A Kinetic Model to Simulate the Reaction Between Slag and Matte for the Production of Ferromanganese Alloy from Steelmaking Slag

Manganese is used as a key alloying element in various advanced steel products to improve their mechanical properties. The authors have proposed an innovative process to recycle Mn from steelmaking slag. In this process, steelmaking slag is first sulfurized to separate P and Mn, and then the matte is oxidized to increase the Mn/Fe ratio. The equilibrium distribution ratio of Mn, Fe, and Ca between slag and matte has been already clarified. To design an industrial process, a kinetic model to simulate the various reactions that occur simultaneously between the matte and slag was developed by applying the coupled reaction model. In this kinetic model, the mass transfer was calculated by the double film theory by assuming the equilibrium at the interface. The calculation results agreed well with the concentration changes of each element in the matte and slag obtained by experiments. The optimum conditions for the treatment were discussed using this model, and multi-step sulfurization and oxidation processes were proposed.