Analysis of glass and glass melts during the vitrification process of fly and bottom ashes by laser-induced plasma spectroscopy. Part I: Normalization and plasma diagnostics

For laser-induced plasma spectroscopy (LIPS) analysis of the maim component s (Si, Al, and Ca) in glasses utilized for vitrification of ashes from wast e incineration, a normalization procedure for line ratios is presented. Eve n in homogeneous glass samples, considerable pulse-to-pulse variations of t he plasma electronic excitation temperature and electron density were obser ved because of changes in the material-laser interaction. A normalization p rocedure is outlined using Saha-Boltzmann equilibrium relationships to incl ude the electronic excitation temperature and density in the calibration mo del. As a result of the normalization, the variation of the line ratios is reduced and linear calibrations for LIPS intensity ratios versus concentrat ion ratios are achieved. For samples with high aluminum concentrations, the analysis was hampered by self-reversal effects. (C) 1998 Published by Else vier Science B.V.