Fabrication and Characterization of Diopside-based Glass-Ceramics from Granite Wastes

Diopside-based glass-ceramics were obtained by mixing 58.2∼61.5 wt% granite wastes with other components. Based on the CaO-MgO-Al2O3-SiO2 (CMAS) system, the effects of CaO/MgO ratio and heat treatment on crystallization, microstructure and properties of the glass-ceramics were investigated. Results showed that the crystallization peak temperature decreased with the replacement of CaO by MgO. Bulk crystallization of CMAS glass-ceramics by one stage heat treatment was achieved by optimizing the CaO/MgO ratio. The most suitable mass ratio of CaO to MgO in this work was 1.25, because of higher crystallinity of diopside and its desirable fine grained microstructure. The mechanical properties of glass-ceramics obtained by one stage heat treatment were a little worse than that of two stage heat treatment. Considering the simpler manufacturing process and lower energy consumption, one stage heat treatment was a more promising and economical method for rolling process.