• Proceedings of the IEEK Conference
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• 2001.10a
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• pp.734-737
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• 2001

A study was conducted in order to remove PVC from the waste plastic film mixture. The fittings of Air Table was modified to increase the separation efficiency of PVC. By using the improved air table, the PE and PVC was successfully separated from PVC-PE film mixture with the yield of PE 90% or more and with the content of PVC in PE 1% or less. The detail of the separation condition and result will be discussed in this paper.

• Journal of Mechanical Science and Technology
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• v.17 no.10
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• pp.1485-1495
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• 2003

We investigate the triboelectrostatic separation of polyvinylchloride (PVC) from mixed plastics in the laboratory scale triboelectrostatic separation system. The flow and electric fields in the precipitator are obtained from the numerical solution of finite volume method. Using these flow and electric fields, we solved the particle motion equation considering the inertia, drag, gravity and electrostatic forces acted on the particles. The particle trajectories are obtained using a Lagrangian method as a function of different important variables such as Reynolds number, Stokes number, electrostatic force, electric charge and electric field distribution, inclined angle of plane electrodes, particle rebounding, particle charge decay rate after impact on the electrode surface, etc., in order to determine the optimal design conditions. The present predicted results for the cumulative yield represent well the experimental ones.

• Resources Recycling
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• v.16 no.5
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• pp.71-76
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• 2007

The mixed plastic waste generated from households after hand-picking and/or mechanical sorting processes amounts to 1,750,000 ton in 2006, and most of these waste are finally end up with landfill and/or incineration due to the lacks of separation technologies and economical reasons. The mixed plastic wastes can not be used as raw materials for chemical and/or thermal recycling processes because of their high content of PVC(upto 4.0 wt.%). In the present research, gravity separation system has been developed to remove PVC from the mixed plastic waste and to recover the PO-type plastics. This system mainly consists of air classification, magnetic separation, one-step crushing, feeding system at fixed rate and wet-type gravity separation system. The gravity system based on centrifugal separation has been developed at capacity of 0.5 ton/h and it consists of mixing, precleaning, separation, dewatering, recovery system and wastewater treatment system, etc. The main objective of this process is to achieve high separation efficiency of polyolefins with less than 0.3 wt.% PVC content and less than 10% moisture content in the final products. In addition, a crushing unit of with 8 rotor system is also developed to improve the crushing efficiency of soft-type plastics. The system with a capacity of 1.0 ton/h is developed and operational results are presented.

• Resources Recycling
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• v.18 no.1
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• pp.13-21
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• 2009

A research on material separation of EVA and PET mixture plastic waste using a triboelectrostatic separator has been carried out. It was found that PP was the best charging material to give the highest charge on the surface of EVA and PET mixture plastics with an opposite polarity. Therefore, a charger of pipe line type using PP material was manufactured for separation of EVA and PET mixture plastic waste. At optimum test conditions that used PP cyclone charger developed in this study, we could separate out PET with a glade of 98.7% and a recovery of 89.7%.

• Journal of the Korea Organic Resources Recycling Association
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• v.21 no.3
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• pp.74-81
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• 2013

In this study, the separation efficiency of wind power selector (the direction of the air flow of the air to perform gravity separation method) of municipal solid waste which was landfilled was investigated to reduce amount of waste that is designed to increase the recycling rate of wastes for the ANSYS CFX Program's numerical methods with wind through the separator. When a suction device designed to suction 1000mL of a plastic bag, the separation efficiency was 100% and when the wind speed was 0.9 m /sec or more and when the wind speed was 1.6 m / sec or more, the efficiency of plastic bottles in a mixture of 500mL and 1500mL plastic bottle waste was 100% and the aluminum screening efficiency of 250mL aluminum can was 100 % when the wind speed was 2.3 m / sec. In the last, 5mm thick compressed aluminum can efficiency was 90 % when the wind speed was 2.4 m / sec.

• Journal of the Semiconductor & Display Technology
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• v.21 no.3
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• pp.92-97
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• 2022

Plastics are classified into 7 types such as PET (PETE), HDPE, PVC, LDPE, PP, PS, and Other for separation and recycling. Recently, large corporations advocating ESG management are replacing them with bioplastics. Incineration and landfill of disposal of plastic waste are responsible for air pollution and destruction of the ecosystem. Because it is not easy to accurately classify plastic materials with the naked eye, automated system-based screening studies using various sensor technologies and AI-based software technologies have been conducted. In this paper, NIR scanning devices considering the NIR wavelength characteristics that appear differently for each plastic material and a system that can identify the type of plastic by learning the NIR spectrum data collected through it. The accuracy of plastic material identification was evaluated through a decision tree-based SVM model for multiclass classification on NIR spectral datasets for 8 types of plastic samples including biodegradable plastic.

• Journal of the Korean Recycled Construction Resources Institute
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• v.8 no.3
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• pp.317-324
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• 2020

Plastic wastes generated from domestic waste are separated by mixed discharge with foreign substances, and the cost of the separation and screening process increases, so recycling is relatively low. In this study, as a fundamental study for recycling mixed plastic wastes generated from domestic waste into concrete aggregates, changes in concrete properties according to the plastic waste types and the substitution rate were evaluated experimentally. The mixed plastic waste aggregate(MPWA) was found to have a lower density and a higher absorption rate compared to the coarse aggregate with good particle size distribution. On the other hand, the single plastic waste aggregate(SPWA) was composed of particles of uniform size, and both the density and the absorption rate were lower than that of the fin e aggregate. It was found that the MPWA substitution concrete did not cause a material separation phenomenon due to a relatively good particle size distribution even with the largest amount of plastic waste substitution, and the amount of air flow increased little. The compressive strength and flexural strength of the PWA substitution concrete decreased as the amount of substitution of the PWA increased due to the low strength of the PWA, the suppression of the cement hydration reaction due to hydrophobicity, and the low adhesion between the PWA and the cement paste. It was found that the degree of deterioration in compressive strength and flexural strength of concrete substituted with MPWA having good particle size distribution was relatively small.

• Resources Recycling
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• v.23 no.4
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• pp.3-11
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• 2014

Large scale generation of plastic waste has generated considerable interest it seeking innovative solutions to waste recycling and reuse. Plastic solid waste(PSW) treatment and recycling processes could be allocated to four major categories, re-extrusion(primary), mechanical recycling(secondary), chemical recycling(tertiary) and energy recovery(quaternary). This review considers the various aspects of the PSW recycling such as recycling methods of PSW, special problems about some proposed process, separation techniques, and recycling of mixed PSW.

• Elastomers and Composites
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• v.43 no.3
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• pp.191-198
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• 2008

It is said that polymer modified asphalt using polyethylene as modifier would show phase separation due to density difference and incompatibility between asphalt and polyethylene. In this study, to prevent coalescence of polyethylene in asphalt, we employed peroxides as phase separation inhibitor. On microscope, peroxides (dicumyl peroxide, lauroyl peroxide) with waste vinyl (comprising low density polyethylene) did not show phase separation, however, rheometer test showed phase separation at molecular level, i.e., polyethylene and asphalt are immiscible ultimately. Mechanical properties (tensile strength, Marshall stability, dynamic stability) showed waste vinyl-modified asphalts are highly resistant to plastic deformation and these properties are even better than those of Superphalt.

• Resources Recycling
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• v.30 no.3
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• pp.70-81
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• 2021

This study evaluated the recyclability of waste plastics in used coffee capsules disposed of as municipal waste. For recycling, a new material separation process was developed to remove the coffee grounds through primary crushing, washing, sieving, and secondary crushing, followed by corona discharge electrostatic separation. Furthermore, for the under 10 mm size fraction samples, the aluminum removal and the plastic recovery were 95.4% and 98.3%, respectively, under optimal conditions. In addition, for the 15 mm fraction samples, the aluminum removal and the plastic recovery were 91.3% and 97.2%, respectively. To evaluate the recyclability of the separated waste plastics, the samples were pelleted, and their material properties were analyzed. No hazardous substances were detected, and the results were similar to those for homo-PP. Therefore, it was confirmed tha t sufficient functiona lity existed a s recycled PP. However, owing to the da rk color of the pellets, limited applications to black or dark products are expected.