The first paper describes a glass foaming process with fly ash and SiC. They reach densities down to 500 kg/m³, which is still quite high. The addition of fly ash is quite new in this perspective. In this system, not only glass but also fly ash is recycled. Leaching out tests confirm that these foams have enough chemical stability to be used as thermal insulation. Arjan Steiner made a thesis about foaming fly ash from municipal waste as already mentioned in a previous post.
In a second paper bottle and flat glass is foamed with 3 to 10% waste plaster. Also in this case, densities down to 500 kg/m³ (6% plaster) are reached with an acceptable leaching out test. These foams can probably be used as cellular glass gravel thermal insulation, while thermal conductivities of 0.12 W/mK are reached.
The above papers convert a maximum of waste to ecologic cellular glass thermal insulation. Indeed fly ash, plaster waste and waste glass are crying to be recycled in a second life.