Augite-anorthite glass-ceramics from residues of basalt quarry and ceramic wastes

Dark brown glasses were prepared from residues of basalt quarries and wastes of ceramic factories. Addition of CaF2, Cr2O3 and their mixture CaF2-Cr2O3 were used as nucleation catalysts. Generally, structures with augite and anorthite as major phases and small amount of magnetite and olivine phases were developed through the crystallization process. In the samples heat treated at 900 degrees C the dominant phase is augite, whereas the content of anorthite usually overcomes the augite at higher temperature (1100 degrees C). Fine to medium homogenous microstructures were detected in the prepared glass-ceramic samples. The coefficient of thermal expansion and microhardness measurements of the glass-ceramic samples were from 6.16x10(-6) to 8.96x10(-6) degrees C-1 (in the 20-500 degrees C) and 5.58 to 7.16GP, respectively.