Preparation and microstructure evolution of novel ultra-low thermal conductivity calcium silicate-based ceramic foams

In this study, municipal solid waste incineration fly ash (MSWI FA) was used as a new raw material for the ceramics industry and a novel ultra-low thermal conductivity calcium silicate-based foams (CSFs) was prepared by the direct foaming method. The effects of the addition of foam and borax on the sintering behavior and microstructural evolution of the CSFs were investigated. With the optimal amount of foam, the CSFs had an apparent porosity of 63.43%-67.49%, bulk density of 0.75-0.84 g/cm(3), compressive strength of 1.83-3.21 MPa, and room-temperature thermal conductivity of 0.213-0.235 W/(m.K). Notably, the whisker morphology, pore structure, and sintering behavior of the samples can be controlled by changing the amount of borax. The prepared ceramic foams can be applied in the fields of thermal insulation, filtration, and catalyst carriers.

Automated summary

In this study, municipal solid waste incineration fly ash was used to prepare a novel calcium silicate-based foam material with ultra-low thermal conductivity. The addition of foam and borax was found to affect the sintering behavior and microstructural evolution of the foams. The resulting ceramic foams show potential applications in thermal insulation, filtration, and catalyst carriers.