• Resources Recycling
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• v.7 no.2
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• pp.16-22
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• 1998

Recently, the new technology for the recycling of waste plastics as an alternative he1 of blast furnace ha been developed. In this shldy, the test of plastics injection into a tuyere af the foundry blast furnace were carried out. The injection rate of plastics far this tcst facility war expressed as follows, ${W}_{s}=0.265\frac{{delta}PA}{U}_{g}$, where. Ws, AP, A and Ug are plastic conveying ratc (kgisec), pressure drop between feed hopper and blaqt pressure (alm), cross sectional area of conveying pipe (mi) and superficial velocity of transport air (mhzc) respcctiuely. From the results of semi-continuous test operation during 96 hours, the replacement raho mned out to be 1.38 according to the injection rate of 6. 4 kg-plasticsit-p. With increasing the rate of plaslics injcchon, the content of hydrogen in top gas became increased and the brick temperahlre at bzlly was also increased due to Lhe changes ot the combustion zone shape.

• Clean Technology
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• v.17 no.3
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• pp.191-200
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• 2011

Natural polymers, biopolymers, and synthetic polymers based on renewable resources are the basis for the 21th portfolio of sustainable and eco-friendly plastics but high-volume consumable plastics continue to be dominated by nondegradable petroleum-based materials. Three factors have recently made biodegradable polymers economically attractive: (i) rising costs of petroleum production resulting from the depletion of the most easily accessible reserves, (ii) environmental and economic concerns associated with waste plastics, and (iii) emissions of carbon dioxide from preparation of petroleum-based materials. These pressures have driven commercial applications based on biodegradable polymers which are related to reduction of carbon dioxide in processing, such poly(hydroxy alkanoate) and poly (lactide). Since initial degradation of these polymers leads to catastrophic mechanical failure, it is necessary to control the rate of initial degradation for commercial applications. In this article, we have a critic review on the recent progress of polymer modification for the control of degradation.

• Journal of the Korean Society for Marine Environment & Energy
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• v.5 no.2
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• pp.35-40
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• 2002

By the introduction of cleaning and drying processes, thermal extrusion system for the volume reduction of used polystyrene buoys was developed. It was tested in the costal area for the determination of operational reliability. By the removal of oyster shells and cleaning of salt, waste polystyrene buoys was changed to the raw material of plastics. The lower cost of one-tenth compared with that of the outer request treatment is promising the practical use of waste buoys' volume reduction system.

• Proceedings of the IEEK Conference
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• 2001.10a
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• pp.215-219
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• 2001

Impurities removal from waste carbon black was carried out to produce high-grade carbon black. A lot of hydrophilic carbon black is produced as a byproduct of the hydrogen production process by flame decomposition of water. Due to its impurity content such as sulphur, iron, ash and etc., it can only be used as low-grade carbon or burnt out. High-grade hydrophilic carbon black is 3-5 times more expensive than oil-based carbon black because of its process difficulties and requires pollutant treatment. Hydrophilic carbon is normally used far conductive materials for batteries, pigment for plastics, electric wire covering, additives for rubber, etc.. In these applications, hydrophilic carbon must maintain its high purity. In this study magnetic separation, froth flotation and ultrasonic treatment were employed to remove impurities from the low-grade hydrophilic carbon black. As results, the ash, iron and sulphur content of product decreased to less than 0.01wt.%, 0.0lwt.% and 0.3wt.% respectively, and the surface area of product was about 930 $m^2$/g.

• Journal of the Korean Society of Clothing and Textiles
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• v.44 no.5
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• pp.984-1003
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• 2020

The global fashion industry produces significant carbon emission and micro-plastics in oceans. Studies on sustainable design methods as such environmental issues in fashion are becoming intensely problematic. This study conducted a case study on 100 upcycle fashion brands to propose strategical upcycle fashion designs to compete in a sustainable fashion market. A literature review indicated that 3 types of textile wastes are generated as upcycling materials: post-producer, pre-consumer and post-consumer. Wastes are categorized together with 3 types of techniques: redesigning, reconstruction and handcrafting. This research derived 7 types of upcycle fashion designs that have the following features: to make luxury upcycle fashion products, to make sustainable grunge looks, to re-evaluate deadstocks, to recover vintage clothes, to convert waste into craft-arts, to offer solutions for damaged products, and to make zero-waste small fabric waste. The study results show that key drivers in the upcycle fashion design are the redesignability of materials and technique-related costs. This study implies that adopting appropriate design features can be a useful strategy for designers. New technologies will solve current problems and encourage them to design products in a new circular value system.

• Journal of the Korean Society for Marine Environment & Energy
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• v.18 no.3
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• pp.207-215
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• 2015

In the last decade, increasing national research fund for recycling the waste FRP (fiber reinforced plastics) ships which has caused environmental problems, improves the technology making concrete-reinforcing fibers out of the waste FRP. Furthermore, the concrete with recycled FRP fiber was tested for the structural performance. Experimental strength tests show that use of recycled FRP powder does not reduce the compressive strength of high strength concrete, and does increase the fire resistance performance of high strength concrete significantly. But, the study in investigating the properties of recycled fiber powder from waste FRP has not been completed because of the absence of the method of separation of mat layer from the waste FRP. This study is to propose a new extracting method of the mat layer from waste FRP, which is the efficient and environment friendly system. and thus it is considered to be the useful recycling method for fire resistance high concrete products or structures.

• Solar Energy
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• v.18 no.3
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• pp.197-203
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• 1998

A 5 ton/day pilot scale two-phase anaerobic digester was constructed and tasted to treat Korean food wastes in Anyang city. The process was developed based on 3 years of lab-scale experimental results on am optimim treatment method for the recovery of biogas and humus. Problems related to food waste are ever Increasing quantity among municipal solid wastes(MSW) and high moisture and salt contents. Thus our food waste produces large amounts of leachate and bed odor in landfill sites which are being exhausted. The easily degradable presorted food waste was efficiently treated in the two-phase anaerobic digestion process. The waste contained in plastic bags was shredded and then screened for the removal of inert material such as fabrics and plastics, and subsequently put into the two-stage reactors. Heavy and light inerts such as bones, shells, spoons and plastic pieces were again removed by gravity differences. The residual organic component was effectively hydrolyzed and acidified in the first reactor with 5 days space time at pH of about 6.5. The second, methanization reactor part of which is filled with anaerobic fillters, converted the acids into methane with pH between 7.4 to 7.8. The space time for the second reactor was 15 days. The effluent from the second reactor was recycled to the first reactor to provide alkalinities. The process showed stable steady state operation with the maximum organic rate of 7.9 $kgVS/m^3day$ and the volatile solid reduction efficiency of about 70%. The total of 3.6 tons presorted MSW containing 2.9 tons of food organic was treated to produce about $230m^3$ of biogas with 70% of methane and 80kg humus. This process is extended to full scale treating 15 tons of food waste a day in Euiwang city and the produced biogas is utilized for the heating/cooling of adjacent buildings.

• Resources Recycling
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• v.18 no.6
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• pp.10-17
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• 2009

Degradation of the organic component in the waste were carried out by superheated steam in a pressurized vessel. The effects of waste characteristics, reaction temperature and residence time on the degradation rate have been determined. The biodegradable organic components such as food and paper waste have been degraded, and plastics, wood and metal were remained without degradation. The degradation efficiency is decided by the desizing rate of the waste, and the waste mixture with 23% biodegradable organic component shows higher desizing rate than that of the 43% of the biodegradable organic component in a short residence time and the desizing rate is found to be 90% in the maximum condition.

• Journal of the Korea Organic Resources Recycling Association
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• v.17 no.2
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• pp.101-111
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• 2009

In this study, the physico-chemical characteristics of municipal solid waste (MWS) which was treated in gangwon area were investigated. It is necessary to measure the characteristics of municipal solid waste for build a waste treatment and RDF facility and for data-base and total managing of the landfill. It was found that the average density of solid wastes is in the range of $101.8{\sim}199.8kg/m^3$. This MSW was composed of 30.7% of food wastes, 36.3% of papers, 15.8% of plastics & vinyls, 1.9% of textiles, 3.2% of wood and 1.5% of rubber & leathers respectively. Most of MSW are composed of food, paper and plastic waste and the combustible waste is more than 90%. For three components, moisture is 44.6%, combustible component is 47.7% and ash is 7.7% respectively. The chemical elements are carbon, oxygen, and hydrogen on the dry basis of wastes. The low heating value of the MSW measured by calorimeter was obtained as 2,631 kcal/kg, and the high heating value of the MSW was obtained as 3,310 kcal/kg.

• 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.