• Title/Summary/Keyword: Resource recycling

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Experimental Study on Evaluation on Volume Stability of the Electric Arc Furnace Oxidizing Slag Aggregate (전기로 산화슬래그 골재의 체적안정성 평가에 관한 실험적 연구)

  • Lim, Hee Seob;Lee, Han Seung
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.21 no.2
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    • pp.78-86
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    • 2017
  • As the amount of slag generated annually increases, attempts to recycle slag as high value products are underway in order to develop an efficient resource recycling industry based on slag and derive economic benefits as well. However, the application of electric arc furnace (EOS) slag as construction material is practically limited because of the unstable substances included in it, such as free CaO.(EOS contains a small amount of free CaO, but several limitations still exist. Slag is stored for more than 3 months depending on the quantity of slag, which leads to additional economic loss. In this study, the amount of free CaO present in EOS is quantitatively evaluated to examine its qualities as a potential construction material and verify its application as concrete material. The quantitative analysis of free CaO present in EOS is performed using ethylene glycol. The free CaO contents of EOS samples were found to be below 0.5%. This satisfies the criteria specified in KS F 4571, which states that the CaO content should be below 40% and $CaO/SiO_2$ ratio should be below 2.0. In addition, it was confirmed that free CaO content difference appears to be dependent on the aging period and storage position.

Study on Efficient Carbonizing Conditions When Carbonizing Fish Offal (어류폐기물의 탄화처리시 효율적 탄화조건에 관한 연구)

  • Jeong, Byung Gon
    • Journal of the Korean Society for Marine Environment & Energy
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    • v.17 no.4
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    • pp.268-273
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    • 2014
  • Experiments on carbonization were conducted using fish offal generated from fish market for the purpose of resource recycling. Elemental composition of fish offal and effect of carbonation temperature on the overall yield were investigated. Carbon and hydrogen contents of fish offal were 51.1% and 7.6%, respectively in view of elemental composition. Particularly, nitrogen and sulfur contents were as high as 9.8% and 1.0%, respectively. These values suggests that odor problem of fish offal can be serious. Comparing elemental composition of fish offal with other waste materials, it is thought that carbon and hydrogen contents are considerably high. These implies that thermal disposal will be the best option for final disposal method of fish offal. As a results of carbonization experiments on Mackerel, Hairtail, Croaker and mixed sample of Mackerel, Hairtail and Croaker, carbonization patterns were quite similar irrespective of fish species. Carbonization yield was varied significantly depending on carbonization temperature at the carbonization time of 5 minutes and 10 minutes. When the carbonization time was maintained longer than 30 minutes, yield variation depending on time variation at each temperature was insignificant. Thus, it can be concluded that effect of carbonization time on overall yield was minor when the carbonization time was maintained longer than 30 minutes. Primary vaporization in carbonization conducted at the temperature of $400^{\circ}C$ was minor. Thus, difference of yield between temperature of $500^{\circ}C$ and $400^{\circ}C$ was appeared greatly. It can be concluded that yield difference depending on carbonization temperature can be neglected if the carbonizing temperature exceed $600^{\circ}C$ and carbonizing time exceed 10 minutes at the same time.

Feasibility Evaluation of Co-Incineration with MSW for Efficient Recycling of the Rejects after Separation Processes in MRF (재활용 기반시설에서 발생하는 선별 잔재물의 자원화를 위한 도시생활폐기물과의 혼합소각 가능성 평가)

  • Shin, Taek-Soo;Sung, Baek-Nam;Yeon, Ik-Jun;Cho, Byung-Yeol;Kim, Kwang-Yul
    • Journal of Korean Society of Environmental Engineers
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    • v.33 no.10
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    • pp.767-773
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    • 2011
  • The purpose of this study was to investigate the possibility of an alternative fuel resource by incinerating a mix of combustible MSW (municipal solid waste) and offals after separating recyclable material at the MRF (material recovery facilities) location. We analyzed the physical and chemical properties including the 3-contents, the calorific value, and chemical compositions of the separation rejects in MRF, and compared the results with combustible MSW. Moreover, we experimented the trend of combustible properties and the concentration change of air pollutants at mixed incineration in the MSW incinerator. According to the results of the experiment, the separation rejects showed higher heating value (5,865 kcal/kg), and lower moisture and ash content than combustible MSW. Since we have incinerated MSW in the MSW incinerator mixing the offals at 30% and 50% respectively, we know that the change of the concentration of dust, $SO_2$, $NO_2$, and CO did not appear significant, and not exceed the pollutants emission regulation. But, considering the enhancement of the HCl emission concentration (max. 33.7 ppm) at the co-incineration of the 50% offals, we believe that the proper mixing ratio of the separation rejects would become within 30%.

Improvement of Blast Furnace Slag Mortar Using the Recycled Fine Aggregates Depending on Improvement Material Type and Replacement Ratio (품질향상재 종류 및 치환율 변화에 따른 순환잔골재 사용 고로슬래그 모르타르의 품질향상)

  • Han, Cheon-Goo;Kim, Dae-Gun
    • Journal of the Korean Recycled Construction Resources Institute
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    • v.7 no.1
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    • pp.76-83
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    • 2012
  • In this study, the research examined the effect on FC, WG, RP replacement ratio on the quality improvement of BS mortar using the RA. First of all, the flow value increased as the FC contents increased, and decreased as the WG and RP contents increased. The air contents was reduced as the FC and RP contents increased, but was increased as the WG contents went up While the compressive strength of 1 : 7 mix proportion increased with the increase of the FC and WG contents, it decreased as there was more RP contents. The compressive strength of RP could increase as the mix proportion increased, but the difference depending on the improvement material type and replacement ratio decreased gradually. The absorption deteriorated as the FC and RP contents increased in all the mix proportions, but improved a little when WG was used. Meanwhile, the absorption decreased as the compressive strength improved in all the mix proportions as a correlation, but the order was FC, RP and WG depending on the quality improvement material types. The FC and WG were most favorable in terms of quality improvement as a total analysis, and the RP and WG was most effective in terms of economical efficiency and resource recycling.

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Nutrient Value and Yield Response of Forage Crop Cultivated in Reclaimed Tidal Land Soil Using Anaerobic Liquid Fertilizer (간척지 토양에서 혐기소화액비 시용에 따른 사료작물의 생산성과 사료가치 평가)

  • Shin, Kook-Sik;Hwang, Won-Jae;Lee, Seung-Heon;Kim, Chang-Hyun;Yoon, Young-Man
    • Korean Journal of Organic Agriculture
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    • v.20 no.4
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    • pp.669-685
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    • 2012
  • This study was carried out to investigate the nutrient value and yield response of corn, barley, and sudangrass by the application of anaerobic liquid fertilizer in two tidal land soil in order to design the resource recycling agricultural system between livestock and forage crop cultivation in a environment friendly agricultural region. Forage crop yields at reclaimed tidal soil during were at the level of 64~76% comparing with forage crop yields at upland soil in the cropping system of corn, barley, and sudangrass. And yields of forage crops were in the order of barley > corn > sudangrass in the cultivated cropping system for 2 year. Relative feed values (RFVs) of forage crops were 88%~106% for corn, 90%~111% for barley, and 91%~113% for sudangrass, and the carrying capacity of beef cattle (Hanwoo) was 5.8~8.6 head/year/ha for the corn-barley cropping system of one year, and 4.8~6.7 head/year/ha for the barley-sudangrass cropping system of one year. Also, carrying capacity of beef cattle (Hanwoo) was highest in the application level of anaerobic liquid fertilizer 200%.

Study on Stable Use of Stainless EAF Oxidizing Slag as Fine Aggregate of Concrete (스테인리스 전기로 산화슬래그의 콘크리트용 잔골재 활용방안 검토)

  • Cho, Bong-Suk
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.18 no.3
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    • pp.133-142
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    • 2014
  • Recently, more focus is shift to imbalances in aggregate market supply and demand and an exhaustion of natural resources. In this situation, Electric arc furnace oxidizing slag (EAF Slag) has high application possibility as aggregate for concrete due to similar property with general aggregate. In this study, We've got the plan to assure the chemical stability of EAF Slag, and then experimentally tested the mechanical performance and durability for the fine aggregate used EAF Slag. On this test result, we suggest the application plan. At the result of this study, it shows that EAF slag would reduce the surface defect such as pop-out due to natural aging for the fixed hour and adjustment the grain size of EAF Slag. And mechanical performance and durability according to the replacement rate of concrete service, were revealed more than equal or equal compare to general aggregate. Hereafter, quality control must precede not to impede the beauty of concrete surface as assure the safety for aging and processing. And, to establish the environmental resource recycling system for by-products of steel, it should be made development of various application and guideline of quality control for the EAF slag aggregate. Moreover, it must be constantly studied all kind of engineering performance and durability for related to this study.

Levels of Persistent Organic Pollutants in Waste Paper and Waste Lumber and Evaluation of their Sources (폐지와 폐목재에서의 잔류성 유기오염물질의 농도 및 배출원 추정)

  • Hwang, In-Kyu;Lee, In-Seok;Oh, Kwang-Joong;Kim, Ji-Won;Park, Hung-Suck;Oh, Jeong-Eun
    • Journal of Korean Society of Environmental Engineers
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    • v.32 no.9
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    • pp.870-878
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    • 2010
  • We investigated the concentration and the sources of ubiquitous persistent organic pollutants [i.e., 17 toxic polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs), 12 coplanar polychlorinated biphenyls (Co-PCBs), and 16 priority polycyclic aromatic hydrocarbons (PAHs)] in waste papers and lumbers from industrial complexes. The total concentrations in waste papers and lumbers ranged from 9.69~176.77 pg/g-dry and 0.14~0.25 pg/g-dry for 17 PCDD/Fs, 109.95~4097.25 pg/g-dry and 28.23~59.88 pg/g-dry for 12 Co-PCBs and 9.30~52.18 ng/g-dry and 0.82~1.82 ng/g-dry for 16 PAHs respectively. Generally, the concentration of these pollutants in waste papers was higher than those in waste lumbers. OCDD was dominant in waste papers and lumbers and the PCDD/F patterns of these samples were similar with that of stack gas. The distribution patterns of Co-PCBs in wastes were related with commercial PCB products, indicating the effect of commercial PCB products on ubiquitous environment. The diagnostic ratios of several PAH compounds in waste paper showed that they were related with pyrogenic sources.

Set up and Running Status of School Gardening at Elementary Schools - Focus on Jeollabuk-do (초등학교 학교 텃밭의 조성현황과 운영실태 분석 - 전북지역을 중심으로)

  • Jang, Yoonah;Jeong, Sun Jin;Han, Kyeong Suk;Gim, Gyung Mee;Choi, I Jin;Heo, Joonyung
    • The Korean Journal of Community Living Science
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    • v.28 no.4
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    • pp.613-623
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    • 2017
  • This study was conducted to investigate the set up and running status of school gardening at elementary schools in Jeollabuk-do. Among 416 elementary schools in Jeollabuk-do, 164 schools (39.4%) had school gardens. Ninety-seven schools in cities and 67 in counties had school gardens. The total area and school garden size at schools in Jeollabuk-do were $45,490m^2$ and $277m^2$ per school, respectively, as well as $1.6m^2$ per students. School gardens varied in type, and percentages of outdoor and off-campus gardens were 67.2% and 17.2%, respectively. There were differences in the set up, type of garden, annual operating budget, and participants in school garden programs according to the location (city or county) of the school The installation and automation of facilities in the garden (such as greenhouse, tool shed, resource recycling facility, etc.) were poor. Most schools grew various kinds of plants, including vegetables, crops, ornamentals, and fruits. Teachers most often operated school gardens and taught students. Teachers had difficulty managing school gardens due to absence of knowledge about sustaining gardens. Most respondents reported the need for a school garden training program. Sixty-one percent of schools reported that the garden was used for academic instruction, especially during class. The majority of respondents agreed that school gardens have a positive effect and wanted to increase classes related to school gardens. Accordingly, in order to sustain school gardens and maximize their effects, systematic and customized support is needed that considers the characteristics and circumstances of the school. The facilities and features of the garden should be improved, and the school garden training program for teachers should attempt to reduce the effort required to manage the garden and increase utilization efficiency. In addition, participation of garden coordinators, parents, and community volunteers in managing gardens and implementing garden lessons is required.

Preparation of Electrocatalysts and Comparison of Electrode Interface Reaction for Hybrid Type Na-air Battery (Hybrid type Na-air battery를 위한 촉매들의 제조 및 전극 계면 반응 성능 비교)

  • Kim, Kyoungho
    • Journal of Adhesion and Interface
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    • v.22 no.1
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    • pp.1-7
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    • 2021
  • The importance of high capacity energy storage devices has recently emerged for stable power supply through renewable energy generation. From this point of view, the Na-air battery (NAB), which is a next-generation secondary battery, is receiving huge attention because it can realize a high capacity through abundant and inexpensive raw materials. In this study, activated carbon-based catalysts for hybrid type Na-air batteries were prepared and their characteristics were compared and analysed. In particular, from the viewpoint of resource recycling, activated carbon (Orange-C) was prepared using discarded orange peel, and performance was compared with Vulcan carbon, which is widely used. In addition, a Pt/C catalyst (homemade-Pt/C, HM-Pt/C) was synthesized using a modified polyol method to check whether the prepared activated carbon can be used as a supported catalyst, and a commercial Pt/C catalyst (Commercial Pt/C) and electrochemical performance were compared. The prepared Orange-C exhibited a typical H3 type BET isotherm, which is evidence that micropore and mesopore exist. In addition, in the case of HM-Pt/C, it was confirmed through TEM analysis that Pt particles were evenly distributed on the activated carbon supported catalyst. In particular, the HM-Pt/C-based NAB showed the smallest voltage gap (0.224V) and good voltage efficiency (92.34%) in the 1st galvanostatic charge-discharge test. In addition, the cycle performance test conducted for 20 cycles showed the most stable performance.

Foundation Properties of Cement Mortar in the Use of Fine Aggregate of Coal Gasification Slag (석탄가스화 용융슬래그를 잔골재로 활용하는 시멘트 모르타르의 기초적 특성)

  • Park, Kyung-Taek;Han, Min-Cheol;Hyun, Seung-Yong
    • Journal of the Korean Recycled Construction Resources Institute
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    • v.7 no.2
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    • pp.116-122
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    • 2019
  • This study evaluated the properties of Coal gasification slag(CGS) according to the CGS contents of cement mortar condition as a basic step to examine the applicability of CGS as concrete fine aggregate. Flow increased with increasing CGS contents for both Crushed sand a(CSa) and Crushed sand b+Sea sand(CSb+SS), but the amount of air contents decreased to the opposite tendency. Based on 28 days is maximum compressive strength was obtained at CGS 50% when CSa was used and CGS 75% when CSb+SS. The flexural strength were the maximum at 25% and 50% of CGS, but the tendency was similar to the compressive strength. Compared with CSa, the compressive strength and flexural strength 5% higher than those of CSb+SS, in CGS using of were about 5% higher than those of unused CGS. As a result of comprehensive study on the quality of mortar according to the CGS contents, it can be concluded that when CGS is mixed with fine aggregate at about 50%, it can contribute to securing workability and strength development positively so that resource recycling and quality improvement can be achieved at the same time.