Preparing WEEE plastics for recycling – How optimal particle sizes in pre-processing can improve the separation efficiency of high quality plastics

Abstract

The production of electrical and electronic equipment is a fast-growing industrial sector, which also results in growing generation of waste electrical and electronic equipment (WEEE). An efficient separation is a prerequisite in order to achieve a high recyclability of WEEE plastics and produce pure types of plastics. The scope of the paper is to investigate the influence of particle size on the recyclability of post-shredding plastic fractions from WEEE pre-processing. For this purpose, different shredding technologies for WEEE, their output particle size, the sorting technologies and their required input particle size were investigated and compared. Sample analysis of plastic flakes provided from pre-processors is performed. The results show that the different sorting technologies require different particle size ranges for efficient separation. Three scenarios were investigated in order to identify optimal output particle sizes for improved plastic recycling. The results suggest that a particle size between 10–20 mm increases the sorting efficiency and thus recyclability of the plastic fractions and minimizes the losses into fines. Further recommendations to pre-processors and recyclers include improving the communication between the end-of-life actors, to standardize the particle size range (10–20 mm) as well as not to dispose the fine fraction but to find recyclers operating appropriate fines sorting technologies.