Reduction Behavior and Direct Reduction Kinetics of Red Mud-Biomass Composite Pellets

Abstract: A large amount of red mud is discharged in the aluminum oxide production process, which contains a variety of valuable metals and is considered as a secondary resource. In order to reveal the mechanism of red mud carbon thermal reduction process, isothermal reduction experiments on carbon-bearing pellets of red mud were investigated with biomass carbon as a reducing agent. In this study, the reduction temperatures were conducted using a microwave stove in the temperature range from 850 to 1250 ℃, and the C/O molar ratio was 1.1. The results show that the reduction process of red mud is governed by a carbon gasification reaction, and the apparent activation energy is 88.44 kJ/mol. The optimum reduction process conditions were established to be 1150 ℃ for 13 min. Graphical Abstract: [Figure not available: see fulltext.]