Effect of Composition and Temperature on the Viscosity and Electrical Conductivity of Ferronickel Slags

The electrical behavior of the electric smelting furnace (ESF) in ferronickel production is primarily governed by slag conductivity, which is closely linked to ionic mobility. This study examines the relationship between slag viscosity and electrical conductivity through experimental measurements and thermodynamic modeling. The viscosity and conductivity of actual ferronickel slags were measured, and synthetic slags with similar compositions were analyzed to isolate the effects of individual oxides. Results show that viscosity decreases with increasing basicity and FeO content, while solid-phase formation at lower temperatures sharply increases viscosity. Electrical conductivity rises with temperature due to reduced viscosity and enhanced ionic transport, and increases markedly up to 17 wt.% FeO owing to higher Fe ion concentrations and partial electronic conduction. Actual ferronickel slags exhibited slightly higher conductivity than synthetic ones, likely due to minor oxides such as NiO. These findings provide insight into the coupled thermophysical and electrical behavior of ferronickel slags, offering guidance for optimizing ESF efficiency and operation.