Numerical Study of Evaporation Behavior of Molten Manganese Metal During Electroslag Recycling Process

Electroslag remelting (ESR) technology has been adopted to recycle the rejected electrolytic manganese metal scrap. In this study, a transient 3D coupled numerical model accounting for the electromagnetism, multiphase flow, heat transfer, and solidification was elaborated and used to simulate the evaporation behavior of the molten manganese metal (MM) during the ESR process. The volume of fluid approach was employed to capture the interfaces between the gaseous manganese, molten slag, and molten MM. The evaporation rate of the molten MM was defined by applying the Lee model, while the enthalpy-porosity formulation described the solidification. An industrial experiment via a commercial-scale ESR furnace was conducted for the model validation. The research findings indicate that the molten MM’s evaporation occurs during the droplet falling and in the metal pool. Then, gaseous manganese bubbles ascend to the molten slag-free surface, thus promoting the melt movement, especially the slag-metal pool interface fluctuation. The evaporation rate of the molten MM is promoted by the increased applied current and the reduced ambient gauge pressure. The recycling ratio drops from 81.75 to 71.79 pct with the applied current increase from 3000 to 4000 A and drops from 78.19 to 73.71 pct with the ambient gauge pressure reduction from 0 to − 1000 Pa.