A novel route for the fabrication of melilite-spinel porous ceramics with ultralow thermal conductivity and sufficient strength.

Melilite-spinel porous ceramics with high apparent porosity, sufficient strength and ultralow thermal conductivity were successfully prepared via a direct-thermal decomposition route using the solid waste of phosphorus tailings and coal gangue as raw materials. The micropores are derived from the in situ decomposition of dolomite and kaolinite, whose morphology, distribution form and quantity determine the thermal insulation performance and physical properties of porous ceramics. Melilite-spinel porous ceramics with an ultralow thermal conductivity of 0.036 W/(m·K) (tested at 200 °C), an apparent porosity of 61.3% and a compressive strength of 2.95 MPa, exhibited promising application prospects in thermal insulation materials used for high-temperature fields. [ABSTRACT FROM AUTHOR]