Application of Electrostatic Separation to the Recycling of Plastic Wastes: Separation of PVC, PET, and ABS

Abstract

Plastics are widely used in everyday life as a useful material, and thus their consumption is growing at a rate of about 5% per year in Korea. However, the constant generation of plastic wastes and their disposal generates environmental problems along with economic loss. In particular, mixed waste plastics are difficult to recycle because of their inferior characteristics. A laboratory-scale triboelectrostatic separator unit has been designed and assembled for this study. On the basis of the control of electrostatic charge, the separation of three kinds of mixed plastics, polyvinyl chloride (PVC), poly(ethylene terephthalate) (PET), and acrylonitrile-butadiene-styrene (ABS), in a range of similar gravities has been performed through a two-stage separation process. Polypropylene (PP) and high-impact polystyrene (HIPS) were found to be the most effective materials for a tribo-charger in the separation of PVC, PET, and ABS. The charge-to-mass ratio (nC/g) of plastics increased with increasing air velocity in the tribo charger. In the first stage, using the PP cyclone charger, the separation efficiency of particles considerably depended on the air velocity (10 m/s), the relative humidity (< 30%), the electrode potential (> 20 kV), and the splitter position (+2 cm from the center) in the triboelelctrostatic separator unit. At this time, a PVC grade of 99.40% and a recovery of 98.10% have successfully been achieved. In the second stage, using the HIPS cyclone charger, a PET grade of 97.80% and a recovery of 95.12% could be obtained under conditions of 10 m/s, over 25 kV, a central splitter position, and less than 40% relative humidity. In order to obtain 99.9% PVC grade and 99.3% PET grade, their recoveries should be sacrificed by 20.9% and 27%, respectively, with moving the splitter from the center to a (+)6 cm position.

Recycling of Postindustrial and Postconsumer Plastics Containing Flame Retardants

“…However, sieving or air classification have no impact on the FR system. Electrostatic separators are applied to separate mixtures of two or three different polymers by means of electrostatic forces [24]. If one of the three plastics in the input stream contains (B)FR, this process may separate FR equipped from other plastics.…”

Transdisciplinary Research in Sustainable Operations – An Application to Closed‐Loop Supply Chains

“…In addition, worldwide production of 260 million tons of plastic and the projected annual production growth of 5% in this area indicate the need for sustainable resource management and intelligent recovery through CLSC processes (Miskolczi et al ., ). The current recycling quota of less than 20% highlights the potential for further research that could improve recovery quotas (Park et al ., ).…”

Methods of Recycling, Properties and Applications of Recycled Thermoplastic Polymers

“…For example, polypropylene and polystyrene are recycled and they are used in the back-cabinets of TVs, flow fans, balancers of washing machines, base frames, dewatering tanks and protection nets of air conditioners. Also, polypropylene products are recycled in fresh food cases of refrigerators and water tanks of washing machines [71][72][73][74][75].…”