Study On Corundum - Mullite Ceramic Materials And Hydrocarbon Fracturing Proppant

The oil and gas fracturing proppant, as a kind of ceramic particles products with high strength and high value-added, are widely used in underground mining of petroleum and natural gas. And it can support the rock fracture and increase the diversion rate of oil and gas. Currently, the study of oil and gas fracturing proppant preparation are widely used different grades of bauxite as its main raw material. However, the proppant companies sinter the ceramsite proppant with the high-grade bauxite to catch up with the high-quality proppant which produced by the abroad company. Ultimately, it forms “leave the rich, abandon the poor” mineral pattern of extraction-production-extraction and leads to the waste of bauxite resources seriously. In this paper, according to the problem of the ceramsite proppant in practical production, the block samples of corundum-mullite duplex phase as the experimental foundation are sintered with the high grade bauxite. Then the experiment mainly study oil and gas fracture proppant of low density with low grade bauxite. Meanwhile, both microstructure and physical property are studied on the two materials.The experiment of block samples mainly study corundum-mullite ceramic with raw materials of II bauxite, Kaolin clay and additive of pyrolusite powder. The result shows that the pyrolusite powders have a greatly effect on the microstructure, compactness and mechanical strength of corundum-mullite system. The corundum-mullite ceramics of block samples with 4wt% pyrolusite powders present well microstructure and reasonable properties, including suitable bulk densification, apparent porosity and optimal compressive strength. Furthermore, the grain gaps are intertwined by the skeleton of the rod-like mullite grains and granular corundum grains. It can conducive to higher standard formation of dense structure. And the same time, the pyrolusite powders promote the formation of glass phases at high temperature and certain amount of glass phases effectively improve the densification and compressive strength through the effect of flowing-bonding and the mechanism of liquid mass transfer. Moreover, during the formation of crystalline Mn2Al3(AlSi5O18), the Mn4+ of MnO2 replace the Al3+ of mullite phase and Mn4+ ion change to Mn2+ ion, generating the lattice distortion and solid solution strengthening, and the properties of matrix are enhanced.The experiment mainly research oil and gas fracture proppant of low density with raw materials of IV bauxite, additive of dolomite powder and pyrolusite powder. The experiment confirmed that the excellent fracturing proppant can be developed. And the granular corundum grains are diffused in the mullite grain gaps of ceramsite and it increase compactness of the matrix. Moreover, the manganese elements of pyrolusite powders decrease the minimum eutectic temperature, improving the liquid phase separation ability at high temperature. The doping elements also reduce the apparent porosity and improve the compactness. Especially, it increases the mechanical strength of ceramsite. With 3wt% pyrolusite manganese powder, the ceramsite proppant have the excellent microstructure and physical properties at sintering temperature of 1520 oC. Furthermore, this proppant can meet the requirements of the enterprise about the low density oil and gas fracture proppant. And the bulk density is 1.28g/cm3, the apparent density is 2.82g/cm3, crushing rate reaches 2.84% under 35 MPa closure pressure.