Metodo per la realizzazione di prodotti ceramici comprendenti materiale riciclato

The usage of glasses as additives for traditional ceramics has been extensively investigated. Although interesting (for the properties of the final products), this solution does not generally allow a large absorption of glass. The present application illustrates a novel approach, consisting in replacing the feldspar flux, in the formulation of porcelain stoneware tiles, completely with finely powdered glass, with a specially designed chemical composition, derived from the melting of several inorganic waste (mainly consisting of mining residues and glass cullet). For an optimized glass/clay ratio, the ceramic materials, obtained sintered in a temperature range of 950-1050°C, exhibited a complex of mechanical properties similar to that of conventional porcelain stoneware, which must be sintered at much higher temperatures. This is mainly attributable to interactions between the glass and clay residues upon heat treatment, favoring the precipitation of several reinforcing crystal phases. The presented process brings several advantages in the field of ceramic manufacturing. A large quantity of waste is potentially absorbed in the form of raw materials, so that ceramic production leads to important environmental benefits. Secondly, the generally high costs of inorganic waste vitrification (due to the high energy consumption during melting) could be reduced or compensated, by the usage of powdered glass (whose production is much simpler than that of massive glass objects and could exploit the low cost plants, currently available in large ceramic industries, dedicated to the preparation of glazes) and the remarkable savings in the raw materials (feldspar fluxes are generally expensive) and in the energy consumption in the sintering process of the new ceramics.