Analysis of the Basic Properties and Dephosphorization Mechanism of Red Mud-Based Fluxing Agents in Converter Steelmaking

Studying the slag and phosphorus removal efficiency of red mud pellets on an industrial scale is crucial for reducing costs and increasing efficiency in the steelmaking process and optimizing the use of red mud as a high-value resource. This study explored the effects of the binder dosage, pellet moisture, drying temperature, red mud particle size, and other parameters on the compressive strength of red mud pellets in the pellet preparation process. The formation mechanism of red mud pellets was also explored. The compressive strength of red mud pellets is 572.83 N/P under optimal parameter conditions, which meets the production requirements. New composite binders were adsorbed onto the surface of red mud through hydrophilic groups, such as hydroxyl groups, thereby strengthening the interaction between particles. The basic physical properties of a CaO-FeO-SiO₂-Al₂O₃-Na₂O red mud-based slag system were determined using FactSage calculations and slag system measurement experiments. Al₂O₃, Na₂O, and FeO in red mud had a melting effect, whereas low temperature, high alkalinity, and Na₂O improved the fluidity of the flux system and promoted steel dephosphorization. Industrial application tests showed that red mud-based slag agents have industrial application prospects. Industrial application experiments showed that the red mud-based slag system can reduce the temperature of molten steel by 46.72 °C and increase the phosphorus removal rate by 12.5%. The use of red mud flux can save 3.52% per ton of steel in the steelmaking process compared to the original process. This study provides theoretical guidance and technical support for the production and practical application of red mud-based slag agents.