Study on quantitative analysis of slag based on spectral normalization of laser-induced plasma image

To reduce the influence of laser-induced breakdown spectroscopy (LIBS) experimental parameter fluctuations to quantitative analysis of slag components, a normalization method using integral intensity of plasma image was proposed and a series of experiments with slag samples were performed. Mg II 279.55 nm, Ca II 396.85 and Ca I 422.67 nm were selected as analytical lines, and analytical curves of reference mass fractions versus spectral line intensities were established. With the increment of set threshold for edge extraction of plasma image, the determination coefficients and relative standard deviations of analytical curves were improved gradually and reached the optimum values when the threshold was equal to 10 000. Comparing with the results without normalization and normalized by whole spectrum area, the relativity between spectral line intensity and mass fraction can be enhanced efficiently after normalized by integral intensity of plasma image. The verification experiments with Ti alloy samples further confirmed the conclusions mentioned above.