Facile Synthesis of Carbon-Coated LiFeBO₃ Microspheres by Spray Drying and Their Structural Properties

Kang, Leeseung,An, HyeLan,Jung, Seungmin,Nahm, Sahn,Lee, Chan Gi American Scientific Publishers 2018 Science Of Advanced Materials Vol.10 No.9

La-doped p-type ZnO nanowire with enhanced piezoelectric performance for flexible nanogenerators

Kang, Leeseung,An, HyeLan,Park, Ji Young,Hong, Myung Hwan,Nahm, Sahn,Lee, Chan Gi Elsevier 2019 APPLIED SURFACE SCIENCE - Vol.475 No.-

<P><B>Abstract</B></P> <P>In recent years, energy harvesting has attracted considerable attention as a promising method to convert waste energy to useful energy. In particular, piezoelectric energy harvesters are of significant interest, because they have a simple structure and can be used to harvest energy regardless of weather or other environmental conditions. In accordance with the miniaturization trend of electronic devices driven by low power, piezoelectric nanogenerators (PENGs) using various nanostructured materials are being developed. Among them, ZnO nanowires (NWs) are most widely used for the use of PENGs. However, while research on n-type ZnO NWs is extensive, studies on p-type ZnO NWs are insufficient owing to their poor stability. In this study, La-doped p-type ZnO (La:ZnO) NWs were synthesized by a hydrothermal method to expand the applications of p-type ZnO and determine their potential as PENGs. XRD analysis showed that La<SUP>3+</SUP> ions was well doped without the formation of any secondary phases and caused a change in the lattice parameter when compared to that of undoped ZnO. XPS analysis was performed to investigate the surface elemental compositions of La:ZnO NWs, and the morphology of La:ZnO NWs was investigated using SEM and TEM. We further studied the piezoelectric output performance of undoped and La-doped ZnO NWs, and found that La:ZnO NWs showed improved piezoelectric output performance as a result of electron screening effect of the p-type semiconductor.</P> <P><B>Highlights</B></P> <P> <UL> <LI> La-doped p-type ZnO (La:ZnO) NWs were synthesized by a hydrothermal method. </LI> <LI> Their physical and chemical properties are systemically investigated. </LI> <LI> La-doping can improve piezoelectric performance by electron screening effect. </LI> <LI> La:ZnO nanogenerators are good candidates for power sources in electronic devices. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Recovery of Tin from Printed Circuit Boards Disassembled from Waste Liquid Crystal Displays

( Sungkyu Lee ),( Leeseung Kang ),( Myung-hwan Hong ),( Dongyoon Shin ),( Sung-su Cho ),( Hyun Seon Hong ) 한국폐기물자원순환학회(구 한국폐기물학회) 2015 한국폐기물자원순환학회 3RINCs초록집 Vol.2015 No.-

Waste PCBs (Printed Circuit Boards) from LCDs (Liquid Crystal Displays) contain valuable raw materials, Sn, Cu, and other noble metals. Among these, high purity tin was obtained by electro-winning after appropriate acid leaching of tin. For this, leaching and electro-winning process parameters were optimized for solution stability, dissolution and electrolytic efficiency. Two aqueous procedures were developed and tested for electro-winning at mass-production capable basis: (1) HCl leaching after preliminary HNO₃ dissolution was quite effective in leaching high proportion of Sn as analyzed by ICP (Inductively Coupled Plasma) method. (2) Direct one-step leaching in H₂SiF₆ + H₂SO₄ + H₂O₂ was also tested and the solution was finally selected as electrolytes in electro-winning due to massproduction capability. The most efficient recovery of tin was observed after 7h electro-winning in aqueous H₂SiF₅ + H₂SO₄ + H₂O₂ maintained at 40: 96%-pure tin was obtained with 93.2% recovery rate.

Size and shape control of metal nanoparticles in one-pot synthesis

Dongyoon SHIN,Leeseung KANG,Chan Gi LEE 한국진공학회 2016 한국진공학회 학술발표회초록집 Vol.2016 No.8

국내에서 발생하는 폐디스플레이 제품의 재활용 가능한 유가자원 분석

김세열 ( Seyul Kim ),강이승 ( Leeseung Kang ),안혜란 ( Hyelan An ),이찬기 ( Chan Gi Lee ) 한국폐기물자원순환학회(구 한국폐기물학회) 2018 한국폐기물자원순환학회 춘계학술발표논문집 Vol.2018 No.-

국내 디스플레이 제조 기술은 세계적으로 인정받을 만큼 그 수준이 상당히 높으며, 디스플레이 산업 역시 빠르게 성장하고 있다. 현재 국내 디스플레이 생산과 수요의 꾸준한 증가 추세와 전자 제품의 짧은 순환주기를 고려하였을 때 향후 폐디스플레이의 발생량은 급증할 것으로 예측된다. 하지만 국내 폐 디스플레이 재활용 기술은 폐 디스플레이를 구성하는 단일부품에 대해서만 일부 재활용되고 있는 실정이며, 현재 국내 폐 디스플레이 발생량에 대한 공식적인 통계자료 역시 부족한 실정이다. 본 연구에서는 국내에서 가장 많이 발생하는 40 ~ 42인치, 32인치 크기의 LG, 삼성에서 제조된 폐 LCD 모델을 선별하여 분석을 진행하였다. 폐 LCD 제품을 플라스틱, PCB, LCD 패널, 금속, CCFL 모듈, 시트, 기타 폐기물(전선, 스피커 등)으로 해체·분리하여 회수 가능한 유용자원의 종류와 구성비를 조사하였다. 분리 회수된 자원은 제품의 제조연도와 크기에 따라 특성변화를 분석하여 향후 통합 재활용공정 개발을 위한 기초자료로 활용하고자 하였다. 폐 LCD 제품의 평균중량은 모든 크기의 제품에서 제조연도가 최근과 가까울수록 감소하는 특징을 보였다. 분리된 PCB와 금속 부품의 경우 중량비가 제조연도에 따라 감소하였으나 LCD 패널 및 플라스틱의 경우 오히려 증가하였다. 특히 플라스틱 재질은 제조사별로 다양한 종류가 사용되어 고부가의 재활용공정을 위해서는 플라스틱 선별이 중요한 공정임을 제안하였다. 본 연구에서 구축된 데이터베이스 자료는 폐 LCD 제품 재활용률 향상 뿐만 아니라 고부가 재활용 공정 도입을 통해 친환경 고효율 해체공정시스템 구축에 기여할 것이다.

Recycling of metal-organic chemical vapor deposition waste of GaN based power device and LED industry by acidic leaching: Process optimization and kinetics study

Swain, Basudev,Mishra, Chinmayee,Kang, Leeseung,Park, Kyung-Soo,Lee, Chan Gi,Hong, Hyun Seon,Park, Jeung-Jin Elsevier 2015 Journal of Power Sources Vol.281 No.-

<P><B>Abstract</B></P> <P>Recovery of metal values from GaN, a metal-organic chemical vapor deposition (MOCVD) waste of GaN based power device and LED industry is investigated by acidic leaching. Leaching kinetics of gallium rich MOCVD waste is studied and the process is optimized. The gallium rich waste MOCVD dust is characterized by XRD and ICP-AES analysis followed by aqua regia digestion. Different mineral acids are used to find out the best lixiviant for selective leaching of the gallium and indium. Concentrated HCl is relatively better lixiviant having reasonably faster kinetic and better leaching efficiency. Various leaching process parameters like effect of acidity, pulp density, temperature and concentration of catalyst on the leaching efficiency of gallium and indium are investigated. Reasonably, 4 M HCl, a pulp density of 50 g/L, 100 °C and stirring rate of 400 rpm are the effective optimum condition for quantitative leaching of gallium and indium.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Recycling of GaN a MOCVD waste of LED industry is investigated. </LI> <LI> Addresses waste of GaN based power device industry and environmental directives. </LI> <LI> A leaching process has been optimized and leaching kinetics is investigated. </LI> <LI> A techno-economical feasible, environment friendly and occupational safe process. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

국내 구리 함유 폐자원의 재활용 상용화 기술 및 연구동향 분석

강이승,안혜란,강홍윤,이찬기,Kang, Leeseung,An, HyeLan,Kang, Hong-Yoon,Lee, Chan Gi 한국자원리싸이클링학회 2019 資源 리싸이클링 Vol.28 No.1

구리는 뛰어난 전기전도성 및 열전달 특성으로 인해 많은 전자기기 및 건축 부품에 활용되고 있고 니켈 등 다른 도금의 밑 도금으로 사용되는 등 현대 산업에서 필수적으로 사용되는 소재이다. 뿐만 아니라 차세대 산업군에서 배선, 센서, 데이터 장비의 사용량과 중요도가 더욱 커지면서 그 활용도가 더욱 커질 것으로 예상됨에도 불구하고 유럽발 경제위기, 중국 경제 저성장 기조, 트럼프 대통령의 공공 산업설비 투자 공약 등에 따라 가격이 급동하는 추세를 보여 안정적인 수급 확보 및 자원관리에 어려움을 겪는 실정이다. 국내 구리 사용량의 거의 대부분을 전기동을 이용하여 사용하기 때문에 본 연구에서는 상용화 되고 있는 구리 재활용 기술과 연구 단계에 머물고 있는 구리 재활용 기술을 구분하여 각각의 기술적 수준을 파악하였다. 이를 통해 각 공정별 특징과 향후 기술개발이 요구되는 분야를 고찰해 보고자 하였다.

Recovery of Indium from Indium Chloride Solutions by Leaching, Enrichment, and Cementation

( Sungkyu Lee ),( Dongyoon Shin ),( Leeseung Kang ),( Sung-soo Ryu ),( Hyun Seon Hong ) 한국폐기물자원순환학회(구 한국폐기물학회) 2015 한국폐기물자원순환학회 3RINCs초록집 Vol.2015 No.-

A three-step, batch type recovery method was developed to produce indium powders from dilute indium chloride solutions prepared by dissolving indium tin oxide (ITO) electrodes from waste liquid crystal display (LCD) panels in concentrated hydrochloric acid (HCl) solutions. A 5-L batch process was used with individual experimental parameters for cementation, such as temperature and time, which were varied to optimize their effects on the physicochemical properties and purity of the recovered indium powders and the recovery rate. A validation experiment was performed by preparing indium bearing solutions in a 5-180 min kinetic study of indium cementation with aluminum in aqueous HCl solutions at 65℃. The indium powders obtained from the cementation processes were further characterized using various analytical tools, such as ICP/AES, X-ray diffraction (XRD), and scanning electron microscope-energy dispersive X-ray spectroscopy (SEM-EDS). Cementation at 60℃ for 10 min resulted in the optimal process efficiency, with a recovery rate and indium purity of 70 and 99.8% respectively.

국내 인쇄회로기판의 재활용 상용화 기술 및 연구동향 분석

안혜란,강이승,이찬기,An, HyeLan,Kang, Leeseung,Lee, Chan-Gi 한국자원리싸이클링학회 2017 資源 리싸이클링 Vol.26 No.4

최근 전자산업의 급격한 성장으로 전자부품스크랩의 발생량 역시 빠르게 증가하고 있다. 특히 전자부품스크랩의 구성부품 중 인쇄회로기판(PCB)은 금, 은, 구리, 주석 및 니켈 등 일반금속부터 귀금속 및 희소금속까지 포함하고 있는 중요한 재활용 대상이다. 하지만 국내에는 일부 대기업을 중심으로 한 PCB 처리 및 재활용 기술이 상용화되어 있으며 그 외 처리량에 대해서는 정확하게 집계되지 않고 있는 실정이다. 이에 따라 몇몇 도시광산 업체 및 연구소, 대학교를 중심으로 기존 대기업 중심의 상용화 공정 외에 PCB로부터 유가금속을 회수하고 원료로 재사용하는 연구가 진행되고 있다. 따라서 본 연구에서는 국내의 폐 PCB의 처리 및 회수현황과 재활용 기술 동향을 분석하였고, 이를 통해 PCB 폐자원의 자원순환 활성화에 기여하고자 하였다. Recently, the amount of electronic scrap is rapidly increasing due to the rapid growth of the electronics industry. Among the components of electronic scrap, the printed circuit board(PCB) is an important recycling target which includes common metals, precious metals, and rare metals such as gold, silver, copper, tin, nickel and so on. In Korea, however, PCB recycling technologies are mainly commercialized by some major companies, and other process quantities are not accurately counted. According to present situation, several urban mining companies, research institutes, and universities are conducting research on recovery of valuable metals from PCBs and/or reusing them as raw materials that is different from existing commercialization process developed by major companies. In this study, we analyzed not only current status of collection/disposal process and recycling of waste PCBs in Korea but also the trend of recycling technologies in order to help resource circulation from waste PCBs become more active.

폐디스플레이 CCFL에 존재하는 형광체 내 희토류 원소 회수 기술 동향 분석

강이승,신동윤,이지은,안중우,홍현선,Kang, Leeseung,Shin, Dongyoon,Lee, Jieun,Ahn, Joong Woo,Hong, Hyun-Seon 한국분말야금학회 2015 한국분말재료학회지 (KPMI) Vol.22 No.1

Flat panel display devices are mainly used as information display devices in the 21st century. The worldwide waste flat panel displays are expected at 2-3 million units but most of them are land-filled for want of a proper recycling technology More specifically, rare earth metals of La and Eu are used as fluorescent materials of Cold Cathode Flourscent Lamp(CCFL)s in the waste flat panel displays and they are critically vulnerable and irreplaceable strategic mineral resources. At present, most of the waste CCFLs are disposed of by land-filling and incineration and proper recovery of 80-plus tons per annum of the rare earth fluorescent materials will significantly contribute to steady supply of them. A dearth of Korean domestic research results on recovery and recycling of rare earth elements in the CCFLs prompts to initiate this status report on overseas research trends and noteworthy research results in related fields.