Inductively coupled plasma tandem mass spectrometry (ICP-MS/MS) has great advantages in the analysis of trace and ultra-trace impurity elements in high-purity refractory metals. In this study, the high matrix introduction (HMI) ICP-MS/MS method was employed to analyze specific interfering elements in high-purity refractory metals, such as trace silver (Ag) in high-purity niobium (Nb), trace platinum (Pt) in high-purity hafnium (Hf), and trace gold (Au) in high-purity tantalum (Ta). The HMI parameters were optimized: the carrier gas flow was 0.45 L/min, and the dilution gas flow was 0.65 L/min,enabling direct quantification using calibration curves without matrix matching.The reaction mode and action mechanism of O₂/NH₃ in tandem quadrupole mass spectrometer (MS/MS) mode was investigated to eliminate the mass spectral interference of matrix on tested elements. Ag was analyzed in the O₂ on-mass mode (primary mass filter Q1=107, secondary mass filter Q2=107) with the flow rate of 0.50 mL/min. Pt and Au were analyzed in the NH₃ mass shift mode (Pt: Q1=194, Q2=228; Q1=195, Q2=229. Au: Q1=197, Q2=231) with the flow rate of 0.75 mL/min and 0.50 mL/min, respectively. The linear ranges of Ag, Pt, and Au were 0.10-50.0 ng/mL,with correlation coefficients (r) all greater than 0.999.The limits of detection were in range of 0.001-0.035 μg/g. The standard solution of Ag, Pt, and Au with known concentration was added into high-purity Nb, Hf and Ta matrixes for the standard addition recovery tests. Moreover, the precision investigations of measurement results were also conducted. The experimental results showed that the spiked recoveries of Ag, Pt, and Au were between 83.0% and 113.0%. The relative standard deviations (RSD, n=6) of determination results were between 3.0% and 7.9%. The proposed method was applied for the analysis of three high-purity refractory metals, and the results were compared with those obtained by glow discharge mass spectrometry (GDMS). It was found that the determination results of two analysis methods were basically consistent.

The morphology and distribution of free-cutting phases in free-cutting steel are important factors influencing their cutting properties. In order to develop new austenitic free-cutting stainless steels, the free-cutting phases in chalcogenide (303F, 303Cu, 304F), lead-based (303Pb), and selenium-based (304Se) austenitic free-cutting stainless steels were observed and analyzed by metallographic microscopy, scanning electron microscopy (SEM), energy dispersive spectrometry (EDS), electron probe microanalyzer (EPMA), microhardness tester and inclusion three-dimensional corrosion etching technology. The existence forms of each free-cutting element in steel were investigated, and the differences of free-cutting phases and microhardness in each austenitic free-cutting stainless steel were compared. The results showed that among all kinds of austenitic free-cutting stainless steels, the 304 (Se addition) steel exhibited the largest average equivalent diameter and average area. Specifically, the average equivalent diameter was 3.66 μm, and the average area was 15.10 μm². The average aspect ratio of inclusions in 304 (Se addition) steel was 2.54, and most of the inclusions were ellipsoidal-shaped. The inclusions with aspect ratio of 1-3 accounted for 73%, which was significantly higher than that of 58% in 303Cu steel and 55% in 303Pb steel. The existence forms of free-cutting elements in the steel were different: S in the steel formed free-cutting phase MnS; Cu existed in solid solution in the steel matrix; Pb existed in steel in the form of agglomerate or it was distributed in two ends of MnS; Se formed Mn (Se,S) composite inclusions in the steel which could resist rolling deformation so that the morphology tended to be fusiform; some Mn (Se,S) composite inclusions wrapped the hard Al₂O₃ core to improve the cutting performance of steel. Among various types of austenitic free-cutting stainless steel, 304F steel had the highest average micro-hardness value, which was 309 HV_0.1. The average micro-hardness value of 304 (Se addition) steel was 229HV_0.1. Due to the effect of Cu to reduce the strain hardening, the average micro-hardness value of 303Cu steel was the lowest, i.e., 156HV_0.1.

Accurate determination of rare earth elements (REEs) in vanadium-titanium magnetite is essential for evaluating the resource potential of REEs in such ores. Samples were digested using an open-vessel digestion method with an HNO₃-HF-H₂SO₄ acid system. Instrumental conditions were optimized as follows: sampling depth of 3 mm, radio-frequency power of 1 350 W, and nebulizer gas flow rate of 1.05 L/min. The isotopes ⁸⁹Y, ¹³⁹La, ¹⁴⁰Ce, ¹⁴¹Pr, ¹⁴⁶Nd, ¹⁴⁷Sm, ¹⁵¹Eu, ¹⁵⁷Gd, ¹⁵⁹Tb, ¹⁶³Dy, ¹⁶⁵Ho, ¹⁶⁶Er, ¹⁶⁹Tm, ¹⁷²Yb, and ¹⁷⁵Lu were selected for determination. Interference equations were applied to correct for polyatomic ion interference on ¹⁵⁷Gd, ¹⁵⁹Tb, ¹⁶⁵Ho, ¹⁶⁶Er, and ¹⁶⁹Tm. The interference from high concentrations of Ti and Fe in the solution was also evaluated and compensated. A method for the determination of REEs in vanadium-titanium magnetite by open-vessel acid digestion-ICP-MS was established. Under the optimized conditions, the correlation coefficients of the calibration curves for all REEs were not less than 0.999 3. The limits of detection (LOD) ranged from 0.007 to 0.25 μg/g, and the limits of quantification (LOQ) were between 0.028 and 1.00 μg/g. The proposed method was applied to the determination of REEs in actual samples, yielding relative standard deviations (RSDs, n=6) of 0.85% to 3.6% for all elements. The similar REE distribution patterns observed for three vanadium-titanium magnetite samples from different mining areas in Chengde, Hebei Province, indicate they share a similar material source.

Polycyclic aromatic hydrocarbons (PAHs) in water can cause cancer, teratogenesis and mutagenesis, which are harmful to ecosystems and human health. Therefore, the accurate and convenient determination of PAHs content in water is of great significance. In this study, the water samples were enriched by solid-phase extraction (SPE). After concentration by nitrogen blowing, the qualitative and quantitative analysis of samples was conducted by gas chromatography-tandem mass spectrometry (GC-MS/MS) in multiple reaction monitoring (MRM) mode. The experimental parameters were optimized, including different extraction methods, types of extraction columns, pH of extraction solution, types of matrix modifiers, residual chlorine content and removal methods, volume of extracted water samples, and chromatographic and mass spectrometric conditions. 0.1 g of ascorbic acid was added into 1 000 mL of water sample to remove the residual chlorine followed by adjusting pH ≤ 2 with phosphoric acid. Then 25 g of sodium chloride, 10 mL of isopropanol and 10 mL of n-hexane were added as the matrix modifiers. Finally, 16 kinds of PAHs in water were enriched by automatic solid-phase extraction using MIP-PAHs solid-phase extraction column as the carrier. The linear correlation coefficients of calibration curves for 16 PAHs in the linear range of 5.0-250 μg/L were all not less than 0.999 5. The limits of detection in this method for 16 PAHs were 0.89-1.97 ng/L, and the limits of quantification were 3.56-7.88 ng/L. Four actual water samples, including underground water, surface water, drinking water, and tap water, were determined according to the experimental method. The relative deviations of parallel samples were 0.11%-11.5%, and the spiked recoveries were 79.0%-123%. Samples of groundwater, surface water, drinking water, and tap water from the supply network with potential pollution risks around a coking plant were quantitatively analyzed.The relative standard deviations (RSD, n=7) of determination results were 1.9%-12%, and the spiked recoveries were between 71.5% and 119%.

Gadolinium fluoride is the main raw material for the production of metallic gadolinium and gadolinium iron. The content of impurities in gadolinium fluoride will directly affect performance of products. Therefore, it is important to determine the content of impurity elements efficiently and accurately. In this study, an analysis method for the determination of trace impurity elements in gadolinium fluoride by direct current glow discharge mass spectrometry (DC-GDMS) was developed. Tantalum strip and graphite powder were selected as the conductive medium and binder. The powder sample was filled in a square space with a side length of 5 mm surrounded by tantalum strip and embedded in graphite powder, realizing the direct solid analysis of gadolinium fluoride powder. The key parameters were obtained through systematical optimization: the discharge current was 30 mA; the discharge voltage was 1 200 V; the argon flow rate was 400 mL/min; the pre-sputtering time was 10 min. The contents of 70 impurity elements in high purity gadolinium fluoride were determined in seven replicates according to the experimental method. The relative standard deviations (RSD, n=7) of determination results of all detected elements were not more than 30% (when the content of impurities in the sample was greater than 1 μg/g, the RSD was not more than 10%). The results were verified and compared with inductively coupled plasma tandem mass spectrometry (ICP-MS/MS). The t-test results indicated that there was statistical consistency between two methods for the elements specified in product standard except for Ca and Si. The specimens obtained in this sample preparation method had good appearance regularity and high mechanical strength. The proposed method provided a reliable solution for the detection of impurity elements in rare earth fluorides.

With the continuous increase in municipal solid waste incineration fly ash production, its resource utilization has become increasingly urgent. This study investigated the leaching of valuable metals from fly ash using an oxalic acid-sulfuric acid composite system. The effects of oxalic acid concentration, liquid-to-solid ratio, volume ratio of oxalic acid to sulfuric acid, leaching temperature, and time on the extraction rates of Al, Zn, Cu, and Fe were systematically examined. The results showed that under the optimized conditions (0.8 mol/L oxalic acid, a liquid-to-solid ratio of 15 mL/g, an oxalic to sulfuric acid volume ratio of 9∶6, a temperature of 80 °C, and a time of 90 min), the leaching rates of Al, Zn, and Fe all exceeded 98%, while that of Cu was over 93%. The composite system not only provided sufficient H⁺ but also selectively complexed target heavy metals. Oxalic acid, with its excellent complexation and reductive dissolution capabilities, formed soluble complexes with metal ions. The synergistic effect of the combined acids effectively enhanced metal leaching. The leaching kinetics were fitted using the unreacted shrinking core model. The apparent activation energies for Al, Zn, Cu, and Fe, calculated via the Arrhenius equation, ranged from 17.83 to 21.40 kJ/mol, indicating that the leaching process was likely governed by a mixed mechanism involving both surface reaction and diffusion control.

Given the current lack of research on equiaxed/single crystal bimetal superalloys, K447A/DD412 dual-alloy dual-property test bars were successfully fabricated via a secondary pouring process in this study. The effect of hot isostatic pressing(HIP) on their microstructure was investigated. Analysis of the as-cast microstructure revealed a wide transition zone between the two alloys with no interfacial oxidation, indicating a good metallurgical bond. The overall microstructure of the bimetal test bar could be divided into four regions: K447A, DD447, a compositional transition zone (CTZ), and DD412. Significant compositional and microstructural differences were observed among these regions. The area fraction of eutectic and carbides gradually decreased from K447A to DD412, while the area fraction of the dendritic γ′ phase increased correspondingly. After hot isostatic pressing treatment, microporosity was essentially eliminated. The area fraction of eutectic and carbides decreased overall, though their morphology did not change significantly. Additionally, the morphology of the dendritic γ′ phase was refined, and its area fraction increased. It should be noted that the HIP-treated microstructure still exhibited issues such as excessively large γ′ phase size, which requires further optimization through subsequent solution and aging heat treatments. This study provides a theoretical and experimental basis for the development of dual-alloy dual-property blisks.

The accurate determination of vanadium (V), chromium (Cr) and arsenic (As) contents in aluminum and aluminum alloys is of great significance for the production and application of aluminum and aluminum alloys. When the silicon content (mass fraction, the same below) in aluminum and aluminum alloys was less than 0.5%, the sample was dissolved with mixed acid (V_HCl∶V_HNO3∶V_H2O=10∶1∶10). When the silicon content was not less than 0.5%, the sample was dissolved with 200 g/L sodium hydroxide solution followed by acidification with mixed acid. In the tandem quadrupole (MS/MS) mode, the mass-to-charge ratio (m/z) of the primary mass filter (Q1) was set to 51, 52, and 75. Then, NH₃ and O₂ were successively introduced into the collision/reaction cell. ³⁵Cl¹⁶O⁺ reacted with NH₃ through redox reaction to form polyatomic ions with m/z values not equal to 51. ⁵²Cr⁺ and ⁷⁵As⁺ reacted with O₂ to form ⁵²Cr¹⁶O⁺ and ⁷⁵As¹⁶O⁺, respectively. The interfering ions ³⁵Cl¹⁶OH⁺ and ⁴⁰Ar³⁵Cl⁺ could not react with O₂. Therefore, the m/z of the second mass filter (Q2) were set to 51, 68, and 91. Only ⁵¹V⁺, ⁵²Cr¹⁶O⁺, and ⁷⁵As¹⁶O⁺ passed through and were detected by the detector, thereby avoiding the mass spectrometric interference of ³⁵Cl¹⁶O⁺,³⁵Cl¹⁶OH⁺, and ⁴⁰Ar³⁵Cl⁺. Accordingly, the method for the determination of V, Cr and As in aluminum and aluminum alloys by inductively coupled plasma tandem mass spectrometry (ICP-MS/MS) was established. The flow rates of NH₃ and O₂ were optimized: the flow rate of NH₃ was set at 0.40 mL/min and the flow rate of O₂ were selected at 1.20 mL/min. The linear relationship was good for the mass concentration in range of 0.25-50.00 ng/mL, and the correlation coefficients were higher than 0.999 5. When the sample was dissolved with mixed acid, the limits of detection for testing elements were 0.024-0.12 μg/g, and the limits of quantification were 0.080-0.39 μg/g. When the sample was dissolved with 200 g/L sodium hydroxide solution, the limits of detection for testing elements were 0.064-0.17 μg/g, and the limits of quantification were 0.22-0.56 μg/g. The aluminum alloy standard sample was determined according to the experimental method, and the found results were basically consistent with the certified values. The contents of V, Cr and As in aluminum and aluminum alloys with different silicon contents were determined. The relative standard deviations (RSD, n=11) of determination results were between 1.4% and 9.4%, and the spiked recoveries were between 95% and 115%.

Magnesite is an important industrial mineral raw material. The accurate determination of trace elements in magnesite is of great significance for the environmental protection, resource utilization, and geological research. Traditional analytical methods suffer from low sensitivity and inadequate capabilities in multi-element simultaneous detection, which cannot meet the efficient analysis requirements for trace elements. Therefore, an analysis method for the determination of eight trace elements (including As, Co, Cu, Pb, Th, La, U, and Li) in magnesite by inductively coupled plasma mass spectrometry (ICP-MS) was established in this study. The pretreatment conditions of sample were systematically optimized: the mixed acid system was composed of 5 mL HNO₃, 2 mL HF, 1.5 mL HClO₄ and 1.5 mL HCl; the sample was digested in closed system at 180 ℃ for 6 h; the sample mass was 0.100 0 g. The collision reaction cell technology was employed to eliminate the polyatomic ion interference caused by high-magnesium matrix. The mass spectrometry interference of As, La and U could be eliminated under kinetic discrimination (KED) mode (using He gas with 2% H₂). The contents of Co, Cu, Th, and Li were determined under standard (STD) mode (He collision). In addition, the mass numbers of elements for determination were optimized. ¹⁰³Rh was introduced online as an internal standard for the dynamic calibration, which effectively overcame the matrix effects and instrumental signal drift. The linear correlation coefficients of calibration curves for testing elements were all higher than 0.999. The limits of detection ranged from 0.001 to 0.008 μg/g, and the limits of quantification were between 0.004 and 0.025 μg/g. The contents of As, Co, Cu, Pb, Th, La, U and Li in CSMs magnesite composition analysis (GBW07865 and GBW07866) were determined according to the experimental method. The relative standard deviations (RSD, n=6) of determination results were between 2.6% and 3.4%, and the relative errors (|RE|) were between 1.75% and 4.88%. The analysis results of five actual magnesite samples indicated that the contents of eight trace elements were all at low level. Two samples of them were selected for the method comparison (this method and microwave digestion-ICP-MS). The measurement results showed good consistency, which further proved the reliability of proposed method.

Alloying is an important way to improve the comprehensive properties of zinc-aluminum alloy. The accurate and rapid determination of alloying elements (including bismuth, chromium, manganese, nickel and titanium) is crucial to the product quality control and the development of high-performance alloy. In this study, the sample was dissolved with dilute aqua regia. Bi 223.061 nm, Cr 267.716 nm, Mn 257.611 nm, Ni 231.604 nm and Ti 336.121 nm were selected as the analytical lines. High-purity zinc was used for matrix matching to eliminate the matrix effect. The method for the simultaneous determination of five alloying elements (bismuth, chromium, manganese, nickel and titanium) in zinc-aluminum alloy by inductively coupled plasma atomic emission spectrometry (ICP-AES) was established. The linear correlation coefficients of calibration curves for testing elements were all higher than 0.999 5. The limits of detection of this method were between 0.02 and 0.43 μg/g. The contents of bismuth, chromium, manganese, nickel and titanium in three certified reference materials of zinc-aluminum alloy and two zinc-aluminum alloy actual samples were determined according to the experimental method. The measurement results of certified reference materials were consistent with the certified values. For the actual samples, the relative standard deviations (RSD, n=8) of determination results ranged from 0.48% to 1.9%, and the spiked recoveries were between 94% and 106%.

Vanadium-aluminum alloy is an important additive for the smelting of high-performance titanium alloys. The accurate determination of elemental contents is of great importance for the smelting process of titanium alloys. In this study, a method for the simultaneous determination of the contents of seven elements (including aluminum, silicon, iron, chromium, molybdenum, yttrium, and phosphorus) in vanadium-aluminum alloys by aqua regia digestion-inductively coupled plasma atomic emission spectrometry (ICP-AES) was established. Al 396.15 nm, Si 251.61 nm, Fe 259.94 nm, Cr 205.55 nm, Mo 202.03 nm, Y 371.03 nm and P 213.62 nm were selected as the spectral lines for aluminum, silicon, iron, chromium, molybdenum, yttrium, and phosphorus, respectively. The linearity of calibration curves of testing elements was good with correlation coefficients (r) all higher than 0.999. The limits of detection in this method were 0.000 3%-0.002 1% (mass fraction, the same below), and the limits of quantification were 0.001%-0.007%. The proposed method was applied for the determination of aluminum, silicon, iron, chromium, molybdenum, yttrium, and phosphorus in actual AlV55 vanadium-aluminum alloy sample. The relative standard deviation (RSD, n=7) of determination results were between 0.50% and 7.8%, and the spiked recoveries were between 96% and 105%.

The thallium in lead smelting slag has high toxicity. Since the occurrence matrix is complex, there is no standard method for the analysis of thallium in lead smelting slag. In this study, a method for the determination of thallium by inductively coupled plasma atomic emission spectrometry (ICP-AES) after adsorption preconcentration with polyurethane foam was established. The sample was digested with mixed acid system containing 15 mL of hydrochloric acid, 5 mL of nitric acid, 10 mL of hydrofluoric acid, 2 mL of perchloric acid, 5 drops of sulfuric acid (1+1) and bromine water. The interference of silicon and carbon could be effective eliminated. Meanwhile, thallium was converted to Tl (Ⅲ) which could be adsorbed. The optimization experiments indicated that the adsorbing effect of Tl (Ⅲ) by polyurethane foam was best when 0.10-0.20 g (4-6 drops) of bromine water was added into 5% aqua regia medium to make the solution show stable pale yellow. After adsorption, 10.00 mL of 3.0 g/L sulfurous acid solution was used as the eluent to achieve the quantitative elution of thallium by heating in boiling water for 20 min. Tl 190.856 nm was selected as the analytical line. The emission spectral intensity of thallium showed good linear relationship with the mass concentration in range of 0.50-20.00 μg/mL, and the linear correlation coefficient was 0.999 8. The limit of detection of this method was 1.12 μg/g. The content of thallium in actual lead smelting slag sample was determined according to the experimental method. The relative standard deviation (RSD, n=9) of determination results were between 3.1% and 4.0%, and the spiked recoveries were between 95.5% and 101.7%. The measurement results were consistent with those obtained by inductively coupled plasma mass spectrometry (ICP-MS). The proposed method was accurate and reliable, which was suitable for the quantitative analysis of thallium in lead smelting slag.