• Resources Recycling
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• v.13 no.1
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• pp.39-46
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• 2004

Triboelectrostatic separation process is a technology that different particles charged after contact and rubbing different materials are separated in a high electric field. This technology has an advantage in that it can be used for separating non-conducting materials such as plastics unlike other electrostatic separation processes. There are two objectives in this study. One is to develop an effective continuous tribo-electrostatic separation process. The other is to apply the developed device for the separation of mixed plastics. Results show that almost all tested plastics reaches over 95% in yield and grade after separation.

• Journal of Photoscience
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• v.8 no.1
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• pp.33-37
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• 2001

Picosecond absorption spectroscopy has been employed in the study of the solvent dynamics of 1, 2, 4, 5-tetracyanobenzene/biphenyl derivative radical ion pairs, and the resulting rates of radical ion pair separation are faster in acetonitrile than in dichloromethane. In an effort to account quantitatively for such solvent effect on the rate of radical ion pair separation, an equation for the rate of radical ion pair separation is introduced, in which the rate depends exponentially on the electrostatic interaction energy in the radical ion pair. In our analysis of the types of electrostatic interaction energy based on the conducting spheres in dielectric continuum was chosen, and the rate equation employing this electrostatic energy provided information on the distance on the distance of radical ion pair separation and solvation energy of the radical ion pair, thereby providing quantitative explanation for the observed solvent effect on the rate of radical ion pair sepaaration.

• Proceedings of the KSME Conference
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• 2000.11b
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• pp.538-543
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• 2000

The purpose of this study is to develope electrostatic separation system for recycling of mixed waste plastics. The electrostatic separation system is designed and investigated the separation efficiency for separating of mixed waste plastics. Electrostatic separation system consisted of a tribocharger, separator (two electrode), collector (5 tray) and controller (positive/negative high voltage power supply). The tribocharger is a fluidized bed using tribo-electrification mechanism between particles and particles. In experimental results, the tribocharger of the fluidized bed was more effective separation efficiency. It showed the purity of $85{\sim}99\;%$ and the recovery of $80{\sim}98\;%$ from the powder of mixed plastics such as LDPE, HDPE, PP, PS, PET and PVC. Especially, In the separation experiment of Polyvinylchloride(PVC) which generates hazardous hydrogen chloride gas in case of the combustion. its purity was over 99 % and recovery was over 95 %.

• 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.15 no.1 s.69
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• pp.28-36
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• 2006

The development of material separation technique for waste plastic recycling are the necessary situation restricted by law the reclamation and incineration of waste plastic after 2004, with enforcement of EPR (Extended Producer Responsibility) system. As the this study is the research on the development of electrostatic separation techniques for recycling of life circles waste plastic by development of charging material and charger, the separation efficiency can be improved. Therefore, we developed the charger and electrostatic separator to increase charging efficiency and material separation per object plastics, rising these equipments, we removed PVC up to $99\%$ from two kinds of mixed plastics. And in case of restricting PVC content such as PET, we developed the separation technique that can remove PVC up to $99.99\%$ from PET with PET recovery about $80\%$. Also, as we separated over $98\%$ for three kinds of mixed plastics, and then established material separation technique to increase recycling of plastic.

• Proceedings of the Korean Institute of Resources Recycling Conference
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• 2005.10a
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• pp.23-33
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• 2005

The development of material separation technique for waste plastic recycling are the necessary situation according to restrict by law the reclamation and incineration of waste plastic after 2004 year, pith enforcement of EPR (Extended Producer Responsibility) system. As the this study is the research on the development of electrostatic separation techniques for recycling of life circles waste plastic, it can improve separation efficiency according to development of charging material and charger. Therefore, we developed the charger and electrostatic separator to increase charging efficiency and material separation per object plastics, using these equipments, we removed PVC up to 99% from two kinds of mixed plastics. And in case of restricting PVC content such as PET, we developed the separation technique that can remove PVC up to 99.99% from PET with PET recovery about 80%. Also, as we separated over 98% for three kinds of mixed plastics, and then established material separation technique to increase recycling of plastic.

• Resources Recycling
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• v.28 no.6
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• pp.96-105
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• 2019

Automobile shredder residue (ASR) is the final waste produced when end-of-life vehicles (ELVs) are shredded. ASR can be separated using mineral-processing operations such as comminution, air classification, magnetic separation, and/or electrostatic separation. In this work, trajectory analyses of conductors (copper) and non-conductors (glass) in the ASR have been carried out using induction electrostatic separator for predicting or improving the ASR-separation efficiency. From results of trajectory analysis for conductors, the trajectories of copper wire by observation versus simulation for coarse particles of 0.5 and 0.25 mm showed consistent congruity. The observed 0.06 mm fine-particles trajectory was deflected toward the (-) attractive electrode owing to the charge-density effects due to the particle characteristics and relative humidity. In the case of non-conductors, the actual trajectory of dielectric glass deflected toward the (-) electrode, showing characteristics similar to those of conductive particles. The analyses of stereoscopic microscope and SEM & EDS found heterologous materials (fine ferrous particles and conductive organics) on the glass surface. This demonstrates the glass decreasing separation efficiency for non-ferrous metals during electrostatic separation for the recycling of ASR. Future work will require a pretreatment process for eliminating impurities from the glass and advanced trajectory-simulation processes.

• Journal of Mechanical Science and Technology
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• v.15 no.6
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• pp.804-812
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• 2001

A triboelectrostatic separation system for removing unburned carbon from coal fly ash is designed and evaluated. Fly ash from a coal-fired power plant is used as an accepted additive in concrete where it adds strength, sulfate resistance and reduced cost, provided acceptable levels of unburned carbon are maintained. Unfortunately, unburned carbon in coal fly ash absorbs some of other additives and reduces the concrete strength. This paper describes to investigate dry triboelectrostatic process to separate unburned carbon from coal fly ash and utilize it into economically valuable products. The laboratory-scale triboelectrostatic separation system consists of a particle feeding system, a tribocharger, a separation chamber, and collection systems. Particles of unburned carbon and fly ash can be imparted positive and negative surface charges, respectively, with a copper tribocharger due to differences in the work function values of the particles and the tribocharger, and can be separated by passing them through an external electric field. Results showed that fly ash recovery was strongly dependent on the electric field strength and the particle size. 70wt% of fly ash containing 6.5wt% of carbon contents could be recovered at carbon contents below 3%. The triboelectrostatic separation system showed a potential to be an effective method for removing unburned carbon from coal fly ash.

• Proceedings of the IEEK Conference
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• 2001.10a
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• pp.597-601
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• 2001

Waste plastics amount is more than 3.5 million tons and 30% of industrial waste in 1998, Korea but recycling rate of industrial waste plastics is quite low because the material separation technology from the mixed waste plastic powders is not commercially available so far. This study covers the triboelectrostatic separation of polyvinylchloride (PVC) materials collection chambers and controllers. PVC and PET powders can be imparted negative and positive surface charges, respectively, due to the difference of triboelectric charging series between particles and particles in the fluidized bed tribocharger, and can be separated by passing them through an external electric field. The extract content and yield of PVC separation from the mixed PVC and PET plastic powders are 90.0% and 98.2%, respectively. The electrostatic separation system using the fluidized bed tribocharger shows the potential to be an effective method for removing PVC materials from other mixed plastics.

• Journal of ILASS-Korea
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• v.7 no.2
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• pp.7-15
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• 2002

A particle flow visualization, electrostatic charging measurement and separation of triboelectrically charged particles in the external electric field by a fluidized bed tribocharger are conducted for the removal of PVC particles from mixed waste plastics. The laboratory-scale triboelectrostatic separation system consists of the fluidized bed tribocharger, a separation chamber, a collection chamber and a controller. PVC and PET particles can be imparted negative and positive surface charges respectively due to the difference of triboelectric charging series between particles and particles in the fluidized bed tribocharger, and can be separated by passing them through an external electric field. To visualize these charged particles, He-Ne laser is used with cylindrical lenses to generate a sheet beam. In the charging measurement, the particle motion analysis system (PMAS), capable of determining particle velocity and diameter. is used to non-intrusively measure particle behavior in high strength electric field. The average charge-to-mass ratios of PVC and PET particles are $1.4\;and\;1.2{\mu}C/kg$, respectively. The highly concentrated PVC (91.9%) can be recovered with a yield of about 96.1% from the mixture of PVC and PET materials for a single-stage processing. The triboelectrostatic separation system using the fluidized tribocharger shows the potential to be an effective method for removing PVC from mixed plastics for waste plastic recycling.