Design of Red Mud-based Desiliconization and Dephosphorization Flux and its Application in Ferromanganese

Abstract

To alleviate the environmental pressure from the massive discharge of red mud (RM), and develop an economical and environment-friendly ferromanganese desiliconization and dephosphorization process, a novel RM-based desiliconization and dephosphorization flux for ferromanganese was designed and verified through thermodynamic analyses and high-temperature experiments. The results showed that the designed RM-based flux had good melting property, desiliconization capability, and dephosphorization capability after adjusting the experimental temperature and the lime:RM ratio (wt%). Especially, when the temperature was 1623 K and the lime:RM ratio (wt%) was 0.5, the best desiliconization and dephosphorization effects (desiliconization rate of 77.24% and final silicon content of 0.28%, dephosphorization rate of 31.89% and final phosphorus content of 0.31%) were achieved in the situation of high manganese content (≥63.5%). Also, the final slag could continue to remove phosphorus from low silicon ferromanganese. This work verified the feasibility of applying the RM-based flux to the ferromanganese desiliconization and dephosphorization process, which has significant environmental and economic benefits.