Preparation and Properties of MgO-MgAl<sub>2</sub>O<sub>4</sub>-FeAl<sub>2</sub>O<sub>4</sub> Bricks in Cement Kiln

Abstract

Sintered magnesia with different particle sizes, fused MgAl2O4and FeAl2O4were used as the raw materials. FeAl2O4is added in MgO-MgAl2O4bricks at different ratios to gradually replace MgAl2O4. After the raw materials were molded and sintered at the tunnel furnace with the temperature 1 530°C for 10 hours, the MgO-MgAl2O4-FeAl2O4bricks could be made. After the analysis of the phase composition, microstructure and routine performance of the specimens, the influence by adding FeAl2O4to the samples on the properties such as thermal shock resistance, adhesion strength of kiln crust are discussed as the key point. The result shows that the addition of FeAl2O4has no evidently influence on the apparent porosity and volume density. The cold compressive strength of the samples reduces gradually with the addition of FeAl2O4, and it decreases obviously when the amount of FeAl2O4is more than 8%. When the addition of FeAl2O4is 5% FeAl2O4in the MgO-MgAl2O4-FeAl2O4bricks, MgAl2O4and FeAl2O4can combine each other’s advantages. The thermal shock resistance not only decreased obviously but the adhesion strength to kiln crust is increased.