Papers by Author: Yan Qing Cai

Abstract: The MgO-Al₂O₃-Fe₂O₃ composite was prepared at 1600°C for 3h with magnesia powder and alumina powder as raw materials and with ferric oxide powder as additive. The effect of the molar ratio of MgO/Al₂O₃ on the sintering and thermal shock resistance of the composite materials was studied. The results showed that increasing the molar ratio of MgO/Al₂O₃ could improve the densification of the Al₂O₃-Fe₂O₃ composites, with the molar ratio of MgO/Al₂O₃ increased from 3 to 5, densification of the composites didn't increased but decreased. The optimum molar ratio of MgO/Al₂O₃ of the Al₂O₃-Fe₂O₃ composite is equal to 3, the sample MA-3 exhibits better sintering densification and thermal shock resistance. Its primary crystal phases are spinel and periclase, and less amount of sosoloid 20MgO·19Al₂O₃·Fe₂O_3. So, the MgO-Al₂O₃-Fe₂O₃ composite is acceptable for application in cement rotary kiln linings and high temperature gas filter support.

Abstract: The composites in the MgO-Al₂O₃-Fe₂O₃ system were prepared using high pure magnesia and alumina as raw materials and ferric oxide powder as additive. The effect of sintering temperatures on the sintering performance and thermal shock resistance of the composites was studied. The results showed that both the apparent porosity and linear change ratio of the samples decreased with the increase of sintering temperatures, and their bulk density and bending strength increased accordingly. The sample sintered at 1550°C exhibits excellent thermal shock resistance. The XRD and SEM results indicated that the crystal phase of the samples remained the same, but their microstructure became denser as the sintering temperatures increased from 1500°C to 1600°C. As a result, the composites could be sintered at about 1550°C, which has a potential application in cement rotary kiln linings.