During the analysis of associated elements in coal and gangue samples by conventional methods, the ashing treatment is required. However, the operation of this process is complicated, and some elements are easily volatilized and lost. The traditional acid dissolution method cannot effectively remove organic matter, which will lead to lower determination results. In addition, there is no standard method for the determination of Li. In this study, referring to the idea of acid used for decomposing samples in GB/T 16659-2024 and DZ/T 0279.3-2016, the strong oxidizability of HNO₃, H₂SO₄ and H₂O₂ was employed to oxidize the organic matter in samples into carbon dioxide for removal. The adsorption and wrapping of carbon-containing substances on the samples were eliminated and the process of decarbonization by high-temperature burning was avoided. The addition of HF significantly enhanced the decomposition effect of silicon-containing minerals. The method for determination of Li, Be, V, Co, Ni, Cu, Ga, Pb, Mo, Sb, Th and U contents in coal and gangue by inductively coupled plasma mass spectrometry (ICP-MS) was established. The linear correlation coefficients (r) of calibration curves were between 0.999 1 and 1.000. The limits of detection in this method were 0.012-0.58 μg/g, and the limits of quantification were 0.08-2.32 μg/g. Three certified reference materials for composition analysis of trace harmful elements in coal were determined according to the experimental method. The relative standard deviations (RSD,n=7) of the measurement results for Be, Co, Ni, Cu, Pb, Mo, Sb, Th and U were between 1.9% and 8.7%, and the absolute values of relative error (RE, n=7) were between 0.28% and 7.31%. For the elements of Li,V,Ga, which have no certified values, the relative standard deviations (RSD,n=7) of the measured results were between 1.8% and 4.5%, and recovery rates were between 98% and 103%. Additionally, the results were compared with those obtained by sealed-vessel digestion-ICP-MS and they were found to be in good agreement. A statistical comparison using a t-test indicated no significant difference between the results derived from the two sample preparation methods.

The introduction of rare earth elements into sintered flux can significantly enhance the impact toughness of weld metal. The accurate determination of lanthanum and cerium contents in sintered flux is of great significance. The current standard system for the analysis of sintered flux is not yet perfect, lacking standard methods for the determination of lanthanum and cerium. Moreover, there are no relevant research reports. Therefore, it is particularly necessary to develop a method suitable for the determination of lanthanum and cerium in sintered flux. In this study, first, it was confirmed through scanning electron microscopy energy dispersive spectroscopy (SEM-EDS) that lanthanum and cerium in sintered flux exist in the form of oxides or silicon-calcium-iron multi-element alloys. Then the digestion effects of four digestion techniques, i.e., closed acid dissolution, high-temperature alkali melting, microwave digestion, and open acid dissolution, were compared. Meanwhile, the influence of medium acidity and matrix effect on the measurement results in determination by inductively coupled plasma atomic emission spectroscopy (ICP-AES) was explored and discussed. Finally, the open acid dissolution method using hydrochloric acid-nitric acid-hydrofluoric acid-sulfuric acid mixture was adopted. The solution medium was 10.0% aqua regia. La 398.852 nm and Ce 446.021 nm were selected as the analysis lines for lanthanum and cerium. The contents of lanthanum and cerium in sintered flux were determined by ICP-AES. The experimental results showed that the sample could be digested with hydrochloric acid-nitric acid-hydrofluoric acid-sulfuric acid mixture in open acid dissolution mode. When the sample mass does not exceed 0.300 0 g, The influence of matrix effect on the determination of lanthanum and cerium could be ignored. The linear correlation coefficients of calibration curves for lanthanum and cerium both reached 0.999 9. The limits of detection for lanthanum and cerium in this method were 0.000 2% and 0.000 3% (mass fraction, the same below), and the limits of quantification were 0.000 5% and 0.001 1%, respectively. The contents of lanthanum and cerium in sintered flux were determined according to the experimental method. The relative standard deviation (RSD, n=7) of determination results were between 0.19% and 1.1%, and the recoveries were between 98.7% and 101.8%. The determination results of lanthanum and cerium were consistent with those obtained by X-ray fluorescence spectrometry (XRF).

Manganese pellets are important raw materials and auxiliary materials used in the process of steel smelting to improve the quality of steel. The national standard methods for the determination of manganese oxide, calcium oxide and phosphorus contents have the disadvantages of cumbersome operation, time consuming and high material consumption. In this study, the analysis method for the determination of manganese oxide, calcium oxide and phosphorus in manganese pellets by inductively coupled plasma atomic emission spectrometry (ICP-AES) was established. 2.5 g of anhydrous sodium carbonate and boric acid mixed flux was used in alkali fusion of sample at 900 ℃ for 20 min. Then, the mixture was leached with hydrochloric acid. The calibration curves were prepared by matrix matching method to eliminate the influence of matrix effect. Mn 260.569 nm, Ca 317.933 nm and P 177.495 nm were selected as the analytical lines of manganese, calcium and phosphorus, respectively. The calibration curves had good linearity and the linear correlation coefficients (r) were all greater than 0.999. The limits of detection for components were all in range of 0.008%-0.028% (mass fraction). The contents of manganese oxide, calcium oxide and phosphorus in two manganese pellet samples were determined according to the experimental method, and the relative standard deviation (RSD, n=11) of determination results were all less than 3%. Two manganese pellet samples were determined according to the experimental method and national standard method (determination of manganese by ammonium ferrous sulfate titration method (GB/T 1506-2016), determination of calcium by EDTA titration method (GB/T 1511-2016), and determination of phosphorus by phosphomolybdenum blue spectrophotometry (GB/T 1515-2002)), and the measurement results of two methods were consistent. The proposed method effectively solved the problem that it was difficult to accurately and rapidly determine the contents of manganese oxide, calcium oxide and phosphorus in manganese pellets, and it could be used for the routine detections.

In the process of recovering ammonium perrhenate from the waste acid system of copper smelting flue gas, thallium will co-crystallize with rhenium into the ammonium perrhenate crystals. As a highly toxic and harmful substance, it not only affects the quality of ammonium perrhenate products, but also causes environmental pollution. At present, the current industry standard method (YS/T 902-2013) for the determination of thallium in ammonium perrhenate, with a determination range of 0.000 1%-0.005 0% (mass fraction, the same below), cannot meet the detection requirements of trace thallium. Therefore, it is necessary to establish a new method. In this study, the sample was directly dissolved with nitric acid (without the separation of rhenium matrix). Tl 351.924 nm was selected as the analytical line for the determination of thallium. The method for the determination of trace thallium in ammonium perrhenate by inductively coupled plasma atomic emission spectrometry (ICP-AES) with acid dissolution was established. The linear correlation coefficient (r) of calibration curve was 0.999 3. The limit of detection (LOD) of this method was 0.000 03%, and the limit of quantification (LOQ) was 0.000 1%. The content of thallium in six ammonium perrhenate samples was determined according to the experimental method. The relative standard deviation (RSD, n=7) of determination results were between 1.0% and 3.6%, and the spiked recoveries were between 95% and 107%, which could both meet the requirements of GB/T 32465-2015. The determination results were consistent with the reference values and those obtained by microwave digestion-ICP-AES and flame atomic absorption spectrometry (FAAS). The t test indicated that the proposed method had no significant difference with other two comparison methods (microwave digestion-ICP-AES and FAAS).

Zinc oxide concentrates for zinc smelting are produced by pyrometallurgical volatilization and enrichment processing of zinc-containing materials. They serve as substitutes for zinc concentrates in zinc smelting, which can significantly alleviate the shortage of zinc resources in China. Imported zinc oxide concentrates that comply with the standard YS/T 1343-2019 Zinc Oxide Concentrate for Zinc Smelting and pass verification are exempt from being managed as solid waste. In this study, using imported zinc oxide concentrates as raw materials, three grades of certified reference materials (CRMs) zinc oxide concentrate for zinc smelting (namely ZnO50, ZnO60, and ZnO70) were successfully developed. This involved processes including chemical composition design, sample preparation, homogeneity/stability assurance measures, phase analysis, chemical content analysis, and uncertainty evaluation. These CRMs are certified for eight components:zinc oxide, iron, fluorine, chlorine, cadmium, mercury, arsenic, and zinc. This series of CRMs features rational chemical composition design and accurate certified values (including standard values and uncertainties). Furthermore, their validity period can reach up to 10 years when stored at room temperature in dark conditions. These developed CRMs provide support for on-site rapid screening, precise laboratory testing, detection method validation, proficiency testing activities, and effective quality management control.

High-carbon-high-chromium bearing steel forms a substantial amount of carbides during heat treatment, including both micron-sized primary carbides and nano-sized secondary carbides. The properties of the steel are determined by the type, content, morphology, and size of these carbides. To comprehensively characterize the precipitated phases under different heat treatment conditions, a suitable electrolytic regime was first selected. Then, the matrix was dissolved via electrolytic extraction, preserving the precipitated phase powder. The phases were identified, and their structural characteristics were determined by X-ray diffraction (XRD). Their morphology was examined, and chemical analysis was performed using scanning electron microscopy (SEM) with energy-dispersive X-ray spectroscopy (EDS). A chemical dissolution method for the precipitated phases was established experimentally. The elemental composition and total amount of the extracted precipitates were quantified by inductively coupled plasma atomic emission spectrometry (ICP-AES). Finally, the particle size distribution was analyzed using a laser particle size analyzer. The results showed that the precipitated phases were relatively large and highly stable. A mixture of sulfuric and nitric acid was required to achieve complete dissolution. In the annealed sample, most of the precipitates were M₂₃C₆ with a small amount of M₆C, whereas only M₂₃C₆ was present after tempering. The precipitate particles were larger in the annealed state and became finer after tempering.

The literature data in the field of inductively coupled plasma mass spectrometry (ICP-MS) was systemically collected and its technological development sequence was analyzed by visualization technology based on bibliometric method. The results indicated that the technological development of ICP-MS presented three different stages, there is a differentiation phenomenon in current industrialization stage, i.e., a decrease in the number of papers and an increase in patents. The research hotspot analysis showed that although the detection objectives have extended to the fields of food and biomedicine, the environmental heavy metal detection and geological dating still dominate. The technological development has a dual path of deepening methods and expanding applications. The highly cited papers and journals jointly confirm its core support role in geochronology, petrogenesis and deposit research. The study showed that the interdisciplinary collaboration is a key driving force for the sustainable technology innovation, and the technology fusion and application boundary expansion are required in the future to jointly drive the innovation. This study can provide reference for the technical layout and interdisciplinary intersection in the field of analytical chemistry.

To address the corrosion issue of platinum-gold crucible during the fusion sample preparation of ferroniobium, the effects of sample particle size, oxidant composition and dosage, and a stepwise pre-oxidation procedure were investigated. The results indicated that when the sample particle size was controlled at 0.074 mm, the fusion time could be reduced by 10 min compared to the sample particle size of 0.096 mm. A novel composite oxidant system of Li₂CO₃-LiOH-KNO₃ (mass ratio of 12∶20∶5) was employed. This system leveraged the alkaline fusion by LiOH and the assisted fusion from CO₂ release during Li₂CO₃ decomposition, while utilizing the mild oxidation characteristics of KNO₃ to replace the traditional Na₂O₂/BaO₂, significantly enhancing the reaction controllability. The interference from Br with the determination of 0.20% Al could be completely eliminated under the following experimental conditions: the fusion temperature of 1 100 ℃, 1.0 mL of LiBr solution, and a fusion time of 20 min. Based on these findings, a three-stage pre-oxidation method suitable for programmable fully automatic electric fusion furnaces was developed. In this method, the commercially available Li₂B₄O₇ crucible was used. The mass ratio of sample (0.25 g) to Li₂B₄O₇ and composite oxidant was controlled. After gradient pre-oxidation at 500-750 ℃, the sample was fused at 1 100 ℃. This approach not only completely avoided the corrosion risk of platinum-gold crucible, but also ensured the homogeneous formation of glass fusion beads. The calibration curves were established using standard reference materials, primary standard substances, and standard solutions of ferroniobium. The analysis method for simultaneous determination of eleven major and minor components (including Nb, Ta, Si, Al, P, Mn, Co, Cr, Ti, Fe and Sn) in ferroniobium by X-ray fluorescence spectrometry (XRF) was established. The linear correlation coefficients of calibration curves in this method were all not less than 0.999 5. One synthetic ferroniobium sample was determined according to the experimental method. The relative standard deviations (RSD, n=8) of determination results for Nb, Ta, Si, Al, P, Mn, Co, Cr, Ti, Fe and Sn were between 0.14% and 2.9%. One actual production sample of ferroniobium was selected for the comparison of this method and other methods as well as standard addition recovery tests. The results indicated that the determination values of Nb, Ta, Si, Al, P, Mn, Ti and Sn were consistent in two methods. The spiked recoveries of Fe, Cr and Co were between 101% and 110%.

The high mineralization degree and complex matrix components of brine result in severe matrix interference in the quantitative analysis of multiple elements. In this study, a method of standard addition correction-inductively coupled plasma emission spectrometry (ICP-AES) was developed. The gradient addition of standard solution into sample solution was used to eliminate the matrix effect. Under the recommended working parameters of the instrument, K 769.897 nm, Mg 279.078 nm, B 249.678 nm, Li 670.790 nm, Rb 780.027 nm and Cs 894.347 nm were selected as the analytical lines for potassium, magnesium, boron, lithium, rubidium and cesium, respectively. The simultaneous determination of potassium, magnesium, boron, lithium, rubidium and cesium in brine with the same matrix was achieved. The linear correlation coefficients of calibration curves for tested elements were all greater than 0.999 5. The limits of quantification in this method were between 0.036 mg/L and 1.20 mg/L. The contents of potassium, magnesium, boron, lithium, rubidium and cesium in brine samples from different regions were determined according to the experimental method. The relative standard deviations (RSD, n=11) of determination results were not more than 2.0%, and the recoveries were between 97.4% and 104.5%.

Silicon content is a key indicator affecting the performance of Fe-6%Si high-silicon steel thin strip, and its accurate determination is of great significance for product quality control. Conventional gravimetric methods for determining silicon in such materials face problems such as difficulty in sample dissolution, severe corrosion of crucibles, and tedious procedures for detecting silicon in the filtrate. To overcome these problems, an improved analytical method combining gravimetry with an empirical correction was proposed in this study. In this method, 1.0 g of sample was digested with a mixed acid system containing 20 mL of hydrochloric acid and 20 mL of nitric acid. The residue was fused with a boric acid-sodium carbonate mixed flux at 1 050 ℃ for 30 min. The combined filtrate was then dehydrated with 25 mL of perchloric acid for 20 min, during which silicon was converted to and removed as silicon dioxide. The silicon content was calculated from the mass difference before and after volatilization. An empirical correction value of 0.095% was introduced to compensate for the silicon loss in the filtrate, yielding the total silicon content. This method was applied to determine silicon in two Fe-6%Si high-silicon steel thin strip samples. The relative standard deviations (RSD, n=7) of the determination results for the two samples were 0.65% and 2.7%, respectively. The spike recoveries ranged from 98.0% to 102%. The accuracy of the method was verified using a certified reference material of silicon steel (YSBC15335-94), and the determination error was within the permissible difference specified in GB/T 5687.2-2007. The proposed method effectively solves the problems of difficult sample dissolution and crucible corrosion, simplifies the filtrate analysis through the empirical correction, and significantly improves the analytical efficiency.

The microstructure, texture, and magnetic properties of a thin-gauge non-oriented silicon steel with 87% cold rolling reduction ratio were investigated after annealing at temperatures ranging from 640 to 1 000 ℃, using optical microscopy (OM), X-ray diffraction (XRD), and electron backscatter diffraction (EBSD). The results show that the cold-rolled sheet is primarily composed of deformation bands elongated along the rolling direction, with shear bands being nearly absent. Its texture was characterized by a strong α-fiber and a weak γ-fiber. During recrystallization annealing at 640-760 ℃, the intensity of the α-fiber texture continuously weakened, while the intensities of the γ-fiber and α^*-fiber textures increased. {111}<112> grains preferentially nucleated and grew within the deformed grains of the γ-fiber texture, gaining a numerical advantage. In contrast, {114}<481> grains nucleated at the grain boundaries of the deformed microstructure possessing the α-fiber texture. As the annealing temperature increased from 820 to 1 000 ℃, the average grain size of the annealed sheet increased from 20.5 μm to 162.0 μm. Compared to the {111}<112> grains, the {114}<481> grains exhibited a 7.22% higher frequency of high-angle grain boundaries and a 9.22% lower frequency of low-angle grain boundaries, indicating a greater advantage in grain boundary mobility. Consequently, the α^*-fiber texture was enhanced and became the dominant texture, while the γ-fiber texture weakened. After annealing at 970 ℃ for 3 min, the annealed sheet reached a critical grain size of 135.3 μm, resulting in the minimum iron loss P_1.5/50 of 2.26 W/kg.

The cation exchange capacity (CEC) is an important technical index for evaluating the properties of zeolites. This study established a method for determining the CEC of zeolites by replacing slow filter paper filtration with centrifugation, followed by equilibrium titration. The effects of exchange solution concentration, exchange temperature, exchange time, and the number of elution cycles on the determination results were investigated. The optimal experimental conditions were determined as follows: using 1 mol/L ammonium chloride solution as the exchange solution, reacting at 100 ℃ for 30 min, and performing 3 elution cycles. The CECs of zeolite standard materials with low, medium, and high levels were determined using this method. The obtained results were all within the permissible range of the certified values, with relative standard deviations (RSD, n=6) between 1.2% and 1.5%. Ten zeolite samples were treated by centrifugation and slow filter paper filtration, respectively, followed by CEC determination using the equilibrium titration method. The results showed that the processing time for a single sample using the centrifugation method was consistently around 3 h, while that for the slow filter paper filtration method could take up to 18 h. For low-content samples (28.72-60.99 cmol/kg, using the centrifugation method as reference), the relative deviation between the results obtained by the two methods ranged from -2.68% to 3.90%. For medium-to high-content samples (72.58-122.37 cmol/kg), the relative deviation ranged from 17.02% to 33.06%. The results obtained by the slow filter paper filtration method were consistently higher, indicating that the centrifugation method yields more reliable results. The proposed method significantly improves detection efficiency and accuracy.