Bulk nucleated fine grained mono-mineral glass-ceramics from low-silica fly ash

Cr2O3-nucleated fine grained mono-mineral glass-ceramics of augite were produced from low-silica fly ash and additives of SiO2, Al2O3 and MgCO3, via two steps of heat treatment for nucleation and crystal growth. The starting glass approached the composition of CaMg0.75Al0.4Fe0.1Si1.75O6, derived from CaMg0.75Al0.5Si1.75O6, which belongs to diopside – Ca-Tschermak solid solutions. The influence of Cr2O3 (up to 0.75 wt.%) on the development of crystalline phases, the properties and the microstructure of the resultant glass-ceramics crystallized at different temperatures was investigated.