Effect of Temperature and Water Glass Addition on the Microstructure and Physical Properties of Soda–Lime Foam Glass

This work aims to study the effect of sodium silicate additive on the microstructure and physical properties of foam glass fabricated from the recycled soda–lime glass regarding the process temperature of 700 to 900°C. Sodium silicate was added as a cost-effective environmental foaming agent in 10 to 30 wt % to recycled soda–lime glass powder (maximum size of 63 μm), pressed and heat-treated for 30 min. X-ray diffraction, scanning electron microscopy, and thermogravimetry analysis were used to characterize the phase evolution, porosity, morphology, and the foam-forming ability, respectively. Bulk and true density, as well as flexural strength, were measured. The results showed that for samples containing 20 wt % water glass treated at 800°C, bulk density and strength values was 0.54 g/cm 3 and 5.3 ± 0.7 MPa, Theses samples have higher strength than commercial foam glasses with uniformly distributed pores of 66.67% confirmed by the SEM images.