Sintering Kinetics Property of High-alumina Bauxite

The sintering kinetics of high-alumina bauxite containing A1203 of 88% （in mass fraction, referred to as Al2Oa88 ） was investigated. The corresponding sintering property was characterized by X-ray diffraction and scanning electron microsco- py, respectively. The results show that the sintering densification of Al2O388 is enhanced as the temperature increases. The sintering process of high-alumina bauxite（Al2O3 88） is based on the liquid-phase sintering mechanism. The content of liquid- phase increases along with a rearrangement of particles when the sintering temperature is 〉1 100 ℃. The dissolution-precipita- tion phenomenon is observed at 1 500℃, in which the dissolution of corundum can accelerate the mass-transfer and enhance the densification. The growth of corundum and the formation of the closed pores in the sample at 1 600 ℃ corresponds to the re- crystallization process. Based on the isothermal sintering kinetics, the measured linear shrinkage has a linear relationship in double logarithmic coordinates at 1 450, 1 500 and 1 550 ℃, respectively, and the sintering activation energy of high-alumina bauxite（ Al2 0388 ） is calculated to be 289 kJ/mol.