| As the component for necessary detecting , light elements (mainly refer to elements with atomic number from 12 to 20, as Al, Si, S, K, Ca and etc. ) can be the beneficial or harmful elements. There are high demands to the accuracy, precision and speed of light elements measuring in industrial circulation. The EDXRF analysis technique has been widely used in the industrial field, and this method has numerous advantages, such as the high speed of analysis, wide range of survey, stable and reliable results, easy to realize automation and on-line analysis. But the application of EDXRF technique on light elements'qualitative and quantitative analysis is greatly limited because the fluorescence yield and the energy of characteristic X-ray are low as the efficiency of excitation and detection, the energy of K-series'spectral line is quite close, and the significant influence of matrix effect.In this paper, the application of EDXRF technique on the light elements'analysis (mainly are S, K, Ca) is studied, based on the 863 national project of the research on analysis system for X-ray probe in seafloor situ. The optimum experimental conditions for light elements'analysis have been discussed. The detection limit of S, and the contents of S, Ca in coal sample, K, Ca in national standard sample have been measured. The main research contents and conclusion are as follow:(1) The element of S K in different samples is measured by direct measurement in vacuum with and without converter target respectively. Compared the results measured by the equipments above, the former average value of peak to background ratio about S is 2.11 and the latter is 6.42.The former average value of peak to background ratio about K is 1.53 and the latter is 7.82. The former average value of peak to background ratio about Ca is 1.45 and the latter is 7.69.(2) The detection limits of S in solid and liquid samples are measured by experimental device with converter target. The detection limit of S is 500μg/g in solid sample and 500μg/ml in liquid sample.(3) The contents of S, Ca in coal sample are measured by experimental device with converter target. The relative error between measured value and recommended value of S is from 0.2% to 7.5%. The relative error of Ca is from 0.2% to 9.3%.(4) The contents of K, Ca in GSS samples are measured by experimental device with converter target. The relative error between measured value and recommended value of K is from 0.5% to 3.7%. The relative error of Ca is from 0.1% to 28.6%.The research shows that the peak to background ratio and the accuracy of light elements are higher by experimental device with converter target than direct measurement. But the disadvantages of this method are low efficiency of excitation and slow speed of analysis, which can be overcame by choosing X-ray light tube with lager power, detector with higher sensitivity and further improvement of vacuum measurement. This study provides a basis for further study and using of EDXRF technique in light element analysis field. Meanwhile, the research results had some degree of guiding significance to broad the application sphere of energy dispersive X-ray fluorescence analyzer. |
