Influence of tabular and white fused alumina aggregates on Young’s modulus evolution versus temperature in refractory castables

Abstract

The main alumina aggregates used in refractory applications are Tabular Alumina (TA) and White Fused Alumina (WFA). The different processing routes applied in producing TA and WFA greatly impact the final microstructure of these aggregates. The effects of the distinct microstructural properties in the aggregates in terms of grain sizes and porosity on the thermomechanical behaviour of refractory castables are not well understood. Young's modulus evolution with temperature was measured on alumina-based refractory castables containing either tabular or white fused alumina aggregates. Acoustic emissions were also measured to monitor microcracks developed in the refractory castables during cooling after being subjected to high temperatures. Fine TA and WFA aggregates were discovered to induce little to no microcracks in the refractory castables. Meanwhile, coarse WFA aggregates induced significant microcracks compared to TA aggregates in the alumina-based refractory castables. This paper has demonstrated successfully the influence of the varying grain sizes within alumina aggregates in promoting non-linear behaviour in refractory castables that potentially can be promising in thermal shock applications.