Freeze linings in the Al2O3–CaO–SiO2 system

Abstract

Degradation of refractory lining in pyrometallurgical furnaces can be prevented by cooling down the furnace shell and solidifying a protective layer of slag, called freeze lining, on top of the refractory. Freeze lining behaviour in the high and low SiO region of the AlO–CaO–SiO system was investigated using the previously established cooled probe technique. Temperatures in the freeze lining were determined through a combination of direct measurements and linking measured compositions with equilibrium temperatures. Bath–freeze lining interface temperatures ranging from the solidus to the liquidus temperature were observed depending on composition. As opposed to freeze linings in other systems, considerable porosity was found to be present. A freeze lining containing dicalcium silicate was found to shatter on quenching, suggesting this type of freeze lining may not be advisable to use in industrial applications.