Kinetic Analysis of the Refining Process for High Mn–High Al Steel

To elucidate the mechanisms of the refining process for high Mn–high Al steel, kinetic calculations are performed based on effective equilibrium reaction zone model. Combined with laboratory‐scale thermal experiments, a comprehensive discussion is conducted regarding 1) mass transport of elements, 2) potential reoxidation of the steel melt, and 3) kinetics of Mg evaporation. In the initial 0–5 min, the mass transfer coefficients in the slag and the steel are 1.62 × 10 −5 and 2.43 × 10 −4 m s −1 , respectively. From 5 to 60 min, these coefficients decrease to 1.08 × 10 −5 and 1.62 × 10 −4 m s −1 . After the slag addition, the evaporation loss of Mn is negligible, while that of Mg is quite significant. The escape of Mg vapor leads to continuous reduction of MgO in molten slag, which accelerate the erosion of MgO refractory and decrease the yield of Al. The Mg evaporation process is determined by the mass transport in the slag phase. As the reaction progressed, the apparent viscosity of the slag increases with the accumulation of solids, which in turn inhibit the volatilization of Mg.