Das Projekt "Thermische Rueckstandsbehandlung zur Ueberfuehrung in glasartige Rest- und Wertstoffe" wird vom Umweltbundesamt gefördert und von Paul Scherrer Institut durchgeführt. How can residues from waste incinerators be recycled? Two complementary vitrification systems for waste incineration residues developed by ABB: - The Deglor-system: a glass furnace based process operating with an oxidizing atmosphere, suited for small and medium throughputs (treatment of fly ashes). - The AshArc-system based on a DC hollow electrode arc operating under reducing conditions, suited for large throughputs (bottom ashes with or without fly ash, fly ash in very large incineration plants). Aims of the SPPU-project: The aim of the joint SPPU-project was to study the composition and properties of the produced glass-like residues a function of the operation conditions in the respective furnaces. The results of these investigations should give facilitate the production of valuable and usable products from these residues. Contributions within the SPPU-project: Our main contribution was the operation of our test and pilot facilities under specified conditions. Samples of the resulting glass were analyzed in detail by EMPA Duebendorf, investigating both chemical and physical properties of the glass. The topic of valuable products from the vitrified material was followed up by EMPA St. Gallen. At PSI small scale fundamental experiments concerning the evaporation of heavy metals were performed. Some summarized results: The vitrification of different incineration residues (fly ashes with and without flue gas cleaning products, fine fractions of bottom ashes) did always result in glass products showing a good leaching resistance. A huge data base characterizing these products was gained. - A method to determine the retention time of materials in the Deglor furnace was successfully tested. Based on this method, the positive effect of a longer retention time in the furnace was demonstrated revealing a more complete evaporation of most heavy metals and of chloride and sulfur. The special case of zinc was investigated in depth by the PSI. - A 2 t/h AshArc test run under reducing conditions revealed very low residual heavy metal contents in the glass. - The physical characterization of the glass gave new input concerning the use of this materials for added value products like vitreous ceramics. This has to be further investigated. Very promising is the use of the glass as a partial substitute for cement in slowly binding concrete.