基于能量色散型X射线荧光光谱法煤中全硫含量的测定  

Determination of total sulfur content in coal by using energy-dispersive X-ray fluorescence spectrometry

作　　者：陈旭鑫 李子琪 骆丁玲 张润元 姚志湘[3] 张锴[1] CHEN Xuxin;LI Ziqi;LUO Dingling;ZHANG Runyuan;YAO Zhixiang;ZHANG Kai(Beijing Key Laboratory of Pollutant Monitoring and Control in Thermal Power Production Process,North China Electric Power University,Beijing 102206,China;Shanxi Pingshuo Gangue-fired Power Generation Co.Ltd.,Shuozhou 036800,China;College of Biological and Chemical Engi-neering,Guangxi University of Science and Technology,Liuzhou 545006,China)

机构地区：[1]华北电力大学热电生产过程污染物监测与控制北京市重点实验室,北京102206 [2]山西平朔煤矸石发电有限责任公司,山西朔州036800 [3]广西科技大学生物与化学工程学院,广西柳州545006

出　　处：《煤炭学报》2020年第8期2933-2939,共7页Journal of China Coal Society

基　　金：国家科学自然基金资助项目(U1610254);中央高校基本科研业务费资助项目(2017MS020,2018ZD03)。

摘　　要：针对艾士卡法、库仑滴定法、高温燃烧中和法和红外光谱法等现有国家标准煤中全硫含量测量方法所需化学试剂多、操作复杂和耗时较长的问题,提出了一种采用能量色散型X射线荧光光谱仪快速、无损和可靠测定煤中全硫含量的方法。该方法是一种相对分析方法,通过将未知样品与已知硫含量的样品谱图对比以进行定量分析。通过实验确定了应用该方法分析煤中硫元素的适宜制样方式、制样条件和测量条件;经过样品数据采集、谱图预处理和基体校正后,建立了相应的校准曲线。结果表明:硼酸镶边垫底压片法的制样效果良好,在12 MPa、保压40 s条件下可获得表面光滑平整、不易破裂的样片;实验所确定的硫元素测量管电压和管电流分别为13 kV和800μA;采用真空装置可以有效控制轻基体背景散射严重及硫元素特征谱线易被空气吸收的问题;通过减小样品粒径和采用经验系数法校正相结合的办法可以降低基体效应的影响;对谱图进行平滑预处理后,有效地增强了谱图分辨率,提高了测量准确性。能量色散型X射线荧光光谱法可将煤中全硫含量的测量时间压缩至60 s;所建立的校准曲线R2为0.9963,随机选取10个待测样品,除个别样品的测量结果略有差异外,其余均在库仑法的范围内;特低硫样品的再现性和重复性试验RSD分别为3.21%和1.57%,低中硫样品对应的RSD分别为0.56%和0.47%,中高硫样品的RSD分别为0.26%和0.22%。Eschka method,Coulometric Titration method,High Temperature Combustion method and Infrared Spectroscopy method have been used to determine the total sulfur content in coal by Chinese national standards,which have several shortcomings,such as more chemical reagents consumption and complicated operating procedure.Based upon Energy Dispersive X-Ray Fluorescence(EDXRF)spectrometer,a rapid,reliable and non-destructive method has been developed for determining the total sulfur content in coal.As a relative analysis method,EDXRF obtains the total sulfur content in any coal by comparing the spectra with those of known samples.The preparation procedure of samples was explored,and the measuring conditions were selected for determining the sulfur content in coal.A reasonable calibration curve was suggested after sample data collection,spectral pretreatment and matrix correction.Experimental results show that smooth and unbreakable tablets are obtained by employing powder tableting with boric acid as adhesive at 12 MPa for 40 seconds.13 kV and 800μA are reasonable voltage and current,respectively.A vacuum device adopted in this study can reduce the scattering caused by light matrix as well as the absorption of sulfur’s characteristic X fluorescence line by air.The matrix effect can be corrected by using the empirical coefficient method together with small particle size.The resolution of selected spectra is enhanced and the accuracy of measured data is improved when smooth method is used for pretreatment procedure.The method suggested in this study could shorten the measuring time to 60 seconds and R2 is 0.9963 for the correction curve.EDXRF data from 10 random samples are consistent with Coulomb Method except two of them.The relative standard deviation(RSD)of the reproducibility and repeatability tests are respectively 3.21%and 1.57%for ultra-low sulfur coal samples,whilst 0.56%and 0.47%for low-medium sulfur coal ones,0.26%and 0.22%for medium-high sulfur samples.

关 键 词：煤 硫含量 能量色散型X射线荧光光谱 粉末压片法 测量条件优化 

分 类 号：TQ531[化学工程—煤化学工程]