Effect of MgAl_2O_4 Micropowcfer on Physical Properties of Corundum Castables

摘要

Corundum-based castables were prepared by using tabular corundum, micropowder of MgAl_2O_4 spinel and calcium aluminate cement as raw materials, as well as the addition of dispersion agent and retarder. The effect of spinel contents on physical properties of the castables has been investigated. The results showed that as the samples were heat treated at 1100° and 1600°C, the linear shrinkage rate decreased and the strength of rupture and crushing at room temperature increased with spinel content increasing, while apparent porosity and bulk density remained the same. The hot modulus of rupture increased from 12 to 20 MPa with 67% growth rate, and crushing strength after thermal shock increased from 80 to 105MPa with 32% growth rate. The increasing of high-temperature properties was attributed to the staggered distribution between MgAI_2O_4 spinel and CA_6.