Development of Silicate Glasses with Granite Waste

Granite is an igneous stone with high quartz (SiO2), whose processing generates millions of tons of fine residue annually in Brazil. Among the various definitions of glass, the most widely used is that it is a physically homogeneous substance obtained by cooling a melting inorganic mass, which solidifies without crystallizing, therefore, glasses do not have a regular atomic arrangement and, hence, are called amorphous. The objective of this work was to characterize a granite chemically and morphologically and to use it as the main raw material for producing silicate glasses of the soda-lime and borosilicate types. The characterization of the granite waste revealed that the silica (SiO2) is the major component, followed by the alumina (Al2O3), in grains of angular shapes, which favors the glass production process. The glasses produced were colored (green and amber), totally amorphous and with densities consistent with the values quoted in the literature, for each type of glass. The results show that this waste can be used as raw material in glassmaking, thus obtaining a correct destination for this waste.