Slag Reduction and Viscosities Interaction in Ferromanganese Process

Abstract

Slag reduction and viscosity are closely related in the practical operation of a submerged arc furnace for ferromanganese (FeMn) production. The viscosity of slag is dependent on temperature and its composition, and influences different aspects in the FeMn production process, namely reduction kinetics and final MnO content of slag, slag–metal separation, slag flow in the furnace, and ultimately furnace tapping. As such, it is paramount to establish knowledge about the relationship between slag reduction and viscosities. The kinetics of MnO reduction in FeMn slags based on Nchwaning, Comilog, and UMK ores were investigated between 1400 and 1550 ∘C . The extent of reduction was determined by thermogravimetry, slag morphology, and change during reduction was examined by electron probe micro-analyzer and slag viscosities calculated using FACTSage 8.1 thermochemical software. Results show that viscosity of primary FeMn slag is higher and decreases with increasing dissolution of solid phase into liquid as temperature increases.