Preparation of sintered foam glass with high fly ash content

Foam glasses with 50 wt.%, 60 wt.% and 70 wt.% fly ash are prepared using fly ash and flux agent sodium borate with sodium silicate as foaming agent at the temperature of 800 °C. Heat treatment at 800 °C for 1 h of pellets having different fly ash mass percentages results in well-sintered bodies of dark gray color featuring a vitreous aspect with smooth surface. The effect of amount of fly ash on the density, porosity, mechanical strength and microstructure is evaluated. The experimental results show that the foam glass with 70 wt.% fly ash exhibits the excellent comprehensive properties and the suitable sintered temperature is 800 °C.

► The fly ash content in the foam glasses changes from 50 wt.% to 70 wt.%.
► The form glasses have simple heat treatment conditions (800 °C, 1 h).
► The form glass with 70 wt.% fly exhibits the excellent comprehensive properties.