Preparation of mullite refractories with low thermal conductivity and high strength

Abstract

In the work, a novel mullite refractory was prepared by using coal gangue and low-grade raw bauxite as main raw materials, and the effect of the low-grade raw bauxite content and temperature on the microstructure and properties of mullite refractories was investigated. Both the green densities and cold compressive strength of mullite refractories increased with the increase of low-grade raw bauxite; also, the addition of low-grade raw bauxite had no significant effect on the thermal conductivity of such refractories treated at 1500°C. When the addition of low-grade raw bauxite was 34.5%, the compressive strength of the refractories treated at 1600°C was up to 104.3 MPa, and its thermal conductivity tested at 1000°C was only 1.02 W/(m K).