• 한국자기학회:학술대회 개요집
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• 한국자기학회 2014년도 자성 및 자성재료 국제학술대회
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• pp.71-71
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• 2014

• 자원리싸이클링
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• 제27권3호
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• pp.8-15
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• 2018

Nd-Fe-B 폐 영구자석으로부터 회수한 염화희토류용액을 PC88A에 의한 경희토류(Pr, Nd)/중희토류(Tb, Dy) 분리정제에 대한 용매추출 연구를 진행하였다. 회분식 실험 단계에서 추출제(PC88A) 농도 0.5 M, 추출 후 평형 pH는 0.8~1.0(feed의 초기 pH 1.3), 세정액(HCl)의 농도는 0.1 M, 탈거액(HCl)의 농도는 2 M 이상일 때 분리 효율이 좋은 것을 확인하였다. 이 결과값을 혼합침강조에 적용하여 초기 조건에서 운용 조건을 변화시키면서 180시간 운용하여 3N급의 경희토류(Pr, Nd)/중희토류(Tb, Dy)금속 이온으로 분리정제 후 회수하였다.

• Advances in environmental research
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• 제5권2호
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• pp.125-140
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• 2016

The paper is focused on the economic analysis of two hydrometallurgical processes for recovery of yttrium and other rare earth elements (REEs) from fluorescent phosphors of spent lamps. The first process includes leaching with sulphuric acid and precipitation of a mixture of oxalates by oxalic acid, the second one includes leaching with sulphuric acid, solvent extraction with D2EHPA, stripping by acid and recovery of yttrium and traces of other rare earths (REs) by precipitation with oxalic acid. In both cases the REEs were recovered as oxides by calcination of the oxalate salts. The economic analysis was estimated considering the real capacity of the HydroWEEE mobile's plant ($420kg\;batch^{-1}$). For the first flow-sheet the cost of recycling comes to $4.0{\euro}kg^{-1}$, while the revenue from the end-product is around $5.40{\euro}kg^{-1}$. The second process is not profitable, as well as the first one, taking into account the composition of the final oxides: the cost of recycling comes to $5.2{\euro}kg^{-1}$, while the revenue from the end-product is around $3.56{\euro}kg^{-1}$. The process becomes profitable if the final RE oxide mixture is sold for nearly $50{\euro}kg^{-1}$, a value rather far from the current market prices but not so unlikely since could be achieved in the incoming years, considering the significant fluctuations of the Res' market.

• 한국원자력학회:학술대회논문집
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• 한국원자력학회 2001년도 춘계학술발표회요약집
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• pp.377.1-377
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• 2001

• Bulletin of the Korean Chemical Society
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• 제12권1호
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• pp.10-12
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• 1991

• 한국자기학회지
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• 제21권4호
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• pp.147-150
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• 2011

1980년대 초 희토류 자석이 발견된 이래 지난 30년간 희토류 본드 자석은 지속적으로 성장해 왔으며, 그 적용 분야도 보다 다양해 지고 있다. 현재 희토류 본드 자석은 컴퓨터 주변기기, 자동차, 소비 가전, 사무 자동화 분야 등 우리의 일상 생활과 주변에서 광범위하게 사용되고 있다. 하지만, 2010년 하반기부터 시작된 희토류 원료 가격의 급등은 2011년 2사분기 들어 수직 상승에 가까운 전대미문의 폭등세를 보이며 관련 산업에 적지 않은 충격을 가져오고 있다. 이로 인해 그 동안 성능 대비 가격 경쟁력을 바탕으로 페라이트 자석 시장을 꾸준히 잠식하며 양적인 성장과 응용 분야를 확대해 왔던 희토류 본드 자석 업계의 성장방향에 근본적인 변화가 불가피할 것이 분명하며, 향 후 지속 가능한 성장을 위하여 새로운 패러다임 또는 비즈니스 모델의 도입이 반드시 필요하다. 본 글에서는 희토류 본드 자석에 주로 사용되는 희토류 원료의 최근 가격 동향을 간략하게 알아 보고, 희토류 본드 자석의 주요 응용 분야와 희토류 본드 자석용 분말의 개발 동향에 대해서 알아 보았다.

• Safety and Health at Work
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• 제4권1호
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• pp.12-26
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• 2013

In concert with the development of new materials in the last decade, the need for toxicological studies of these materials has been increasing. These new materials include a group of rare earths (RE). The use of RE nanotechnology is being considered in some green applications, to increase their efficiency by using nano-sized RE compounds, and therefore hazard evaluation and risk assessment are highly recommended. This review was conducted through an extensive contemplation of the literatures in toxicology with in vitro and in vivo studies. Major aspects reviewed were the toxicological evaluations of these elements and metallic compounds at the molecular and cellular level, animal and human epidemiological studies and environmental and occupational health impacts on workers. We also discuss the future prospect of industries with appliances using RE together with the significance of preventive efforts for workers' health. To establish a safe and healthy working environment for RE industries, the use of biomarkers is increasing to provide sustainable measure, due to demand for information about the health risks from unfavorable exposures. Given the recent toxicological results on the exposure of cells, animals and workers to RE compounds, it is important to review the toxicological studies to improve the current understanding of the RE compounds in the field of occupational health. This will help to establish a sustainable, safe and healthy working environment for RE industries.

• 한국산업보건학회지
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• 제26권3호
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• pp.237-252
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• 2016

Objectives: This study was conducted in order to improve the current understanding of rare earths(RE) and to provide supporting data for establishing occupational health policies by reviewing the toxicological data and issues caused by the use of RE compounds in various fields. Methods: To evaluate the potential toxicity of RE from the viewpoint of occupational health, we summarized extensive reviews of relevant articles in the toxicology(animals and cells), occupational health and safety, and epidemiologic literature. Results: Although occupational RE exposure occurs extensively from ore mining and refining to end users in various industrial applications, epidemiologic study has not been performed among workers up to now. Bioaccumulation and adverse effects of RE have also been mentioned in ore mining regions and nearby residences, but safety standards for each process are insufficient. Moreover, because new commercial recycling technology will soon be applied to various industries, regulation and policies are needed for preventing abuse of recycling. In the results of animal toxicity for a few REs(mostly cerium, lanthanum, and gadolinium), toxicities of liver, lung, blood, and the nervous system were identified due to oxidative stress, but study of long-term RE exposure is required. Understanding the dual effect for RE and discovery of biomarkers pose a scientific challenge in further mechanism studies. Conclusions: In the future, additional hazard evaluation based on animal experiments is required, alongside continuous research for developing analytical methods and discovering biomarkers. Finally, RE occupational health and safety management needs to be integrated into the sustainable use of these materials.

• 대한화학회지
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• 제33권3호
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• pp.304-308
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• 1989

Methyl Thymol Blue(MTB) 발색시약을 사용하여 $Lu^{3+},\;Eu^{3+},\;Sm^{3+}$ 및 $Pr^{3+}$ 원소의 흡수분광광도법에 의한 정량법을 확립하였다. ligand와 금속의 몰비는 1:1이었으며 Hexamethylenetetramine 완충용액으로 pH 6.5로 만들었을 때 MTB의 최대흡수파장은 440 nm이며 희토류-MTB 착물의 최대흡수파장은 610 nm로 나타났고 용액의 흡광도는 발색 후 7시간 정도까지 일정한 흡광도를 나타내며 $0{\sim}110{\mu}g/50ml$의 범위에서 Beer의 법칙에 따른다. phosphate, EDTA, citrate같은 리간드이온들은 희토류 -MTB의 흡광도에 크게 영향을 주며 각각의 희토류 원소분석의 선택성은 없다. 메틸알코올, 에틸알코올 및 아세톤 용매에서도 희토류-MTB 용액의 흡광도는 변하지 않았다. 몰흡광계수는 $1.2{\sim}2.0{\times}10^4mol^{-1}{\cdot}l{\cdot}cm^{-1}$이다.

• 한국광학회:학술대회논문집
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• 한국광학회 2005년도 제16회 정기총회 및 동계학술발표회
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• pp.280-281
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• 2005