High purity polyolefins recycling by melt separation

Post-consumer wastes, such as WEEE (Waste from Electric and Electronic Equipment), HW (Household Waste) and ASR (Automotive Shredder Residue), can be considered an important resource of polyolefins. Such wastes are composed of a complex mixture of different materials. Recoverable high purity polyolefins are difficult to select mainly for two reasons: i) the complexity of the waste mixtures, characterized by the presence of different polymers and other polluting materials (wood aluminium, copper, stone, glass, etc), ii) the similar physical attributes (density) of potypropylene (PP) and polyethylene (PE). A new quality control strategy has been developed, based on the different melting points of the two target polyolefin's (PP and PE). In particular, an innovative and specialized device has been designed and realized. Several tests have been carried out according to different process parameters in order to define the best operative conditions to realize PE and PP recognition and separation. The results showed that this technique can be successful in the quality control of the purity of PP and PE flow streams.