Low-temperature sintering of bauxite-based fracturing proppants containing CaO and MnO2 additives

Bauxite-based fracturing proppants with high strengths were prepared at sintering temperatures below 1200 °C via the addition of CaO and MnO2. The effects of CaO and MnO2 addition on the sintering behavior and the crush resistance of the bauxite-based proppants were investigated. The addition of CaO and MnO2 promoted the formation of a low-temperature liquid phase, allowing a decrease in the sintering temperature. When the MnO2 content was increased in the additive, the proppants displayed enhanced crystallinities and denser microstructures, and proppants doped with 2 wt% CaO and 2 wt% MnO2 exhibited the lowest breakage ratio, because of their higher density and greater reinforcement with mullite whiskers.