Based on the pore size design of microporous aggregate by numerical simulation applying porous media model,α-Al2O3 micropowder,industrial Al2O3 fine powder,α-Al2O3 micropowder + Ca CO3 fine powder were used as starting materials,respectively,to prepare three microporous corundum aggregates specimens,named as A1,A2 and A3. Two lightweight Al2O3- Mg O castables were prepared by selecting A1 or A3 as aggregate with0. 6 μm of average pore size, then performances of castables with microporous corundum aggregates and castables with tabular corundum aggregates were compared. The results show that:( 1) the microporous corundum aggregates with bulk density of 3. 1- 3. 5g·cm- 3,apparent porosity of 5%,closed porosity of8%- 13%,and smaller thermal conductivity at 800 ℃than tabular corundum,can be prepared by sintering at above 1 800 ℃;( 2) compared to normal Al2O3- Mg O castables,the two lightweight Al2O3- Mg O castables have lower bulk density and higher apparent porosity;lower change rate in dimensions and higher strength firing at 1 500 ℃; and lower thermal conductivity at 600 and 800 ℃;( 3) compared to normal Al2O3- Mg O castables,Al2O3- Mg O castable with A1 has higher penetration index,and that with A3 has higher corrosion index and lower penetration index.
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