Packaging waste are commonly used as new raw materials reducing the
depletion of natural resources. The separation between the different materials is mandatory
if the application in high value added products is desired. Today, one challenge for
recycling is the separation of shredded polymers with approximate density. In this chapter
the specific problems related with the separation of PS (Polystyrene) from PET
(Polyethylene Terephthalate) and PVC (Polyvinyl Chloride) are addressed.
The most important international literature describing experimental studies are reviewed
and a summation of the experimental work supervised by the author is presented. The
application of gravity concentration and froth flotation is proposed. The results of the
experimentation carried out with representative samples of post-consumer packaging
plastics at laboratory scale and in a pilot plant continuously operated are presented. The
study confirmed the process feasibility but highlighted some difficulties and limitations.
Keywords: Recycling, Froth flotation, Gravity concentration, PET, PVC, PS.
