Inductively coupled plasma mass spectrometry is one of the powerful analytical methods for trace elements due to its high sensitivity and low detection limit. However, the simultaneous determination of major elements and trace elements is performed in many applications, which requires a wide linear dynamic range. Based on the dual-mode detector for inductively coupled plasma mass spectrometer (ICP-MS), a correction method for detection mode of this type of detector, namely Pulse Analog (PA) correction method, was investigated. Firstly, according to the dynamic range desired, the negative high voltage and positive high voltage of the detector was determined. The appropriate threshold voltage for this detector was obtained to ensure that the test signal was collected, and the noise signal was removed (the counting value at 220 u was less than 0.1 cps). Then the flow rate of helium (He) gas for collision reaction cell was determined, so that the counting value of test element at the concentration of 0.1 ng/L was less than 10 cps. Finally, the signal testing was conducted to determine the overlapping elements and their test data. The Pulse-Analog correction coefficient (abbreviated as PA coefficient) was calculated. Cubic polynomial fitting was performed to obtain the PA coefficients of elements in whole mass range. The fitting methods of spline interpolation and cubic polynomial were compared. The results showed that the fitting data by cubic polynomial were closer to the trend of original data within the whole mass range of 2-250 u. The proposed calibration method was validated using low, medium, and high mass number elements of Be, Cd, and U (0.1 ng/L-100 mg/L) with a linear dynamic range of 9 orders of magnitude. The results showed that the determination coefficients of calibration curves were all 1.000, and the determination coefficients of calibration curves were all higher than 0.999 5 under logarithmic coordinates of the test data. The superalloy certified reference material of GBW01636, which contained Cu, Ga, As, and Bi with content span in four orders of magnitude, was selected for verification, and the results showed that the test values were basically consistent with the certified values. The proposed correction method could achieve the simultaneous determination of major and trace elements with a linear dynamic range of up to 9 orders of magnitude, which could meet the test requirements of wide concentration range in certain applications.

The initial crystal temperature of electrolyte increases with the increase of molecular ratio of aluminum electrolyte. On the contrary, the primary crystal temperature decreases. The accurate determination of molecular ratio of aluminum electrolyte has important guiding significance for the production. Among several methods of molecular ratio determination, X-ray diffraction (XRD) is widely used in electrolytic aluminum enterprises due to its advantages of simple sample preparation and fast analysis speed. However, with the complexity of aluminum electrolyte components, many companies have found that the molecular ratio determined by XRD could not well guide the production, and the determination results have great difference from those obtained by chemical analysis. Because the principle and influencing factors of molecular ratio determination by XRD are not clear enough, it is difficult to find out the reason for the difference. In view of the above problems, the determination principle of molecular ratio by XRD was analyzed. The theoretical formula for the determination of molecular ratio of complex aluminum electrolytes by XRD was derived, and the phase and diffraction peak were given. The reasons of inaccurate measurement results were investigated, which had a certain guiding role for the industrial development.

The determination of lead content in lead ore is of great significance for the trade settlement. When the lead content in lead ore is determined by lead sulfate precipitation separation-Na₂EDTA titration, chromium, barium, arsenic, antimony, tin and bismuth in the sample will interfere with the determination. The sample was dissolved with ammonium fluoride-hydrochloric acid-nitric acid-perchloric acid system. The interference of chromium was eliminated by adding hydrochloric acid repeatedly in perchloric acid system. The interference of arsenic, antimony and tin was eliminated by adding hydrobromic acid in perchloric acid system. Sulfuric acid was added in hydrochloric acid system to react with barium to form barium sulfate precipitate. At this time, lead could react with chloride ions to form complex ions, and would not form precipitate with sulfuric acid. After filtration, the filtrate and insoluble slag were obtained. On the one hand, sulfuric acid was added into the filtrate to react with lead to form lead sulfate precipitate followed by refiltration. The precipitate of lead sulfate was dissolved with acetic acid-ammonium acetate buffer solution (pH 5.5) and thioglycolic acid was added to eliminate the interference of bismuth, then the content of lead was determined by Na₂EDTA titration. On the other hand, the insoluble slag was treated by sodium peroxide fusion, and the content of lead was determined by inductively coupled plasma atomic emission spectrometry (ICP-AES). The contents of lead in the filtrate and the insoluble slag were summed, realizing the determination of lead in lead ore and overcoming the interference of chromium, barium, arsenic, antimony, tin and bismuth in sample. The contents of lead in lead ore samples were determined according to the proposed method. The relative standard deviations (RSD, n=11) of determination results were 0.20%-0.31%, and the recoveries were 99.5%-100.6%. The lead contents in certified reference material/standard sample of lead concentrate were determined according to the proposed method, and the results were basically consistent with the certified value/standard value.

The main components of nickel ore are nickel, copper, iron and sulfur. Where in the content of sulfur is in range of 20%-37%, and such a relatively high content has great influence on the lead fire assay separation and enrichment results. In order to obtain the proper lead button, the appropriate ratio of fire assay ingredients was selected in experiments. Silver nitrate was used as protective agent to reduce the loss of gold, platinum and palladium during cupellation. The obtained composite particle was dissolved, and the contents of gold, platinum and palladium were determined by inductively coupled plasma atomic emission spectrometry (ICP-AES). The contents of gold, platinum and palladium in nickel ore were determined according to the experimental method, and the relative standard deviations (RSD, n=11) of measurement results were 4.1%-10.6%, 2.7%-6.5% and 1.9%-8.0%, respectively. The spiked recoveries of gold, platinum and palladium were 97%-100%,99%-103%, and 98%-103%, respectively. The proposed method effectively solved the lead fire assay ingredient for nickel ore with various sulfur contents. The contents of gold, platinum and palladium could be directly determined after dissolving the obtained composite particle.

During determination of trace Tl in converter graphite sphere sample by inductively coupled plasma mass spectrometry (ICP-MS), the coexisting elements, including Hg, Pb, and rare earth elements (Ir, Os, Re, etc) will cause polyatomic interference with the determination of ²⁰⁵Tl⁺ in the form of hydride polyatomic ions (¹H²⁰⁴Hg⁺, ¹H²⁰⁴Pb⁺) and rare earth compound ions (¹²C¹⁹³Ir⁺, ¹⁴N¹⁹¹Ir⁺, ¹⁶O¹⁸⁹Os⁺ and ¹⁸O¹⁸⁷Re⁺). The sample was calcinated at 750 ℃ for 1 h and then dissolved with 10 mL HCl-10 mL HNO₃-5 mL HF-3 mL HClO₄ system. In tandem quadrupole (MS/MS) mode, the mass-to-charge ratio (m/z) of the first-stage mass filter (Q1) was set to 205, so that ²⁰⁵Tl⁺ entered the collision reaction pool with ¹²C¹⁹³Ir⁺,¹⁴N¹⁹¹Ir⁺,¹⁶O¹⁸⁹Os⁺,¹⁸O¹⁸⁷Re⁺, etc. At the same time, O₂ was introduced into the collision reaction cell, which could react with ²⁰⁵Tl⁺ to form ²⁰⁵Tl¹⁶O⁺, while the interference ions did not react with O₂. The m/z of the second-stage mass filter (Q2) was set to 221, so that only ²⁰⁵Tl¹⁶O⁺ could pass through and entered the detector, thus eliminating the mass spectral interference. Based on this, a method for determination of trace Tl in converter graphite sphere by inductively coupled plasma tandem mass spectrometry (ICP-MS/MS) at oxygen reaction mode was established. The flow rate of O₂ was optimized and 0.5 mL/min was selected. The matrix effect and the effect of internal standard correction were investigated. The results showed that the matrix effect could be ignored, and the influence of instrument signal drift on the determination could be overcome by the internal standard correction of 5 μg/L In. The linear range of this method was 0.01-1.00 μg/L, the linear correlation coefficient was 0.999 8, the limit of detection was 0.000 65 μg/g, and the limit of quantification was 0.002 0 μg/g. The recovery tests of Tl in converter graphite sphere sample were conducted according to the proposed method, and the recoveries were between 95% and 105%. The contents of Tl in converter graphite sphere samples were determined by the proposed method. The relative standard deviations(RSD,n=11) were between 1.6%-2.4%, and the results were basically consistent with graphite furnace atomic absorption spectrometry.

The accurate and rapid determination of molybdenum content in geological samples is of great significance for the development and utilization of molybdenum ore,geological scientific research,and many other fields.Since molybdenum is an element which is hardly ionized, the determination method by flame atomic absorption spectrometry(FAAS) usually has low sensitivity and high limit of detection.The sampling of redox system can increase the air-acetylene flame temperature,thus enhancing the absorbance sensitivity of molybdenum.On the basis of this principle,a method for the determination of molybdenum(0.002%) in geological samples by FAAS was established using perchloric acid as the oxidant and sucrose as the reducing agent.Under the optimized experimental conditions,the mass concentration of molybdenum in range of 2-20 μg/mL had a good linear relationship with the corresponding absorbance,with a correlation coefficient of 0.999 8.The sensitivity was 0.010 6 mL/μg,the limit of detection was 0.000 7%,and the limit of quantification was 0.002%.The content of molybdenum in certified reference materials of molybdenum ore for composition analysis was determined according to the experimental method.The maximum relative error between the found results and the certified values were all less than the relative error tolerance(Y_B) specified in DZ/T 0130-2006 The Specification of Testing Quality Management for Geological Laboratories.The relative standard deviations(RSD, n=9) of the determination results were between 1.5% and 8.2%.

The suspected cracking of girth weld cracking in automatic welding was found in site non-destructive testing for one pipeline engineering of high-grade X80M steel with pipe diameter of 1 422 mm.In order to analyze the causes for the girth weld cracking in automatic welding of X80M pipeline steel,a series of test methods were employed to find out the formation reason of cracking,including chemical composition analysis of steel pipe and welding material,non-destructive testing positioning of cracking,cutting of cracking defects,macro and micro morphology and structure observation of cracking,microhardness,analysis of cracking and nearby regions.The analysis results showed that the cracking was located on the filling layer of weld joint.Cu was enriched in the nearby matrix of cracking,which was mainly in isometric crystal.The surrounding microhardness was obviously higher than the weld which was far away from the cracking.Moreover,the cracking was extended along with the grain boundary.Cu was found inside of cracking and surrounding areas.Combined with welding information in site,the copper contact tube contacted with groove wall in the process of filler welding,leading to short circuit.The high temperature due to the short circuit caused the hot melting of contact position between copper contact tube and groove.The molten Cu entered the weld and diffused along the grain boundary,resulting in Cu enrichment area and cracking of the girth weld.

The import volume of cobalt increases rapidly in recent years due to the wide application of new energy technology.Some solid wastes are also declared in the name of cobalt smelting intermediates.Since the smelting intermediates of cobalt have no obvious phase structure characteristics,they cannot be accurately identified by the conventional sensory inspection and single X-ray diffraction (XRD).In this paper,XRD was combined with X-ray fluorescence spectrometry(XRF),super depth-of-field microscope,thermogravimetric analysis and scanning electron microscope(SEM) for the attribute identification of two intermediates in hydrometallurgy of cobalt which had no obvious diffraction peaks.The comprehensive characterization results showed that two cobalt-containing materials were cobalt hydroxide,which belonged to the intermediate products in hydrometallurgy of cobalt.The confirmation of sample source provided scientific basis for the customs supervision and resource utilization.

The content of barium in copper anode slime is one of the important technical indexes in the process of recovering precious metals from copper anode slime by Kaldor furnace, which directly affect the recoveries of precious metals such as gold and silver. The sample was treated in nickel crucible by alkali fusion with the mixed flux of sodium hydroxide and sodium carbonate. The refractory barium sulfate was converted into barium carbonate which could be easily dissolved in hydrochloric acid. After treatment by hot water leaching and filtration, the filtrate was abandoned so that most of the interfering ions were removed. The precipitate was dissolved with hydrochloric acid. Then masking agent of EDTA-calcium salt (CaY^2-) was added to mask these ions such as iron, aluminum, lead, copper, nickel and zinc. Potassium dichromate was added to react with barium ion to form barium chromate precipitate, realizing the separation of barium from other impurities. The barium chromate precipitate was dissolved with hot hydrochloric acid (1+9) in the original beaker. The content of barium in sample was indirectly determined by iodometry. Thus, a method for determination of barium in copper anode slime was established by iodometry with alkali fusion and barium chromate precipitation separation. The experimental results showed that 0.50 g of copper anode slime sample could be completely decomposed with 6 g of the mixed flux of anhydrous sodium carbonate and sodium hydroxide (mass ratio of 1∶2) at 700 ℃ for 30 min. The effects of overnight aging at room temperature and aging in water bath at 95 ℃ for 2-3 h on the determination of barium were compared. It was found that the determination results of two methods were basically the same. The interference test showed that the interference of coexisting elements in the sample could be ignored. The contents of barium in copper anode slime samples were determined according to the proposed method. The relative standard deviations (RSD, n=7) of determination results were between 0.23% and 2.0%, and the recoveries were between 99% and 101%. Inductively coupled plasma atomic emission spectrometry (ICP-AES) was used for method comparison, and the determination results of the two methods were basically consistent.

Hot rolled enamel steels are required to have sufficient fish-scale resistance. Improving the hydrogen storage property, that is,increasing the hydrogen trap, the most effective method is to increase the content of precipitated phase in the steel. In this paper, in order to quantitatively analyze the precipitates of hot-rolled enamel steels with different aging treatments, the precipitates are separated from the matrix by electrolysis extraction method. The morphology and structure of the precipitates after extraction are characterized by scanning electron microscopy (SEM) and X-ray diffraction (XRD). Rietveld full spectrum fitting method is used to calculate the composition and content of different precipitates. The nano-scale precipitates are characterized by transmission electron microscopy (TEM) and three dimensional atomic probe (3DAP). Finally, the relationship between precipitate phase and hydrogen storage property in hot rolled enamel steel is discussed. The XRD results show that the main kinds of precipitate in hot-rolled enamel steel are Ti₂CS, TiC_0.95 and TiC_0.3N_0.7. TEM results show that the precipitates with diameter above 150 nm contain sulfur, which are carbon sulfide titanium. Precipitates with diameter about 100 nm are titanium carbide, and a large amount of precipitation with diameter about 10 nm, with disordered distribution, which are confirmed as titanium carbide by 3DAP. The sample treated at 850 ℃ has the highest precipitation content, reaching 0.39%, and the specific surface area of the particles is also the largest.The hydrogen penetration experiment shows that it has the longest average penetration time and higher hydrogen storage performance.

Aiming at the surface cracking problem of TA1 pure titanium cold rolled sheet, the causes of cracking were analyzed by means of macroscopic analysis,scanning electron microscope(SEM),chemical analysis,optical microscope and microhardness tester.The results showed that the cracking of cold rolled sheet was located in the serious surface wrinkle area,and there was a hard α phase area in the center of the wrinkle area.The hard and brittle α phases formed by the enrichment of oxygen elements could not be deformed synchronously during the rolling process,leading to surface wrinkles with different degrees of internal cracking.The area with low oxygen enrichment formed shallow surface wrinkles,while the area with high oxygen enrichment formed serious surface wrinkles.At the same time,the abnormal enrichment of impurity Al elements in some hard α areas aggravated the embrittlement of materials,forming cleavage fracture.The internal cracking wrinkle defect in the sheet expanded to the macroscopic surface cracking in advance.

At present, the detection methods of zinc concentrate are mainly wet chemical methods. However, the sample preparation of these methods is complicated and the operation is cumbersome. Therefore, it is of great significance to find an accurate and rapid detection method for zinc concentrate to improve the detection efficiency. In this study, the handheld X-ray fluorescence spectrometer was employed for the rapid detection of five major and minor components in zinc concentrate, including Zn, S, Fe, Ca and Pb. The samples were prepared by grinding and tableting. Different drying periods were set to explore the effect of moisture content. It was found that the higher the moisture content, the greater the relative error (RE) of the determination results. The relative error of Pb with lower content in the sample was up to 39.02% when the moisture content was the largest. Different ball milling time was also set to explore the influence of particle size, and it was found that the change of particle size had the greatest impact on S and Fe. The relative error reached 10.43% and 19.68% when the ball milling time was 3 h, respectively. Moreover, more accurate measurement results could be obtained for the sample with smaller particle size, the ball milling time of 9 h was determined. Different compression time was also investigated to explore the effect of tablet thickness, and the holding time of 60 s was determined in experiments. Four zinc concentrate samples were detected according to the experimental method. The relative standard deviations (RSD, n=5) of Zn,S,Fe and Ca were all less than 1.5%, and the RSD of Pb with lower element content was also less than 3%. The measured values of inductively coupled plasma optical emission spectrometry (ICP-OES) were used as reference values, and the measured values of the experimental methods were compared with the reference values. It was found that the relative errors of the detection results of all five elements was less than 10%, which could meet the requirements of routine analysis and detection. The proposed method had important reference value for the rapid detection of minerals.

Accurate determination and control of carbon content in praseodymium neodymium fluoride-lithium fluoride electrolytes is of great significance for the monitoring of praseodymium neodymium alloy production process and the quality of finished products. A method for the determination of carbon content in praseodymium neodymium fluoride-lithium fluoride electrolyte by high-frequency combustion infrared absorption was established. The analytical time was controlled at 35 s, and the sampling mass was 0.20-0.30 g. The standard sample of steel was used for the preparation of single-point calibration curve. Tungsten, tin, and iron were selected as the flux. An orthogonal experiment with four factors and three levels was designed, and the investigation factors includes the mass of tungsten, the mass of tin, the mass of iron, and the adding sequence of flux and sample. Through the experiments, the adding sequence of flux and sample was pure iron + sample + tungsten and tin. The dosage of flux was 0.60 g of iron, 1.20 g of tungsten, and 0.40 g of tin. The limit of detection of method was 0.000 255% (mass fraction, the same below), and the limit of quantification was 0.000 85%. Three different batches of praseodymium neodymium fluoride-lithium fluoride electrolyte samples were measured according to the experimental method, and the relative standard deviations (RSD, n=11) of determination results were between 2.8% and 3.3%. The Grubbs outlier judgment method was used to identify the outliers. The Grubbs G_Max of measurement results of three batches was 1.463, 1.503, and 1.335, and the G_Min was 1.704, 1.639, and 1.669, respectively. They were all less than the Grubbs critical value G_(0.05,11)=2.234 (significant level α=0.05), indicating that there were no abnormal values in the measurement results. The standard steel sample was used into the sample for spiked recovery tests, and the recoveries were between 96% and 105%.

To enhance the development and utilization of metal materials, the precise control of physical properties and mechanical performance of metal materials is crucial, wherein the hydrogen plays a particularly key role in influencing these aspects. In this paper, the impact and hazards of hydrogen on the performance of metal materials were summarized. The methods for determining hydrogen content in metal materials in recent years were introduced, mainly including physicochemical method, tube furnace heating-thermal conductivity/infrared method, inert gas protection pulse furnace heating-thermal conductivity/infrared method, inert gas protection pulse furnace heating-mass spectrometry method, thermal desorption-mass spectrometry method, etc. The corresponding analysis principles, instrument structures, and technical characteristics were summarized. The review of applicable detection objects, analysis range, detection limits, and other specifications could enable the technicians in relevant fields to have a comprehensive understanding of hydrogen content detection in metal materials.

Solid wastes identification were conducted on a batch of samples declared as “lead ore” with high content of arsenic and iron. Through the feature detection and analysis including elemental content, phase composition, microtopography, particle size distribution and pH of leaching solution, it was found that the main phases of this sample were jarosite and scorodite. The main elements included S, Fe, Si, As, Al and Ca, while the content of Pb was low, which was not consistent with the characteristic of common lead ores. Several solid wastes with similar composition were compared to infer the sample source. Several possibilities of sample source were excluded: jarosite slag in traditional zinc hydrometallurgy, oxygen pressure leaching slag of zinc concentrate, arsenic slag of flue gas cleaning in lead-zinc smelting, or arsenic deposition slag of mineralized arsenic fixation of metallurgical waste water. Finally, it was inferred that the sample was possible the lead-zinc ore tailings which was exposed to the earth′s surface. The refused ore mainly containing scorodite and jarosite was formed after long-term oxidization. According to GB 34330-2017, the sample was identified as solid waste.

The technological development process in rapid detection of molten steel composition in steelmaking as well as the current mainstream technological achievements, including the process flow, process layout, pneumatic sampling system, automatic sample preparation system, automatic spectral process optimization, and automatic fluorescence flow optimization in fully automatic rapid analysis systems, were introduced in this paper. In particular, the contents included the breakthroughs in some new technologies, technical characteristics and application experience such as spectral manipulator, dual vision analysis system, automatic spectral development, automatic reporting of spectral results, automatic judgment of abnormal points, improvement of converter sample analysis speed, and preference setting of special steel. Moreover, the replacement of carbon-sulfur meter by X-ray fluorescence spectrometer(XRF) for hot metal desulfurization analysis, the replacement of grinder by milling grinder for processing iron samples, and use of the latest technologies for grinding tablet press were also introduced. The fully automated laboratory was a leap in the rapid analysis process of molten steel in steelmaking. It was started from the import of a complete set of software and hardware, including pneumatic sample pipelines. After years of optimization and improvement, and on the basis of fully digesting and absorbing advanced foreign technologies, the domestic automatic analysis systems had comprehensively broken through in terms of process flow, precision control, inspection cycle, and operational effectiveness. In addition, the future prospects of rapid analysis of molten steel in steelmaking was also discussed.

The analysis and determination of radioactive elements including uranium (U) and thorium (Th) in niobium-tantalum ores is a key step in the exploitation process of niobium-tantalum ore, and it has important significance for the radiation safety assessment and environmental protection. In this study, the quantitative analysis of radioactive U and Th in niobium-tantalum ore was investigated in the laboratory based on laser-induced breakdown spectroscopy (LIBS) combined with random forest (RF) algorithm. The contents of U and Th in eleven niobium-tantalum ore samples were determined using the traditional high purity germanium (HPGe) γ spectrometer, which were used as the reference values for LIBS. Nine of the samples were set as the training set for RF modeling, while the remaining two samples were used as the test set for model validation. The LIBS spectra after full spectral area normalization and the corresponding contents were used as the dataset for the RF algorithm. Firstly, the number of decision trees parameter of RF was optimized through five-fold cross-validation. Then, the influence of wavelength feature selection of LIBS spectra on the prediction results was explored by setting the importance score threshold. The results showed that, by combining the wavelength feature selection and optimizing the decision tree parameters, the root mean square error of calibration (RMSEC) of U and Th in the training set was 48 μg/g and 313 μg/g, respectively. For the prediction of U and Th contents in 2# and 6# samples, the root mean square error of validation (RMSEV) of test set was 141 μg/g and 209 μg/g for U, and 750 μg/g and 914 μg/g for Th, respectively. The relative standard deviations (RSD) of multiple measurement results for both elements were both within 7%. Moreover, the average value of multiple measurements was compared with the measurements by the γ spectrometer, and the relative error (RE) of prediction for two elements was within 8%. These results indicated that the combination of LIBS technology with the RF algorithm could effectively achieve the quantitative analysis of radioactive U and Th in niobium-tantalum ores, which provided a reference for the accurate mining and evaluation of niobium-tantalum ores.

The conventional method for microstructure inspection of aluminum alloy is mainly metallographic method. However, this method is complicated in operation, easy to misjudge the slightly overburnt structure, and the grain display effect is not ideal, which has certain limitations. In order to analyze the microstructure of aluminum alloy more conveniently and accurately, the determination method for microstructure of 2A12 aluminum alloy was systemically investigated based on cross section polisher (CP) and electron back scattering diffraction (EBSD). The results show that compared with the conventional metallographic method, the burnt microstructure of aluminum alloy processed by cross section polisher could be determined sensitively and accurately under the optical microscope without corrosion, and the phase and grain size could be further analyzed accurately by electron backscattering diffraction.

Laser-induced breakdown spectroscopy (LIBS) is an atomic spectroscopy technique, and it has shown great potential in the field of metal failure detection.As one of the important indicators to measure metal aging,the detection of grain size grade by LIBS is of great significance for the prediction of failure characteristics.In this study,12Cr1MoV steel,which is widely used in industry,was selected and the grain size grade of the metal was evaluated using a portable LIBS device.Firstly,principal component analysis(PCA),linear discriminant analysis(LDA),recursive feature elimination(RFE)-LDA were used to reduce the dimensionality of the spectral data.Then the metal grain size grade evaluation model was established based on the data after dimensionality reduction using the support vector machine(SVM) and multilayer perceptron(MLP) classification algorithms.The influence of the remaining features on the classification performance of the model after the preliminary RFE screening of the data was explored.The results showed that the combination of RFE and LDA could improve the classification accuracy of the evaluation model,and it was found that the model constructed by further combination with MLP classification algorithm had the highest classification accuracy,which reached 94.05%.The proposed modeling scheme could effectively realize the evaluation of grain size grade of 12Cr1MoV steel based on portable LIBS equipment.

In this paper, the classification system of Chinese reference materials was briefly introduced, and the classification of geological reference materials, especially Chinese geological reference materials, was discussed.The 7th type of geological reference materials in the existing Chinese reference material classification and other types of geological material reference materials commonly used for geological analysis in China were mainly classified and evaluated, including the reference materials for bulk analysis, ultrafine geological reference materials, chemical phase and speciation analysis reference materials, micro-area in-situ analysis reference materials, isotope and geochronology analysis reference materials, organic pollutant analysis and environmental radioactivity measurement reference materials.As the most diverse and the largest number of reference materials for bulk analysis, they were classified and reviewed according to the fields of rocks, sediments, soils, ores, single minerals, precious metals, energy minerals, building materials, nuclear geological materials and environmental chemistry. The main contents included the number of reference materials, the number of samples and the number of property data. Finally, the classification of reference materials of complex geological materials and other existing problems in the development of geological reference materials in China were discussed,and relevant suggestions were put forward.Total 82 references were cited in this paper.

A case of imported goods declared as “nickel-cobalt material” was characterized by multi-technology combination, and its source attribute was confirmed through analysis, and the feasibility of whether it could be used as raw material was discussed. The results provided technical support for import supervision. X-ray fluorescence spectrometry, carbon-sulfur analysis, headspace gas chromatography mass spectrometry, pyrolysis gas chromatography mass spectrometry, X-ray diffraction analysis, electro microscope energy spectrum, potentiometric titration, atomic absorption spectrometry and thermogravimetric analysis combined with sensory detection were employed for the testing. It was compared with the relevant literatures for traceability analysis. The micro-morphology, elemental composition, physical phase composition, toxic substances, organic compounds and other characteristics of the sample were analyzed. The results showed that the sample was mainly a ternary material of nickel-cobalt-lithium manganate, and also contained a small amount of metal aluminum chips, elemental carbon and organic compounds, which had the composition characteristics of lithium-ion battery cathode wafers. Combined with the appearance and composition characteristics of the sample, it was confirmed that the sample was the recycled powder of lithium-ion battery cathode wafers.

In order to solve the corrosion problem of platinum crucible caused by reducing substances in nickel-chromium pig iron samples during high temperature melting, a one-step melting method was developed to prepare nickel-chromium pig iron glass sheet. 0.1 g of sample was weighed. The flux was added by 5.0 g of lithium tetraborate, 2.0 g of lithium metaborate, and 1.5 g of lithium tetraborate covering method. 1.0 g of lithium carbonate was used as oxidant. After the sample was melted at 700 ℃ for 10 min and 850 ℃ for 10 min, a smooth, flat and uniform glass sheet was obtained with 500 g/L lithium bromide solution as release agent. The production samples with a certain content span and a certain content gradient, which were determined by national standard methods, were used as calibration sample series to draw calibration curves. The overlapping corrections of iron and silicon were conducted with chromium, respectively. The matrix corrections of spectral lines of nickel, chromium and phosphorus were not required. The prepared glass sheet was determined by X-ray fluorescence spectrometry (XRF). Thus, a method for determination of total iron(TFe), nickel, phosphorus, chromium and silicon in nickel-chromium pig iron was established. The contents of TFe, nickel, phosphorus, chromium and silicon in five nickel-chromium pig iron samples were determined according to the proposed method, and the relative standard deviations (RSD, n=11) were between 0.13% and 1.3%. The proposed method was compared with national standard methods and inductively coupled plasma atomic emission spectrometry (ICP-AES). It was found that the results were basically consistent. In the proposed method, the procedures of pre-oxidation and melting were integrated by a fully automatic melting furnace for sample preparation. The complicated wall hanging operation was not required. Moreover, it could effectively protect the crucible from corrosion.

The chemical composition, metallographic structure, macro and micro morphology of fracture splitting, and mechanical properties of C70S6 material connecting rod were detected and analyzed by spark discharge atomic emission spectrometer, metallographic microscope, scanning electron microscope (SEM) and universal tensile testing machine. The fracture splitting drop-dregs cause and mechanism of connecting rod big head hole were analyzed. The results showed that the fracture splitting drop-dregs position was mainly near billet parting plane, and the grain size at the parting plane of drop-dregs connecting rod was Grade 6.5. The content of ferrite was 7.0% (mass fraction, the same below), and the grain size difference of the whole fracture splitting surface was Grade 3.5. The edge of dropped steel slag showed obvious characteristics of ductile fracture. The grain size at the parting plane of no drop-dregs connecting rod was Grade 5, and the ferrite content was 5.0%. The grain size difference of fracture splitting surface was Grade 0.5, and the microstructure uniformity was good. The microstructure showed the characteristics of brittle cleavage. The comprehensive analysis showed that the microstructure of connecting rod billet was not uniform, the local grains were fine, and the overall grade difference was large, resulting in the high local plasticity of billet material, which was the root cause of the chip loss. By adjusting the production and heat treatment process of the bar for forging connecting rod, the grain size of microstructure was coarsened, the grain size difference and ferrite content was reduced. Consequently, the problem of drop-dregs loss was completely eliminated.

High antimony and bismuth material is an intermediate product in the smelting process of non-ferrous metals. The accurate determination of gold content in high antimony and bismuth material has great significance to guide the smelting production and market transaction. When the content of gold in high antimony and bismuth material is analyzed by lead fire assay gravimetric method, antimony and bismuth easily enter the lead buckle, which will seriously influence on the forming of lead buckle. It is not conducive to the cupellation, leading to great determination error of gold. In experiments, based on the characteristic that antimony hydride and bismuth hydride were easily volatile, the high-valence antimony and bismuth were reduced to low valence with sodium sulfite. Then potassium borohydride was added to react with antimony and bismuth to form the corresponding hydrides, which could be volatilized and separated. The residue was directly used for lead fire assay. The separation of antimony and bismuth from gold could be realized without filtration and roasting. The method for the determination of gold in high antimony and bismuth materials by lead fire assay gravimetric method was established. The dosages of sodium sulfite and potassium borohydride were optimized. The results showed that the antimony and bismuth in sample could be removed by volatilization under the following experimental conditions: 10.00 g of sample was transferred into 500 mL triangular flask; after adding 50 mL of aqua regia (1+1), the solution was heated on electric hot plate to almost dryness; then 20 mL of hydrochloric acid (1+1), 10 mL of sodium sulfite solution, and 50 mL of saturated potassium borohydride solution were added; after stirring, the solution was heated on electric hot plate to dryness. The mass of lead oxide and silicon dioxide in the ingredients was optimized, and the optimal mass was 80 g and 5 g, respectively. The content of gold in high antimony and bismuth material was determined according to the experimental method. The relative standard deviations (RSD, n=7) of the results were between 0.49% and 3.1%, and the found results were basically consistent with those obtained by bismuth fire assay-inductively coupled plasma atomic emission spectrometry. High purity gold was added into high antimony and bismuth material containing different gold contents for the spiked recovery test. The spiked recoveries were between 96% and 103%.

MFI molecular sieve is an important catalyst for catalytic cracking of heavy oil and methanol-to-gasoline, and the silicon-aluminum ratio is a major index influencing its catalytic performance.The sample was treated by super microwave digestion with hydrochloric acid, nitric acid and hydrofluoric acid, which overcame the problem of difficult digestion of high silicon samples. The oxygen mass transfer mode of tandem mass spectrometry(MS/MS) was adopted to determine Si with the mass-to-charge ratio of the first mass filter(Q1) of 28 and the second mass filter(Q2) of 60, and the flow rate of oxygen was controlled at 0.40 L/min. The helium collision cell mode of unipolar rod was adopted to determine Al with the flow rate of helium as 3.0 L/min. Sc and Ge were selected as the internal standard element for the correction of Si and Al, respectively. The determination of Si and Al in molecular sieve was realized by inductively coupled plasma tandem mass spectrometry (ICP-MS/MS) with super microwave digestion. Therefore, the silicon-aluminum ratio could be calculated. In order to avoid the volatilization loss of Si, the time for addition of hydrofluoric acid was investigated. It was indicated that the determination result of Si was higher when the hydrofluoric acid was added after microwave digestion than that obtained before microwave digestion. Moreover, its corresponding relative standard deviation was lower. Therefore, the addition of hydrofluoric acid after microwave digestion could effectively avoid the loss of Si. Under the optimized experimental conditions, the linear ranges of calibration curve for Si and Al were 50-1 000 μg/L and 5-400 μg/L, respectively. The correlation coefficients were both 1.000 0. The limits of detection were 0.003 1 μg/g and 0.001 4 μg/g, and the limits of quantification were 0.010 2 μg/g and 0.004 5 μg/g, respectively. MFI molecular samples were determined according to the proposed method, and the determination results of Si and Al were basically consistent with those obtained by inductively coupled plasma atomic emission spectrometry (ICP-AES). The relative standard deviations (RSD, n=7) were 2.5% and 3.1% for Si and Al, respectively. The recoveries were 95%-110% and 90%-110%, respectively.

The main chemical components of crude cobalt hydroxide include cobalt, copper, iron, manganese, calcium, magnesium and aluminum, and their contents are decisive indicators to determine the grade of crude cobalt hydroxide. Energy dispersive X-ray fluorescence spectrometry (ED-XRF) could be used to replace the chemical wet method to determine the contents of cobalt, copper, iron, manganese, calcium, magnesium, and aluminum in crude cobalt hydroxide, which could shorten the analysis cycle and achieve simultaneous and rapid determination of each element. The powder pellet preparation was conducted. After the sample was ground to 74 μm and boric acid was used as the binder base edge, the sample was pressed into a smooth and flat specimen with pressure of 10 s at 15 t. 16 crude cobalt hydroxide production samples with certain gradient in concentration of each element, which could cover the content range of each element in crude cobalt hydroxide, were selected as the calibration sample series to plot the calibration curves. The contents of these elements in calibration sample series were determined by industry standard of YS/T 1157-2016. The empirical coefficient method was adopted for matrix correction. A method for rapid determination of cobalt, copper, iron, manganese, calcium, magnesium, and aluminum in crude cobalt hydroxide by ED-XRF was established. The linear correlation coefficients of the calibration curves for these elements were all greater than 0.998. The detection limits of this method were in range of 0.001 4%-0.093%. The same cobalt hydroxide sample was used for precision tests according to the proposed method. The relative standard deviations (RSD, n=11) of determination results for these elements were between 0.11% and 3.9%. In addition, 4 crude cobalt hydroxide samples from non-calibration series were selected and determined according to the proposed method as well as industrial standard of YS/T 1157-2016. The difference of the two methods could meet the reproducibility limit requirements specified in industrial standard of YS/T 1157-2016.

Dolomite-bearing fluorite contains dolomite and calcium silicate. The existing test methods are greatly affected by the fluorite types and the experimental conditions. It is difficult to avoid the interference of dolomite, calcium silicate, and other components, which leads to higher determination results of calcium fluoride. In this paper, the content distributions of dolomite and calcium silicate in primary filtrate and secondary filtrate were analyzed by respective determination of magnesium and silicon in primary filtrate, secondary filtrate and sample. Then the determination process was optimized combined with fluorine content in primary filtrate. Dolomite-bearing fluorite was dissolved with 10% acetic acid, and calcium fluoride in primary residue was extracted with aluminum trichloride solution. The content of fluorine in primary filtrate was determined by fluoride ion selective electrode method, and the content of calcium in secondary filtrate was determined by inductively coupled plasma atomic emission spectrometry (ICP-AES). The results of the two methods were converted into calcium fluoride content and then added together. Consequently, a method for determination of low-grade calcium fluoride in dolomite-bearing fluorite was established by ICP-AES combined with fluoride ion selective electrode. The effect of aluminum trichloride matrix on the determination of calcium in range of 10.00-40.00 μg/mL was investigated. The results showed that aluminum trichloride matrix had great matrix effect on the determination of calcium. Therefore, the standard solution series were prepared by matrix matching method. The contents of calcium fluoride in dolomite-bearing fluorite samples were determined according to the proposed method, and the relative standard deviations (RSD, n=7) of determination results were between 0.21% and 0.64%. The recoveries were between 99.2% and 100.3%. The proposed method could eliminate the interference of dolomite and calcium silicate in dolomite-bearing fluorite on determination results of calcium fluoride.

Nitrogen content is one of the important parameters to measure the performance of steel slag accelerant, so it is necessary to determine the content of nitrogen in steel slag accelerant. 0.10 g of sample was weighed and transferred into tin foil. After packing the sample, the tin foil was pressed and sealed and then put into nickel basket. The nickel basket was transferred into graphite duplex crucible for determination. The calibration curve was drawn with powdered reference materials of iron dust, nitride ferromanganese, high nitrogen ferrochrome and vanadium nitrogen alloy powder, which could cover the range of nitrogen content in steel slag accelerant. Meanwhile, the nitrogen content was at a certain gradient. Consequently, a method for determination of nitrogen content in steel slag accelerant was established by inert gas fusion-thermal conductivity. Under the optimized experimental conditions, the nitrogen content in the sample showed a good linear relationship with its corresponding peak area. The correlation coefficient of calibration curve was 0.999 3. The limit of detection was 0.003%, and the limit of quantification was 0.010%. The contents of nitrogen in 4 steel slag accelerant samples was determined according to the proposed method in parallel for 7 times, and the relative standard deviations (RSD) of determination results ranged from 0.91% to 1.7%. 2 steel slag accelerant samples (0.05 g) were used for recovery test by adding about 0.05 g of reference material of iron dust or nitride ferromanganese. The recoveries were between 95% and 102%.

The rapid and accurate determination of nitrogen in aluminum-calcium complex deoxidizer has important guiding significance for the deoxygenation in steelmaking. 0.200 0 g of sample was mixed with 0.4 g of nickel as the flux. The analytical power was set at 5.5 kW. The calibration curve was prepared with nitrogen standard solution series. Thus, a method for determination of nitrogen in aluminum-calcium complex deoxidizer was established by inert gas fusion-thermal conductivity. The experimental results showed that the nitrogen mass in range of 100.0-1 000.0 μg had a linear relationship with its corresponding peak area. The linear correlation coefficient was 0.999 2. The limit of detection of this method was 0.000 3%, and the limit of quantification was 0.001%. The contents of nitrogen in aluminum-calcium complex deoxidizer samples were determined according to the proposed method, and the relative standard deviations (RSD, n=9) of determination results were between 1.4% and 3.3%. Nitrogen standard solutions were added respectively into aluminum-calcium complex deoxidizer samples for recovery tests according to the proposed method. The recoveries were between 96% and 103%.

The glow discharge spectrum has the advantages of high stability, sharp spectral lines, small background, less interference and stratified sampling, so it has been widely used in the solid composition analysis of conductor materials (such as metal and alloy) and non-conductor samples (such as glass, ceramic and geological sample). Taking GDS850A glow discharge optical emission spectrometer (GD-OES) as an example, 6 fault cases were summarized, including on-line anomaly, spectral tracing anomaly, internal circulation water flow anomaly, reamer non-rotation, new and old electrode replacement, and photomultiplier tube replacement. By analyzing the structure and working principle of GD-OES, the fault reasons were found, and the treatment measures were introduced. Through these 6 fault phenomena, analysis and processing methods, the reference was provided for the laboratory maintenance personnel who met the similar faults and help them quickly recover the fault and reduce the fault rate of instrument, thus to ensure that it could work steadily and effectively.

1215 MS free-cutting steel has good machinability,and its surface quality can directly affect the production and processing of products.After drilling of 1215 MS free-cutting silver bright rod produced by one steel plant,the cracks were observed at the core of the parts.In order to find out the causes of drilling cracks,the corresponding area of the sample was studied by means of scanning electron microscope and energy dispersive spectrometer (SEM/EDS).The results showed that the metallographic structure of 1215 MS free-cutting steel was mainly composed of ferrite + pearlite,which accounted for 92.0% and 4.4%,respectively.The coarse pearlite banded structure was found on the cracking side of the sample,and its equivalent diameter could be up to 15.0 μm,while the equivalent diameter of ordinary pearlite was only 6.2 μm.Compared with the ferrite structure,the average hardness of pearlite structure was higher,which was 243 HV0.01.The high hardness pearlite band led to uneven force of the drill bit during drilling,resulting in material cracking.

At present,ZAF method is the most commonly used correction method for quantitative analysis by electron probe microanalysis(EPMA).The essential of ZAF method is to accurately measure the K factor of each element in the sample,and then the iterative calculation (mathematical correction) of K factors are conducted.The understanding of this correction process is helpful for the correct and accurate setting of experiment conditions in quantitative analysis.For the samples with high content of ultra-light elements or strong matrix effect,the K factors have great difference with the actual concentration.Meanwhile,the correction coefficients are also higher.In this case,the accurate measurement of K factors is especially important.In this paper,the mathematical process of iterative calculation for ZAF method was deducted,indicating that K factor was the core of ZAF quantitative analysis.Based on the quantitative results of micro-region analysis of CrTiAlC magnetron sputtering material(the mass fraction of carbon was about 8%),the physical reason for causing great difference between K factor and actual concentration of C and Al were analyzed,and each item of ZAF correction coefficients were investigated.The mathematical iteration process of ZAF quantitative analysis and the parameter setting for quantitative analysis of sample system with strong matrix effect could be further understood.

The effects of magnification,image resolution,beam size,working distance,detection area and gray threshold on the analysis results of carbides and nonmetallic inclusions in H13 steel by scanning electron microscope(SEM) were discussed.A method for simultaneous measurement of inclusions and carbides by SEM was determined.The results showed that with the increase of magnification,the increase of carbide quantity was obviously greater than that of inclusion quantity.For the inclusions and carbides in H13 steel(above 1 μm),the magnification was recommended to be about 200.The image resolution and magnification had consistence for the identification of the smallest particle size.The resolution above 512×512 was recommended for the H13 steel.The quantity density of carbides and inclusions in H13 steel increased first and then decreased with the increase of beam current,which was related to that the optimal resolution of SEM could be obtained under the maximum beam current.The working distance had little influence on the particle type,quantity and size,and it mainly affected the counting of energy spectrum.The larger the detection area was,the longer the detection time was.In the actual test,the detection area of H13 steel should be guaranteed to be more than 20 mm² in order to ensure the effectiveness of the results.Dual threshold setting should be adopted for testing carbides and inclusions in H13 steel.

The accurate and rapid determination of impurity elements in organic amines was of great significance for improving the desulfurization performance of organic amines. In the experiments, 1.00 mL of sample was dissolved with nitric acid-hydrogen peroxide at 300-350 ℃. Al 237.312 nm, Ca 396.847 nm, Fe 259.940 nm, Mg 280.270 nm, Mn 257.610 nm, Pb 220.353 nm and Zn 213.856 nm were selected as the analytical lines. The contents of aluminum, calcium, iron, magnesium, manganese, lead and zinc were determined by inductively coupled plasma atomic emission spectrometry (ICP-AES). The method for determination of aluminum, calcium, iron, magnesium, manganese, lead and zinc in organic amines by ICP-AES was established. The mass concentration of elements in range of 0.10-10.00 μg/mL showed a linear relationship to the corresponding emission intensity, and the correlation coefficients were all higher than 0.999 9. The limits of detection of aluminum, calcium, iron, magnesium, manganese, lead and zinc in this method were between 0.000 5-0.007 2 μg/mL, and the limits of quantification were 0.001 7-0.024 1 μg/mL. The proposed method was applied for the determination of aluminum, calcium, iron, magnesium, manganese, lead and zinc in two organic amine samples, and the relative standard deviations (RSD, n＝11) of the determination results were between 1.3% and 5.6%. The found results were basically consistent with those obtained by inductively coupled plasma mass spectrometry (ICP-MS). The recovery tests of organic amine samples were conducted according to the experimental method, and the spiked recoveries were between 97.0% and 103.4%.

The cumulative damage of chloride ions in the production process of alumina and aluminum hydroxide is great. It can cause the reduction of seed decomposition rate and the corrosion of production equipment, and also affect the quality of final products of alumina and aluminum hydroxide. Therefore, it is of great significance to determine the chlorine content in alumina and aluminum hydroxide efficiently and accurately. After the sample was treated by microwave digestion with phosphoric acid, and the silver nitrate standard solution was selected as the titrant, a method for determination of chlorine in alumina and aluminum hydroxide was established by silver nitrate potentiometric titration. The results showed that the samples of alumina and aluminum hydroxide could be completely decomposed in 10 mL of phosphoric acid by microwave digestion at 220 ℃ for 50 min. The addition of hydrogen peroxide could eliminate the interference of sulfide, sulfite and thiosulfate in the sample. The effect of phosphoric acid concentration on the titration results of chlorine was investigated. The results showed that the dosage of phosphoric acid had no obvious influence on the determination when it reached 10 mL. The detection limit of the method was 0.002%. The contents of chlorine in the samples of alumina and aluminum hydroxide were determined according to the proposed method. The relative standard deviations (RSD, n=6) of determination results were between 0.65% and 9.2%, and the recoveries were between 97% and 103%.

300 series stainless steel belongs to high Cr-Ni steel,and there is strong absorption enhancement effect among alloying elements.Therefore,the matrix effect in sample must be corrected during the determination of alloying elements in 300 series stainless steel by X-ray fluorescence spectrometry(XRF).In this study,the X-ray fluorescence intensities of 12 alloying elements in 15 certified reference materials of 300 series stainless steel were determined by XRF,and the calibration curves were drawn.The matrix effect was corrected by two theoretical α coefficient methods, i.e., De Jongh equation and COLA equation.The results showed that the correction effect of COLA equation on Cr was much better than the De Jongh equation.However,for Ni with comparative content range,there was no significant difference.The possible reason was that Cr in 300 series stainless steel was mainly affected by the enhancement effect of Fe and Ni,and the corresponding theoretical influence coefficients(α_Cr,Fe and α_Cr,Ni) varied greatly with the change of Fe and Ni contents.The relative standard deviation(RSD) was 10.4% and 12.0%,respectively.The COLA equation could adjust the value of theoretical α coefficient according to the change of element contents,so it was applicable for the correction of elemental content in range of 0-100% (mass fraction,the same below).Ni was mainly affected by the absorption of Fe and Cr,so the variation of calculated theoretical influence coefficients (α_Ni,Fe and α_Ni,Cr) was small,the RSD was only 1.6% and 1.7%,respectively.Therefore,good correction results could be achieved even if the fixed theoretical α coefficient(i.e., De Jongh equation) was used.In addition,there was strong spectral overlapping interference among alloying elements in 300 series stainless steel.LiF220 crystal and slit of 0.15° with higher resolution were employed in experiments to reduce the overlapping interference among spectral lines.The further scanning showed that only the overlapping interference correction of CrKβ_1,3 to MnKα_1,2 and MoL_I to PKα_1,2 was required.Therefore,the correction was conducted by the empirical coefficient method based on concentration correction.The sample of 300 series stainless steel was determined for 11 times in parallel according to the experimental method.The results showed that the RSDs of determination values were all less than 1% when the element contents were higher than 0.1%.As the element contents were lower than 0.1%,the RSDs were all less than 10%.Three standard samples (which were not selected for the preparation of calibration curves) and two production samples of stainless steel were determined according to the experimental method,and the found results were consistent with the standard values of certified reference materials or those obtained by the wet method.

The total chlorine content is one of the important indicators for evaluating the quality of iron ore, so it is important to establish a method for determination of total chlorine content in iron ores. The difficulty for determination of total chlorine in iron ore by X-ray fluorescence spectrometry (XRF) lies in the fact that chlorine is easily polluted, lost at high temperature, and lack of certified reference materials containing chlorine with sufficient concentration span. The sample was pre-dried at 105 ℃ and then directly fused with the mixed flux (lithium tetraborate and lithium metaborate were mixed at mass ratio of 12∶22), avoiding the possible contamination of chlorine and loss of chlorine in pre-ignition oxidation process. The calibration sample series with certain concentration gradients were prepared with sodium chloride of primary reagent and ferric oxide of high purity reagent to draw the calibration curve. The matrix effects among elements were corrected by the theoretical α coefficient method. The determination of total chlorine in iron ore was realized by wavelength dispersion-XRF with fusion sample preparation. The linear correlation coefficient of calibration curves was 0.999 6. The detection limit was 0.003 2% (mass fraction, the same below), and the detection range was 0.016%-1.2%. Four iron ore samples were selected, and 11 sample sheets were prepared and determined in parallel according to the proposed method, respectively. The relative standard deviations (RSD, n=11) of determination results were between 0.28% and 3.9%. 7 certified reference materials and 4 synthetic samples of iron ore prepared with sodium chloride of primary reagent and ferric oxide of high purity reagent were determined according to the proposed method. The results showed that the average found (AVE) of 10 samples was within the expanded uncertainty scope of standard value/reference value (Ac). The difference of AVE and Ac for the other certified reference material was slightly higher than the expanded uncertainty, but AVE-Ac≤C, indicating that there was no significant statistical discrepancy between the determination result and standard value. The further t test showed that there was no significant difference between AVE and Ac for these 11 samples.

In order to reveal the formation and growth laws of dendrite structure in the forming process of casting single-crystal superalloy, a set of methods for detection, recognition, qualitative and quantitative analysis of dendrite structure was developed based on the multi-element content distribution analysis function of self-developed high-throughput micro energy dispersive X-ray fluorescence spectrometer (μ-EDXRF). An area of 6 mm×6 mm was selected on the sample surface after polishing treatment for the scanning with step of 10 μm. The content distribution maps of Ni, Ta, W and Re and other elements were obtained, and the uneven dendritic segregation could be observed. In order to make the dendrite pattern clearer and easier for qualitative recognition and quantitative analysis, a series of image processing operations such as denoising, point-to-point algebraic operation and binarization recognition were carried out on each distribution map. Moreover, the dendrite processing module in the matching software was developed according to GBT 14999.7, so as to automatically complete the recognition, positioning, counting of dendrite structure and dendrite spacing calculation. The quantitative detection of segregation of each element in dendrite could be also completed using the characteristic of μ-EDXRF. The proposed method was applied for the analysis of DD5 single-crystal superalloy sample. The measured dendrite spacing was 304.2 μm, which was consistent with that by metallographic microscope. It was found that the difference of average content of Ni, Ta, W and Re elements at positive and negative segregation points was more than 2%.

H13 (4Cr5MoSiV1) steel is one of the most widely used hot-working die steels at present.The inclusions and carbides in steel are the key factors affecting its performance and service life. The distribution law of inclusions and carbides in the H13 die casting billet was analyzed with metallographic microscope, scanning electron microscope and non-aqueous electrolyzer based on the analysis by Thermo-Calc software.The results showed that: from edge to core of H13 die casting billet, the small inclusions with equivalent diameter D≤3 μm gradually decreased, while the large inclusions of D≥5 μm gradually increased. The equivalent diameter of inclusions increased from 2.82 μm to 3.86 μm, the density of inclusions decreased from 177 to 47 PCS/mm², and the area ratio was [0.057%, 0.098%]. The inclusion types were mainly MnS and Al₂O₃, which was consistent with the calculated results. The morphologies of carbides in H13 from edge to core were changed as follows: granular, massive, flake, and long-strip. The size ranged from a few microns to 100 μm. They were mainly dark gray V-rich MC carbides, bright white Mo-rich M₆C carbides, and light gray Cr-rich M₂₃C₆ carbides.

There is a great variety of manganese-containing minerals in manganese ore,and the classification is complex.However,the current methods for phase analysis of manganese ores have some disadvantages such as tedious operations,inconsistent procedures,and lack of detail description.In experiments,the manganese ores with different types and contents from various mining areas were selected.The monomineral test was conducted to select the leaching agent.Manganese carbonate was leached with 50 g/L aluminum nitrate in boiling water bath for 60 min.Manganese oxide was leached with 30 g/L hydroxylamine sulfate-1% (V/V) sulfuric acid in boiling water bath for 60 min.The residue was decomposed with acid to obtain manganese silicate.The content of manganese in treated solution was determined by inductively coupled plasma atomic emission spectrometry(ICP-AES).The method for the chemical phase analysis of manganese ore was established.The limits of detection were (in manganese):0.000 3% for manganese carbonate phase,0.000 5% for manganese oxide phase,and 0.000 3% for manganese silicate phase.One manganese carbonate raw ore and one manganese oxide raw ore were determined according to the experimental method.The relative standard deviations(RSDs,n=12) of determination results were less than 5.0%,which could meet the quality management requirements in DZ/T 0130.3-2006 The specification of testing quality management for geological laboratories.The proposed method was applied for the determination of certified reference materials of manganese ore for chemical phase analysis,i.e.,GBW(E)070256(manganese carbonate ore) and GBW(E)070258(manganese oxide ore).The relative errors(REs) of determination results of main phases were less than 1%.For other phases,the REs were less than 10%,which also could meet the requirements in DZ/T 0130.3-2006.