Preparation of High Strength, Low Thermal Conductivity Mullite Insulating Firebrick with Spherical, Low-Connectivity Pores

Abstract

In order to solve the contradiction between the strength and thermal conductivity of porous materials, mullite insulating firebrick (M-IFB) with high strength and low thermal conductivity with spherical-low connectivity porous were success fully prepared by in-situ reaction synthesis mullite bonded by yeast/glucose foaming and polymer foaming, using kyanite tailings and alumina as the main raw material. Control of the porosity and properties of mullite insulating firebrick can be easily and accurately achieved by adjusting the heat treatment temperature and the amount of forming agent. The compressive strengths, bulk density, thermal conductivities, liner change and porosities ranged from 25.86-53.26 MPa, 0.58 to 1.61 g/cm3, 0.236-0.599 W/(m·K), -1.01 to -0.426% and 66.89 to 78.63%, respectively. The high porosity and high strength mullite insulating firebrick prepared by this method are expected to be used in various applications due to their superior thermal shock resistance, low thermal conductivity compared to alumina hollow pellets.

Keywords: mullite insulating firebrick, high strength, low thermal conductivity