Research on Magnesium Reduction Slag for Dephosphorization of Low-Silicon Hot Metal in Steelmaking Process

Abstract

The melting temperature and viscosity of magnesium reduction slag were calculated by using Factsage thermodynamic software. The composition range of the magnesium-slag-based dephosphorizing agent was analyzed by drawing a multiphase diagram of the slag system. The Box–Behnken high-temperature dephosphorization experiment was designed to study the effect of different composition of magnesium-slag-based dephosphorizers on the dephosphorization rate of the steelmaking process. The results show that magnesium slag can be used as a slag-forming agent for smelting low-silicon hot metal to promote slagging, and the effect of each factor on the phosphorus removal rate is ranked, and the results are ω(Fe2O3) > basicity > ω(Al2O3): ω(Al2O3) has no significant effect on the rate of phosphorus removal. When the basicity was 2.8, ω(Fe2O3) was 25.94%, ω(Al2O3) was 6.73%, and ω(MgO) was 6%, the dephosphorization rate reached a maximum of 96.7%, and the error was experimentally verified to be 2.6% from the predicted value, indicating that the model can be optimized to determine the best magnesium-slag-based dephosphorization agent and has a good prediction of dephosphorization effect.

Keywords

• magnesium reduction slag
• steelmaking
• low-silicon hot metal
• dephosphorization agent
• response surface