Effect of corundum aggregate kind on properties of high purity corundum refractories

          High purity corundum brick specimens with w (Al2O3)≥99.0% were prepared using white fused corundum and tabular 

corundum (≤3 mm) as aggregates,alumina powder (≤75 μm) and alumina micropowder (d50≈3.5 μm) as matrix,machine- 

shaping,and firing at 1650,1700,1750 and 1800 ℃ for 3 h,respectively to compare the effect of two kinds of corundum aggregates 

on the properties.The mechanical properties at room temperature and high temperatures,hot creep resistance,thermal shock 

resistance and slag resistance of the fired specimens were measured.The results show that,1750 ℃ is the optimum firing 

temperature for high purity corundum refractories made of tabular corundum or white fused corundum.The specimens with tabular 

corundum aggregates have better mechanical properties,slag penetration resistance and creep resistance than ones with white 

fused corundum aggregates.The main reasons may be that the tabular alumina particles have small crystals and rough 

surfaces,thus the specimens with tabular corundum have non-interpenetrating micro-pores in the microstructure,and good 

combination between aggregates and matrix.There are a small amount of β-Al2O3 crystal agglomerates in white fused 

corundum,which form some liquid during hot creep.So the tabular alumina is the ideal raw material for high purity corundum 

refractories.