Recovery of Gold from Electronic Scrap by Hydrometallurgical Process

Lee, Churl-Kyoung,Rhee, Kang-In,Sohn, Hun-Joon The Korean Institute of Resources Recycling 1997 資源 리싸이클링 Vol.6 No.3

A series of processes has been developed to recover the gold from electronic scrap containing about 200~600 ppm Au. First, mechanical beneficiation including shredding, crushing and screening was employed. Results showed that 99 percent of gold component leaves in the fraction of under 1mm of crushed scrap and its concentration was enriched to about 800 ppm without incineration. The crushed scrap was leached in 50% aqua regia solution and gold was completely dissolved at $60^{\circ}C$ withing 2 hours. Other valuable metals such as silver, copper, nickel and iron were also dissolved. The resulting solution was boiled to remove nitrous compounds in the leachate. Finally, a newly designed electrolyzer was tested to recover the gold metal. More than 99% of gold and silver were recovered within an hour by electrowinning process.

Synthesis of $LiCoO_{2}$ Nanoparticles From Leach Liquor of Lithium Ion Battery Wastes by Flame Spray Pyrolysis

Lee Churl Kyoung,Chang Hankwon,Jang Hee Dong,Sohn Jeong-Soo The Korean Institute of Resources Recycling 2005 資源 리싸이클링 Vol.14 No.6

페리튬이온전지로부터 회수된 코발트와 리튬 침출액으로부터 화염분부열분해법에 의하여 $LiCoO_{2}$ 나노분말을 제조하였다. 리튬 및 코발트 성분을 함유하는 전극물질은 열처리 및 기계적 처리에 의해 그 농도를 증가 시켰다. 리튬이온전지 양극물질을 질산으로 용해한 다음 침출액중 Li과 Co의 당량비가 1.0 되도록 $LiNO_{3}$로 조절하여 화염분무열분해용 전구체를 제조하었다. 화염분무열분해법에 의해 제조된 $LiCoO_{2}$ 분말의 평균입자크기는 전구체의 몰 농도가 증가하면서 증가되었으며, 화염온도 역시 입자의 크기를 증가시켰다. 변수실험 결과 $11{\~}35nm$ 크기의 결정형 $LiCoO_{2}$ 나노분말을 제조할 수 있었다 또한 나노 $LiCoO_{2}$의 전극재료로서의 가능성을 확인하기 위하여 충방전 특성 평가와 같은 전기화학적 분석을 수행하였다. [ $LiCoO_{2}$ ] nanoparticles were synthesized from leach liquor of lithium ion battery waste using flame spray pyrolysis. Electrode Materials containing lithium and cobalt could be concentrated with thermal and mechanical treatment. After dissolution of used cathode materials of the lithium battery with nitric acid, the molar ratio of Li/Co in the leach liquor was adjusted at 1.0 by adding a fresh $LiNO_{3}$ solution. The nanoparticles synthesized by the flame spray pyrolysis showed clear crystallinity and were nearly spherical, and their average primary particle diameters ranged from 11 to 35 nm. The average particle diameter increased with an increase in the molar concentration of the precursor. Raising the maximum flame temperature by controlling the gas flow rates also led to an increase in the average diameter of the particles. The $LiCoO_{2}$ powder was proved to have good characteristics as cathode active materials in charge/discharge capacity and cyclic performance.

The Recovery of Tellurium from Copper Anode Slimes by Hydrometallurgical Processes

Lee, Churl-Kyoung,Rhee, Kang-In,Sohn, Hun-Joon The Korean Institute of Resources Recycling 1997 資源 리싸이클링 Vol.6 No.3

The recovery of tellurium from Te-cement obtained during the processing of copper anode slimes was carried out by a series of hydrometallurgical processes, i.E. leaching Te-cement in NaOH solution, precipitation of impurities with the addition of ${Na}_{2}S$ followed by direct electrowinning of tellurium in NaOH solution. The optimum conditions for each process were determined and discussed in terms of various parameters associated with each step to maximize the recovery and purity of tellurium. The final purity of tellurium from electrownning in alkaline solution was found to be more than 99.9%.

Electrocatalytic Performance of Pb-Ru Pyrochlore Prepared by the Amorphous Citrate Precursor Method for Bifunctional Air Electrodes

Lee, Churl Kyoung,Sohn, Hun-Joon 대한금속학회 2002 METALS AND MATERIALS International Vol.8 No.2

Pb-Ru pyrochlore has been of interest as bifunctional electrocatalyst for an air electrode. An amorphous citrate precursor (ACP) process has been optimized to prepare Pb-Ru pyrochlore powders with high surface areas with consequent improvement of its electrocatalytic performance in an air electrode. The surface area of the final powder is 30 ㎡/g, which is larger than the value obtained by the conventional hydroxide method. A PTFE-bonded gas diffusion electrode loaded with pyrochlore catalysts prepared by the ACP method showed good bifunctional performance. The electrode loaded with only 10 ㎎/㎠ of pyrochlore powder prepared by ACP showed good bifunctional performance, i.e. 100 ㎃/㎠ for oxygen reduction and 100 ㎃/㎠ for oxygen evolution, at 0.6 and 1.6 V vs. RHE, respectively. This performance compares well to the results from lower-area pyrochlore at much higher loading.

Amorphous Citrate Precursor 법으로 제조한 La0.6Ca0.4CoO3 와 Pb2Ru2O6 의 전기화학적 촉매능

이철경(Churl Kyoung Lee),손헌준(Hun Joon Sohn) 한국공업화학회 1999 공업화학 Vol.10 No.3

N/A N/A

폐 리튬이온전지로부터 유가금속 회수

이철경(Churl Kyoung Lee),양동효(Dong Hyo Yang) 한국공업화학회 2001 공업화학 Vol.12 No.8

N/A N/A

분사법으로 제조한 아연분말에서 금속첨가물이 아연전극의 자기방전에 미치는 영향

이철경 ( Churl Kyoung Lee ) 한국공업화학회 1995 공업화학 Vol.6 No.5

알칼리용액에서 아연분말의 포화용해도와 아연의 부식 및 수소과전압에 미치는 금속첨가물 Pb, In, Bi의 영향을 조사하였다. 아연의 포화용해도는 OH^-의 농도가 클수록 증가하였으며, 전해법에 의한 경우가 화학적 방법에 의한 용해보다 포화용해도가 2∼3배 높았다. 아연전극의 가속부식과 분극 실험결과, KOH 농도가 증가할수록 아연의 부식이 심해지며, 아연을 미리 포화시킨 용액에서의 부식속도는 크게 감소하였다. 그리고 순수아연의 경우 거의 대부분의 전해액에서 완전히 부식되는 반면에 아연전극에 Pb, In, Bi를 첨가하는 경우 수소과전압을 크게 증가함으로써 부식속도가 크게 감소하였다. 전극의 충방전을 반복하여야 하는 이차전지용 전극으로 아연을 사용하는 경우, 금속첨가물 Pb, In, Bi는 아연전극의 수소과전압을 크게 증가시켜 자기방전 및 수지상 전착을 억제하였다. 또한 전해액의 KOH 농도를 최소로 하고 전해법에 의하여 아연을 포화시키면 전극의 자기방전을 감소시키면서 아연의 과포화 용해에서 기인하는 전극변형 및 활물질 응집을 억제할 수 있다. The effect of metallic additives on the solubility, corrosion and hydrogen overvoltage of zinc was investigated. The saturation solubility of zinc was increased with the increase of OH^- concentration. The solubilty of zinc by electrochemcal method was 2 to 3 times higher than that by the chemical method. The rate of zinc corrosion was decreased with the decrease of KOH concentration and with the increase of zincate(Zn(OH)₄^(2-)). Hydrogen overvoltage of zinc electrode was increased by the addition of Pb, In, Bi. And thus zinc electrode less corroded. The self-discharge and dendrite deposits of zinc should be avoided in the secondary battery where charge and discharge are repeated. The rate of self-discharge in zinc electrode was decreased by either the addition of Pb, In, Bi or the modification of KOH electrolyte. It was also prevented that dendrite deposits, shape change and active materials agglomeration in electrode occurred due to the oversaturation of zinc.

리튬전지 전극물질 재활용을 위한 습식공정의 개선

이철경 ( Churl Kyoung Lee ) 대한금속재료학회(구 대한금속학회) 2014 대한금속·재료학회지 Vol.52 No.7

A new hydrometallurgical route was investigated for improvement in the recycling of valuable metals from electrodes of lithium batteries. The recycling process involves reductive acid leaching, doublesolvent extraction, and direct electro-winning in an organic solution. The dissolution rate of metal from the electrodes was up to 90% in 2 M sulfuric acid with hydrogen peroxide (10 vol%) at 75 ℃, within 60 min. The improvement of dissolution by hydrogen peroxide seems to be due to reduction of Co(III) to Co(II), which can readily be dissolved. Cobalt and lithium were extracted into Cyanex 272 and a room-temperature ionic liquid of [EMIM] TFSI, respectively, whereas most nickel and manganese did not move to the organic phases. Lithium in the [EMIM] TFSI could be directly reduced as a form of metal by non-aqueous electrowinning. The dense electrodeposits were composed of metallic lithium and an alloy with a gold substrate. †(Received September 26, 2013)

Anti-Adipogenic Effects on 3T3-L1 Cells and Zebrafish by Tanshinone IIA

Park, Yu-Kyoung,Obiang-Obounou, Brice Wilfried,Lee, Jinho,Lee, Tae-Yun,Bae, Myung-Ae,Hwang, Kyu-Seok,Lee, Kyung-Bok,Choi, Jong-Soon,Jang, Byeong-Churl MDPI 2017 INTERNATIONAL JOURNAL OF MOLECULAR SCIENCES Vol.18 No.10

<P>Tanshinone IIA is a diterpene quinone isolated from the roots of <I>Salvia miltiorrhiza</I> bunge that has traditionally been used in China for the treatment of cardiovascular and cerebrovascular disorders. Although there is recent evidence showing that tanshinone IIA has an anti-obesity effect, its underlying mechanism of anti-obesity effect is poorly understood. Here, we investigated the effect of tanshinone IIA on lipid accumulation in 3T3-L1 preadipocytes and zebrafish. Notably, tanshinone IIA at 10 μM concentration greatly reduced lipid accumulation and triglyceride (TG) contents during 3T3-L1 preadipocyte differentiation, suggesting its anti-adipogenic effect. On mechanistic levels, tanshinone IIA reduced the expression levels of CCAAT/enhancer-binding protein-α (C/EBP-α), peroxisome proliferator-activated receptor-γ (PPAR-γ), fatty acid synthase (FAS), and perilipin A but also the phosphorylation levels of signal transducer and activator of transcription-3/5 (STAT-3/5) in differentiating 3T3-L1 cells. In addition, tanshinone IIA strongly inhibited leptin and resistin mRNA expression in differentiating 3T3-L1 cells. Importantly, the tanshinone IIA’s lipid-reducing effect was also seen in zebrafish. In sum, these findings demonstrate that tanshinone IIA has anti-adipogenic effects on 3T3-L1 cells and zebrafish, and its anti-adipogenic effect on 3T3-L1 cells is largely attributable to the reduced expression and/or phosphorylation levels of C/EBP-α, PPAR-γ, FAS, perilipin A, and STAT-3/5.</P>

Study of Electrochemical Redox of Gold for Refining in Non-aqueous Electrolyte

Lee, Jae-O,Park, Gwangwon,Park, Jesik,Cho, Youngju,Lee, Churl Kyoung Korean Society for Precision Engineering 2015 International Journal of Precision Engineering and Vol.16 No.7

The electrorefining of gold by simple electrolysis was investigated in the ionic liquid, 1-ethyl-3-methyl-imidazolium bis (trifluoromethanesulfonyl)imide (EMIMTFSI) with titanium tetrachloride (<TEX>$TiCl_4$</TEX>) used as a supporting electrolyte at room temperature. From the cyclic voltammetry results, optimal electrorefining conditions were found for selective dissolution of gold from an anode and for selective reduction on a cathode under potentiostatic conditions, in which is able to obtain pure gold on a cathode surface. The composition, crystal structure, and morphology of pure gold were confirmed by X-ray diffraction and scanning electron microscopy with energy-dispersive spectroscopy. The electrodeposited gold was uniformly distributed on the platinum electrode surface without any impurities by non-aqueous electrolysis at room temperature.