Geopolymers can be obtained also by the alkali activation of
cullet soda-glass with sodium or potassium hydroxide solutions
and curing at 40–60 C [8]. In our previous work, binding materials
were synthesized starting from waste glass with/without red mud
admixtures by alkaline activation with NaOH solution [9]. The
main reaction products formed in these systems are sodium silicate
hydrates or/and sodium silicate aluminate hydrates with
amorphous to crystalline morphologies. The presence of sodium
silicate hydrates or/and sodium silicate aluminate hydrates in the
hardened geopolymer is likely to act as a foaming agent therefore
it should be possible to produce foamed materials without the use
of other foaming agents.
Therefore, in this study we assess the possibility to produce
foamed materials by the thermal treatment of geopolymers
resulted by the alkali activation of waste glass (cullet) with/without
red mud admixtures. We present also results regarding the
synthesis and thermal treatment of geopolymers obtained by alkali
activation of waste glass and red mud mixture with the liquid part
of red mud slurry (filtrate). To our best knowledge no information
are presently available regarding the synthesis and properties of
this type of foamed geopolymers.