Patent ID: 8225937

Claim:
A method for separating flame-protected from flame-retardant-free polymers from a mixture comprising flame-protected and flame-retardant-free polymers based on polystyrene, the copolymers and/or blends thereof, the method comprising: contacting said mixture comprising flame-protected and flame-retardant free polymers based on polystyrene, the copolymer and/or blends thereof with at least one liquid or gaseous separation medium; wherein the separation medium is a mixture of water and a solvent miscible with water with a density >1 g/cm 3 or a salt solution and wherein the separation medium has a specific density in the range of 1.06 to 1.14 g/cm 3 so that the polymers in a sink fraction are separated from those in a float fraction, or a separation being effected by means of an air separator, wherein a part of the polymers being entrained more strongly by the air flow of said separator whilst another part of the polymers being deflected less because of their density.