Study on Sulfur Transfer Behavior during Refining of Rejected Electrolytic Manganese Metal

Abstract

A slag treatment method was proposed to recycle rejected electrolytic manganese metal. To improve the sulfur removal ratio, computational fluid dynamics and experimental studies of the sulfur transfer behavior during the refining process were carried out. Experiments of slag-metal reaction for desulfurization were carried out using an electric resistance furnace at temperatures ranging from 1773 K to 1923 K. A transient three-dimensional coupled numerical model was established to represent the three-phase flow, heat and mass transfer in the experiment. The desulfurization rate was described by a metallurgical kinetics module, which was related to the slag composition, the interfacial tension coefficient, the flow and the temperature of the melt. The predicted sulfur content agreed reasonably well with the measured data. The temperature of the fluids at the outer side of the crucible was higher than that at the center, resulting in a larger sulfur partition ratio and a more vigorous flow. The sulfur transfer rate was higher at the outer edge of the molten slag–molten manganese interface. The sulfur removal ratio increased from 51.4% to 85.1% with a change in heating temperature from 1773 K to 1873 K, and slightly dropped to 83.3% when the heating temperature increased to 1923 K. The heating temperature of 1873 K is the optimal choice for recycling in the present work.