there are abnormal values, if there are no abnormal values, calculating the average value of each group, if there are abnormal values, eliminating the abnormal data;

[0032] The normality test includes: performing a normality test on all the data and the unit average numbers of all elements in the standard samples that do not meet the preset standards. If the statistic W of the normality test is W≥W0.05, then all the data are considered to conform to the normal distribution; if the statistic W of the normality test is in the range of W0.01≤W<W0.05, it conforms to the approximate normal distribution, and the tested data are retained; if the statistic W of the normality test is W<W0.01, then the data of all elements are considered non-normal distributed, and the tested abnormal data are excluded;

[0033] The outlier test includes: testing the outliers of all elements in the standard samples that do not meet the preset standards. If the minimum value Gmin and the maximum value Gmax of the tested statistic are both less than or equal to G0.05, then it is considered that there are no outliers in the elements of the tested standard samples and they meet the preset standards; if the minimum value Gmin and the maximum value Gmax of the tested statistic are both greater than G0.05 but less than or equal to G0.01, then it is considered that there are no outliers in the elements of the tested standard samples and they meet the preset standards; then no outlier processing is performed on the tested data, and the tested data are retained; if the minimum value Gmin and the maximum value of the tested statistic are both greater than G0.01, then it is considered that there are outliers, and the abnormal data are excluded;

[0034] The equal-precision test includes: performing an equal-precision test on all elements in the standard samples that do not meet the preset standards; if the statistic C of the equal-precision test is C≥C0.05, then it is of equal precision, and each component of the elements in the standard samples meets the preset; if the statistic C of the equal-precision test is C0.05>C≥C0.01, then it is considered of equal precision, and the data are retained; if the statistic C of the equal-precision test is C0.01>C, then it is not of equal precision, and the abnormal data are excluded.

[0035] Furthermore, in the above method for preparing nickel-iron standard samples containing high-content harmful elements, the standard uncertainty is calculated and determined by the following formula:

[0036]

[0037] where: u CRM represents the standard uncertainty obtained by detecting the segregation of chemical elements in samples with regular shapes, u char represents the standard uncertainty obtained by detecting the segregation of chemical elements in samples with regular shapes, u bb represents the uncertainty component of chemical elements in the standard samples, u lts represents the long-term stability uncertainty of chemical elements in the standard samples, u sts represents the short-term stability uncertainty of chemical elements in the standard samples;

[0038] In the above formula

[0039] Where: S represents the single measurement standard deviation of the fixed value data statistics, and n represents the number of data groups.

[0040] In a second aspect, the present invention further provides a standard sample prepared according to the above-mentioned method for preparing a nickel-iron standard sample containing a high content of harmful elements, comprising the following components in weight percentage:

[0041] Ni: 34.00%~36.00%; Fe: 64.00%~66.00%; As: 0.009%-0.011%; Sb: 0.009%-0.01 1%; Sn: 0.005%-0.007%; Pb: 0.005%-0.007%; Bi: 0.002%-0.004%; C: 0.10%-0.20 %; Si: 0.50%~0.60%; Mn: 0.10%-0.20%; P: 0.010%-0.020%; S: 0.006%-0.007%; Cr: 0.30%~0.40%; Cu: 0.04%~0.05%; Co: 0.60%-0.70%; N: 0~0.0020%; the rest are unavoidable impurities.

[0042] Furthermore, the above standard sample includes the following components in weight percentage:

[0043] Ni: 35±1.5%; Fe: 65±2.5%; As: 0.010±0.002%; Sb: 0.010±0.002%; Sn: 0.006±0.002%; Pb: less than or equal to 0.006±0.002%; Bi: 0.003±0.002%; C: 0.10%-0.20%; Si: 0.50%~0.60%; Mn: 0.10%-0.20%; P: 0.010%-0.020%; S: 0.006%-0.007%; Cr: 0.30%~0.40%; Cu: 0.04%~0.05%; Co: 0.60%-0.70%; N: 0~0.0020%; the rest are unavoidable impurities.

[0044] The main advantages of the technical solution of the present invention are as follows:

[0045] In the method for preparing a standard sample of nickel iron containing high content of harmful elements of the present invention, the present invention realizes the smooth addition of high content of harmful elements in nickel iron by preferably selecting nickel iron raw materials with low impurity content, coordinating various pure metal elements, smelting in a vacuum induction furnace, and adding metals or alloys of harmful elements. By designing the elements of the nickel iron standard sample, the harmful elements in the designed nickel iron standard sample are the above-mentioned high content, the nickel iron raw materials are smelted to obtain the sample, and the sample with uniform harmful elements in the standard sample is obtained by segregation detection, the standard sample of the target size is obtained by turning, and the elements and their contents are obtained by fixed value analysis and mathematical statistics to meet the above elements, ensuring that the organizational structure of the sample is good, the harmful element content is high and meets expectations, and the chemical composition uniformity of harmful elements and other elements is good. The standard sample for chemical analysis of nickel iron containing high content of harmful elements prepared by the present invention has high harmful element content, large batch size, good uniformity between batches, accurate fixed value, good component stability, and meets the requirements of laboratory for accurate analysis quality control of harmful elements in nickel iron. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] The drawings described herein are used to provide a further understanding of the embodiments of the present invention and constitute a part of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0047] Figure 1 The figure is a flow chart of a method for preparing a nickel-iron standard sample containing a high content of harmful elements according to an embodiment of the present invention. DETAILED DESCRIPTION

[0048] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the specific embodiments of the present invention and the corresponding drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0049] The technical solution provided by the embodiments of the present invention is described in detail below with reference to the accompanying drawings.

[0050] Aiming at the defects of a set of standard samples for spectral analysis of nickel iron series developed by our unit in 2014; standard samples for chemical analysis of nickel iron (FeNi40) with a nickel content of 43.70% developed in 2020, there is no addition design of harmful elements (specifically arsenic (As), antimony (Sb), tin (Sn), lead (Pb) and bismuth (Bi) elements in the present invention, and the above-mentioned harmful elements can also be referred to as five harmful elements). At the same time, due to the lack of nickel iron chemical standard samples of the five harmful elements in existing products, the application of the five harmful elements as standard samples is restricted. In order to fill and improve the demand for the chemical composition content of the five harmful elements in nickel iron products, after a long period of demonstration and research, a nickel iron chemical standard sample containing a high content of the five harmful elements was designed and developed, especially for nickel iron FeNiX products with grades such as FeNi20, FeNi30, FeNi40, FeNi50 and FeNi70, X represents the nickel content in the nickel iron product, to fill the gap in this field.

[0051] Specifically, as attached Figure 1 As shown, an embodiment of the present invention provides a method for preparing a nickel-iron standard sample containing a high content of harmful elements. The nickel-iron standard sample prepared by the method contains the following chemical elements in the following percentages:

[0052] Ni: 34.00%~36.00%; Fe: 64.00%~66.00%; As: 0.009%-0.011%; Sb: 0.009%-0.01 1%; Sn: 0.005%-0.007%; Pb: 0.005%-0.007%; Bi: 0.002%-0.004%; C: 0.10%-0.20 %; Si: 0.50%~0.60%; Mn: 0.10%-0.20%; P: 0.010%-0.020%; S: 0.006%-0.007%; Cr: 0.30%~0.40%; Cu: 0.04%~0.05%; Co: 0.60%-0.70%; N: 0~0.0020%; the rest are unavoidable impurities;

[0053] The preparation method thereof comprises the following steps:

[0054] Standard sample smelting: smelt the nickel-iron raw material containing the preset content of Ni and Fe in a vacuum induction furnace, slowly heat it to 1550℃±50℃ until the nickel-iron raw material is completely melted, stir and mix well and keep warm for 30 minutes, add harmful elements when the temperature drops to 1050℃±50℃ under a protective atmosphere, stir and heat in the furnace and keep warm for 30 minutes, then cast and mold under the furnace bottom to obtain the sample;

[0055] Standard sample preparation: After removing the surface burrs and peeling the obtained sample, a sample with a regular shape is obtained;

[0056] Segregation detection: Use chemical analysis methods to perform segregation detection on the obtained regular-shaped samples, and compare the detection results with the standard uncertainty to obtain samples that pass the initial uniformity inspection;

[0057] Turning and packaging of standard samples: Turn the samples that have passed the initial uniformity inspection, and select and retain samples with a size of 0.18mm-0.60mm and a mesh size of 30-80 after grinding. Turn over and mix multiple samples as a group and then package them as standard samples;

[0058] Sampling test: Take a number of packaged standard samples as samples, use ICP-MS method to analyze the harmful chemical elements in the samples, and determine the minimum sample weight;

[0059] Uniformity test: Under the same measurement conditions and analysis environment, a small sample weighing and high precision analysis method is used to measure multiple independent data for each of all elements to be tested in the sample, and the variance analysis test method is used to test the uniformity data. If the test is qualified, a standard sample that has passed the uniformity test is obtained;

[0060] Fixed value analysis: The standard samples that have passed the uniformity test are subjected to fixed value analysis using the benchmark analysis method or an accurate and reliable chemical wet analysis method to obtain standard samples that meet the preset standards;

[0061] Mathematical statistics: Perform mathematical statistics on the data obtained from the inspection of standard samples that meet the preset standards to obtain standard samples with chemical elements that meet the target content.

[0062] Thus, the nickel-iron standard sample with a high content of harmful elements that can be prepared by the above-mentioned method for preparing the nickel-iron standard sample containing a high content of harmful elements of the present invention can especially make the contents of arsenic and antimony 0.01±0.001%, the contents of lead and tin 0.006±0.001%, and the content of bismuth 0.003±0.001%, which are all about 5-10 times the contents of the five harmful elements of conventional nickel-iron. At the same time, the nickel content of the nickel-iron standard sample prepared in the present application is 35±1%, and the iron content is 65±2%. In the present invention, by designing the elements of the nickel-iron standard sample, the harmful elements in the designed nickel-iron standard sample are made to have the above-mentioned high content, the sample is obtained by smelting the nickel-iron raw material, and the sample with uniform harmful elements in the standard sample is obtained by segregation detection, the standard sample of the target size is obtained by turning, and the elements and their contents that meet the above-mentioned elements, especially the harmful elements that meet the initial element design, are obtained by fixed value analysis and mathematical statistics.

[0063] Specifically, in order to make the harmful elements in the nickel-iron standard sample prepared by the method for preparing the nickel-iron standard sample containing a high content of harmful elements in the present invention more stable and the content more accurate, the above method also includes stability determination and standard sample traceability, wherein: the stability determination includes storing the standard sample whose chemical elements meet the target content for a preset time, and regularly measuring the content of the chemical elements in the standard sample during the preset storage time to determine the stability of the chemical elements in the standard sample; the standard sample traceability includes determining the chemical elements of the standard sample to determine the accuracy of the elements and their contents contained in the standard sample.

[0064] In some optional implementations of this embodiment, the nickel-iron standard sample prepared by the above method contains at least the following percentages of chemical elements:

[0065] Ni: 35±1.5%; Fe: 65±2.5%; As: 0.010±0.002%; Sb: 0.010±0.002%; Sn: 0.006±0.002%; Pb: less than or equal to 0.006±0.002%; Bi: 0.003±0.002% or Ni: 34.00~36.00; Fe: 64.00~66.00; As: 0.009-0.011%; Sb: 0.009-0.011%; Sn: 0.005-0.007%; Pb: 0.005-0.007%; Bi: 0.002-0.004%.

[0066] The harmful elements referred to in the present invention mainly include As, Sb, Sn, Pb and Bi.

[0067] In some optional implementations of this embodiment, the nickel-iron raw material is preferably a nickel-iron raw material with high purity nickel, high purity iron, high purity chromium and low impurity content. The harmful elements added when the temperature drops to 1050°C ± 50°C under a protective atmosphere are the elements shown above, and the order of addition is metals or alloys of As, Sb, Sn, Pb and Bi.

[0068] In some optional implementations of this embodiment, in order to facilitate the lathing of the prepared samples, the casting mold under the furnace bottom is preferably a rectangular structure, so that the smelting and casting samples obtained are approximately rectangular structures or cube structures. After the surface burrs and peeling of the rectangular or cube-shaped nickel-iron samples are removed on a sawing machine, regular rectangular samples are obtained for segregation detection.

[0069] In some optional implementations of this embodiment, in order to make the results of segregation detection more accurate and improve the efficiency of segregation detection, when performing segregation detection, taking a rectangular sample as an example, 5-9 points are evenly distributed on one side and the vertical side and on the diagonal position, and a chemical analysis method is used to perform segregation test on the five harmful elements. The average value and standard deviation of the 5-9 test results are calculated, and the standard deviation is compared with the expected uncertainty. If the standard deviation meets the expected uncertainty, the sample is qualified and can be processed, machined and bottled. If the standard deviation does not meet the expected uncertainty, the sample has segregation, and after the regular segregation is removed, it is further machined and mixed for bottling.

[0070] Specifically, in the above-mentioned uniformity test process, it is necessary to proceed after the segregation test is qualified. If the segregation test fails, it is necessary to continue the test until the segregation test is qualified and then the uniformity test is performed. In the grinding process, a grinder can be used for grinding. When packaging the screened standard samples of qualified size, glass bottles with lids can be used for packaging. After the standard samples are fully mixed by manual overturning for no less than 20 times, they are packaged in clean and dried glass bottles and covered with plastic caps with linings.

[0071] Combined with practical applications, the data values ​​for testing the uniformity of the actually prepared standard samples are shown in the following table:

[0072] element Ni As Sb Sn Pb Bi average value 34.25 0.0092 0.0112 0.0062 0.0063 0.0026 Very bad 0.08 0.0005 0.0006 0.0005 0.0005 0.0003 Standard Deviation 0.03 0.0002 0.0002 0.0002 0.0002 0.0001 RSD 0.09 2.17 1.79 3.23 3.17 3.85 Analytical methods Dimethylglyoxime gravimetric method ICP-MS ICP-MS ICP-MS ICP-MS ICP-MS

[0073] According to the above table, it can be seen that the harmful element content in the nickel-iron standard samples containing harmful elements prepared according to the method of the present invention has no obvious element segregation phenomenon, and the initial uniformity inspection meets the design requirements.

[0074] In some optional implementations of the present embodiment, in order to make the sampling detection more efficient and ensure the accuracy of the sampling detection, in the above-mentioned sampling detection, the number of samples extracted is no more than one thousand at most. Exemplarily, in the present embodiment, 20 minimum units are selected as samples by random sampling, and harmful elements such as As, Sb, Sn, Pb and Bi and other elements in the selected samples, such as carbon, silicon, manganese, phosphorus, sulfur, nickel, chromium and other elements are analyzed. It is determined that a small sample weighing amount and a good precision inspection method and a minimum sample weighing amount can be adopted. The principle of the minimum sample weighing amount is to weigh the sample as small as possible while ensuring that the analysis is accurate. In order to obtain the lowest minimum sample weighing amount as possible, the inspection method of the five harmful elements As, Sb, Sn, Pb, and Bi uses the ICP-MS method.

[0075] Exemplarily, in order to make the sampling quantity, inspection method and minimum sample weight in the present invention, different inspection methods can be used for different elements designed in the present invention to determine the minimum sample weight of specific elements. The specific inspection methods used and the data of the determined minimum sample weight are shown in the following table:

[0076] Inspection elements Inspection methods Minimum sample weight (g) As, Sb, Sn, Pb, Bi ICP-MS 0.05 Ni Dimethylglyoxime gravimetric method 0.10 Fe Titanium trichloride-potassium dichromate titration method 0.10 C.S Infrared absorption method after combustion in high frequency induction furnace 0.25 Si, Mn, P, Cr, Cu, Co ICP-AES method 0.20

[0077] Specifically, the above-mentioned uniformity test using the variance analysis test method includes:

[0078] Measure multiple independent data for each of the elements that need to be fixed in the sample, and compare the variance statistic F of the data with the Fα0.05 critical value; if the variance statistic F of each element is less than or equal to the Fα0.05 critical value, the uniformity of all elements in the sample meets the requirements; if the variance statistic value of each element is greater than the Fα0.05 critical value, the uniformity of all elements in the sample does not meet the requirements; at the same time, calculate the sample bottle inhomogeneity variance Sbb 2 .

[0079] Among them, the above S bb 2 Calculate according to the formula in ISO Guide 35 "Value determination of reference samples - General principles and statistical methods".

[0080] For example, in combination with actual application conditions, under the same instrument measurement conditions and analysis environment, three independent measurement data are measured for each bottle of all elements, and the variance test method is used to test the uniformity of all data. If the variance statistic F value of each element is less than Fα 0.05 (1.85) critical value, proving that the uniformity of the standard sample meets the requirements. And according to the relevant formula, calculate the sample bottle inhomogeneity variance Sbb 2 And provide certain uniformity test data, statistic F and other data.

[0081] Specifically, the nickel-iron grades are mainly FeNi20, FeNi30, FeNi40, FeNi50, FeNi70, etc., among which FeNi30 and FeNi40 are the most common. In this embodiment, FeNi35 is taken as an example. The nickel content is the combination of the high point of FeNi30 (Ni: 25-35%) and the low point of FeNi40 (Ni: 35-45%). It is the most common nickel-iron product, and its composition is close to nickel-iron FeNi35. According to actual applications, the uniformity test result data obtained by the above uniformity test is shown in the following table:

[0082]

[0083]

[0084] Specifically, in order to make the determination of each element and its content in the nickel-iron standard sample containing harmful elements prepared by the present invention more accurate, when performing fixed value analysis, the prepared standard sample is subjected to fixed value analysis in a laboratory or testing center with testing qualifications. At the same time, in order to ensure the accuracy of the detection, at least two testing laboratories or testing centers can be used to test the same element, and the average value of the test results can be used as the test result.

[0085] In some optional implementations of this embodiment, the detection methods for each element are shown in the following table:

[0086] element Analytical methods used As Microwave digestion-ICP-MS method, hydride generation-atomic fluorescence spectrometry, ICP-AES method, ICP-MS method Sn Microwave digestion-ICP-MS method, ICP-AES method, ICP-MS method Pb Microwave digestion-ICP-MS method, ICP-AES method, ICP-MS method Sb Microwave digestion-ICP-MS method, hydride generation-atomic fluorescence spectrometry, ICP-AES method, ICP-MS method Bi Microwave digestion-ICP-MS method, ICP-AES method, ICP-MS method C Gas volume method after combustion in a tube furnace, infrared absorption method after combustion in a high-frequency induction furnace Si Perchloric acid dehydration weight method, reduced silicomolybdate spectrophotometry, ICP-AES method Mn Sodium (potassium) periodate spectrophotometry, ICP-AES method P Bismuth phosphomolybdenum blue spectrophotometry, ICP-AES method S Potassium iodate titration method after combustion in a tube furnace, infrared absorption method after combustion in a high-frequency induction furnace Ni Dimethylglyoxime gravimetric method, EDTA titration method Cr Diphenylcarbazide spectrophotometry, ICP-AES Cu Flame atomic absorption spectrometry, ICP-AES Co Flame atomic absorption spectrometry, ICP-AES Fe Titanium trichloride-potassium dichromate titration method

[0087] As can be seen from the table above, except for iron, which uses a titration analysis method, the values ​​of other elements are determined using two or more accurate and reliable analysis methods based on different principles. This ensures that the standard samples prepared in the present invention can be traced back to SI units and international and national standards, and pass at least two laboratory post-test centers for each element, so that the results of the element analysis and testing are accurate and reliable, meeting the requirements for the development of metallurgical standard samples.

[0088] Specifically, mathematical statistics are performed on standard samples that meet the preset standards, and standard samples that do not meet the preset standards are tested using one or more of the following test methods: method precision test, normality test, outlier test, or equal precision test. If they meet the test standards, they are used as the original statistical data of the standard samples for mathematical statistics; if they do not meet the test standards, the non-compliant data are eliminated.

[0089] Specifically, standard samples that do not meet the preset standards are tested using one or more of the following test methods: method precision test, normality test, outlier test, or equal precision test, where:

[0090] The method precision test includes: each test unit or test laboratory provides four analysis data for each characteristic quantity value, and a cooperative value determination unit provides the four analysis data for each characteristic quantity value as a group of data, and the four analysis data of each characteristic quantity value are examined with 1.3 times of the indoor precision r of the element value determination analysis method or the allowable difference to determine whether there are abnormal values; if there are abnormal values, the abnormal values ​​are eliminated; after there are no abnormal values, the average values ​​of each group of each characteristic quantity value are calculated;

[0091] The normality test includes: examining the normality of the data of each group by the Shapiro-Wilk method. Specifically, perform a normality test on all the data and the unit average numbers of all elements in the standard samples that do not meet the preset standards. If the statistic W of the normality test is W≥W0.05, it is considered that all the data conform to the normal distribution; if the statistic W of the normality test is in the range of W0.01≤W<W0.05, the data to be tested are retained; if the statistic W of the normality test is W<W0.01, it is considered that the data of all elements are non-normally distributed, and the abnormal data to be tested are excluded; where the above W0.05 represents the meaning of W(0.05, n), the above W0.01 represents the meaning of W(0.01, n), 0.05 represents the significance level, 0.01 represents the significance level, n represents the number of groups of measured data or the number of all data, W(0.05, n) represents the normal statistic of the element when the significance level is 0.05 and the number of groups of measured data or the number of all data is n, and W(0.01, n) represents the normal statistic of the element when the significance level is 0.01 and the number of groups of measured data or the number of all data is n.

[0092] The outlier test includes: testing whether there are outliers in the data of each group or each data by the Grubbs criterion. When performing the test, test the outliers of all elements in the standard samples that do not meet the preset standards. If the minimum value Gmin and the maximum value Gmax of the statistic to be tested are both less than or equal to G0.05, it is considered that there are no outliers in the elements of the standard samples to be tested and they meet the preset standards; if the minimum value Gmin and the maximum value Gmax of the statistic to be tested are both greater than G0.05 but less than or equal to G0.01, it is considered that there are no outliers in the elements of the standard samples to be tested and they meet the preset standards, then no outlier processing is performed on the data to be tested and the data to be tested are retained; if the minimum value Gmin and the maximum value of the statistic to be tested are both greater than G0.01, it is considered that there are outliers and the abnormal data are excluded; where the above G0.05 represents the meaning of G(0.05, n), the above G0.01 represents the meaning of G(0.01, n), 0.05 is the significance level, 0.01 is the significance level, n represents the number of groups of measured data, G(0.05, n) represents the Grubbs critical value when the significance level is 0.05 and the number of groups of measured data is n, and G(0.01, n) represents the Grubbs critical value when the significance level is 0.01 and the number of groups of measured data is n.

[0093] The equal precision test includes: using the Cochrane test method to perform an equal precision test on all elements in the standard sample that do not meet the preset standards; specifically, when performing the test, if the statistic of the equal precision test (Cochrane statistic) C≥C0.05, then the precision is equal, and the element components in the standard sample meet the preset standards; if the statistic C of the equal precision test is in the range of C0.05>C≥C0.01, it is regarded as equal precision and the data is retained; if the statistic C of the equal precision test is in the range of C0.01>C, then the precision is unequal and the abnormal data is eliminated; wherein 0.05 is the significance level, 0.01 is the significance level, n represents the number of measured data groups, C0.05(n) represents the Cochrane critical value when the number of measured data groups is n when the significance level is 0.05, and C0.01(n) represents the Cochrane critical value when the number of measured data groups is n when the significance level is 0.01.

[0094] Specifically, the above standard uncertainty is calculated and determined by the following formula:

[0095]

[0096] Where: u CRM represents the standard uncertainty of the segregation detection of chemical elements in a sample of regular shape, u char represents the standard uncertainty obtained by the segregation detection of chemical elements in a sample of regular shape, u bb Represents the uncertainty component of the chemical element in the standard sample, u lts represents the long-term stability uncertainty of chemical elements in standard samples, u sts Represents the short-term stability uncertainty of chemical elements in standard samples.

[0097] Specifically, the standard uncertainty caused by the segregation detection of the regular-shaped sample is calculated and determined by the following formula:

[0098]

[0099] Where: S represents the single measurement standard deviation of fixed value statistics, and n represents the number of data groups.

[0100] Determination of Expanded Standard Uncertainty

[0101] The calculation formula for the expanded uncertainty of the characteristic value is: U = ku CRM ;

[0102] Among them, the above uncertainty component u bb 2 This is Sbb in the above uniformity statistics table. 2 In practical applications, due to the good stability of metallurgical standard samples, the long-term stability uncertainty u ltsand the short-term stability uncertainty u sts can be ignored, S is the single measurement standard deviation of fixed value statistics, n is the number of data sets, u char is the standard uncertainty caused by the measurement, k is the coverage factor, and in practical applications, k is taken as 2 when calculating according to the 95% confidence interval.

[0103] Using the above method, combined with practical applications, the calculation of standard value, standard deviation and uncertainty is shown in the following table:

[0104]

[0105]

[0106] Using the above method, combined with practical applications, the summary of standard values, standard deviations and uncertainties is shown in the following table:

[0107]

[0108] This standard sample was analyzed again after one year of storage, and the stability test results are shown in the following table:

[0109]

[0110]

[0111] According to the above table, there is no significant difference between its chemical composition and the designed chemical composition, which meets the design requirements.

[0112] In summary, the present invention achieves the smooth addition of high-content harmful elements in ferronickel by preferably selecting ferronickel raw materials with low impurity content, coordinating various pure metal elements, smelting in a vacuum induction furnace, and adding metals or alloys of harmful elements. Ensure that the organizational structure of the sample is good, the content of harmful elements is high and in line with expectations, and the chemical composition uniformity of harmful elements and other elements is good. The standard sample for chemical analysis of ferronickel containing high-content harmful elements prepared by the present invention has high content of harmful elements, large batch size, good uniformity between batches, accurate fixed value, good composition stability, and meets the requirements of laboratory for accurate analysis quality control of harmful elements in ferronickel.

[0113] In a second aspect, the present invention also proposes a standard sample prepared by the above-mentioned method for preparing a nickel-iron standard sample containing a high content of harmful elements, which is suitable for nickel-iron products. The prepared standard sample has a good organizational structure, a high content of harmful elements and meets expectations, and the chemical composition uniformity of the added harmful elements and other elements is good. The prepared standard sample includes the following components in weight percentage:

[0114] Ni: 34.00%~36.00%; Fe: 64.00%~66.00%; As: 0.009%-0.011%; Sb: 0.009%-0.01 1%; Sn: 0.005%-0.007%; Pb: 0.005%-0.007%; Bi: 0.002%-0.004%; C: 0.10%-0.20 %; Si: 0.50%~0.60%; Mn: 0.10%-0.20%; P: 0.010%-0.020%; S: 0.006%-0.007%; Cr: 0.30%~0.40%; Cu: 0.04%~0.05%; Co: 0.60%-0.70%; N: 0~0.0020%; the rest are unavoidable impurities.

[0115] In some optional implementations of this embodiment, the prepared standard sample also includes the following components in weight percentage:

[0116] Ni: 35±1.5%; Fe: 65±2.5%; As: 0.010±0.002%; Sb: 0.010±0.002%; Sn: 0.006±0.002%; Pb: less than or equal to 0.006±0.002%; Bi: 0.003±0.002%; C: 0.10%-0.20%; Si: 0.50%~0.60%; Mn: 0.10%-0.20%; P: 0.010%-0.020%; S: 0.006%-0.007%; Cr: 0.30%~0.40%; Cu: 0.04%~0.05%; Co: 0.60%-0.70%; N: 0~0.0020%; the rest are unavoidable impurities.

[0117] In another achievable implementation of this embodiment, the standard sample prepared according to the above method for preparing a nickel-iron standard sample containing a high content of harmful elements contains at least the following components in weight percentage:

[0118] Ni: 35±1%, Fe: 65±2%, As: 0.010±0.001%, Sb: 0.010±0.001%, Sn: 0.006±0.001%, Pb: less than or equal to 0.006±0.001%, Bi: 0.003±0.001%.

[0119] In summary, the standard sample prepared by the present invention has a high content of harmful elements, a large batch size, good uniformity and consistency between batches, accurate fixed values, and good component stability. It meets the laboratory's requirements for accurate analysis and quality control of harmful elements in ferronickel, can meet the experimental needs for ferronickel chemical analysis of harmful elements, and fills the gap in ferronickel standard samples containing harmful elements.

[0120] It should be noted that, in this article, relational terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In addition, "front", "back", "left", "right", "upper" and "lower" in this article are all referenced to the placement state shown in the accompanying drawings.

[0121] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for preparing a nickel-iron standard sample containing a high content of harmful elements, characterized in that: Contains the following chemical elements in the following percentages: Ni: 34.00%~36.00%; Fe: 64.00%~66.00%; As: 0.009%-0.011%; Sb: 0.009%-0.011%; Sn: 0.005%-0.007%; Pb: 0.005%-0.007%; Bi: 0.002%-0.004%; C: 0.10%-0.20%; Si: 0.50%-0.60%; Mn: 0.10%-0.20%; P: 0.010%-0.020%; S: 0.006%-0.007%; Cr: 0.30%~0.40%; Cu: 0.04%~0.05%; Co: 0.60%-0.70%; N: 0~0.0020%; the rest are inevitable impurities; The preparation method thereof comprises the following steps: Standard sample smelting: smelt the nickel-iron raw material containing the preset content of Ni and Fe in a vacuum induction furnace, slowly heat it to 1550℃±50℃ until the nickel-iron raw material is completely melted, stir and mix well and keep warm for 30 minutes, add harmful elements when the temperature drops to 1050℃±50℃ under a protective atmosphere, stir and heat in the furnace and keep warm for 30 minutes, then cast and mold under the furnace bottom to obtain the sample; Standard sample preparation: After removing the surface burrs and peeling the obtained sample, a sample with a regular shape is obtained; Segregation detection: Use chemical analysis methods to perform segregation detection on the obtained regular-shaped samples, and compare the detection results with the standard uncertainty to obtain samples that pass the initial uniformity inspection; Turning and packaging of standard samples: Turn the samples that have passed the initial uniformity inspection, and select and retain samples with a size of 0.18mm-0.60mm and a mesh size of 30-80 after grinding. Turn over and mix multiple samples as a group and then package them as standard samples; Sampling test: Take a number of packaged standard samples as samples, use ICP-MS method to analyze the harmful chemical elements in the samples, and determine the minimum sample weight; Uniformity test: Under the same measurement conditions and analysis environment, multiple independent data are measured for each of all elements to be tested in the sample, and the uniformity data is tested using the variance analysis method. If the test is qualified, a standard sample that has passed the uniformity test is obtained; Fixed value analysis: The standard samples that have passed the uniformity test are subjected to fixed value analysis using the benchmark analysis method or the chemical wet analysis method to obtain standard samples that meet the preset standards; Mathematical statistics: Perform mathematical statistics on the data obtained from the inspection of standard samples that meet the preset standards to obtain standard samples with chemical elements that meet the target content.

2. The method for preparing a standard sample of ferronickel containing high levels of harmful elements according to claim 1, wherein: It also includes stability testing and standard sample traceability, including: The stability determination includes storing a standard sample having a target content of chemical elements for a preset time, and regularly measuring the content of the chemical elements in the standard sample during the preset storage time to determine the stability of the chemical elements in the standard sample; The traceability of the standard sample includes determining the chemical elements of the standard sample and ensuring the accuracy of the elements and their contents contained in the standard sample.

3. The method for preparing a standard sample of ferronickel containing high levels of harmful elements according to claim 1, wherein: The prepared standard sample contains at least the following chemical elements in percentage: Ni: 35 ± 1.5%; Fe: 65 ± 2.5%; As: 0.010 ± 0.002%; Sb: 0.010 ± 0.002%; Sn: 0.006 ± 0.002%; Pb: less than or equal to 0.006 ± 0.002%; Bi: 0.003 ± 0.002%.

4. The method for preparing a standard sample of ferronickel containing high levels of harmful elements according to claim 1, wherein: The harmful elements include As, Sb, Sn, Pb, and Bi.

5. The method for preparing a standard sample of ferronickel containing high levels of harmful elements according to claim 1, wherein: The homogeneity test using the analysis of variance test method includes: The variance statistics F value and Fα of all the elements packaged in the sample are measured for multiple independent numbers 0.05 Critical values ​​are compared; If the variance statistic F value of each element is less than or equal to Fα 0.05 If the critical value is exceeded, the uniformity of all elements in the sample meets the requirements; If the variance statistic F value of each element is greater than Fα 0.05 The critical value indicates that all elements in the sample do not meet the uniformity requirements, so the inhomogeneity variance Sbb of all elements in the sample is calculated. 2 .

6. The method for preparing a standard sample of ferronickel containing high levels of harmful elements according to claim 1, characterized in that: Performing mathematical statistics on the standard samples that meet the preset standards, and for the standard samples that do not meet the preset standards, after testing using multiple test methods such as method precision test, normality test, outlier test, or equal-precision test, if they meet the test standards, they are used as the original statistical data of the standard samples for mathematical statistics; If they do not meet the test standards, the non-conforming data is excluded.

7. The method for preparing a standard sample of ferronickel containing high levels of harmful elements according to claim 6, characterized in that: Using multiple test methods such as method precision test, normality test, outlier test, or equal-precision test to test the standard samples that do not meet the preset standards, where: The method precision test includes: comparing all the data of all elements in the standard sample that does not meet the preset standards with 1.3 times the indoor precision r or the allowable difference, examining and judging whether there are outliers. If there are no outliers, calculate the average value of each group. If there are outliers, exclude the outlier data; The normality test includes: performing a normality test on all the data of all elements and the unit average number in the standard sample that does not meet the preset standards. If the statistic W of the normality test ≥ W0.05, it is considered that all the data conform to the normal distribution; if the statistic W of the normality test is in the range of W0.01 ≤ W < W0.05, it conforms to the approximate normal distribution, and the tested data is retained; if the statistic W of the normality test < W0.01, it is considered that the data of all elements is non-normal distribution, and the abnormal data to be tested is excluded; The outlier test includes: testing the outliers of all elements in the standard sample that does not meet the preset standards. If the minimum value Gmin and the maximum value Gmax of the tested statistic are both less than or equal to G0.05, it is considered that there are no outliers in the elements of the tested standard sample and it meets the preset standards; if the minimum value Gmin and the maximum value Gmax of the tested statistic are both greater than G0.05 but less than or equal to G0.01, it is considered that there are no outliers in the elements of the tested standard sample and it meets the preset standards, then no outlier treatment is performed on the tested data and the tested data is retained; if the minimum value Gmin and the maximum value of the tested statistic are both greater than G0.01, it is considered that there are outliers, and the abnormal data is excluded; The equal precision test includes: performing equal precision test on all elements in the standard sample that do not meet the preset standards; if the statistic C of the equal precision test is ≥ C0.05, then the precision is equal, and the components of the elements in the standard sample meet the preset standards; if the statistic C of the equal precision test is in the range of C0.05>C≥C0.01, then it is regarded as equal precision and the data is retained; if the statistic C of the equal precision test is in the range of C0.01>C, then the precision is unequal and the abnormal data is eliminated.

8. The method for preparing a standard sample of ferronickel containing high levels of harmful elements according to claim 1, characterized in that: The standard uncertainty is calculated using the following formula: Where: u CRM represents the standard uncertainty of the segregation detection of chemical elements in a sample of regular shape, u char represents the standard uncertainty obtained by the segregation detection of chemical elements in a sample of regular shape, u bb Represents the uncertainty component of the chemical element in the standard sample, u lts represents the long-term stability uncertainty of chemical elements in standard samples, u sts It represents the short-term stability uncertainty of chemical elements in standard samples; In the above formula Where: S represents the single measurement standard deviation of the fixed value data statistics, and n represents the number of data groups.

9. A standard sample prepared by the method for preparing a nickel-iron standard sample containing a high content of harmful elements according to any one of claims 1 to 8, comprising the following components in weight percentage: Ni: 34.00%~36.00%; Fe: 64.00%~66.00%; As: 0.009%-0.011%; Sb: 0.009%-0.011%; Sn: 0.005%-0.007%; Pb: 0.005%-0.007%; Bi: 0.002%-0.004%; C: 0.10%-0.20%; Si: 0.50%-0.60%; Mn: 0.10%-0.20%; P: 0.010%-0.020%; S: 0.006%-0.007%; Cr: 0.30%~0.40%; Cu: 0.04%~0.05%; Co: 0.60%-0.70%; N: 0~0.0020%; The rest are inevitable impurities.

10. The standard sample according to claim 9, characterized in that: The composition comprises the following components by weight percentage: Ni: 35±1.5%; Fe: 65±2.5%; As: 0.010±0.002%; Sb: 0.010±0.002%; Sn: 0.006±0.002%; Pb: less than or equal to 0.006±0.002%; Bi: 0.003±0.002%; C: 0.10%-0.20%; Si: 0.50%~0.60%; Mn: 0.10%-0.20%; P: 0.010%-0.020%; S: 0.006%-0.007%; Cr: 0.30%~0.40%; Cu: 0.04%~0.05%; Co: 0.60%-0.70%; N: 0~0.0020%; The rest are inevitable impurities.

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