The Effect of Sintering Temperature on Phase Evolution and Sintering Mechanism of Ceramic Proppants with CaCO₃ Addition

Low-cost ceramic proppants were successfully prepared from natural bauxite and solid waste coal gangue via CaCO₃ additive. 40 wt% of bauxite in raw materials was replaced by coal gangue, which significantly reduced the manufacturing costs. The apparent density, bulk density, acid solubility and breakage ratio of the proppant sintered at different temperatures were systematically investigated. The phase composition and morphological structure were determined using X-ray diffraction (XRD) and scanning electron microscopy (SEM). The results show that the amount of liquid phase affected the solid phase reaction velocity by changing sintering mechanism. When the sintering temperature was 1350 °C, the optimum size of the mullite crystal particles and the optimum amount of the liquid phase were observed and the samples exhibited the best performance.

Keywords:
Ceramic proppants; crystal growth; sintering temperature; mullite; mechanism