• 자원리싸이클링
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• 제19권6호
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• pp.51-60
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• 2010

리튬이차전지 양극스크랩으로부터 코발트와 리튬을 회수하기위해 물리적 전처리, 침출, 용매추출 및 회수실험을 행하였다. 실험재료로 제조공정에서 발생되는 코발트계 양극스크랩을 사용하여 단위공정별 최적조건을 구하였다. 물리적전처리 최적조건은 온도 $500{\sim}550^{\circ}C$, 파쇄날 회전속도 1000rpm이었으며, 침출 최적조건은 300rpm, 2M $H_2SO_4$, 2.5M $H_2O_2$, $95^{\circ}C$이었다. D2EHPA(bis(2-ethylhexyl) phosphoric acid) 와 PC88A를 각각 알루미늄과 코발트의 추출제로 사용하여 분리.정제하였으며, 코발트는 염기성시약을 사용하여 $Co(OH)_2$로, 리튬은 탄산나트륨 및 LiOH를 사용하여 탄산리튬($LiCO_3$)으로 회수하였다. $Co(OH)_2$는 열처리를 하여 삼산화코발트($Co_3O_4$)로 만들고 분쇄기를 사용하여 10 ${\mu}m$정도의 입자를 만들었다. 최적조건에서 코발트와 리튬 회수율은 99%이상, 리튬회수율은 99%이상이었으며, 삼산화코발트의 순도는 99.98%이상이었다.

• 한국세라믹학회지
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• 제24권3호
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• pp.257-262
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• 1987

The characteristics of cobalt oxide powders prepared by hot petroleum drying method from the cobalt acetate were evaluated by DTA/TGA, XRD, BET, SEM and density measurement. The cobalt oxide powder could be prepared by hot petroleum drying of the emulsion of cobalt acetate salt solution and the subsequent thermal decomposition of the acetate at 300$^{\circ}C$. As the concentration of the salt solution and the calcination temperature of the dried powder increased, the surface area of the synthesized powder decreased due to the particle growth, so that after sintering the density and grain size decreased. For the same concentration of the salt solution, the surface area and sinterability of the powder by hot petroleum drying increased in comparision with those by conventional drying.

• 한국환경과학회지
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• 제6권2호
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• pp.133-139
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• 1997

말로네이트 제조 공정에서 발생되는 폐액으로부터 용매추출법을 적용하여 코발트 회수 연구를 하였다 용매 추출에서의 주요 변수는 용매의 선택, pH, 코발트 농도, 역추출 온도 등이며 이러한 변수들의 영향을 조사하였다. 용매로써 DEHPA와 PC88A가 사용되었으며 이들 용매의 평형추출 곡선을 구하였다. 공장설계 조건을 찾기 위하여 Mccabe-Tiele 선도를 작성하였고, 연속 공정인 믹서-세틀러 장치를 가동하였다. 본 연구 결과 폐액 중에서 코발트는 99.9% 이상 회수되었고, 회수된 황산코발트의 순도는 99.9% 이상이었다.

• 전기화학회지
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• 제6권2호
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• pp.158-160
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• 2003

We have reported to make nanostructured cobalt oxide electrode that have large capacitance over than 400 F/g (specific capacitance) and good cycleability. But, it had serious demerits of low voltage range under 0.5 V and low power density. Therefore, we need to increase voltage range of cobalt oxide electrode. We report here on the electrochemical properties of sol-gel-derived nanoparticulate cobalt xerogel in 1M KOH solution and aqueous polymeric gel electrolyte. In solution electrolyte, cobalt oxide electrode had over 250 F/g capacitance consisted of EDLC and pseudocapacitance. In gel electrolyte, cobalt oxide electrode had around 100 F/g capacitance. This capacitance was only electric double layer capacitance of active surface area. In solution electrolyte, potassium ion as working ion reacted with both of layers easily. However, In gel electrolyte, reacted with only surface-active layer. Itis very hard to reach resistive layer. So, we have studied on pretreatment of electrode to contain working ions easily. We'll report more details.

• The Korean Journal of Ceramics
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• 제4권1호
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• pp.43-46
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• 1998

We have investigated the formation and thermal stability of cobalt aluminide(CoAl) thin films on GaAs. In order to obtain cobalt-aluminide thin films, we deposited a multilayer of Co/Al on GaAs, and subsequently annealed the samples at 80$0^{\circ}C$ for 30 min. After annealing, single-phase cobalt aluminide was produced showing a flat and uniform interface with GaAs. which indicates that cobalt aluminide (CoAl) is thermally stable with GaAs. In addition, the adherence and mechanical properties of the as-deposited, and annealed Co/Al multilayer structure on GaAs are compatible with those required for device fabrication processes. The electrical property of the CoAl/GaAs contact shows rectifying characteristics, indicating that the diodes were usable as rectifying gate electrodes.

• 센서학회지
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• 제24권1호
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• pp.35-40
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• 2015

Electrospinning method has easy preparation of nanofibers with a simple and versatile technique. Electrospun nanofiber is widely used by the simple approach and have great potentials in the numerous applicaitons of medicine, photonics, catalysts, sensors, etc. including advantage of their specific characteristics such as large surface to volume ratio. This paper focused on the fabrication of cobalt electrospun nanofibrer for applications such as electronic, optical and mechanical devices by metal based material. We fabricated cobalt nanofibers on aluminum foil by an electrospinning method. The electrospinning process was performed at a high voltage, 8 kV. The distance between the needle tip and the solution surface in the bath was 5 cm. The PVB - cobalt based nitrate solution was filled in a 10 mL syringe connected to a 22 gauge needle. We confirmed electrospun cobalt nanofiber after annealing process by SIMS (Secondary Ion Mass Spectrometry) analysis. The concept design, fabrication and results of mapping measurements are reported.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2011년도 제40회 동계학술대회 초록집
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• pp.113-113
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• 2011

Cobalt oxide 박막은 gas sensor, electro-chromic 소자 그리고 energy storage 소자등 광범위한 분야에서 연구되고 있으며 sputtering, CVD 그리고 electrochemical deposition 를 포함한 다양한 방법으로 증착할 수 있다. 최근에는 원자층 증착 방법을 이용한 cobalt oxide박막 증착이 연구되었는데, cyclopentadienyl계열의 전구체와 ${\beta}$-diketonate계열의 전구체를 이용하였다. 하지만 전구체의 낮은 증기압으로 인해 낮은 growth rate (약 0.02~0.05 nm/cycle)을 보였다. 본 연구에서는 증기압이 높은 전구체인 CCTBA (dicobalt hexacarbonyl tert-butylacetylene) 를 선정하여 원자층 증착 공정의 growth rate를 향상시키고자 하였다. 반응기체로는 O3을 사용하여 cobalt oxide 박막을 증착하였다. 반응기체의 주입시간 및 공정온도를 달리하여 시편을 증착한 결과 $80^{\circ}C$에서 0.1 nm/cycle로 기존의 보고된 growth rate보다 높은 수치를 얻을 수 있었다. 또한 증착된 cobalt oxide 박막내 조성분석과 I-V 측정 등을 이용하여 물리적, 전기적 특성을 규명하였다

• Journal of Radiation Protection and Research
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• 제15권2호
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• pp.7-16
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• 1990

알우미나, 실리카겔, 제오라이트 3A, 카오린 그리고 나트륨-벤토나이트에 대한 방사성코발트 및 루테늄 흡착을 수소이온농도, 핵종 농도 그리고 이온강도를 함수로 고찰하였다. 토양에 대한 코발트 및 루테늄의 지연계수는 공극율 측정으로 결정하였다. 코발트 및 루테늄의 가수분해 분자종은 물리적 흡착반응으로 고체 표면과 상호작용한다. 코발트 및 루테늄의 후로인드릿히 흡착 등온식은 직선이다. 코발트 및 루테늄의 흡착은 이온강도의 증가에 따라 감소한다. 지연계수에서 공극율 증가효과는 분배계수의 증가효과와 반한다.

• Journal of Magnetics
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• 제22권2호
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• pp.175-180
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• 2017

CoNi alloy films prepared from electrolytes with various concentrations of cobalt ions were studied in the paper. Influences of different cobalt ions concentrations on electrochemistry processes, components, microstructures, surface morphologies and magnetic properties of CoNi films were investigated. It was found that CoNi film plating was a kind of anomalous codeposition process. The percentage of cobalt content in CoNi films was higher than that of in the electrolyte. Moreover, with the rise of cobalt ions concentrations, the percentage of cobalt content in the samples increased gradually. CoNi films possessed crystal structures with four stronger diffraction peaks. However, CoNi films prepared from bath with higher cobalt ions possessed hcp structures which contributed to dendrite structures resulting in the increase of coercivity.

• Korean Chemical Engineering Research
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• 제57권3호
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• pp.313-320
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• 2019

Extraction/separation of cobalt by supported liquid membrane has been reviewed. The review discusses various directions associated with the supported liquid membrane process, such as the kind of supported liquid membrane, the principle of supported liquid membrane, transport mechanism involved, and the advantages and disadvantages of the supported liquid. Finally, extraction and separation of cobalt from other metals using extractant through supported liquid membrane have been reviewed. Separation of cobalt using various reagents and cobalt recovery from scrap using commercial extractant can be a potential perspective from the application of supported liquid membrane application.