Qualitative and quantitative analysis of steatite using calibration-free laser-induced breakdown spectroscopy in conjunction with x-ray fluorescence spectroscopy and Fourier-transform infrared spectroscopy.

Abstract

The qualitative and quantitative study of raw steatite was carried out using a pulsed nanosecond Nd:YAG laser set to fundamental harmonic (1064 nm) at atmospheric pressure. To cross-validate the data, x-ray diffraction (XRD), x-ray fluorescence (XRF) spectroscopy, and Fourier-transform infrared spectroscopy (FTIR) were used. The analysis of optical emission spectra in the wavelength range 200-720 nm showed the existence of silica (Si), magnesium (Mg), and calcium (Ca). The plasma temperature and electron number density were estimated using the Boltzmann plot and Stark-broadening line profile methods, with results at 4906 K and ${1.47}\times{{10}^{17}}\;{{\rm cm}^{- 3}}$, respectively. The quantitative study was carried out using the calibration-free laser-induced breakdown spectroscopy (CF-LIBS) process, assuming local thermodynamic equilibrium and an optically thin plasma, and the following results were obtained: Si = 63.37%, Mg = 35.95%, and Ca = 0.671%. The quantitative findings obtained using the CF-LIBS approach were consistent with those obtained using XRD, XRF, and FTIR, demonstrating the applied methods' potential to be effective and complementary for the qualitative and quantitative study of multiphase raw steatite.