Processing of molten solid residues

Abstract

An alternative way of recovery, recycling and re-integration of solid wastes on a laboratory scale is demonstrated. The analysed synthetic slags belong to the System SiO2-Al2O3-CaO-MgO-Fe2O3-K2O-Na2O. Α polynomial model has been developed by means of a computing program in order to calculate some important technological features directly from a variable oxide concentration and to determine a processable composition. Furthermore, a concept of maximum application of the residues is suggested for slags from waste incineration and other industrial processes with relative low volatile components. Rolling has been chosen as the most suitable forming technique, because recycling melts show a short forming interval and an aggressive behaviour towards refractory materials. It is possible to form plates or tiles which afterwards can additionally be shaped e.g. to create profiles or breaking points. Because of their affmity to crystallization the glassy end-products can be devitrified at the surface (into semicrystalline products, i.e. glass-ceramics) to receive a better resistance. The present results show the possibility of using well known forming and treating processes to make high value products from low-value by-products, with a considerable economical advantage.