Analysis of glass and glass melts during the vitrification of fly and bottom ashes by laser-induced plasma spectroscopy. Part II. Process analysis

Laser-induced plasma spectroscopy (LIPS) is employed for in situ and on-line process analysis of major glass constituents during a vitrification process for fly and bottom ashes from waste incineration. The system is based on an Nd:YAG laser for plasma ignition, while the elemental emissions from the plasma are detected time-resolved by an intensified multichannel analyzer. The perpendicular, single axis, imaging optics allow a remote sensing of the composition of the hot glass melt. Taking into account the plasma characteristics for calibration, good agreement between the LIPS analysis and the established reference analysis is achieved for the concentration ratios of SiO₂, Al₂O₃, and CaO. In addition, LIPS is applied to the analysis of aerosols generated by homogeneous nucleation during the heating-up of the investigated fly ashes. A distinctive temperature dependence of the heavy metal concentration of the aerosols is observed.