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-lin e process analysis of major glass constituents during a vitrification proce ss 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 th e 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 chara cteristics for calibration, good agreement between the LIPS analysis and th e established reference analysis is achieved for the concentration ratios o f SiO2, Al2O3, and CaO. In addition, LIPS is applied to the analysis of aer osols generated by homogeneous nucleation during the heating-up of the inve stigated fly ashes. A distinctive temperature dependence of the heavy metal concentration of the aerosols is observed. (C) 1998 Published by Elsevier Science B.V.