• 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.

• International journal of advanced smart convergence
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• v.9 no.1
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• pp.70-81
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• 2020

Plastics that we use and simply throw away have a life span of about 500 years and barely decompose. The practice of producing and using common plastics needs to be challenged. Until now, they have been useful in the industrial structure of mass production, but it can be said that there is a lack of research into new materials to introduce and apply in terms of material recycling. As a result of this, we have come to the uncomfortable realization of the fact that we cannot incinerate or reuse these precious resources indiscriminately. No matter how well-designed a product is, it has a competitive advantage if production and consumption activities, waste, collection, sorting and treatment are considered in terms of a continuous cycle, and in this respect, Extended Producer Responsibility (EPR) can help. We are implementing the EPR system, and active industrialization in the field of recycling is required, which is also a challenge for producers to participate actively in recycling and seek to save and recycle resources in design and manufacturing. Against this backdrop, We would like to examine the possibilities, through various studies and developments on product design of recyclable materials, which is being conducted mainly in Europe. In particular, we would like to examine the methods, and value of solving environmental problems and the active efforts to achieve this in the design world, and in particular the case of product design using recycled plastics.

• Journal of Korea Society of Waste Management
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• v.35 no.8
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• pp.692-700
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• 2018

In this study, the results of PBDEs and HBCDs of the products and waste that contain BFRs such as domestic electronic products, automobiles and textile products were compared with international management standards, and their excess rates were calculated. Deca-BDE was detected among the PBDEs in TV rear cover plastics, car seats, automotive interior plastics, and automobile shredding residues of products and waste containing BFRs. The comparison with Basel Convention management standards (1,000 mg/kg) for PBDE-containing wastes (4 types in total) shows that the excess rate of all samples was less than 1.5%. The estimated excess rate compared to the EU and Basel convention management standards (1,000 mg/kg) for PBDEs (4 species + deca-BDE) and TV rear cover plastics was 37.5% (30 of 80 samples exceeded the standards). The estimated excess rate compared to the Basel convention management standards (1,000 mg/kg) for HBCD, building materials products and waste was 15.7% (17 of 108 samples exceeded the standards). In the case of PBDEs, it is necessary to remove only the rear cover of CRT TV among the electric and electronic products and treat it in the flame retardant treatment facility to improve the recycling collection system. In the case of HBCD, it is necessary to appropriately dispose of the recycled materials, heat insulation materials, TV plastics, and styrofoam in marine fishery among construction materials and restrict the use as recycled raw materials.

• Resources Recycling
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• v.24 no.4
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• pp.38-49
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• 2015

The importance of recycling came to the fore by increasing of waste electrical and electronic equipment(WEEE) generation. Small WEEE recycling in particular represents a big challenge in Korea because it has various items and components. Main materials of small WEEE are typically well known for metals (copper, iron, aluminum, etc.), PCBs and plastics. Not only Korea but also overseas, the laws for small WEEE were in effect in order to recycle effectively, but the technology is not catched up with the regulation which has to recycle an allocated account of WEEE. In addition, recycling technologies and processes for small WEEE are not developed enough to recycling center properly. In that sense, if we develope the recycling process, have not only technology competitiveness but also resource conservation, improving the environment and economic profits. Therefore, through the analysis of economic value of recycled small WEEE, and current technologies both domestically and internationally, we design conceptual recycling process of small WEEE, and consider the way forward.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.47 no.4
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• pp.66-75
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• 2015

Disposable diaper waste is consisted of plastic, fiber, and SAP (Super Absorbent Polymer). They are valuable to be used as raw materials of other products including plastic blocks and pulp mold. Nevertheless, disposable diaper waste have been disposed by landfill and incineration without recycling. Due to strict environmental regulations it is necessary to develop fractionation technique to recycle the disposable diaper waste. In this study the fractionation technique using pilot-scale stock preparation units was investigated. Process for separation of plastic and fibers from disposable diaper waste was composed by the combination of pilot-scale pulper, drum screen, screen and cleaner. Recovery rate of plastics and fiber was checked according to the various operating conditions. In drum screen, recovery rate of plastic was high when the cut size of disposable diaper waste was $5cm{\times}5cm$. The highest recovery rate of fiber was achieved with 0.3 mm slot screen. It is important to control the neutral state of SAP for improvement of recovery rate of fiber since SAP can be swelled easily in water. Therefore SAP can be controlled efficiently by the addition of calcium chloride into the pulper. Consequently recovery rates of plastics and fibers were over 90 and 80% under the optimum pilot operating conditions.

• Journal of the Korea Organic Resources Recycling Association
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• v.1 no.2
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• pp.299-315
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• 1993

This study was performed to investigate the recycling activity of solid waste. Three study area were selected, which were Dobonggu in Seoul, Siheung City and Kimpogun. The amount of recycled out of the solid waste generated was between 0.02 kg per capita/day -0.10 kg per capita/day. The recovery rate of the waste paper was 42.7%, which was the highest, followed by glass bottles, cans and plastics. The waste paper was the most important item concerning its weight percentage and amount of sales. It comprised more than 60% in its weight and sales amount out of the total recycled item. Glass bottles placed the second. Amount of sale for the recycled item was less than 5 Won per capita/day, this is very low. The Recycling Drive Association, a private organization was mainly organized by public administrational basis and its activity was simply concentrated on the reclassification of the collected recyclables. Generally, citizen's participation and the member's satisifaction was low since there was no economic incentives. In this paper, some strategies were suggested and evaluated to increase citizen's recycling activity.

• Journal of the Korea Organic Resources Recycling Association
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• v.16 no.1
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• pp.70-78
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• 2008

In this study, the composition and physico-chemical characteristics of school waste which is located in B area, kyunggi-do was investigated. It is necessary to measure the characteristics of school waste to build the data-base for resource and recycling of waste. This school waste was composed of 12.25% of food wastes, 56.26% of papers, 9.26% of plastics&vinyls, 1.52% of textiles, 3.70% of wood, 0.11% of rubbers&leathers and others, respectively. Most of school wastes are mainly composed of paper and plastic waste and composition of combustible waste was about as 90%. From 3-components analysis, contents of moisture, combustible component, and ash was 5.72%, 88.29% and 5.98%, respectively. Moisture content was higher in Agricultural Dwelling school area compare to the urban dwelling school area. The chemical element of the school waste has the high order of carbon, oxygen, hydrogen on the dry basis of wastes and the low heating value of the MSW which is measured by calorimeter is shown as 3720.44kcal/kg.

• Journal of the Architectural Institute of Korea Structure & Construction
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• v.36 no.4
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• pp.153-161
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• 2020

This study investigates the recycling potential of demolition waste (DW) according to building structure, while considering economic aspects. For that, this study surveyed 1,034 residential buildings to collect reliable information on demolition waste generation rates (DWGRs). This study suggested a method for operational cost calculation for each stage and carried out an inventory analysis. The economic value of recycled DW materials was also calculated. And then, the recycling potential(RP) was calculated by building structures and waste types. RP by building structure was low (27-40%), and RP was found in the order of masonry-block, wooden, RC and concrete-brick. By type of DWs, the RP of aggregates was considerably lower than 7%, and DWs such as wood, plastics, and metals showed more than 100% RP. Considering the results of this study, In order to improve the RP of buildings and DWs, the diversification of products that recycled waste like aggregates (i.e., mortar, concrete, bricks, blocks, tiles) and the development of high value-added products are considered to be the most urgent problems. Based on the above RP results, this study proposed a more advanced method for life cycle assessment of buildings and demolition waste.

• Journal of Korea Society of Industrial Information Systems
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• v.5 no.4
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• pp.47-54
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• 2000

In general, computer industry is known as clean sector, but computer is a complicated assembly which is highly hazardous substances such as lead, cadmium, mercury, Hexavalent chromium, plastics etc. This paper was presented the quantity of hazardous substances in the personal computer and the problem of its disposition-incinerating, landfilling, recycling. Also EPR which is the solution of e-waste was introduced.

• 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.