Mineral Phase and Physical Properties of Red Mud Calcined at Different Temperatures

[摘要] Different characterizations were carried out on red mud uncalcined and samples calcined in the range of 100°C–1400°C. In the present paper, the phase composition and structural transition of red mud heated from room temperature are indicated by XRD, TG-DTA, and SEM techniques. The mean particle diameter, density, and bond strength of these samples also have been investigated. The results indicate the decomposition of gibbsite into Al2O3and H2O between 300°C and 550°C and calcite into CaO and CO2in the interval of 600–800°C. Tricalcium aluminate and gehlenite are formed in the range of 800–900°C. Combined with the SEM images, the results of physical property testing show that the particle size and the strength each has a continuous rise during the heat treatment from 150°C to 1350°C. But the value of density will undergo a little drop before 450°C and then increases to a higher value at the temperature of 1200°C. These obtained results provide an important base for the further studies of comprehensive utilization of red mud.

[学科分类] 材料工程