Optimization of matrix pore structure and its effects on physicochemical properties of corundum castables.

In this paper, the effects of the matrix pore structure on the strength and corrosion resistance of corundum castables are reported. Pore diameters of castables fired at 110 °C could be decreased from 550 nm to 72 nm when 4% Al 2 O 3 -SiO 2 gel powder was added. The pore diameter of the castables decreased from 850 nm to 500 nm after firing at 1100 °C, but increased from approximately 2 μm–8 μm after firing at 1500 °C. The strength of castables fired at 1500 °C increased remarkably with the addition of Al 2 O 3 -SiO 2 gel powder. A maximum cold modulus of rupture (CMOR) of 62.34 MPa was obtained when 4% Al 2 O 3 -SiO 2 gel powder was added. After slag corrosion, the penetration index fell from 16.6% to 4%, suggesting that a homogeneous pore size distribution and a smaller pore size played an important role in improving the penetration resistance. [ABSTRACT FROM AUTHOR]