Determination Of Trace Impurity Elements In Graphite By DC Arc Spectrometry

Graphite,which is called "black gold" in industry,is an important mineral resource.It is also a necessary non-metallic material for the development of modern science and technology.The purity of graphite has an important effect on its performance.Because graphite is refractory,it is difficult to accurately detect trace impurities by ordinary chemical method or conventional instrumental analysis.The common method of graphite analysis is to burn the graphite samples,and then dissolve it by acid.Finally,use the instrument analysis methods such as ICP-MS or ICP-AES to detect.However,individual elements are easily lost during high temperature ignition.Partial oxidation is dissolved incompletely during the acid dissolution process.And there are matrix effect and background interference in the process of detection.The direct current arc excite high energy,the vast majority of the atoms or ions can be fully excited,and it has high sensitivity to most of the measured elements.The traditional DC arc spectrometer has a long process and many steps.Usually after the spectrum,the spectral line is developed and fixed.The spectrum line is fixed by the spectroradiometer.Finally,the spectral line blackening is measured by the micrometer,and the logarithmic working curve is artificially drawn to calculate the results.The whole process is complicated and time-consuming.It is also possible to introduce larger measurement errors in the process of multi-link operation.Therefore,the traditional DC arc spectrum method cannot meet the needs of modern material analysis rapidly.The modern DC arc spectrometer uses full spectrum reading technology to realize real-time background and internal calibration,without many steps,it can read the test data directly,greatly improve the detection speed,and analyze the wide range of wavelengths,and can realize the detection of more kinds of elements.In this paper,the appropriate analytical line is determined by experiments,and the experimental conditions are optimized.After the calibration of the spectral line wavelength,the samples were excited.Based on the experimental results,a method for the determination of 15 trace impurity elements(Mg,Co,Ni,V,Ti,Cr,Fe,Mn,Bi,Cu,Al,Si,Ca,Zn,Sn,and Bi)in graphite was established.Under the optimal conditions,limit of quantitation is between 0.5?g/g?8.5?g/g.The recovery range from 90%to 110%.The relative standard deviation(RSD)ranged from 4%to 20%.Compared with the results of glow discharge mass spectrometry,the results are basically the same.The method is suitable for the rapid determination of impurity elements in graphite materials...