Frequently this question comes on the table. A good point to start is a study  for the United Kingdom. This study is looking for a profitable destination of waste glass and in that perpective, they make this study about foamed glass. The study is made in 2003 but became more relevant with the higher demand for thermal insulation. Why should you read this study?

1. It gives a nice description of different production methods.
2. The different outputs of foamed glass are shown: boards, gravel, granules, …
3. The situation of waste glass in the UK is well described
4. The production of more intelligent cellular glass is mentioned like for example the acoustic absorber REAPOR.
5.  It is also demonstrated that the investment cost is too large for a small production plant.

The last point is the reason why starting a production plant is so difficult today. If there is no large market immediately available, you need to find cheap energy, cheap waste glass and cheap labor to start up a small plant. I doubt that today Europe is the place to be.