Thermal-shock resistance of slagging coal gasifier refractories as evaluated by the ribbon test

The thermal-shock resistances of several commercial refractories that are candidates for use in slagging coal gasifier linings were evaluated by use of the ribbon test. Refractories with high chromia content were generally found to have poor resistance relative to those with high alumina content. The thermal-shock-resistance parameter R /sub st/ was found to provide a good measure of the thermal-shock resistance of the refractories. However, for the judicious selection of a parameter for predicting the degradation of refractory materials by thermal shock, information regarding the critical flaw size and the nature of crack propagation (stable vs unstable) is necessary. The retained elastic modulus after thermal shock increased rapidly with increasing R /sub st/ up to a critical value; above this value, the increase in the modulus with further increases in R /sub st/ was relatively small. These results are discussed in terms of their implication for the selection and development of new refractories with improved thermal-shock resistance.