• Resources Recycling
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• v.10 no.4
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• pp.48-57
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• 2001

The main consistent materials and main elements of the bottom ash in municipal solid waste incineration ash according to particle size were investigated and the environmental hazards were considered by investigating the content of dioxin and heavy metals in bottom ash and the concentration of heavy metals in its leachate. The main materials of bottom ash are glasses, ceramics, scraps of iron. As the particle size increases, their percentage weight also increases and their percentage weight was over 70% in 4 mesh~25 mm particle size fraction. The main elements of bottom ash are CaO, $SiO_2$, $Fe_2$$O_3$,$ A1_2$$O_3$and the content of CaO decreases and the content of $SiO_2$increases as particle size increases. The heavy metals accumulate in small particle size fraction. The concentration of heavy metals in each leachate by domestic leaching test is almost similar. As the aging period is prolonged, pH of bottom ash lowers gradually and the leached concentration of Cu and Pb diminishes.

• 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 Korean Recycled Construction Resources Institute
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• v.9 no.2
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• pp.161-166
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• 2021

This study was on leaching test(KSLT) of the aggregate for the products to evaluate the characteristics of contaminants and the possibility of contamination arising from the aggregate. On the basis pH, conductivity, turbidity, TN, TP, COD and heavy metal contents in the aggregate increased as the particle size of the aggregate was smaller. The pH appeared to be 9.9~11.4 which is relatively higher than soil, however, heavy metal has investigated within the 1 region's standard value of soil pollution standards. From the leaching test, there is strong indication that the risk of pollution due to elution of pollutants gets higher with the smaller grain size. Especially conductivity and turbidity are the potential water pollution source and recycled aggregates of 10mm or less could be a potential pollution source since it could elute soluble matters and suspended solid, but there is no proper management standard for them. As a result of evaluating water pollution possibility of the aggregate, the pH displayed in items with a very high possibility of contamination, TN and TP did in item with a low possibility of contamination and on the other hand the heavy metals did in item with a very low possibility of contamination.

• Journal of the Korea Organic Resources Recycling Association
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• v.2 no.2
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• pp.89-98
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• 1994

A survey was carried out in Seoul Metropolitan area during December of 1993 and January of 1994. The objective of the survey was to provide a useful information for the development and improvement of recycling policies, regulations and systems in Korea. Of the 782 individuals contacted, 473 individuals completed and retured surveys, of which 437 were usable. The results were analyzed using a statistical package SAS(Statistical Analysis System). The results indicated that 86% of apartment area has recycling bins, while only 33% of individual house(detached dwelling) area has those. About half of the respondents felt that food waste is the major source of household waste. The most serious problem to recycle more household waste is to provide space to store recyclables at the source. The majority of Seoul Metropolitans(78.5%) are willing to participate in recycling programs, while 14.4% want to participate only when there are economic incentives or benefits. Respondents who want economic incentives appeared to be low income people. 66.1% of total respondents said that they do not use disposables. However, only 53,0% among respondents under 30 years old answered they do not use disposables. People who graduated from middle high school only and are under 30 years old have tendency to dispose of used milk cartons without rincing and drying, while those who are over 40 years old and graduated from university prefered to rinse and dry used milk cartons before disposal. Regarding disposal of newspapers, only 43.9% of the total respondents separated newspaper from other types of used paper. In the case of alumium cans, 22.5% of the total respondents answered that used aluminum cans are not recyclables. Much higher portion (30. 4%) of the respondents who graduated from middle high school only felt that aluminum cans have no value to recycle. The results indicated that education and information regarding recycling are highly desirable.

• Proceedings of the KAIS Fall Conference
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• 2009.12a
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• pp.1030-1033
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• 2009

고형연료(RDF)는 가연성 폐기물을 성형된 형태로 만드는 것으로 화석연료의 대체 에너지로 이용되어질 수 있을 뿐만 아니라 일반 소각설비에 비해 수송성, 저장성이 뛰어나며 발열량이 거의 일정하여 연소 안정성이 우수하고 액체연료나 기체연료의 비해 경제성과 안정성이 높다는 장점이 있다. 하지만 고형연료의 미량 포함되어 있는 중금속 물질에 의해 연소장치의 부식이나 시설 노후 촉진화와 같은 원인을 제공하며, 심각한 환경오염원의 전구물질이 생성될 수 있어 실용화에는 큰 장해 요인이 되고 있다. 따라서 본 연구에는 고형연료의 재료가 되는 폐기물을 분석하여, 중금속성분이 미치는 영향을 조사하고 부존자원의 최적 이용 방안을 도출하며, 이를 바탕으로 부존자원 액상/고상 연료화 기술, 부존자원 복합이용시스템, 폐열활용 시스템과 같은 기술에 적용하여 부존자원 재활용 및 에너지를 최적 활용할 수 있는 D/B 구축을 하는 것이 최종 목표이다.

• Resources Recycling
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• v.32 no.1
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• pp.3-12
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• 2023

Bauxite residues represent industrial wastes that have been accumulating over the past 120 years since the beginning of the alumina industry. They are typically classified as harmful substances owing to their strong alkalinity and salinity characteristics. These residues, with quantities steadily increasing by more than 150 million tons annually worldwide, are recycled into various industrial materials using dealkalization processing. This study investigates the generation process of alkaline substances in bauxite smelting and the recent techniques adopted for controlling their alkalinity. The properties of bauxite residues are known to vary depending on the raw mining and digestion methods. Thus, the dealkalization process must be selected considering the type of alkaline material, local environment, and infrastructure.

• International Journal of Highway Engineering
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• v.7 no.1 s.23
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• pp.21-29
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• 2005

One way to recycle the construction wastes is to use the waste concrete aggregates as the pavement materials. Although there are many studies and technical developments about waste concrete aggregates, the impurities produced in the process of the aggregate production prevent the use of the waste concrete aggregates in the pavement construction. In this study, the impurities included in the recycled waste aggregates were classified into inorganic and organic ones according to their characteristics, and the influences of each impurities on the pavement performance were presented. It was also showed that the limit of impurity content in the lean concrete base through the correlation between the inorganic impurity content and the compressive strength, and that in the granuler subbase layer through the correlation between the organic impurity content and the modified CBR. In conclusion, it is possible to apply waste concrete aggregates for the pavement when inorganic impurity content is less than 10% in the lean concrete base, and organic impurity content is less than 2% in granular subbase.

• Journal of Bio-Environment Control
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• v.13 no.2
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• pp.107-111
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• 2004

This study was conducted to examine the possibility of producing poinsettia with various growing media containing used perlite and rockwool slabs as medium components. Pot plants of Euphorbia pulcherrima 'Freedom Red' were grown in 10 media containing used perlite and particles of rockwool slabs at various ratios including 1:1 and 1:3 (v/v). Medium containing used perlite and peatmoss at 1:3 (v/v) was employed as the control treatment. Height, root length, length of the longest branch, number of roots, leaf area, and width and length of the largest bract of plants grown in media containing used perlite were significantly greater than those in the control. Stem diameter and bract count were not affected by the medium composition. From the results, used perlite and rockwool slabs were proved to be a practically useful materials as medium components for pot production of poinsettia plants.

• Proceedings of the KAIS Fall Conference
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• 2012.05a
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• pp.423-425
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• 2012

레드머드(Red mud)란 Bauxite 광물을 Bayer process 공정을 거쳐 알루미나를 정제하는 과정에서 발생하는 슬러리 형태의 산업폐기물이다. 레드머드는 pH 10-12.5 범위의 높은 알칼리성을 나타내며, 14-21 가지의 광물상을 함유하고 있다. 하지만 유가성 물질이 함유되어 있음에도 불구하고 적절한 처리 방법이 없어 폐기물로써 처리되어지고 있다. 레드머드의 처리 및 보관 부분에서 강우로 인한 지하수 오염, 처리 토지 면적 등과 같은 문제점이 다소 발생하여 효율적인 처리가 시급한 실정이다. 이로 인해 환경, 토목, 건설 등 다양한 분야에서 레드머드를 재활용하기 위해 활발히 연구가 진행되어 지고 있지만 재활용양이 발생량에 비해 극히 적다. 따라서 본 연구에서는 최종 처리되는 레드머드의 부피를 줄여 최종 처리 비용을 감소시키고자 레드머드에 함유되어 있는 유가성 금속 성분 중 $TiO_2$ 성분의 회수 방법 중 초음파를 방사하여 회수하는 방법을 알아보았다.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.6
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• pp.3089-3095
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• 2013

The headliner was made of polyurethane(PU) and glass fiber(GF) composite materials are widely used as a sound insulation material. A large amount of waste materials occurs as a by-product in the headliner manufacturing process. In order to efficiently reuse the headliner waste materials, separation process of the components are very necessary. According to the results of thermal analysis, weight loss showed increase in the order polyurethane foam> non-foaming polyurethane> non-woven fabric> 1st layer> glass fiber in the range of up to $400^{\circ}C$. Analysis of the DSC characteristics, HDPE, LLDPE, PP, and Master Batch by adding additives the wasted scrap. As a result, except for the PP, there was no exothermic transition due to the crystallization.