Tailoring pore structure and properties of waste-derived ceramic foams for lightweight construction

Ceramic foams (CFs) are manufactured by recycling granite waste, coal gangue, and cullet. Additionally, SiC powder is used as the foaming agent. The effect of the sintering temperature, the SiC content, and the presence of additives on the pore structure as well as on the physical and mechanical properties of the CFs has been investigated. A close correlation between the sintering temperature and the pore structure of the CFs is observed. The addition of SiC at 0.5 wt% results in a substantial volume expansion of the sample and in the formation of an internal structure with uniform pores and thin pore-walls. CaO and Na₂HPO₄ additives allow the pores to grow and shrink and increase the uniformity, which then meets different application requirements for insulation, gardening, and in lightweight construction. We believe that the results will generalize the use of mineral waste to manufacture better ceramic products at a lower cost.