A study of direct reduction characteristics of bayer process red mud-coal composite pellets

Abstract

The effects of reduction temperature, particle size, pellet diameter, and the ratio on the reduction rate in red mud-coal composite pellets were studied. The iron phase change of the reduction under different temperatures was analyzed applying X-ray diffraction technique. The microstructure of reduction was investigated using scanning electron microscope. The conclusion of the study is that the reduction reaction rate increased rapidly with the increase of reduction temperature. The reduction of Fe2O3 forming Fe3O4 started under 700°C. At 1100°C, the red mud-coal composite pellets with carbon and oxygen mole ratio 1:1 obtained a good reduction result. The appearance of metal iron and the clear porous structure indicated that the reduction had developed to a high degree.