Difference in pore evolution of calcium aluminate cement-bonded alumina bubble-based castables with micro-sized MgCO3 and Al(OH)(3)

摘要

Micro-sized MgCO3 and Al(OH)(3) were used as inorganic porogenic agents for increasing porosity in alumina bubble lightweight castables. The influence of 0-4 wt% micro-sized MgCO3 and 0-8 wt% micro-sized Al(OH)(3) additions on the porosity, thermal conductivity and strength of castables after firing was investigated. The results indicate that porosities in castables containing micro-sized Al(OH)(3) or MgCO3 after heat-treatment were raised by augmenting micro-sized Al(OH)(3) or MgCO3 contents. It is found that MgCO3 favors the porosity formation more than Al(OH)(3) in castables because of the different formation behavior of calcium aluminates and MgAl2O4 spinel. The dependence of properties of castables on the micro-sized Al(OH) or MgCO3 addition was discussed with respect to the pore evolution.