Study of Replacing Cullet Powder with Sodium Silicate (Na₂SiO₃) on the Properties of Wet-Produced Foam Glass

Foam glass based on waste glass is one of the most important ecological construction materials due to its thermal, acoustic and electromagnetic insulation powers. This work aims to study the effect of Na₂SiO₃ on the characteristics of foam glass made from soda-lime waste glass using CaCO₃ as a foaming agent. Foam glass samples were prepared by sintering at a temperature of 850°C for 10 min with a heating rate of 6.5°C/min. The first sample contains 99 wt % waste glass powder and 1 wt % CaCO₃, and the other samples were developed by replacing a quantity of glass powder with 10, 20, 30 and 40 wt % of Na₂SiO₃. The effect of this substitution on the properties of foam glass was studied using a scanning electron microscope (SEM), a differential thermal analysis (DTA), a thermal gravimetric analysis (TGA), Fourier-transform infrared analysis (FTIR), thermal insulation and mechanical strength tests. Experimental results showed that the addition of Na₂SiO₃ increases the porosity of foam glass giving it a very low thermal conductivity (0.026 Wm^–1 K^–1) by thus increasing its power of thermal insulation.