Spinel Containing High Alumina Castable for Steel Ladles: Use of Dispersing Alumina Replacing Silica Fume

Abstract

Spinel containing alumina castable is important for steel ladle lining due to better slag corrosion and penetration resistances. It helps to produce cleaner steel with improved performance and longer service life for steel ladle. In the present study, alumina spinel castable containing preformed spinel was developed using dispersing alumina, replacing silica fume completely. The effect was studied on the development of spinel containing alumina castable with two different amounts of spinel and two different particle size distributions. The castable compositions were processed conventionally, heat treated at 110, 1000, and 1550°C, and characterized for various refractory-related properties such as bulk density, cold crushing strength, hot strength, thermal shock resistance, and slag corrosion resistance. Phase analysis and microstructural behavior of the castable samples sintered at 1550°C were also studied. The optimized composition was further compared against fume silica-based conventional composition using the same raw materials and processed under similar conditions. The results showed significantly improved properties for the dispersing alumina containing comparison compared to the fume silica batch due to the formation of calcium hexa aluminate (CA6) phase and the absence of any low melting phase. Detailed investigation showed well compact microstructure with platy / needle-like CA6 crystals formed in the dispersing alumina-containing sample, whereas a glassy phase in the fume silica-containing composition.