Understanding the failure and development of innovative refractory materials for hazardous waste incineration

This work deals with the characterization and development of refractory materials for hazardous waste incinerators. The study consists of two parts: In a first step, a failure analysis on industrial waste incineration plants is carried out. Thermodynamic calculations are employed as well as a post-mortem analysis of refractory bricks from six incineration plants. Changes in chemical and mineralogical compositions and microstructure are examined. In order to get the whole picture of the degradation process, a look at the kiln conditions is also taken, regarding temperature, atmosphere, and ash properties. Based on this analysis, the requirements to a more efficient material are deduced: the tasks are to enhance the resistances against thermal shocks and, in particular, thermal fatigue as well as infiltration by the glass-like melts resulting from the incineration residue. In the second part, novel refractory materials are developed and tested at the laboratory scale and under real industrial use. These novel compositions develop within the material a well-dispersed reinforcement from raw minerals used in the refractory industry. The materials were precisely analyzed with regard to the effects of additives and impurities (alkali oxides or others) on the reaction sintering of the system and on the final properties.