The enhanced strength and radiation efficiency of alumina reticulated porous ceramics via coal gangue addition

Al2O3 reticulated porous ceramics (ARPC) are widely selected for high-temperature porous media burners due to their excellent thermal stability. However, the relatively low mechanical property and infrared emissivity of ARPC led to a low lifespan and radiation efficiency of the burner, limiting its application in high-temperature porous burners. In this work, a novel strategy was proposed to synergistically improve mechanical and radiation properties of ARPC and recycle of coal gangue. ARPC with three-layered struts, including microporous alumina-mullite coating, alumina skeleton and filling layer, were prepared by polymer replica technique and vacuum infiltration method. The addition of coal gangue could obviously strengthen ARPC, because coal gangue was attributed to form mullite, as well as the generation of residual compressive stress in the coating of three-layered struts. The decomposition of organic compounds within coal gangue enhanced the degree of microporosity on the coating, thereby increasing infrared emissivity by 21.8%, which increased the surface temperature of porous burner from 857.4°C to 905.7°C.