Quantitative Analysis of Elements in Scrap Steel by Improved Peak Fitting Spectral Standardization Method

In order to solve the problem of higher volatility of laser induced breakdown spectroscopy (LIBS) in quantitative measurement due to equipment and environmental factors, a spectral standardization method based on improved Voigt fuction fitting was proposed. First, the LIBS spectrum data of the scrap steel sample was collected with a high-precision laser; then the relationship among the factors including the standard spectrum intensity and the actual spectrum line intensity, full width at half maximum, etc., was obtained through standard plasma conditions (standard plasma temperature, electron number density, total density of elements to be tested). The approximate Voigt function was used for fitting the relevant peaks, obtaining the important parameters of the standardization, and the process of establishing the standardization model of the samples was completed. As shown by the results, this standardized method was used for quantitatively predicting the contents of elements (Cu, Ni, Si, Cr, Mn) in scrap steel, and the average values of correlation coefficient of determination (R²), predicted root mean square error (RMSEP), and the average relative error (ARE) were 0.981 4, 0.063, and 6.3%, respectively. This method effectively reduced the impact of fluctuations and enhanced the accuracy of analysis, which could quickly detect the elements in scrap steel in industry.