28 April 2025, Volume 45 Issue 4
    

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  • Study on precise registration method for three-dimensional reconstruction of metal materials based on focused ion beam-scanning electron microscope
    YU Xing, LIU Suran, CUI Siyu, SHEN Yixuan
    Metallurgical Analysis. 2025, 45(4): 1-8. https://doi.org/10.13228/j.boyuan.issn1000-7571.012726
    Abstract ( )   Knowledge map   Save
    In this paper, a precise registration method for three-dimensional reconstruction of continuous slice images for focused ion beam-scanning electron microscope (FIB-SEM) was proposed. GH4096 polycrystalline high temperature was selected as an example. The sample surface for three-dimensional reconstruction area was etched with the focused ion beam to form a groove, and a specific preset registration marking line was set. The groove of the etched registration marking line was filled with Pt, and a protective layer of Pt was deposited on the surface area of the sample according to the requirements of three-dimensional reconstruction. The microstructure of the material was subsequently characterized according to the normal three-dimensional reconstruction process. Through the preset registration marking lines on the surface of three-dimensional reconstructed area, the accurate and clear feature points could be obtained on all the slice images during continuous slicing, which could be used for the registration of three-dimensional reconstructed images and the measurement of the spacing between neighboring slices, thus improving the accuracy and efficiency of the image registration. Meanwhile, a new method for accurate registration of FIB-SEM three-dimensional reconstruction images was formed by combining the sum of squared differences (SSD) algorithm of the three-dimensional reconstruction software, based on the specific registration marking settings proposed in this paper. The proposed method overcame the problem of jagged dislocations in the usual registration methods and improved the quality and structural clarity of three-dimensional reconstruction.
  • Research on fine classification of scrap stainless steel based on improved laser-induced breakdown spectroscopy system
    LUO Xingmei, CHEN Weifang, YE Wenhua, GE Mengchao, DING Jiawei, WU Chaozhi
    Metallurgical Analysis. 2025, 45(4): 9-15. https://doi.org/10.13228/j.boyuan.issn1000-7571.012667
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    Laser-induced breakdown spectroscopy (LIBS) system is mostly used in the field of material identification. There are few studies on the fine classification of scrap stainless steel in this field. In addition, the existing LIBS system is sensitive to material height changes and cannot adapt to the classification of scrap stainless steel with variable sizes. At present, there is a lack of intelligent detection and classification equipment in scrap stainless steel industry in China, which has led to the downgrading of a large number of stainless steel scraps. Therefore, it is necessary to further study the use of LIBS equipment for fine sorting of scrap stainless steel by brand. In this paper, the existing LIBS system was improved by using a reflective light receiving optical path to solve the problems of light path obstruction and light path deviation during classification and detection of scrap stainless steel due to the various shapes and sizes of scrap stainless steel. The system could collect the spectral signals of samples within the range of ±3 cm in height. In view of the demand for rapid sorting of scrap stainless steel, a random forest (RF) classification model based on the sparrow search algorithm (SSA) was proposed. The improved system was used to collect spectral data, and the SSA-RF model was imported for training and verification of the classification results. The results showed that the average recognition accuracy of the SSA-RF classification model was 98.31%, and the average recognition time was 0.016 s. The combination of the improved LIBS system and the SSA-RF algorithm could realize the classification of scrap stainless steel of variable sizes with high efficiency and stability, providing a reference method for the classification of scrap stainless steel.
  • Determination of trace fluorine in apatite by electron probe microanalysis
    XU Shuang, XU Congcong, GUO Tengda, WANG Jilin, LIN Peijun, LI Fengchun
    Metallurgical Analysis. 2025, 45(4): 16-20. https://doi.org/10.13228/j.boyuan.issn1000-7571.012654
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    Electron probe microanalysis (EPMA) is one of the most commonly used and cost-effective testing technologies for apatite analysis. However, when the F element is tested using EPMA under conventional conditions (the acceleration voltage is 15 kV, the beam current is 5-10 nA, the beam spot size is 10 μm, the counting time for the F element peak and background is 10/5 s, and the first order is used for testing with priority), a high background can be caused due to the non-linear background effects. Additionally, the beam current and counting time will be reduced due to the stability of F, which is disadvantageous to the determination of micro F. In this paper, a pulse height analyzer (PHA) was used to filter out the non-linear background. The background of trace F was optimized and the linearity was better. The step-by-step test (first, all elements were determined under conventional conditions except for F; then the mass fraction of other elements were fixed; the beam current and the counting time were enhanced to test F only) was combined to improve the testing accuracy of micro F. The average detection limit of F in chlorapatite MGMH#133648 was 179.8 mg/kg, which was reduced by 66%, and the relative standard deviation (RSD, n=10) of the determination results is less than 23%.The proposed method achieved the effective determination of trace F with content around 1 000 mg/kg.
  • In-situ three-dimensional characterization of inclusions in lead-based free-cutting steel
    YAN Chunlian, QI Qige, JU Xinhua, MENG Yang, YANG Rui, QIN Hancheng
    Metallurgical Analysis. 2025, 45(4): 21-28. https://doi.org/10.13228/j.boyuan.issn1000-7571.012699
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    Lead-based free-cutting steel has excellent cutting performance. Pb and MnS inclusions play a key role in its cutting performance. In order to investigate the existence form of Pb in steel as well as its effect on MnS inclusions, the in-situ three-dimensional morphology characterization and statistical quantification of inclusions in lead-based free-cutting steel were carried out using electrolytic corrosion and automatic inclusion analysis technique. The effects of electrolytic experimental parameters and analysis parameters of scanning electron microscope on the three-dimensional characterization of inclusions were discussed. Moreover, the suggestions for optimization were provided. The results showed that MnS in lead-based free-cutting steel was short rod-shaped and ellipsoidal, and Pb was mostly attached to both ends of MnS to form a spindle shape. Pb mainly existed in the form of MnS composite and the area fraction of Pb+MnS composite inclusions was about 30%, while the area fraction of Pb particles that exist independently was less than 2%. When the electrolysis voltage was 18 V and the electrolysis time was 25 s, the three-dimensional morphology of Pb-containing inclusions was clear and prominent, and Pb could be completely retained. During three-dimensional quantitative statistics, it was recommended to eliminate the interference of pearlite structure by Fe filtering. The image contrast could be set with reference to the sulfide inclusion, whose gray level was approximately 5 000 less than the gray level of the iron matrix. Two gray thresholds of inclusions were set to facilitate the identification of all sulfides and Pb-based particles. MnS+Pb composite inclusions should be filtered and statistically analyzed. By optimizing the electrolytic parameters and quantitative analysis parameters, the in-situ three-dimensional characterization of Pb-containing inclusions could be realized. The addition of Pb into steel to complex with MnS could inhibit the deformation and growth of sulfides to be spindle-shaped, or promote the fracture of sulfides to be short rod-shaped, thus modifying the MnS inclusions.
  • Determination of 13 trace impurities in high purity lead by inductively coupled plasma mass spectrometry
    CHEN Shiyun, ZUO Hongyi, TAN Xiuli
    Metallurgical Analysis. 2025, 45(4): 29-35. https://doi.org/10.13228/j.boyuan.issn1000-7571.012698
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    Trace impurities in high purity lead can significantly affect the product quality, and their contents are essential indicators for determination. In this study, the high purity lead sample was dissolved with nitric acid (1+2). The lead matrix was precipitated with sulfuric acid (1+2) and then separated by centrifugation. Fe was determined in He collision mode (He flow rate at 4.8 mL/min), and other elements were determined in standard mode. Meanwhile, the volume error was corrected by volume correction factors. The analysis method of 13 trace impurities (i.e., magnesium, aluminum, manganese, iron, nickel, copper, zinc, arsenic, silver, cadmium, tin, antimony and bismuth) in high purity lead by inductively coupled plasma mass spectrometry was established. The tests indicated that 5.0 g of sample could be completely dissolved with 25 mL of nitric acid (1+2). When 5.0 mL of sulfuric acid (1+2) was added into solution of 5.0 g lead sample for precipitation separation, about 0.93 mL of sulfuric acid (1+2) was residue in sample solution, and the mass concentration of residual lead was approximately 0.13 mg/mL. Scandium or yttrium was selected as internal standard to correct magnesium, aluminum, iron, manganese, nickel, copper, zinc, arsenic, silver, cadmium, tin and antimony, while rhenium selected as internal standard to correct bismuth. The influence of residual sulfuric acid and lead in solution on the determination could be ignored. The linear correlation coefficients of the calibration curves for each tested element were not less than 0.999 1. The limits of detection of this method were in range of 0.002 6-0.15 ng/mL, and the limits of quantification were in range of 0.000 1-0.005 0 μg/g. The proposed method was applied for the determination of 13 trace impurity elements in high purity lead samples. The relative standard deviations (RSD, n=7) of determination results were between 0.59% and 14%, and the recoveries were between 90% and 110%. The impurity elements in high purity lead samples were determined according to the experimental method and inductively coupled plasma atomic emission spectroscopy (ICP-AES), and the found results of two methods were basically consistent.
  • Determination of ferric oxide in silicon glass raw materials by X-ray fluorescence spectrometry with powder pellet preparation
    WANG Rui, SHU Lingxiu, NI Jingjing, WANG Jing, CHEN Shuyong, ZHAO Hongyi
    Metallurgical Analysis. 2025, 45(4): 36-42. https://doi.org/10.13228/j.boyuan.issn1000-7571.012703
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    The quality of glass products is directly affected by the content of ferric oxide (Fe2O3) in the silicon glass raw materials. In this study, the method for determination of Fe2O3 in silicon glass raw materials by X-ray fluorescence spectrometry with powder pellet preparation was investigated to solve the problems of traditional chemical analysis methods such as long analysis time, complex operation and high cost. The pellet preparation conditions, including the particle size, preparation pressure, pressing time, and the type and ratio of binder, were focused on. A series of calibration samples were self-prepared with Fe2O3 and quartz sand to establish the calibration curve. The experimental results indicated that the pellet exhibited good moldability and a smooth, flat surface when it was prepared under the following conditions: 10% microcrystalline cellulose was added into sample with particle size of 75 μm (D90); the mixture was pressed at 15 MPa for 20 s. The linear correlation coefficient of calibration curve for Fe2O3 was 0.999 9. The limit of detection of Fe2O3 was 0.000 51%, and the determination range of this method was from 0.001 5% to 0.10%. The contents of Fe2O3 in two samples of silicon glass raw materials were determined according to the experimental method. The relative standard deviation (RSD, n=7) of determination results was 0.87% and 1.1%, respectively. One certified reference material for component analysis of silicon sandstone and six actual samples of silicon glass raw material were selected. The contents of Fe2O3 were determined according to the experimental method and other methods (phenanthroline spectrophotometry and atomic absorption spectrometry). The results showed that the measured value of certified reference material was consistent with the certified value, and the determination results of actual samples by two methods were consistent. The propose method for determination of Fe2O3 in silicon glass raw materials by XRF with powder pellet preparation could reduce the detection period, save the testing time and economic cost. Moreover, it was easy to operate. The expensive accessories or large amounts of reagents were not required. In addition, no waste liquid was produced. Thereby the proposed method exhibited significant green advantages.
  • Determination of rhenium in copper molybdenum ore by inductively coupled plasma atomic emission spectrometry with synergistic extraction
    ZHANG Lu, LI Yanling
    Metallurgical Analysis. 2025, 45(4): 43-50. https://doi.org/10.13228/j.boyuan.issn1000-7571.012665
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    When inductively coupled plasma atomic emission spectrometry (ICP-AES) is used to determine the content of rhenium in copper molybdenum ore, the matrix elements may cause interference. In order to eliminate the interference of matrix elements with the determination of rhenium, the sample was dissolved with 5 mL of nitric acid and 5 mL of hydrogen peroxide, where rhenium was oxidized to perrhenic acid (HReO4). The ReO4- in sample solution was selectively extracted using the mixed organic liquid of tri-alkylamine (N235) and tributyl phosphate (TBP) (V∶V=1∶1.5). The volume ratio between extractant and sample solution was 1∶4, and the extraction time was 2 min. Subsequently, the rhenium in organic phase was back-extracted using 1.0 mol/L ammonium hydroxide under the following conditions: the volume ratio between extractant and back-extractant was 1∶2, and the back-extracting time was 1 min. Re 189.733 nm was selected as the analytical line for the determination of rhenium. The method for the determination of rhenium content in copper molybdenum ore by inductively coupled plasma atomic emission spectrometry with synergistic extraction was established. The results showed that the linear correlation coefficient of calibration curve was 0.999 2. The limit of detection was 0.000 15%. The content of rhenium in copper molybdenum ore was determined according to the experimental method. The relative standard deviations (RSD, n=6) of determination results were between 1.4% and 2.7%. The spiked recoveries were between 98.3% and 101.5%. The proposed method was applied for the determination of actual sample of copper molybdenum ore, and the measured results were basically consistent with those obtained by spectrophotometry in GB/T 14352.18-2010.
  • Determination of 6 elements in industrial magnesium hydroxide by inductively coupled plasma atomic emission spectrometry
    WANG Weizhi, ZHAO Zhigang, XU Xianning, QI Shengbing, CHENG Jinlian, HU Faxia
    Metallurgical Analysis. 2025, 45(4): 51-56. https://doi.org/10.13228/j.boyuan.issn1000-7571.012671
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    The contents of impurities in industrial magnesium hydroxide directly affect the downstream application fields. Therefore, the accurate and rapid determination of impurities is crucial. In this study, the sample was dissolved with nitric acid (1+1). K 766.490 nm, Na 589.592 nm, Ca 317.933 nm, Li 670.784 nm, Fe 259.940 nm, and B 249.773 nm were selected as the analytical lines of potassium, sodium, calcium, lithium, iron, and boron, respectively. The calibration curves were prepared by matrix matching method to eliminate the influence of matrix effect. The contents of potassium, sodium, calcium, lithium, iron, and boron were determined by inductively coupled plasma atomic emission spectrometry (ICP-AES). The method for the determination of six trace impurity elements in industrial magnesium hydroxide was established. The mass concentration of potassium, sodium, calcium, lithium, iron, and boron in range of 0.50-5.00 mg/L showed good linearity to the corresponding emission spectral intensity. The linear correlation coefficients of calibration curves were not less than 0.999 6. The limit of detection of each element in this method was 0.000 02%-0.000 6%, and the limit of quantification was 0.000 08%-0.002 4%. The proposed method was applied for the determination of potassium, sodium, calcium, lithium, iron, and boron in industrial magnesium hydroxide sample. The relative standard deviations (RSD, n=6) of determination results were between 0.80% and 12%, and the recoveries were between 90.8% and 106.5%, which could both meet the requirements of GB/T 32465-2015 Requirement for verification & validation of detection methods and internal quality control on chemical analysis.
  • Determination of 9 metallogenic elements in polymetallic ores by inductively coupled plasma atomic emission spectrometry with microwave digestion
    YU Lei, ZHANG Chaoqing, WEI Ling, ZHANG Xiaoyi
    Metallurgical Analysis. 2025, 45(4): 57-64. https://doi.org/10.13228/j.boyuan.issn1000-7571.012688
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    Rapid and accurate determination of metallogenic elements in polymetallic ores is of great significance to the development and utilization of mineral resources. During the simultaneous determination of multi-elements in polymetallic ores, three elements (i.e., tin, tungsten and molybdenum) are hardly decomposed by the ordinary acid dissolution method. In addition, the silver content is low and the linear range is narrow, so it is difficult to provide a reasonable optimization scheme to meet the needs of simultaneous determination of multiple elements.In this study, the polymetallic ore sample was treated by microwave digestion in hydrochloric acid-nitric acid-hydrofluoric acid system. The contents of nine metallogenic elements (including copper, lead, zinc, cobalt, nickel, silver, tungsten, molybdenum and tin) in polymetallic ore sample were determined by inductively coupled plasma atomic emission spectrometry (ICP-AES). The correlation coefficients of calibration curves of elements were not less than 0.999 7. The limits of detection in this method were between 0.000 3% and 0.007% (0.4 μg/g for silver). Six national first-class reference materials of polymetallic ores were determined according to the experimental method. The relative standard deviations (RSD, n=6) of determination results for most elements were between 0.42%-6.5%, and the determination results for most elements were within the error range of the identified values. The contents of nine elements in polymetallic ore were determined according to the experimental method and compared with the national standard methods. The results were consistent.
  • Determination of cobalt and cadmium in purified solution of zinc hydrometallurgy by inductively coupled plasma atomic emission spectrometry
    LONG Xingjie, YANG Ping, LIU Chuanshi, WEI Wei, LUO Heng, TIAN Xian
    Metallurgical Analysis. 2025, 45(4): 65-72. https://doi.org/10.13228/j.boyuan.issn1000-7571.012682
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    The contents of cobalt and cadmium in purified solution is the key control index in zinc hydrometallurgy purification process. At present, the control analysis of cobalt and cadmium content in purified solution usually adopts nitroso R salt spectrophotometry and flame atomic absorption spectrometry. However, these methods have some shortcomings such as long analysis process and complicated operation, leading to the slow release of test results and heavy workload of laboratory technician. In this study, 3%(V/V) nitric acid was used as the medium without the pretreatment of sample. The horizontal observation method was used. Co 237.86 nm and Cd 214.44 nm were selected as the analytical lines for cobalt and cadmium, respectively. The dilution ratio of sample was controlled to reduce the influence of matrix effect. The contents of cobalt and cadmium were determined by inductively coupled plasma atomic emission spectrometry (ICP-AES). The method for the determination of cobalt and cadmium in purified solution of zinc hydrometallurgy by ICP-AES was established. The calibration curves of cobalt and cadmium had a good linearity within the linear range, and the linear correlation coefficients were not less than 0.999 9. The limits of detection for cobalt and cadmium were 0.001 2 mg/L and 0.000 9 mg/L, respectively. The contents of cobalt and cadmium in purified solution of zinc hydrometallurgy were determined according to the experimental method. The relative standard deviation (RSD, n=11) was 0.58%-2.8% for cobalt and 0.96%-2.8% for cadmium. The spiked recovery was 97.5%-105.0% and 95%-102.5%, respectively. The measured values had no significant difference with those obtained by nitroso R salt spectrophotometry and flame atomic absorption spectrometry.
  • Determination of arsenic and mercury in coal by hydride generation-atomic fluorescence spectrometry with super microwave digestion
    SHEN Junle, PEI Jian, CHEN Linfei, CHEN Long, LIU Lichao, FENG Li
    Metallurgical Analysis. 2025, 45(4): 73-80. https://doi.org/10.13228/j.boyuan.issn1000-7571.012709
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    The microwave digestion can be used for the pretreatment of arsenic and mercury in coal, but it is difficult to completely digest the anthracite samples with high organic matter content. In order to quickly and accurately determine the total arsenic and total mercury in coal samples such as lignite, bituminous coal, and anthracite, the sample was treated by super microwave digestion at 270 ℃ for 40 min in nitric acid-hydrogen peroxide-hydrofluoric acid system (the volume ratio was 3.5∶2∶0.5), and the method for simultaneous determination of arsenic and mercury in coal by hydride generation-atomic fluorescence spectrometry (HG-AFS) was established in this paper. The linear correlation coefficients of calibration curves of arsenic and mercury were both higher than 0.999 9. The limit of detection for arsenic and mercury in this method was 0.101 and 0.008 mg/kg, and the limit of quantification was 0.337 and 0.027 mg/kg, respectively. The contents of arsenic and mercury in four certified reference materials of coal were determined according to the experimental method, and the determination results were all within the uncertainty range of certified values. The anthracite samples with high organic matter content were pretreated by super microwave digestion, and the contents of arsenic and mercury in digestion solution were determined by HG-AFS and inductively coupled plasma mass spectrometry (ICP-MS). The determination results of two methods had no significant difference. The contents of arsenic and mercury in actual coal samples with different types were determined according to the experimental method. The relative standard deviations (RSD, n=6) were not more than 5.6%, and the spiked recoveries for arsenic and mercury were 92%-104% and 95%-102%, respectively. The super microwave digestion method had some advantages such as easy to operate, low acid requirement and short testing period. Its combination with HG-AFS could realize the simultaneous determination requirements of total arsenic and total mercury in coal samples.
  • Determination of silver in argentiferous alloy by potassium bromide potentiometric titration method
    ZHANG Juntong, SHAN Zhaoyong, LI Guangsheng, ZHU Xingfu, ZHANG Jiajuan, XING Ningning
    Metallurgical Analysis. 2025, 45(4): 81-86. https://doi.org/10.13228/j.boyuan.issn1000-7571.012686
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    Argentiferous alloy refers to alloy products formed by silver and other metals, and the silver content is usually in range of 50%-99% (mass fraction). The procedures of conventional fire assay gravimetric methods are cumbersome and time-consuming, and the accuracy of the test results is not good. In this study, the analysis method for the determination of silver in argentiferous alloy by potassium bromide potentiometric titration was investigated and established. Potassium bromide was selected as the titrant and a smart silver ring electrode was selected as the probe. The reaction end point was judged with the potential change of titration process. The effects of sample mass, nitric acid dosage, dilution volume and interference elements on the determination results were investigated in experiments. It was found that the determination was not affected when the sample mass was 300 mg, the nitric acid (1+2) dosage was 5 mL, the dilution volume was 100 mL, and the content of interference element of palladium was less than 5 mg. The content of silver in three self-made argentiferous alloy samples (the main components were silver and lead) was determined according to the experimental method. The relative standard deviations (RSD, n=11) of determination results were between 0.04% and 0.06%, and the range was 0.12%-0.16%. The determination results were basically consistent with those obtained by national standard method GB/T 15249.2-2009. The content of silver in argentiferous alloy was determined according to the experimental method in proficiency testing. The error of the result was -0.02%-0.02%, and the steady statistics z score was -0.45 and 0.36.
  • Determination of silicon dioxide in silica by gravimetric method with alkali fusion
    XING Yinjuan, LI Tuo, YANG Junhong, YUAN Rui, YANG Juan
    Metallurgical Analysis. 2025, 45(4): 87-91. https://doi.org/10.13228/j.boyuan.issn1000-7571.012605
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    The content of silicon dioxide in silica is one of the important parameters that play a crucial role in the application and trading of silica. However, the existing methods for measuring silicon dioxide in silica were time-consuming, and the errors of results are usually large. In this study, 0.30 g of sample was treated by alkali fusion with 5.0 g of sodium peroxide. After leaching with water, it was acidified with hydrochloric acid (1+1). Twice dehydration was conducted with 10 mL of perchloric acid. Then the sample was burned to constant mass. Then hydrofluoric acid was added to react with silicon to form silicon tetrafluoride, which could be removed by volatilization. The content of silicon dioxide could be calculated based on the mass difference before and after adding hydrofluoric acid. The method for determination of silicon dioxide in silica by gravimetric method with alkali fusion was established. The contents of silicon dioxide in standard sample of silica (BH-0122-1) and three silica samples were determined according to the experimental method. The relative standard deviations (RSD, n=11) of determination results were between 0.11% and 0.19%. The measured result of silicon dioxide content in BH-0122-1 was consistent with the standard value.
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