Thermally crystallized glasses based on industrial wastes

Experimental results for the synthesis of architectural glass-ceramic materials, in the thermally crystallized CaO(MgO,ZnO)-Al2O3(B2O3)-Na2O(K2O)SiO2 glasses has been defined. The using of different types of industrial Romanian wastes-colored or white glass container and glassware, electric power plant fly ashes, residual blast furnace slag and the like, also the method of obtaining glass-ceramic products are disclosed. The process for converting residual raw materials to a new microstructure comprises the conventional glass melting methods, subsequent sintering and surface-induced crystallization of a precursor frit in large size limits. The chemical compositions free from nucleating agent were established. The surface crystallization of the separate grains induces an excellent appearance of this products with beta -wollastonite and anorthite crystals as the major crystalline phases developed in structure. Because of the presence of coloring oxides from waste materials, the obtained frits permit the preparation of high-quality colored ornamental products. For the selected samples, the relationship between chemical composition of wastes, melting and crystallization behavior were investigated as well as the effect of crystallization on certain chemical and mechanical properties of obtained crystalline glass materials. XRD and optical microscopy techniques were used in this purpose.