Effects of Manganese Dioxide and Sintering Temperature on the Properties and Microstructure of a Secondary-Aluminum-Ash Ceramic Proppant

In this study, a ceramic proppant for hydraulic fracturing in oil and gas extraction was prepared by sintering secondary aluminum ash as the main raw material, kaolin as the auxiliary material and manganese dioxide as the additive. The effects of different proportions of manganese dioxide on the physical phase composition and microscopic morphology of the proppant were analyzed with X-ray diffraction and scanning electron microscopy at sintering temperatures of 1170–1270 °C. The results showed that at 1270 °C, the crushing rate of the sample with a 2 w/% manganese dioxide addition was 8.41 %, and the main crystalline phase consisted of corundum and a small amount of mullite. With the addition of manganese dioxide, the ternary eutectic system of MnO2-Al2O3-SiO2 increases, which lowers the corundum generation temperature, accelerates its growth rate and improves the crushing resistance. This study solves the problem of weak crushing resistance of the ceramic-granule proppant prepared from secondary aluminum ash, and achieves an efficient use of waste, which is of great significance for environmental protection and resource recycling.