Abstract

Silicon Carbide based Refractory materials are commonly used in Blast Furnace of iron making application. They compose part of Lower Stack, lower and upper bosh regions in Blast Furnace. Refractories are subjected to severe thermal gradients, Alkali attack, high oxidation atmospheres, high abrasion and Carbon monoxide attack. These refractories also play important role in converting thermal energy to generate electrical energy as by product as well in formation of protecting layer due to high thermal conductivity.

SiAlON bonded SiC materials are advanced over Nitride bonded SiC (NBSiC). In this paper, advantages of SiAlON bonded SiC over NBSiC are discussed. Microstructures and thermo mechanical properties of NBSiC and SiAlON bonded are investigated in order to understand their behaviour in Blast Furnace application. The resulting microstructure deals with SiC grains bonded with Silicon Nitride and SiAlON phases with a high degree of complexity. Microstructural properties of NBSiC and SiAlON bonded SiC refractory are studied  by X-ray diffraction for phase identification and by Scanning Electron Microscope for phase morphology. As these material are used in severe atmospheres of carbon monoxide and alkali, effect of CO-Disintegration and Alkali attack resistance properties also investigated along with long term oxidation.

Overall comparison of microstructural and thermo mechanical properties of NBSiC and SiAlON bonded SiC are studied with illustrations of uses in blast furnace application.