• Waste Use of agro-industrial waste, transforming it into a by-product for use in the production of new materials • Thermal Properties The Importance of Thermal Insulation to Prevent Heat Transfer by Radiation • Density low density to ensure the material can be used and does not compromise other materials The construction sector worldwide has shown significant concern about the environmental impact caused by built environments. The 30th United Nations Climate Change Conference (COP30), to be held in Belém/PA/Brazil in November 2025, will address the global warming experienced across the planet. The material produced in this investigation presents a more economical and sustainable production method, because it replaces traditional materials with residual materials without loss of their technological properties. Closed-cell glass foams were sintered in a microwave oven (850°C - 950°C - 1000°C), using recycled materials as raw materials: glass powder and rice husk ash, with calcium carbonate as a fluxing agent. The foam presented densities (0.29, 0.28, and 0.27 g/cm³), flexural strength (1.62, 1.46, and 1.42 MPa), and thermal conductivity (0.282, 0.283, and 0.281 W/mK), all in accordance with global technological standards for commercial glass foams. SEM results show the formation of closed pores, a characteristic of great importance for this material; XRD analysis results confirm the presence of an amorphous material. The foams produced can be used to coat the walls of built spaces exposed to sunlight, thus reducing heat transfer to the interior and minimizing the need for air conditioning in these environments. This work is aligned with sustainable development, the circular economy, and the valorization of waste through its transformation into co-products.
Fernandes et al. (2026) studied this question.