• 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.

• Resources Recycling
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• v.22 no.1
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• pp.29-35
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• 2013

The study on the recovery of Nylon from a radiator of End-of-Life Vehicle was conducted by using triboelectrostatic separation technique. For the effective separation of the sample(Nylon, PP glass), charge polarity and amount of each sample with various charging materials have been investigated by faraday cage. And then, charging material was selected as carrying out basic separation experiments with materials that can be possible to polarize samples. Finally, the continuos type triboelectrostatic separator was developed with selected charging material and the recovery possibility of the sample was confirmed as carrying out various separation experiments.

• 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.2 s.76
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• pp.56-62
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• 2007

In this study, we carried out the research on triboelectrostatic separation for heavy group plastics (PET, PVC) recovered from wet gravity separation. From the research on charging characteristic for the choice of charging materials, it was found that PP was optimum charging material to make high charging amount with opposite polarity for PET and PVC of heavy group. Therefore, we manufactured a charger of cyclone type using PP material for separation of PET and PVC. At optimum test conditions that used PP cyclone charger developed in this study, we developed a triboelectrostatic separation technique that can separate PET plastic up to grade of 98.5% and recovery of 86.2%. We established new separation technology that could recycle the PET and PVC heavy group plastics recovered from wet gravity separation.

• Resources Recycling
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• v.17 no.1
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• pp.43-50
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• 2008

In this study, we carried out the research on triboelectrostatic separation for materials separation of PET & Nylon recovered to waste plastic beer bottle. From the research on charging characteristic for choice of charging materials, it was found that PMMA was optimum charging material to make high charging amount with opposite polarity for PET & Nylon in waste plastic beer bottle. Therefore, we manufactured a charger of pipe line and cyclone type using PMMA material for separation of PET and Nylon. At optimum test conditions that used PMMA pipe line and cyclone charger developed in this study, we developed a triboelectrostatic separation technique that can separate PET plastic up to grade of 99.6% and recovery of 88.2%. We established new separation technology that can recycle the PET and Nylon recovered from waste plastic beer bottle.

• 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.

• Resources Recycling
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• v.19 no.6
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• pp.77-85
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• 2010

This study was carried out to develop a process flow sheet for recovering valuables (gold and high purity silica) from the gold mine tailings containing 1.7 g/ton of gold and 79.48 wt.% $SiO_2$. Float-sink tests using heavy liquids was conducted to explore the possibility of recovering gold by gravity separation. Hydrocyclone, froth flotation, and triboelectrostatic separatoin tests were conducted to recover high purity silica from the gold mine tailings. The results of float-sink tests showed that particles containing 5.58 g/ton of gold could be obtained at 2.72 specific gravity, but with very low yields around 3%. Meanwhile, all tests with hydrocyclone, froth flotation, and triboelectrostatic separation showed that high purity silica with $SiO_2$ content over 90% could be obtained. The purity could be improved further up to about 94% by employing several recleaning steps in the froth flotation and triboelectrostatic process.

• Resources Recycling
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• v.22 no.6
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• pp.33-40
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• 2013

Due to the environmental problem caused by plastics largely used in various fields, the importance of recycling is being emphasized. A research on material separation of ABS and PS mixed plastic waste, using a triboelectrostatic separator, was carried out for recovery the ABS. As a results of research on charging characteristic for choosing charging material, it was confirmed that ABS was optimum charging material for a tribo-charger in the material separation of ABS and PS. In the material separation using ABS charger, ABS grade of 99.5% and recovery of 92.5% were achieved at 20 kV, splitter position +2 cm from the center and 30% relative humidity. Therefore, material separation technique for recycling ABS and PS mixed plastic waste was established.

• Resources Recycling
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• v.15 no.6 s.74
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• pp.25-32
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• 2006

In this study, waste car tau lamps that usually gets incinerated or buried has been recovered during the dispose process in order to increase the recycling rate of waste cars and the material separation research was performed by applying triboelectrostatic separation method. After a series of charging characteristic test, PMMA materials was confirmed of being an effective charging material for waste car tail lamp material separation, a cyclone charger using PMMA material for continuous process was developed. In optimum test conditions using triboelectrostatic separator developed in this study, high quality PMMA material with recovery rate of 99.0% and 90.2% was achieved from the waste car tail lamp. Therefore, a material separation technology that can recycle tail lamps of waste cars has been established.

• Resources Recycling
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• v.14 no.5 s.67
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• pp.54-61
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• 2005

In 2006, the coal usage that is used as energy source of power plant will meet 16,000 MW which is 30% of the whole energy usage. A Coal deposits among the fossil fuels is very plentiful in natural resources and has high economical efficiency but application technique is very inconvenient. Also when burned for utilization, it generate various toxic and untoxic air pollution materials; fly ash, bottom ash, sulfurous acid gas etc. In this study, we could establish a preparation of clean coal by triboelectrostatic separation. In this study, we made a bench-scale's triboelectrostatic separation equipment using electrostatic technology, and got an optimum conditions of various factors for increasing recovery rate and purification in separation. A test result, we got a clean coal that recovery rate is 68.10%, rejection rate of ash and sulfur content is 31.23% and 28.33%.