This article summarized the sources of endogenous inclusions and exogenous inclusions in detail.The inclusions were classified according to the morphology,composition,deformability and size.The influences of inclusions on the fatigue performance,strength,elongation performance,cutting performance,corrosion property,welding performance,and hydrogen induced cracking of steel were elaborated.Several two-dimensional and three-dimensional detection methods of inclusions were systemically discussed.The extraction methods and detection instruments for various inclusions as well as the removal methods were introduced.

It is difficult to determine the content of silver and cadmium in soil directly and accurately by inductively coupled plasma mass spectrometry (ICP-MS) due to the mass spectral interference of zirconium and molybdenum.In this study,the soil samples were treated by rapid digestion method followed by zirconium separation with ammonia precipitation.¹⁰⁷Ag and ¹¹¹Cd were used as analytical isotopes and the interference of ⁹⁵Mo¹⁶O⁺ with the determination of ¹¹¹Cd in solution was reduced by collision mode.The method for the determination of silver and cadmium in soil by ICP-MS after rapid digestion and ammonia separation was established.The dosage of ammonia and helium flow rate were optimized.The reference materials and samples of soil were analyzed.The results showed that the limit of detection of silver and cadmium in soil was 0.003 and 0.005 mg/kg,respectively.The determination results of soil reference materials were within the certified value and uncertainty range,and the relative standard deviation(RSD) was 1.3%-8.2% and 2.1%-7.9%,respectively. For soil sample,the determination results of ICP-MS method had no significant difference with those obtained by graphite furnace atomic absorption spectrometry(GFAAS).The proposed method could meet the detection requirements of trace silver and cadmium in soil samples.

The establishment of detection method for zinc,cadmium and lead in rare earth flotation samples is of great significance for analyzing the migration and accumulation of harmful elements (such as zinc,cadmium and lead) throughout the flotation chain.After analyzing the phases and element types of each flotation product as well as associated behaviors of zinc,cadmium and lead,the influence of complex matrix on the quantitative analysis of zinc,cadmium and lead in flotation products of rare earth by inductively coupled plasma mass spectrometry(ICP-MS) was studied.The results showed that the rare earth flotation products could be divided into calcium-iron matrix and calcium-cerium-lanthanum matrix according to the difference of major elements.For the 1 000 μg/mL calcium-iron matrix and calcium-cerium-lanthanum matrix solution,the error of determination results after adding 10 ng of zinc,cadmium and lead was less than 15%.The calibration curve was prepared using the series standard solution of calcium-iron matrix and calcium-cerium-lanthanum matrix with matching,and the quantitative analysis results of elements in sample were basically consistent.When the calibration curve was prepared using calcium-iron matrix with matching and without matching,the quantitative analysis results of elements in flotation samples were similar,and the internal standard recoveries were all within the range of 80%-120%.However,the relative standard deviation(RSD) of internal standard recovery of rare earth flotation sample measured by calcium-iron matrix matching(1.85%) was lower than that of non-matching mode(3.84%).The calibration curve was prepared by calcium-iron matrix matching,and the limit of quantification was 38.59,9.14 and 14.68 μg/kg for zinc,cadmium and lead,respectively.The relative standard deviation(RSD, n=6) of each element in rough concentrate was 1.9%-6.4%.The results of element concentration,proportion of elements after mass and quality balance,and sample yield in each flotation product showed that zinc and cadmium were mainly enriched in tailings products,while lead was enriched in concentrate products.

The determination of strontium and barium in high-purity rare earth metals and their oxides by inductively coupled plasma mass spectrometry(ICP-MS) is susceptible to mass spectral interferences of isobar,polyatomic ions,and double charges.The interference of fifteen single rare earth elements(including yttrium,lanthanum,cerium,praseodymium,neodymium,samarium,europium,gadolinium,terbium,dysprosium,holmium,erbium,thulium,ytterbium,and lutetium) with strontium and barium was investigated in experiments.The results showed that yttrium,lanthanum,cerium,erbium and lutetium had mass spectral interference with partial isotopes of strontium and barium,and the isotopes without interferences could be selected for determination.However,ytterbium exhibited double charge interference with the isotopes of strontium,thus requiring matrix separation to eliminate the interference.Except for ytterbium,the rare earth metals and their oxides could be dissolved with nitric acid and hydrogen peroxide,and then directly determined by ICP-MS in 1%(volume fraction,the same below) nitric acid as medium.The metal ytterbium and its oxides were dissolved with nitric acid and hydrogen peroxide,then the matrix was separated using ammonia,and the filtrate was acidified with nitric acid for the determination of strontium and barium.The experiments showed that the recoveries of strontium and barium were 95%-101% with ammonia separation,the residual ytterbium in filtrate was less than 10.00 ng/mL,which had negligible influence on the determination results.Cerium oxide,terbium oxide,thulium oxide and ytterbium oxide were selected from light,medium and heavy rare earths,and the matrix solutions with different concentrations were prepared according to the selected dissolution method to investigate the matrix effect of measured elements and internal standard elements.The results showed that the matrix effects on strontium and barium were basically consistent with the internal standards of rhodium and cesium,respectively.Accordingly,a method for the determination of strontium and barium in high-purity rare earth metals and their oxides by ICP-MS was established.The linear range of strontium and barium was 0-25.00 ng/mL,and the correlation coefficients of calibration curves were all greater than 0.999 5.The limit of detection was 0.004 4-0.18 μg/g,and the limit of quantification was 0.014-0.62 μg/g.The reference materials of cerium oxide,europium oxide and terbium oxide were determined according to the experimental method,and the results were consistent with the standard values.The content of strontium and barium in high-purity metal yttrium,neodymium,samarium,terbium,cerium oxide,terbium oxide,thulium oxide and ytterbium oxide were determined.The relative standard deviation(RSD,n=11) of determination results was 6.2%-14.6%,and the recovery was 88%-114%.

Molybdenum-aluminum alloy is an important additive in titanium alloy smelting.The accurate determination of hydrogen content in molybdenum-aluminum alloy is beneficial for the quality control of titanium alloy from raw materials.In experiments,0.11 g of molybdenum-aluminum alloy sample was melted by heating in a pulse furnace using tin granular as the flux,and then measured using an infrared detector.The analysis power was controlled at 3.5-4.5 kW.The calibration curve was established using the certified reference materials.The determination of hydrogen in molybdenum-aluminum alloy by pulse heating-infrared absorption method was realized.The limit of quantification for hydrogen was 0.000 1%.The experimental method was applied for the determination of hydrogen in MoAl60 and MoAl80 alloy series samples,and the relative standard deviations (RSD,n=11) of determination results was 7.7%-10%.The content of hydrogen in MoAl60 and MoAl80 alloy series samples was determined according to the experimental method and thermal conductivity method.The determination results of two methods were consistent.

Ferromolybdenum is mainly used as an additive of molybdenum(Mo) in the process of steelmaking.The accurate determination of Mo content is of great significance for steel quality control and commercial settlement.The impurity elements in ferromolybdenum such as Si,Cu and As have certain influence on the steel property.In this study,high-purity iron bead was selected as the flux.The mass ratio of sample to flux was 1∶4.The sample was melted to prepare the mushroom-shaped test blocks by high frequency fusion sample preparation.Then a layer with thickness of 1.50 mm was milled from the surface of test block,and the exposed surface was used as the final testing surface.A series of ferromolybdenum reference materials and artificially synthesized calibration samples were selected to draw the calibration curves.The content of Mo,Si,Cu and As in ferromolybdenum was determined by X-ray fluorescence spectrometry(XRF).The linear correlation coefficients of the calibration curves for each element were all greater than 0.999.The limit of detection for Si,Cu,and As was 11.48-427.7 μg/g.The content of Mo,Si,Cu and As in ferromolybdenum sample was determined according to the experimental method,and the relative standard deviation(RSD, n=11) of the measurement results was less than 10%.The experimental method was applied to the determination of Mo,Si,Cu and As in ferromolybdenum certified reference materials and samples.The determination results of reference materials were consistent with the standard values,and the determination results of samples were consistent with reference values which obtained by standard methods including GB/T 5059.1-2014 (Mo),NACIS/C H147:2019 (Si),GB/T 5059.3-2014(Cu) and NACIS/C H147:2019(As).The errors were all less than the critical difference CD_0.95.

Tetradymite contains abundant tellurium and bismuth,and it is often accompanied by certain amount of selenium.If the tetradymite sample is digested with nitric acid,hydrofluoric acid and perchloric acid,and the content of selenium is determined by hydride generation-atomic fluorescence spectrometry(HG-AFS),tellurium and bismuth in matrix will have serious interference with the determination of selenium,which influencing the determination results.In this study,the semi-melting method with Eska’s reagent was adopted for the separation of matrix.The residual rate of tellurium in sample solution was less than 0.1% after separation.The residual rate of bismuth in sample solution was 2.38%-4.17%,which still influenced on the determination of selenium.In order to further reduce the interference of bismuth,the calibration curve was drawn with matrix matching method.The content of selenium was determined by HG-AFS.A method for the determination of selenium in tetradymite was established.The mass concentration of selenium in range of 0.1-20 μg/L showed good linearity to the corresponding fluorescence intensity.The linear correlation coefficient of calibration curve was 0.999 9.The limit of detection was 0.017 μg/g.The content of selenium in three tetradymite samples was determined according to the experimental method,and the relative standard deviation(RSD, n=10) of the measurement results was less than 10%.The results were also compared with those obtained by triple quadrupole inductively coupled plasma mass spectrometry (ICP-MS/MS). The logC(C was the content) of determination results of two methods was in range of-0.07-0.02.

The content of C,Si,P,S,Cr,Mo,Nb,Al,Co,Ti,and Ta in nickel-based superalloy GH4169(hereinafter referred to as GH4169) has an impact on the thermal and mechanical properties of material.Therefore,it is necessary to accurately determine the content of these 11 elements.In this study,the spark discharge atomic emission spectrometry was employed for the determination of above elements in GH4169.The instrument parameters were optimized and the following experimental conditions were finally selected:the argon flushing time was 5 s,the flushing flow rate was 60 L/h,the pre-combustion time was 13 s,the argon analysis flow rate was 60 L/h,and the exposure time of Task 1,Task 2,and Task 3 was 3 s.Pure nickel reference material was selected for the determination of limit of detection.The results showed that the limit of detection of P,S,and Co was less than the lower limit of built-in curve,while the limit of detection of other elements was below 0.003 0%.The certified reference material SRM1249 was selected for the precision testing,and the results showed that the relative standard deviations (RSD) for each element could meet the requirements of the coefficient of variation in GB/T 27417.The certified reference material GH4169 in different batches were selected for the accuracy testing.It was found that the absolutes of the differences between analysis results and certified values were less than the critical difference CD_0.95.The influence of traditional type standardization and virtual type standardization on the analysis results was compared.The results indicated that analysis result of Si had great difference with that obtained by inductively coupled plasma atomic emission spectrometry(ICP-AES) when the certified reference material SRM1249 was used as a type standardized sample to determine GH4169.However,when GH4169 control sample and SRM1249 certified reference material were used as virtual type standardization sample to determine GH4169,the measurement results were consistent with those obtained by ICP-AES and carbon sulfur analyzer.

Molybdenite sample was digested with nitric acid-hydrogen peroxide-sulfuric acid-hydrofluoric acid system in experiments,and the content of molybdenum in molybdenite was determined by inductively coupled plasma atomic emission spectrometry(ICP-AES).The results showed that 0.1-0.5 g of sample could be completely dissolved with 5 mL of nitric acid,1 mL of hydrogen peroxide,5 drops of sulfuric acid and 3 mL of hydrofluoric acid.5%(V/V,similarly hereinafter) hydrochloric acid was selected as the testing medium.As the mass concentration of molybdenum was in range of 50.0-3 000 μg/L,the calibration curve exhibited good linearity with correlation coefficient (r) of 0.999 996.The limit of detection was 0.336 μg/g,and the limit of quantification was 1.12 μg/g.The content of molybdenum in five molybdenite samples was determined according to the experimental method,and the relative standard deviation(RSD,n=11) was 0.67%-4.1%.The content of molybdenum in certified reference materials of molybdenum ore (GBW07141) and tungsten ore(GBW07241) and five molybdenite samples was determined by the proposed method and spectrophotometric method in GB/T 14352.2-2010.The determination results of two methods were consistent.The measured results of molybdenum in two certified reference materials were consistent with the certified values.

The application of intelligent rapid analysis system,which integrated automatic sampling,pneumatic transmission,automatic sample preparation and rapid analysis,in sinter analysis was introduced in this study.A series of comparative experiments were conducted to compare the differences between this automatic system and manual sampling,manual sample preparation,and manual analysis.The experiment results showed that the implementation of the intelligent rapid analysis system confirmed the existence of systematic deviations in the traditional manual sampling,sample preparation and analysis of TFe,SiO₂,CaO,MgO,Al₂O₃,and S in sinter by X-ray fluorescence spectrometry(XRF),with deviation of -0.512%,0.377%,0.550%,-0.092%,-0.195%,and 0.007%,respectively.The F-test values of MgO and Al₂O₃ were both below the critical value,indicating that there was no significant difference in sampling accuracy between two methods.However,the F-test values of TFe,SiO₂,CaO,S contents and basicity were all above the critical value,indicating that the sampling accuracy of the intelligent rapid separation system was better than that of manual sampling.In addition,it could be concluded that there was no significant difference between the methods based on the P value of the t test between pressed powder pellet and high temperature fusion sample preparation,as well as the P value of the t test between manual and automatic pressed powder pellet.Of particular importance,the daytime fluctuations(standard deviation) of content of TFe,SiO₂,CaO,S,and alkalinity in automatic sampling decreased by 43.35%,49.11%,48.96%,48.76%,and 38.68% compared to manual sampling,respectively.By adopting the intelligent rapid analysis system,not only the material quality management process could be optimized to improve the sampling representativeness and sample preparation efficiency,but also the accuracy and reliability of data could be significantly enhanced.

The top-blown furnace smelting slag in copper smelting is a kind of slag containing high content lead and various impurities.In this paper,a method for the determination of lead content in top-blown furnace smelting slag by precipitation separation-EDTA back titration combined with inductively coupled plasma atomic emission spectrometry(ICP-AES) was established.The sample was dissolved with saturated nitric acid solution of potassium chlorate and ammonium hydrogen fluoride.15 mL of sulfuric acid (1+1) was used to precipitate lead ion and barium ion in the solution,achieving the separation from zinc,iron,calcium,copper and aluminum.5 mL of hydrogen bromide was added to volatilize arsenic and antimony in the solution.Excessive EDTA standard titration solution and 5 mL of ammonia were added to the lead-barium sulfate double salt precipitate. The double salt precipitate was dissolved by heating and boiling in the ammonia medium. Hydrochloric acid(1+1) and 30 mL of acetic acid-sodium acetate buffer solution was added,and the pH of solution was adjusted to 5.5.The solution was heated to slightly boiling to fully complex Pb-EDTA and Ba-EDTA.The separation of lead and barium could be achieved due to the stability difference of complex.5 mL of mercaptoacetic acid(1+99) and 0.1 g of ascorbic acid were added to mask bismuth and iron,respectively.Xylenol orange was added as the indicator.Lead acetate solution was used to titrate the residual EDTA standard titration solution and replace the barium ion complexed with EDTA.The dosage of lead acetate solution was appropriately excessive.Then the excessive lead acetate was titrated with EDTA standard titration solution to calculate the lead content. The lead content in the filtrate was determined by ICP-AES to correct the results.The content of lead in copper smelting top-blown furnace smelting slag was determined according to the experimental method,and the relative standard deviations(RSD,n=11) were 0.24% and 0.29%.The relative error of determination results was -0.092%-0.042% for the simulated samples,which could meet the requirements of process production analysis.

The rapid and accurate determination of vanadium in titanium carbide has important significance for the quality control.The sample was dissolved with nitric acid (1+1) and hydrofluoric acid.The residual hydrofluoric acid was neutralized by adding saturated boric acid solution.V 292.402 nm was selected as the analytical spectral line.The calibration curve was drawn by matrix matching method to eliminate the matrix effect.Consequently,the determination method of vanadium in titanium carbide by inductively coupled plasma atomic emission spectrometry(ICP-AES) was established.The mass concentration of vanadium in range of 4.00-20.00 μg/mL showed a linear relationship to the corresponding emission intensity,and the correlation coefficient of calibration curve was 0.999 9.The limit of detection was 0.000 41%(mass fraction).The content of vanadium in three titanium carbide samples was determined according to the proposed method,and relative standard deviations(RSD, n=9) of determination results was less than 2%.The recoveries were between 98% and 102%.The found results were basically consistent with those obtained by flame atomic absorption spectrometry(FAAS).

The analysis of major and minor components in iron ore usually adopts X-ray fluorescence spectrometry(XRF) with fusion sample preparation.In this study,the mixture of Li₂B₄O₇-LiBO₂ (m(Li₂B₄O₇)∶m(LiBO₂)=67∶33) was selected as the flux.0.5 mL of 400 g/L LiBr-400 g/L LiNO₃ was added as the demolding-oxidation mixed reagent.The sample fusion temperature was 1 050 ℃ and the fusion time was 15 min to prepare the glass melt.The contents of 20 components in iron ore (including total iron,silicon dioxide,manganese oxide,phosphorus,sulfur,calcium oxide,magnesium oxide,aluminum oxide,titanium oxide,potassium oxide,sodium oxide,vanadic oxide,chromium,nickel,copper,lead,arsenic,zinc,tin,and barium oxide) were determined by XRF. The certified reference materials or reference materials of tungsten-tin-bismuth ore,tin-lead-copper ore and iron ore as well as artificially synthesized calibration sample series containing copper,lead,arsenic,zinc,and tin were selected to prepare the calibration curves by the empirical coefficient method. The spectral line overlapping correction,matrix correction and internal standard correction were conducted in sequence for the calibration curves. The fitting of calibration curves was good for each component. The contents of 20 components in three iron ore samples were determined according to the experimental method,and the relative standard deviations (RSD,n=11) of determination results were not more than 7.9%. The contents of 20 components in three standard samples and two actual samples of iron ore were determined according to the experimental method,and the found results were consistent with the certified/reference values (determined by national standard methods).