Innovative utilization of red mud through co-roasting with coal gangue for separation of iron and aluminum minerals

Abstract

Red mud and coal gangue are industrial solid wastes discharged during alumina extraction and coal mining, respectively. As these are hazardous materials, their disposal leads to serious environmental issues. In this study, an innovative utilization of red mud through co-roasting with coal gangue for separation and recycling of iron and aluminum minerals is presented. Under optimum co-roasting conditions (550°C for 50min), an iron concentrate containing 57.25% TFe (total iron content) with the recovery of 65.22%, and an aluminum-rich product containing 27.26% Al2O3 with the recovery of 71.37% were obtained after magnetic separation. The characteristics of mixed raw material and products all indicated that the goethite and hematite phases in the mixed raw material were transformed into a magnetite phase after co-roasting, although some of the magnetite generated during co-roasting was oxidized to hematite again. This study demonstrates that co-roasting of coal gangue and red mud is a promising technology for the reduction of iron and activation of aluminum to realize resource recycling without additional materials.