基于多粒子LIBS谱线的自吸收校正方法研究

为克服自吸收效应对炉渣样品定量分析结果的影响，基于快速模拟退火算法的优化过程，结合等离子体发射光谱的基本理论，发展了一种基于多种粒子发射谱线的自吸收校正算法，给出了该算法的流程图。利用前述自吸收校正算法分别对精炼渣和高炉渣样品的激光诱导等离子体发射光谱强度进行校正，并结合无标分析法，对比分析了自吸收校正算法对样品成分定量分析结果的影响。对比自吸收校正前后的Boltzmann图可以看出，经自吸收校正后，等离子体中各粒子的温度均稳定在11600K左右，结果明显趋于一致。利用自吸收校正后同种粒子的等离子体光谱构建的Boltzmann图中，除一组数据外，其他数据在Boltzmann图中的截距基本一致。利用经自吸收校正后的谱线，对两种炉渣样品成分进行定量分析的结果表明：对于精炼渣，MgO的定量分析结果精度不高，若不分析MgO的含量，则CaO，Al₂O₃和SiO₂等成分定量分析结果的相对误差会明显降低;对于MgO含量为8.49%的高炉渣样品，Al₂O₃定量分析结果的精度最高，相对误差为2.38%，MgO最低，相对误差为28.27%，但基本可以反映出该成分在样品中的含量。

Research on Algorithm for Self-Absorption Correction Based on Multi-Particles LIBS Spectra

In order to overcome the influence of self-absorption on quantitative analysis, the optimizing process of very fast simulated annealing algorithm was studied. According to basic theory of plasma emission spectrum, a new algorithm for self-absorption correction based on multi-particles spectra was proposed, and the algorithm flowchart was given. With the self-absorption correction algorithm mentioned above, the spectra of refining slag and blast furnace slag were corrected. The effect of self-absorption correction on the quantitative analysis results was analyzed based on calibration free method. Comparison of Boltzmann plots before and after self-absorption correction indicated that the plasma temperatures calculated with spectra after self-absorption correction tended to be uniform, and remained stable around 11 600 K. The Boltzmann plots constructed with plasma spectra of the same particle after self-absorption correction indicated that the intercepts were almost the same except for one group data. With calibration free method and spectra after self-absorption correction, the contents of components in slag were analyzed. For refining slag, quantitative analysis precision of MgO was low. If ignoring the existence of MgO, the relative errors of quantitative analysis results of CaO, Al₂O₃ and SiO₂ were much smaller. For blast furnace slag in which the content of MgO was 8.49%, the relative error of quantitative analysis result of Al₂O₃ was 2.38%, which was the smallest. And the relative error of quantitative analysis result of MgO was 28.27%, which was still the biggest.