Glass foam experiment with eggshell as foaming agent and red mud as additive material

Glass foam tablets were produced from green, brown, and white glass bottles, eggshell was used as foaming agent, Na-bentonite as binder and red mad as additive material. Each tablet was 10 g and contained 2.5% Na-bentonite and 0.1% eggshell and different content of red mud (0-40 wt%), the rest of the mixture was glass powder. The ground raw materials were homogenized and pressed into glass foam tablets at 30 MPa using a hydraulic piston press. The obtained glass tablets were heat treated at different temperatures. The study shows the chemical compositions of the raw materials, the specimen density of tablets before and after heat treatment, abrasion resistance and falling test of the tablets. From the results it can be concluded that the addition of red mud can reduce the foaming temperature to 800 degrees C from 900 degrees C, even at 1 wt% of red mud content. In this case a significant reduction in specimen density was observed from 1.33 g/cm3 to 0.33 g/cm3. Since the aim is to have a porous, lightweight product suitable for insulation, the specimen density value is important.