Heat-insulating cellular glass - coated with mineral dust on leaving centrifuge

The parent patent described adding a swelling agent to molten glass which then flows through a perforated drum on a centrifuge, the centrifugal force breaking off the strands of glass and a mineral dust being used to stop the fresh particles from sticking together. In the present invention, the fresh particles are fed onto a collecting surface on which mineral dust is spread. The collecting surface pref. consists of a concentric, rotating, ring vessel surrounding the centrifuge, contg. hot mineral dust, and in which the glass particles are rolled or vibrated. The foamed glass has greatly increased strength and wear-resistance; it can be coloured by using coloured mineral dusts.