Thermal shock behaviour of high alumina aggregates derived from sillimanite beach sand with and without Fe2O3 doping

Three types of high alumina aggregates namely sillimanite, mullite and alumina rich aggregates were developed from sillimanite beach sand and calcined Al2O3 by reaction sintering. The various phases present in the sintered compacts were identified by XRD and IR study. Thermal shock behaviour of the aggregates with and without Fe2O3 doping were measured by the room temperature flexural strength retention on ambient air quenching from 1000 C against the number of cycles. All Fe2O3 containing samples showed a strength enhancement on quenching by means of tempering. Attempts have been made to correlate this parameter with the microstructure and phase assembly of the product. 19 refs.