Pilot-Scale Test of Dephosphorization in Steelmaking Using Red Mud-Based Flux

Abstract

Bayer red mud is characterized by its highly oxidizing nature and high alkalinity. It can act as an ideal flux and dephosphorizer in steelmaking. In this study, pilot-scale tests applying the Bayer red mud-based flux in steelmaking have been conducted in a 200-kg, medium-frequency induction furnace. Good slag fluidity and no rephosphorization phenomena are observed. High dephosphorization rates (~90%) and low final [P] (<0.02%) are obtained in the situation of high [C] of 2.0–3.0%, which are of great importance for the production of clean steel. The P2O5 content in the P-rich phase in the red mud-based slag can reach as high as 34.05 wt.%, far higher than the 6.73 wt.% in ordinary industrial slag. This suggests that the Al2O3, TiO2 in Bayer red mud can enhance the solid solubility of phosphorus in the P-rich phase. The data obtained are important for promoting the large-scale application of red mud in steelmaking.