本文选用碳含量差别较大的14个煤样,进行激光诱导击穿光谱实验。引入多元校正的分析方法,实现煤中碳元素的LIBS定量分析。根据煤质的结构特点,得到影响碳元素激发的主要影响因素分别为与碳骨架相连的H、O、N,以及主要的矿物质元素Si、Al、Ca、Fe。选择这些元素常见的特征谱线强度值,作为多元回归分析的输入量,然后根据回归方程变量的筛选原则,确定了用于回归关联式建立的变量,进而得到回归关联式,并通过方差分析和回归统计验证了方程的可行性。结果表明,采用多元校正的分析方法,得到多元回归分析模型预测值与实验室元素分析仪得到的参考值之间的相对误差在5%之内,说明采用多变量校正的分析方法对碳元素进行定量分析,能得到较高的分析精度。
A set of 14 coal samples with different carbon content were used for laser-induced breakdown spectroscopy (LIBS) experiment. In order to quantitatively analyze the carbon content in coal, the multivariate calibration method was used. According to the structural characteristics of coal, the elements H, O, N which are main connected with the carbon skeleton and the major mineral elements Si, A1, Ca, Fe were the main factors affecting on the excitation of carbon. The line intensity of these elements was chosen as independent variables. According to the critical of variable selection, the variables for the regression correlation were determined and the equation was established. The equation was proved to be feasible by using variance and regression analysis. The results calculated from the multivariate calibration were in good agreement with those from laboratory elemental analyzers, while the relative error was within 5% carbon in coal with multivariate calibration can get It demonstrated that quantitative analysis of high precision.