• Resources Recycling
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• v.31 no.3
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• pp.3-15
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• 2022

Lithium is the lightest metal and the first metal in the periodic table. Lithium is used in a variety of applications, including the production of organolithium compounds, as an alloying addition to aluminum and magnesium, and as the anode in rechargeable lithium ion batteries especially for electronic devices and electric vehicles. Therefore, lithium is indispensable metal in our daily lives. The use of lithium continues to rise and has increased from about 14,000 tonnes per year worldwide in the 2000 to about 82,200 tonnes in the 2000. However, lithium is a representative rare metal and ranks 32nd among the abundant elements in the earth's crust. This study reviews the current status of the lithium extraction processes as well as the trend in production amount and use. Lithium is extracted by a various methods depending on the type of resources. These extraction methods are essential for the development of new recycling processes that can extract lithium from secondary lithium resources.

• Resources Recycling
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• v.29 no.4
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• pp.45-50
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• 2020

Producer and distributor of electrical and electronic equipment may directly collect waste electrical and electronic equipment that falls under the class to which the equipment they distributed belongs, or may join KERC(Korea Electronic Recycling Cooperative) and have KERC fulfill the duty to collect on behalf. In this study, the system of calculating the financial contributions is reviewed, and then the defined problems and improvement plan are proposed. First, the standard operation and time should be set for collection and transportation costs, taking into account the operation by collection type. Second, since there is a difference in the screening method of the recycling center, the standard cost for the allocation factor should be set by reflecting the difference in these methods and the characteristics of the product line being processed. Third, it is necessary to secure a budget of sufficient size by determining the median or average value rather than the minimum value in the forecast model for visit collection. This study is suggesting in that it examines the problems of the allotted contributions paid by the mutual aid members to KERC and suggests ways to improve them.

• Resources Recycling
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• v.26 no.3
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• pp.79-91
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• 2017

The core of Hydrogen Fuel Cell Vehicles (FCV) is polymer solid fuel cell (PEFC), and the core material that generates electrochemical electricity in the cell is platinum catalyst. Platinum is localized in South Africa and Russia, and the world production of Pt is about 178 tons per year, which is expensive and recycled. At present, the amount of Pt used in PEFC is $0.2{\sim}0.1mg/cm^2$. In order to reduce the price of the battery and increase the FCV supply, the target is to reduce the amount of Pt used to $0.05{\sim}0.03mg/cm^2$. $Pt-Pd/Al_2O_3$, Pt/C, Pt/GCB, Pt/Au/C, PtCo/C, PtPd/C, etc. by using polyol method using nano Pt, improved Cu-UPD/Pt substitution method and nano-capsule method, Have been researched and developed, and there have been reported techniques for improving the activity of Pt catalysts and stabilizing them. This paper investigates the production technology of nano-Pt and nano-Pt catalysts, recycling of spent Pt catalysts and application trends of Pt catalysts.

• Journal of Advanced Navigation Technology
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• v.14 no.1
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• pp.127-133
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• 2010

The process for establishment of Operational Continuity Management Plan is organized repeatedly of Business Risk Assessment, Crisis Analysis, Business Impact Analysis, Establishing Business Recovery Strategies, Detailed Planning, Plan Execution, Test and Maintenance(Including Monitoring). Therefore, in this paper in response to global environmental change and the construction and operation of social security systems to maximize operational continuity management, crisis management and crisis management systems, building integrated systems for building technology in general and operational continuity management within an organization to understand developed to provide a framework for implementing operational continuity management in terms of crisis management has proposed to build an integrated system.

• Prospectives of Industrial Chemistry
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• v.24 no.2
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• pp.10-21
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• 2021

최근 폐플라스틱의 사용량 증가와 미세플라스틱으로 인한 해양 오염 및 생태계 축적 등의 부정적인 영향으로 인해 플라스틱 업사이클링(upcycling) 및 리파이너리(refinery) 기술에 대한 관심이 증가하고 있다. 화학적 재활용 방법 중의 하나로, 폐플라스틱의 열분해를 통해서 재생 연료 및 화학물질을 생산하는 연구는 90년도에 활발히 진행된 바 있고, 최근의 환경오염에 대한 대응으로서 다시 많은 관심을 받고 있다. 폐플라스틱을 효율적으로 분해하기 위해서는 촉매를 사용하여 분해 속도를 제어해 주어야 하며, 사용된 촉매의 특성에 따라 최종 생성물의 성상이 크게 달라진다. 본 기고문에서는 폐플라스틱의 촉매 열분해를 통해 가솔린, 디젤유 및 항공유와 같은 수송용 연료, 발전용 연료 혹은 방향족 화학 물질을 생산하는 기술들의 최신 연구 동향을 다루고 향후 전망에 대해 기술하고자 한다. 아울러 최근 몇 년간 많은 연구가 있었던 바이오매스와 폐플라스틱의 혼합열분해를 통한 하이브리드 촉매 공동 열분해 기술에 대해서도 다루고자 한다.

• The Journal of the Korea Contents Association
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• v.17 no.1
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• pp.485-495
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• 2017

The purpose of this study was to analyze research trends on recycling of construction wastes. Total 72 research papers published in domestic academic journals from 1995 to 2016 were analyzed. Four indicators were used for analytical framework of this study: research period, research field, research method, and research theme. The greatest amount of researches related to construction wastes recycling were executed during 2006-2010. Over half of the researches were done in architecture area. The most frequently used research method was combined method which used qualitative and qualitative method simultaneously. In terms of research theme, many of the subject researches were interested in understanding the current state of construction wastes recycling. It is recommended for further research to perform meta analysis which extends research subjects and range of keyword in macro perspective.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.31 no.1
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• pp.31-38
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• 1999

Adsorption of polymeric flocculants and dry strength agents onto the surface of papermaking fibers is critical for their effective utilization since the polymeric substances not adsorbed on fibers or fines keep recirculating in the papermaking system to cause various operational difficulties and loss of raw materials. Problems associated with the unadsorbed polymeric substances generate great attention because unprecedent interests in utilization of recycled papers and papermaking system closure. In this study, to understand the effects of recycling on the adsorption propensity of cationic polyacryamide (PAM) dry strength resin onto hardwood bleached kraft pulp fibers and fines a systematic approach was followed. Never dried bleached hardwood kraft pulp was recycled in two different ways. In mode one recycling experiment never dried pulp was beaten then recycled three times by employing simple drying and disintegrating steps. In mode two recycling experiment beating of the recycled pulp was carried out after each recycling step. Adsorption of cationic PAM on fibers and fines was evaluated employing Kjeldahl nitrogen analysis method. The influence of recycling on water retention value, carboxyl content, sheet density and tensile strength of the pulp was examined. As the number of recycling increased, water retention value of the fiber was reduced due to hornification and this in turn caused a decrease in adsorption of cationic PAM. On the other hand, the carboxyl content of the recycled fibers increased because of the oxidation of fibers occurred during drying, and this caused an increase in adsorption of cationic PAM. Because of these two opposing factors the adsorption of the cationic PAM on the recycled fibers decreased and then increased slightly at third recycling step. Increase of PAM adsorption, however, did not provide did not provide and strength improvement for the recycled pulp fibers indicating greater influence of the honification on interfiber bonding.

• 한국신재생에너지학회:학술대회논문집
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• 2011.11a
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• pp.155-155
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• 2011

신재생에너지 수요가 확대됨에 따라 신재생에너지 관련 제품에 소요되는 물질에 대한 관심이 확대되고 있다. 이들 물질은 공급리스크가 존재하는 희유금속이 주를 이루고 있다. 본 연구에서는 신재생에너지 등의 high tech 기술 확대로 인한 희유금속의 수요 및 공급을 전망하고 있는 미국의 critical raw material 관리 전략을 살펴보고자 한다. 미국은 2010년 12월 미국 에너지성(DOE : Department of Energy)에서 위기 물질 전략(Critical Materials Strategy)에 관한 리포트를 공표하였다. 클린 에너지 기술 4개 분야(영구자석, 선진 전지, 태양전지 박막, 형광 물질)에서 핵심이 되는 물질(희유금속 등)의 수급 불균형이 일어날 가능성에 대해 조사를 실시하여 리스크 평가하여 단기, 중단기로 구분하여 위기물질을 선정하였다. 클린 에너지 기술 4개 분야에서 핵심이 되는 물질(네오디움, 디스프로슘, 코발트, 리튬, 랜턴, 세륨, 테룰, 인듐, 갈륨, 유로피움, 테르비움, 이트륨)의 12광종 수급을 2025년까지 전망한 결과 전체적으로 단기(2010년~2015년)보다 중기(2015년~2025년)에 공급 부족이 확대한다고 예측되었다. 단기적으로는 인듐이 약간 부족하는 것 외에 디스프로슘과 이트륨에 관해서도 공급 부족할 것으로 예측되었다. 중기적으로는 코발트(전지 기술에 사용)와 유로피움(고효율 조명용의 형광 물질에 사용) 외 대상이 된 다른 모든 물질은 공급 부족이 발생할 것으로 전망되었다. 이를 종합하여 단기적으로는 디스프리슘, 유로피움, 인듐, 테르븀, 네오디움, 이트륨 등이, 중기적으로는 디스프리슘, 유로피움, 테르븀, 네오디움, 이트륨 등이 위기물질(Critical Material)로 분석되었다. 에너지성은 위기물질을 공급원다각화, 대체물질개발, 리유즈, 리사이클링 등을 국제적 파트너와 함께 추진하여 리스크를 관리할 것이며, 2011년까지 최신정보를 구축하여 위기물질 전략을 재설정할 예정이다. 체계적인 위기물질 선정 및 관리전략 등을 참조하고, 신재생에너지기술 변화에 따른 원재료의 중요성 및 리스크 관리현황을 기초로 우리나라에 적합한 위기관리 물질 선정 및 관리가 필요할 것이다.

• Fire Science and Engineering
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• v.23 no.5
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• pp.72-77
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• 2009

In the recycling procedure of the refrigerator, the fire frequently breaks out. In this study, to clarify the exact cause of the fire, the components and concentration of the materials produced in the process are analysed as well as the problems in the process system, and the protective measure to prevent the fire and the explosion fundamentally is proposed. In this procedure, the preventive measures of fire by removing the combustible materials such as polyurethane and inflammable gases, by removing the ignition sources and by reducing the oxygen concentration to the minimum are proposed along with the protective measures to reduce the damage in the fire. In the crushing procedure where the fire or explosion can break out in diverse ways, the forced ventilation or exhaust system applied to the small partial ventilation facility are installed to reduce the concentration of inflammable gas mixture to lower than the inflammable limit by injecting and exhausting the air forcibly.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.06a
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• pp.344-344
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• 2008

최근 들어, 압전 세라믹스 제조기술의 급속한 발전으로 기계, 전자뿐만 아니라 휴대용 전자기기의 초소형 적층형 압전모터 및 압전변압기 같은 고품질 압전소자의 개발에 있어 특히 소자의 소형화에 따라 나노크기의 분말제조가 연구의 주류를 이루고 있다. 현재 이러한 나노크기의 세라믹스 제조에 사용되는 방법으로는 화학적 공침법, 졸겔법, 수열반응, 그리고 고에너지 볼밀법등이 보고되고 있다. 볼밀링 공정은 세라믹제조 시 필수 불가결한 공정이나 일반적으로 미세화에 그 한계가 있어 $1{\mu}m$이하의 입자크기를 가지는 분말은 제조가 곤란한 것으로 인식되어 왔다. 그러나 고에너지 볼밀을 이용한 볼밀링은 원료의 변형, 파괴 등과 같은 원료의 물리적 변화 뿐만 아니라 원료를 구성하는 원자/분자 구조에 영향을 미쳐 원료의 화학적 특성의 변화를 유발한다. 이러한 화학적 특성의 변화는 이종 원료간의 화학 반응성을 향상시켜 밀링 중에 새로운 화학종의 생성을 유발하게 되는데 이러한 현상을 mechanochemical 효과라 한다. 이러한 mechanochemical 효과는 나노 분말 입자의 제조뿐만 아니라, 분자설계, 재료합성, 자원처리 및 리사이클링 등에도 그 적용이 시도되고 있다. 이러한 mechanochemical 효과를 이용하여 분말을 미세화 함으로써 저온 소결과 재료특성 향상을 기대해 볼 수 있다. 따라서, 이번 연구에서는 우수한 압전 특성을 가진 PMN-PNN-PZT조성을 가지고 시편을 제작하였으며, 고에너지 볼밀시간에 따라 그 압전 및 유전특성을 조사하였다.