Ceramics-Silikáty 69, (4) 543 - 551 (2025)

To address the comprehensive utilisation of low-grade potassium feldspar and further enhance the thermal insulation performance of green building facades, this study proposes the use of low-grade potassium feldspar as the primary raw material, with silicon carbide (SiC) serving as the foaming agent. Porous heat-insulating ceramics for green building exterior walls were prepared by the high-temperature foaming method. The test results demonstrate that the porous ceramic material prepared at a sintering temperature of 1250 °C and a holding time of 30 min exhibits the optimal performance, with a thermal conductivity of 0.072 W/(m-K), a compressive strength of 3.429 MPa, a water absorption rate of 13.5%, and a bulk density of 0.542 g/cm³. With the rise in sintering temperature and the progression of the foaming reaction, the pores within the ceramic material become increasingly concentrated, leading to a generally denser pore structure. With the increase in the sintering temperature, the foaming reaction continued, as the pores in the ceramic material became increasingly dense, the overall pore structure developed greater regularity and uniformity in size, while the pore dimensions gradually increased.