Cyclone Separation Process for Sorting Small-Format Plastics

Abstract

Small format plastics are defined as being less than 2 in. long in two or more dimensions and include items such as loose bottle caps, small cosmetic packaging, and toothbrushes. Current material recovery facility (MRF) infrastructure is usually not designed to recover these smaller objects which typically fall through screens in the glass separation unit operation. A cyclone separation process has been developed to separate the small-format plastics from the glass, improving the purity of the glass stream and allowing the smaller plastics to be returned to the plastic sorting stream. Utilizing density, the cyclone sends the lighter materials through a side outlet (plastics) and collects the heavier materials (glass) through the bottom, resulting in two purified outlet streams. With the current small-scale prototype, plastic separation efficiencies greater than 94% have been observed. The life-cycle assessment and technoeconomic analysis indicate that this new separation step would increase the global warming potential savings and improve the profitability of MRFs.