The Preparation Of Red Mud Environment-friendly Building Ceramic And Its Sintering Mechanism

The large amount of industrial solid wastes, not only seriously damage the ecological environment and do harm to human health, but also waste of resources. Therefore, sustained development and environmental protection is more and more important, the extensive utilization of industrial solid waste and recycling have the great significance. In this paper, two kinds of solid waste, sintering red mud and Bayer red mud are the raw materials, Some additives were used to improve the properties of the ceramic external tiles which was formed by semi-dry pressing.The content of red mud is more than 60%, and implementation of the resources use of the alumina industrial solid wastes.The analysis results of the characteristics, morphology and phase of sintering red mud and Bayer red mud showed that the sintering red mud in the composition of SiO₂ and Al₂O₃ are low and high content of CaO, Bayer red mud in the composition of SiO₂ is low and Al₂O₃, Fe₂O₃ content was high, the two do not meet the requirements of the chemical composition of brick, the need for additives which can be adjusted to achieve the standard of the ceramic tiles on the preparation.The water absorption, porosity, bulk density,bending strength and thermal shoch resistance were measured. The phase compositions and microstructures were tested by XRD, SEM and EPMA. The results showed that the porosity of ceramic interior tiles was about 20-35%, the water absorption was about 10-22%, bulk density was about 1.2-1.8 g/cm³, the bending strength was about 20-35MPa. The main crystalline phases of ceramic interior tiles were CaAl₂Si₂O₈, CaMg (SiO₃)₂, Fe₂O₃, SiO₂, and they interlaced as lath-shaped, so the samples has a high bending strength. The porosity of ceramic external tiles was about 10-21%, the water absorption was about 5-9%, bulk density was about 1.96-2.33g/cm³, the bending strength was about 35-39MPa. The main crystalline phases of ceramic external tiles were Na (AlSi₃O₈) , Fe₂O₃, SiO₂, and they interlaced as lath-shaped, so the samples has a bending strength. The ceramic interior tiles achieve the national standard of GB4100-83 "White pottery glazed tiles" and the ceramic external tiles achieve the national standard of GB11947-89 "Color-glazed ceramic tiles for wall and floor".On the basis of the study prepared by the red mud in ceramic interior tiles and ceramic external tiles, through the C-2, D-2 with different grain grading, the shrinkage of different firing temperatures, Wa, Pa, D and firing temperature, preliminary study on the sintering mechanism of the red mud ceramic tiles, and calculate the sintering activation energy. The results showed that the samples mainly material transport mechanisms were surface-proliferation, size-proliferation and the spread of the border.Sintering dynamic model was the two-diameter ball or the ball with a plane, the sintering activation energy showed that the finer particles, the easier it was sintered, and the lower sintering temperature.