Analysis of Al-Zn alloy refining in an industrial induction skull melter with two crucible types

This paper discusses a numerical and experimental study of the refining process in a vacuum induction furnace. Experiments were conducted using an industry vacuum induction furnace for an Al-Zn alloy under various operating conditions. The measured value was the mass fraction of zinc inside the melt after refining. Two types of cold crucibles, industrial and conceptual, were examined. In the new crucible concept, the bottom wall design resembled a small inverted crucible and was separated from the side walls. The authors developed an in-house code to simulate coupling between electromagnetic and fluid dynamic fields. The evaporation of zinc from the Al-Zn alloy was calculated using the Hertz-Knudsen formulation and implemented to the partial differential equation of the mass conservation as a source term. Such a simplified mathematical model was verified according to the velocity, temperature and mass fraction fields. Relative errors between experimental and numerical results for lower input powers did not exceed 10% and were within the experimental standard deviation. A comparison of crucibles demonstrated the new crucible design significantly shortened the refining time and the coil input power. Finally, these results provided information regarding advantageous refining operating conditions.