Chemical looping gasification of automotive paint sludge with red mud oxygen carrier for flammable gas production

Automotive paint sludge (APS) is a hazardous waste with many harmful substances, which should be properly disposed and managed. Red mud (RM) is a solid waste generated during the production of alumina industry, of which the components are highly similar to the components of synthetic iron-based oxygen carriers. In this study, RM was used as an oxygen carrier (OC) for chemical looping gasification(CLG) of APS to produce flammable gas (H2, CH4 and CO). The effects of different reaction conditions on the production of flammable gas were explored. Among them, the red mud oxygen carrier addition ratio plays a decisive role in the production of CH4, CO and H2. The reaction temperature determines the percentage of CH4 in the flammable gas. Meanwhile, the experimental reaction mechanism was further elaborated. The lattice oxygen in the Fe2O3 of RM-OC can migrate to form reactive oxygen (ROS). In the presence of ROS, the hydrocarbons react to produce large amounts of CH4, while CH4 is cracked to produce large amounts of H2 and CO. This study can provide theoretical basis for the comprehensive utilization of APS and RM, which is of great practical significance for protecting the ecological environment.