• 자원리싸이클링
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• 제28권6호
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• pp.9-17
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• 2019

4차산업 혁명과 에너지 신산업 등의 성장에 따라 희유금속의 사용이 계속하여 증가하고 있으며, 희유금속의 사용 증가에 따라 희유금속의 재활용이 중요해 지고 있다. 본 논문에서는 희유금속 중 하나인 주석 소재의 국내·외 품질 기준 현황과 재활용된 주석의 성능 테스트에 관해 조사하였다. 성능 테스트 결과, 천연자원 주석과 재활용된 주석의 성능 차이는 없는 것으로 분석되었다.

• 한국분말재료학회지
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• 제30권2호
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• pp.101-106
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• 2023

Liquid metal extraction (LME), a pyrometallurgical recycling method, is popular owing to its negligible environmental impact. LME mainly targets rare-earth permanent magnets having several rare-earth elements. Mg is used as a solvent metal for LME because of its selective and eminent reactivity with rare-earth elements in magnets. Several studies concerning the formation of Dy-Fe intermetallic compounds and their effects on LME using Mg exist. However, methods for reducing these compounds are unavailable. Fe reacts more strongly with B than with Dy; B addition can be a reducing method for Dy-Fe intermetallic compounds owing to the formation of Fe₂B, which takes Fe from Dy-Fe intermetallic compounds. The FeB alloy is an adequate additive for the decomposition of Fe₂B. To accomplish the former process, Mg must convey B to a permanent magnet during the decomposition of the FeB alloy. Here, the effect of Mg on the transfer of B from FeB to permanent magnet is observed through microstructural and phase analyses. Through microstructural and phase analysis, it is confirmed that FeB is converted to Fe₂B upon B transfer, owing to Mg. Finally, the transfer effect of Mg is confirmed, and the possibility of reducing Dy-Fe intermetallic compounds during LME is suggested.

• 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.

• 공업화학
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• 제3권3호
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• pp.440-450
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• 1992

함희토류광물로부터 3가지 희토류성분의 추출공정이 국산 monazite에 대한 적절한 추출공정을 찾기위해 조사되었다. 본 연구에서 조사된 3가지 공정은 황산법, 알칼리법및 황산암모늄 분해법이었다. 실험결과로부터 황산법 및 알칼리법이 국산 monazite에 더욱 효과적인 추출공정이었음이 조사되었다. 국산 monazite에 대한 황산법의 적절한 반응조건은 반응온도 $210^{\circ}C$, 반응시간 40분, monazite에 대한 $H_2SO_4$의 고액비 1.5, 황산의 농도 95%였으며, 이 조건하에서 98%의 희토류성분이 추출되었다. 또한 알칼리법에 대한 적절한 반응조건은 반응온도 $140^{\circ}C$, monazite에 대한 NaOH의 무게비 3.0, NaOH의 농도 50%, 침출시간 3시간이었으며, 이 초건하에서 97%의 희토류성분이 추출되었다.

• 한국방사성폐기물학회:학술대회논문집
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• 한국방사성폐기물학회 2004년도 학술논문집
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• pp.337-337
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• 2004

As one of researches for the P ＆ T purposes, a basic experiment on the recovery of actinide elements from the mixture with rare earth elements by means of electrorefining using a liquid cadmium cathode in the LiCl-KC1 eutectic melt was carried out. In order to examine the behaviors of electrodeposition of metal ions on a liquid electrode, recovery experiments of rare earth metals resulting from forming electrodeposits were performed by a galvanostatic electrolysis method at various current densities. A cyclic voltammetric technique was applied to determine reduction-oxidation potential of each metal element in the melt and to detect the changes of the multi component melt composition for on-line monitoring. Also, a collaboration study with RIAR was completed to test the preliminary feasibility on a recovery of actinide elements from the mixture with rare earth elements using a liquid cadmium cathode and actinide metals. Experimental results showed that the ratio of actinides to rare earths, 9: 0.5∼1 led to the rare earth content of about 5∼10 wt% in the deposit.

• 한국분말재료학회지
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• 제25권2호
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• pp.165-169
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• 2018

Rare earth elements (REEs) are considered to be vital to modern industry due to their important roles in applications such as permanent magnets, automobile production, displays, and many more. The imbalance between demand and supply of REEs can be solved by recycling processes. Regarding the needs of industry and society, the International Organization for Standardization, Technical Committee 298 (ISO/TC298) Rare Earths has been recently launched for developing international standards on rare earth elements. In accordance with the suggestion of its constituents, it is tentatively working to develop the appropriate standards under five working groups (WG) on terms and definitions (WG1), element recycling (WG2), environmental stewardship (WG3), packaging, labelling, marking, transport, and storage (WG4), and testing analysis (WG5). The scope and structure of ISO/TC298 on the topic of rare earths is discussed in this document.

• 한국대기환경학회지
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• 제21권6호
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• pp.625-630
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• 2005

This study was focused on the catalytic activity for the combustion of low-concentration methane using various commerical catalysts (six transition metal catalysts in Russia and one rare earth metal (Honeycomb) catalyst in Korea). Catalytic activity was strongly influenced by the type and loading content of metal supported in catalyst. Catalytic performance showed the highest activity in Honeycomb catalyst including rare earth metal, which was the most expensive catalyst, while the next was the catalyst supported Cu with high content (AOK-78-52) and also that supported Cr and Co (AOK-78-56). However, both AOK-78-52 and AOK-78-56 catalysts that were very cheap had lower activation energy than Honeycomb catalyst. In the economical field, both AOK-78-52 and AOK-78-56 catalysts with transition metals showed a good alternative catalyst on the combustion of methane.

• 자원리싸이클링
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• 제30권3호
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• pp.41-46
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• 2021

메탄술폰산은 우수한 물리화학적 특성을 지니고 있어 금속의 침출에 효과적이다. 분자구조 및 코발트와 니켈 금속의 침출자료를 이용하여 메탄술폰산과 황산의 화학적 반응성을 비교하였다. 유발과 공명효과는 두 산의 반응성에 큰 영향을 미쳤다. 동일한 침출조건에서 코발트와 니켈의 침출률은 메탄술폰산보다 황산에서 높았다. 메탄술폰산의 강한 산도와 금속염의 높은 용해도를 고려하면 메탄술폰산을 금속회수시 침출제로 이용하는 것이 가능하다.

• 자원리싸이클링
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• 제30권2호
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• pp.53-60
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• 2021

폐리튬이온배터리에 함유된 코발트, 니켈 및 구리를 회수하기 위한 공정 개발의 일환으로 단일금속과 금속혼합물의 침출을 조사했다. 이를 위해 산화제를 첨가하지 않은 무기산과 유기산을 침출제로 사용했다. 본 논문의 실험조건에서 산화제가 없는 무기산과 유기산에서 구리는 전혀 침출되지 않았다. 염산과 황산용액에서 산의 농도, 반응온도, 반응시간 및 광액농도를 변화시켜 단일 금속를 모두 용해시킬 수 있는 조건을 구했다. 또한 염산과 황산용액에서 금속혼합물로부터 니켈과 코발트를 99% 이상 침출시킬 수 있는 조건을 조사했다. 메탄술폰산으로 코발트와 니켈 금속혼합물을 침출시 낮은 반응온도에서 코발트가 선택적으로 침출됐다.

• 한국분말재료학회지
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• 제28권2호
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• pp.91-96
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• 2021

Rare earth magnets with excellent magnetic properties are indispensable in the electric device, wind turbine, and e-mobility industries. The demand for the development of eco-friendly recycling techniques has increased to realize sustainable green technology, and the supply of rare earth resources, which are critical for the production of permanent magnets, are limited. Liquid metal extraction (LME), which is a type of pyrometallurgical recycling, is known to selectively extract the metal forms of rare earth elements. Although several studies have been carried out on the formation of intermetallic compounds and oxides, the effect of oxide formation on the extraction efficiency in the LME process remains unknown. In this study, microstructural and phase analyses are conducted to confirm the oxidation behavior of magnets pulverized by a jaw crusher. The LME process is performed with pulverized scrap, and extraction percentages are calculated to confirm the effect of the oxide phases on the extraction of Dy during the reaction. During the L ME process, Nd is completely extracted after 6 h, while Dy remains as Dy₂Fe₁₇ and Dy-oxide. Because the decomposition rate of Dy₂Fe₁₇ is faster than the reduction rate of Dy-oxide, the importance of controlling Dy-oxide on Dy extraction is confirmed.