In order to improve some key properties of Al2O3-SiO2 ULC castables,this work investigated the possibility of adding andalusite to improve properties of the Al2O3-SiO2 castables using bauxite (Al2O3 86％) as the main raw material.The influence of andalusite additions up to 40％ was investigated on bulk density(BD),permanent linear change(PLC),HMOR,refractoriness under load (RUL) and Thermal shock resisitance (TSR).TSR test was conducted on the specimens prefired at 1450°C for 5h by quenching from 1000°C into water for 1,3 and 10 cycles.By means of SEM and EDAX,microstructure of the samples was observed and analyzed.Incorporation of andalusite is an effect way to achieve significantly improved hot strength and refractoriness under load.Introduction of andalusite is also beneficial to the enhancement of thermal shock resistance.Residual CMOR ratio at 40％andalusite addition is 30％ more than specimen without andalusite.In-situ formed needle-shaped and network-arranged mullite from mullitization of andalusite at high temperature can provide remarkable benefits to thermal shock resistance and hot modulus of rupture.Volume expansion of andalusite in mullitization is helpful to overcome the shrinkage problem of Al2O3-SiO2 castable lining at high temperature.
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