Feasibility of simultaneous multi-element analysis of quartz sand with impurities by calibration-free laser-induced breakdown spectroscopy and its potential for guiding glass manufacturing

As the main raw material in glass manufacturing, quartz sand and its elementary contents play an important role in glass quality. As raw quartz sand contains a variety of impurities such as metal oxides, which makes traditional chemical analysis methods for determining the chemical composition of quartz sand challenging and cumbersome, and the results are often influenced by the skill level of the analysts and various reagent factors. In this study, we investigate the feasibility of employing calibration-free laser-induced breakdown spectroscopy (CF-LIBS) for simultaneous multi-element analysis of the complex quartz sand. A Nd:YAG laser with a wavelength of 1064 nm and pulse width of 6 ns was used to irradiate the quartz sand sample, which resulted in generation of a plasma plume. The plasma spectra were recorded and analyzed to determine the type of element by finding the atomic (ion) characteristic spectral lines. The corresponding Boltzmann plane plot was drawn according to the relevant parameters of the characteristic spectral lines, and the plasma temperature was calculated. By measuring the Stark broadening of the characteristic spectral lines, the electron density of the plasma was evaluated, and the prerequisite of the local thermodynamic equilibrium of the plasma was verified. The results show that the CF-LIBS method can synchronously and quickly realize the multi-element identification of the sample without the need of a standard reference material. The use of CF-LIBS to measure the quartz sand raw material prior to entering the glass manufacturing process provides a guiding principle for formulating preliminary treatment plans based on the qualitative and quantitative measurement results.