X射线荧光光谱法测定原煤中氯量
XRFS Determination of Chloride in Raw Coal
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摘要: 提出了煤粉直接压片制样-X射线荧光光谱法测定原煤中氯量。将粒径小于74 μm的原煤粉末经90 ℃烘干后置于聚乙烯模具中,以4.16 MPa压力制成直径为35 mm的样片,制成的样品保存于干燥器中应尽快进行测定。选用煤标准物质制作氯的测定范围为0.01%~0.11%(质量分数)之间的标准曲线,并建立了集校准曲线、基体校正及谱线重叠校正为一体的回归方程作为方法的定量基础。求得方法的检出限为15 μg·g-1。用同一标准物质(wCl 0.057%)重复测定12次,测得其相对标准偏差为1.85%。用所提出的方法测定了2个煤标准物质,所得结果与认定值一致。Abstract: XRFS determination of chloride in raw coal with sample preparation of disc sample by direct pressing of coal powder was proposed in this paper. The raw coal was powdered to the size less than 74 μm, dried at 90 ℃ and pressed in a polyethylene mould under a pressure of 4.16 MPa to form a disc sample with its diameter of 35 mm. The sample disc should be kept in desiccator and used for determination as soon as possible. Working curve was prepared with a set of CRM′s covering the range of chloride contents from (w) 0.01% to 0.11%. A 3 in 1 regression equation functioning as working curve, matrix correction and spectral overlapping correction was established and used as basis of quantification. Detection limit of the method was found to be 15 μg·g-1. Value of RSD (n=12) of 1.85% was found by repetitive determinations of a CRM having the certified value of Cl of (w) 0.057%. The proposed method was used in analyzing 2 CRM′s, giving values of Cl contents in consistency with the certified values.