粉末压片-波长色散X射线荧光光谱法测定煤中氟

快速准确测定煤中氟含量,对查清我国煤中氟的分布规律以及生产控制有着重要意义。将样品粉碎至粒度小于74μm,采用硼酸镶边,在压力35t条件下保压25s,制成样片,采用经验系数法校正基体效应,建立了粉末压片制样-波长色散X射线荧光光谱法测定煤中氟含量的方法。采用不同氟含量(质量分数范围37~1496mg/kg)的煤标准样品绘制校准曲线,校准曲线线性相关系数为0.9998,方法检出限为3mg/kg。采用实验方法对3个不同氟含量的煤实际样品平行测定10次,测得结果的平均值与国家标准方法GB/T 4633—2014采用的高温燃烧水解-氟离子选择电极法基本一致,相对标准偏差(RSD,n=10)为1.9%~3.5%。将实验方法应用于煤标准样品中氟含量的测定,测得结果与认定值基本一致。

Determination of fluorine in coal by wavelength dispersive X-ray fluorescence spectrometry with pressed powder pellet

The rapid and accurate determination of fluorine content in coal has important significance for production control and investigation of distribution law of fluorine in coal in China. The samples were grinded to the particle size less than 74μm. After edging with boric acid, the sample was prepared to pressed powder pellet at pressure of 35t for 25s. The matrix effect was corrected by the empirical coefficient method. The determination method of fluorine content in coal by wavelength dispersive X-ray fluorescence spectrometry (WDXRF) with pressed powder pellet was established. The calibration curve was plotted using the certified reference materials of coal with different content of fluorine (the mass fraction was in range of 37-1496mg/kg). The linear correlation coefficient of standard curve was 0.9998. The detection limit of method was 3mg/kg. Three actual samples of coal with different content of fluorine were determined for ten times according to the experimental method. The average of found results was basically consistent with that obtained by high temperature combustion hydrolysis-fluoride ion selective electrode method in national standard method GB/T 4633-2014. The relative standard deviations (RSD, n=10) were between 1.9% and 3.5%. The proposed method was applied for the determination of fluorine content in standard samples of coal, and the found result were basically consistent with the certified values.