Microstructure and fracture mechanism of low density ceramic proppants

Solid wastes coal gangue and magnesium slag were added to prepare low density ceramic proppants at sintering temperatures below 1300 °C. The addition of solid wastes greatly decreases sintering temperature and preparation cost. The morphology and phase composition of the proppants were examined by scanning electron microscopy (SEM) and X-ray diffraction (XRD). The results show that the main crystal phases of the proppants are granular corundum and rod-like mullite, and the proppants have better sphericity. Furthermore, the most suitable sintering temperature is 1250 °C, and the resulting ceramics exhibit transgranular fracture. This means that rod-like mullite crystals provide strong toughening and reinforcing effects.