波长色散X射线荧光光谱法测定煤灰成分的基体效应研究

Research on matrix effect of determination of coal ash composition using wavelength dispersion X ray fluorescence spectrometry

通过对波长色散X射线荧光光谱法(WDXRF)测定煤灰成分中主次量元素的影响因素分析,重点讨论了仪器测量条件优化和元素背景扣除及谱线重叠、基体效应等问题,指出在熔融玻璃片制样过程中应选择合适比例的X荧光专用混合试剂、合理添加量的脱模剂来消除煤灰的矿物效应和粒度效应,以有效降低熔融温度及解决硫的准确测量问题;采用经验系数法和理论α系数法结合对谱线重叠和基体效应进行校正,精密度和准确度令人满意;经标准物质和实际煤灰试样检验,分析结果准确度较高,其与标样值(化学值)对比良好,各元素氧化物含量的相对误差均小于5%;用国家一级标准物质做精密度试验,精密度均小于2%。

Through analyzing the factors which impacted the determination of major and minor components using wavelength dispersion X ray fluorescence spectrometry, this paper discussed some problems such as optimization of working conditions of apparatus, element background deduction, overlap of spectral lines, matrix effect. In the molten glass sampling process, choosing suitable ratio of special mixed reagent of X fluorescence, reasonable addition of mold discharging agent could eliminate the mineral effect and particle size effect of coal ash, decrease the fusion temperature and solve the accurate determination of sulfur; using combine of empirical coefficient method and a coefficient method to do the calibration of overlap of spectral lines and matrix effect, the precision and accuracy could be satisfied; through experiments of standard material and actual coal ash samples, it turned out that the accuracy was relatively high, and moreover, it could meet the standard sample value （chemistry value） well, relative error of oxidizing material of every elements was under 5 % ; taking national standard reference materials in first level to do the precision experiment, the precision was under 2 %.