We found a paper from 2011 about waste glass foaming with CaCO3.

The porous glass ‘foam glass’ is considered as the new glass products fulfill certain requirements in the building industry in particular (thermal and acoustic insulation). The production of foam glass based waste glass plays an important role in environmental protection and also gains in energy. As part of present work, we seek to improve the properties of glass to obtain a building material lighter with excellent insulation properties. The properties of foam glass depend on the porosity and morphology. The present work devoted to analyze the microstructure of the glass produced by scanning electron microscopy and optical microscopy to be more precise on the size and shape of pores constitute this material.

A mixture of glass and 1% foaming agent was compressed and heated up to 850°C. A white foam was obtained. The author found a high open porosity (85%) and a thermal conductivity of 0.031 W/mK, which is a doubtful value for such a large density and which is measured on a small sample. The author describes nicely the principle of acoustic absorption and finds a sound attenuation of 15 dB.

Noise and noise attenuation are becoming important topics next to thermal insulation. Unfaced mineral wool is very efficient but less interesting for the inside air. I guess there is a new future for cellular glass but this time with open cells.