전자스크랩으로부터 티오요소에 의한 은(Ag) 침출

소홍일,이주은,조연철,안재우,류호진 대한금속·재료학회 2018 대한금속·재료학회지 Vol.56 No.7

The leaching behavior of silver from electronic scrap using acidic thiourea solution was studied. The results showed that the silver leaching percentage was affected by the concentration of thiourea and hydrochloric acid, the oxidant such as ferric ions, solid-liquid ratio, temperature, rpm, etc. The leaching percentage of silver decreased with an increase in the solid-liquid ratio, and the leaching rate of silver was enhanced by increasing the thiourea and hydrochloric acid concentration. However, when the concentration of hydrochloric acid and oxidant were increased above 1.0 M and 30 mM, respectively, the leaching rate of silver decreased. When the reaction temperature was above 50 oC, the leaching rate of silver decreased because of the decomposition of thiourea. More than 99 % leaching of silver was achieved under the following conditions: thiourea conc. 0.8 M, HCl conc. : 0.5 M, Temp. : 35 oC, leaching time : 4 hours, solid-liquid ratio : 25 g/L.

염산용액에서 Cyanex 572를 사용하여 [Sm]/[Pr, Nd] 분리를 위한 향류추출 공정변수 계산

이주은,소홍일,장인환,안재우,김홍인,이진영,Lee, Joo-eun,So, Hong-il,Jang, In-hwan,Ahn, Jae-woo,Kim, Hong-in,Lee, Jin-young 한국자원리싸이클링학회 2018 資源 리싸이클링 Vol.27 No.5

For the purpose of optimizing the counter current extraction process for separation of [Sm] and [Pr, Nd] group in hydrochloric acid solution using Cyanex 572 as an extractant, the theory of Xu Guangxian was derived for calculating the optimized extraction factors. From the basic batch test result, the separation factor of [Sm]/[Pr, Nd] was 14.59 at pH 1.75 in extraction process and 14.61 at 0.01 M HCl in scrubbing process. The process parameters can be calculated using a theory of optimum extraction ratio. From the result of calculation, the total extraction and scrubbing stage numbers at counter current process were 11 and for maintain extraction ratio the flow rate ratio of feed solution, solvent solution, scrubbing solution was 6.25 : 1.74 : 5.80 using 0.1 M HCl.

Cyanex 572와 PC88A를 사용하여 Pr 및 Nd 분리 시 향류추출 공정 비교

이주은,소홍일,조연철,안재우,김홍인,이진영 대한금속·재료학회 2018 대한금속·재료학회지 Vol.56 No.8

This study designed a counter current extraction process for comparing the separation efficiencies that are obtained using Cyanex 572 and PC88A for the elements in a Pr and Nd mixed solution. This process involves multiple extraction and scrubbing processes using a mixer settler. The process parameters are calculated using an equation proposed by Xu Guangxian. The separation factor for the extraction and scrubbing process was 0.09 and 0.08 higher when using Cyanex 572 compared to the experimental values obtained using PC88A. The optimized extraction factors such as the stage numbers, feeding solution flow rate, organic phase flow rate, and scrubbing solution flow rate were calculated using the optimal extraction ratio equation. In order to derive optimum extraction conditions, the target purity and recovery ratio of Nd was set to 99.9% and 99% respectively. When using Cyanex 572 for the counter current extraction process, the total number of extraction and scrubbing stages decreased by 11 in comparison with PC88A. A comparison between the extraction, scrubbing stages, and other parameters indicate that Cyanex 572 is preferable over PC88A from the viewpoint of economic efficiency.

티오요소와 염산 혼합 용액에서 사이클론 전해에 의한 은(Ag) 회수

조연철,소홍일,이주은,안재우,류호진,Cho, Yeon-Chul,So, Hong-Il,Lee, Joo-eun,Ahn, Jae-Woo,Ryu, Ho-Jin 한국자원리싸이클링학회 2017 資源 리싸이클링 Vol.26 No.4

A cyclone type electrolytic method was used to recover silver from thiourea-hydrochloric acid mixed solutions. The electrowinning behavior of silver was investigated in different systems, such as the flow rate, current density, silver concentration, thiourea concentration and hydrochloric acid concentration. As the increase of the flow rate, current density and hydrochloric acid concentration, the recovery rate of silver was increased. Whereas, as the increase of silver concentration, the recovery rate of silver was decreased. The thiourea concentration did not affect the Ag recovery and current efficiency. Above 99% of Ag was recovered at the flow rate of 12 L/min., current density of $0.75A/dm^2$, silver concentration of 1.0 g/L, 0.5 M thiourea and 0.1 M hydrochloric acid. In most experimental conditions, silver was recovered as a powder form. 티오요소와 염산 혼합 용액 중 은(Ag)을 금속으로 회수하기 위해 사이클론 전해법을 이용하였다. 유속, 전류밀도, 은 농도, 티오요소 농도, 염산 농도를 주요 변수로 하여 은의 전해회수 거동을 살펴보았다. 유속, 전류밀도와 염산 농도가 증가할수록 은의 회수속도가 증가하였으며, 은 농도가 증가함에 따라 은의 회수 속도는 감소하였고, 티오요소 농도는 은 회수율과 전류효율에는 큰 영향이 없었다. 유속 12 L/min., 전류밀도 $0.75A/dm^2$, 1 g/L Ag, 0.5 M Thiourea, 0.1 M HCl에서 실험하였을 경우 99% 이상의 은 회수율을 보였다. 대부분의 실험 조건에서 은(Ag)은 분말 형태로 회수되었다.

Cyanex 572를 사용하여 [Pr, Nd, Sm]/[La]분리에 대한 향류추출공정 설계

이주은,소홍일,장인환,안재우,김홍인,이진영,Lee, Joo-eun,So, Hong-Il,Jang, In-Hwan,Ahn, Jae-Woo,Kim, Hong-in,Lee, Jin-young 한국자원리싸이클링학회 2018 資源 리싸이클링 Vol.27 No.4

추출제로 Cyanex 572를 사용하여 혼합 용액에서 [Pr, Nd, Sm]그룹과 [La]을 분리하기 위하여 Xu Guangxian이 제시한 이론에 의하여 향류추출 공정의 최적 추출 공정 변수를 계산하고자 하였다. 기초실험으로부터 두 그룹의 최적 분리계수는 추출 공정의 경우 16.80, 세정공정에서는 21.48 이었고, 1.0 M Cyanex 572에 의한 희토류 성분의 추출용량은 0.12 M 이었다. 공정 개발에 필요한 추출 단수, 세정 단수, 유량비 등에 대하여 최적 추출비 이론에 의해 계산하였다. 계산 결과 두 그룹의 희토류 분리에 필요한 단수는 추출 7단 및 세정 4단이며, 원료용액, 추출용액 및 세정용액의 유량비는 25 : 5.67 : 12.27 이었다.

리튬함유 폐액으로부터 전기투석에 의한 리튬의 분리·농축 연구

이주은,소홍일,조연철,장인환,안재우,이재헌 대한금속·재료학회 2019 대한금속·재료학회지 Vol.57 No.10

Electrodialysis was used to develop a highly efficient process for concentrating and recovering Li from the Li-containing waste solution that is generated after recovering Co and Ni from a leach solution of waste cathode materials of Li ion batteries. The optimum conditions were investigated by comparing the concentration of Li in the concentrated solution, water recovery rate, energy consumption and average flow rate. Limiting current density was also checked. The results showed that the concentration ratio of Li was enhanced up to 133.33% at an applied voltage of 10 V and volume ratio(VD/VC) of 4/1. In order to investigate the concentration ratio of Li based on large volume ratio, the total volume of the Li-containing solution was fixed, and the volume ratio of the dilute solution to the concentrate solution was adjusted to 1/1 to 10/1. The concentration ratio of lithium was increased in the initial stage and then decreased due to the osmotic phenomenon. Finally, an the analysis of the experimental results, including concentration ratio, average flux, and energy consumption, determined that the volume ratio(VD/VC) of 3/1 at 10 V of applied voltage was most efficient and the concentrate ratio of Li increased up to 160.61%.

경희토류(La, Ce, Pr, Nd, Sm) 혼합용액에서 Cyanex 572에 의한 추출·분리 거동 고찰

조연철,이주은,소홍일,안재우,김홍인,이진영,Cho, Yeon-Chul,Lee, Joo-Eun,So, Hong-Il,Ahn, Jae-Woo,Kim, Hong-In,Lee, Jin-Young 한국자원리싸이클링학회 2017 資源 리싸이클링 Vol.26 No.4

Cyanex 572에 의한 경희토류 다성분 혼합 용액에서 La, Ce, Pr, Nd, Sm의 분리특성에 대해 연구하였다. 5성분계 혼합 용액에서 추출제 농도가 증가할수록 5성분 모두 $pH_{50}$(추출율이 50%인 pH) 값은 감소하였다. 추출제 농도 0.6 M 이상에서 La과 Ce, Nd와 Sm 는 10 이상의 분리계수 값을 보인 반면, Ce과 Pr, Pr과 Nd 사이의 분리계수는 0.5~2.2로 낮았다. 분리계수 개선을 위해 0.6 M Cyanex 572에 TBP를 첨가하였으나 상 분리 속도나 분리계수 개선 효과는 나타나지 않았다. 실험 결과를 고찰한 결과, La/(Pr, Nd, Sm) 그룹과 (Pr, Nd)/Sm 의 경우는 그룹 별 분리는 가능할 것으로 보이나, (La, Ce) 과 (Pr, Nd)의 그룹분리는 Ce와 Pr 사이의 분리계수가 낮아 어려울 것으로 사료된다. Extraction and separation behaviors of La, Ce, Pr, Nd and Sm from light rare earth multi - component mixed solutions by Cyanex 572 were studied. As extractant concentration increased, the $pH_{50}$ values of all the five components decreased. When extractant concentration was larger than 0.6 M, the separation factor of La and Ce, Nd and Sm was higher than 10, while the separation factor between Ce and Pr, Pr and Nd was as low as 0.5~2.2. Addition of TBP to the 0.6 M Cyanex 572 had little synergistic effect on the phase separation rate and separation factor. From the analysis of experiment results, group separation of [La]/[Pr, Nd, Sm] and [Pr, Nd]/[Sm] could be possible, but in case of the group separation between [La, Ce] and [Pr, Nd] was not available because of the low separation factor between Ce and Pr.

경희토류 혼합용액에서 PC88A와 Cyanex 572에 의한La, Ce, Pr, Nd, Sm의 추출·분리 거동 비교

조연철,이주은,소홍일,안재우,김홍인,이진영 대한금속·재료학회 2018 대한금속·재료학회지 Vol.56 No.2

Solvent extraction of La, Ce, Pr, Nd and Sm from chloride solutions was studied using PC88A and Cyanex 572 as the extractants. Our results indicated that the acidity of the aqueous solution and saponification degree had some effect on the percentage extraction of metal ions. The distribution coefficient of the metal ions increased with increasing aqueous solution pH in both of PC88A and Cyanex 572. But the pH50 value was lowered by about 0.05~0.34 in PC88A. In extraction with saponified Cyanex 572 with NaOH, the distribution coefficients of the metal ions were independent of the degree of saponification, and did little to improve the separation behavior of these metal ions. With Cyanex 572 as the extractant, the separation factor of the binary La/Ce and Nd/Sm was enhanced about 5.0, but Ce/ Pr and Pr/Nd showed no difference in separation factor as compared with PC88A. The group separation factor of La/(Pr, Nd, Sm) and (Pr, Nd)/Sm was increased by 3.0~8.0, but for (La, Ce)/(Pr, Nd) and Ce/ (Pr, Nd) it was only increased by 0.2~0.7 in the Cyanex 572 system.

염산용액에서 사이클론형 전해방식에 의한 주석의 전해채취

조연철,강명식,소홍일,이주은,안재우,Cho, Yeon-Chul,Kang, Myeong-Sik,So, Hong-Il,Lee, Joo-Eun,Ahn, Jae-Woo 한국자원리싸이클링학회 2017 資源 리싸이클링 Vol.26 No.3

염산 용액에서 주석을 금속으로 회수하기 위하여 사이클론 전해채취 방식을 사용하였다. 주석의 전해채취에 미치는 영향을 고찰하기 위하여 유속, 전류밀도, 전해액 중 주석 농도, 염산 농도 영향에 대하여 조사하였다. 유속이 증가하고, 주석과 염산의 농도가 감소할수록 주석의 회수율과 전류효율이 증가하였고, 전류밀도가 증가함에 따라 회수율은 증가하였으나 전류효율은 감소하였다. 유속 18 L/min., $3A/dm^2$, 2.5 g/L Sn, 5 wt.% HCl 조건에서 효과적으로 주석을 회수할 수 있다. Cyclone electrowinning method was used to recover tin to metal in hydrochloric acid solution. The effects of flow rate, current density, tin concentration, and hydrochloric acid concentration on the electrowinning of tin were investigated. As the flow rate increased and the concentration of tin and hydrochloric acid decreased, the tin recovery and current efficiency increased. As the current density increased, the recovery rate increased but the current efficiency decreased. Tin can be effectively recovered at flow rates of 18 L/min., $3A/dm^2$, 2.5 g/L Sn, and 5 wt.% HCl.

폐글리세롤을 탄소원으로 트레할로스 생산을 위한 재조합 대장균 배양 조건 최적화

소홍 ( Hong So ),김성배 ( Sung Bae Kim ),김창준 ( Chang-joon Kim ) 한국미생물생명공학회(구 한국산업미생물학회) 2016 한국미생물·생명공학회지 Vol.44 No.4

전처리 폐글리세롤을 기질로 사용한 재조합 대장균 배양에서 트레할로스 생산성에 영향을 미치는 핵심 변수들을 도출하고 반응표면 분석법을 사용하여 트레할로스 생산을 극 대화하기 위한 최적조건을 탐색하였다. 37℃에서 IPTG로 induction 하는 배양이 27℃ 또는 induction 하지 않은 배양에 비하여 세포생장 및 트레할로스 생산성이 높았다. Box-Behnken design 실험계획법을 사용하여 배지중의 NaCl, 발리다마이신 및 IPTG의 농도를 최적화하였다. 통계분석결과 IPTG와 NaCl의 농도는 트레할로스 생산에 영향을 미쳤으나 발리다마신의 영향은 크지 않은 것으로 확인되었다. 등고선도 분석을 통해 298 mM NaCl이 첨가되고 0.1 mM의IPTG로 induction되는 배양에서 가장 많은 양의 트레할로스가 생산되는 것으로 예측되었다. 최적화된 조건에서 생산 균주는 세포 밀도(OD₆₀₀) 5.4 ± 0.2에서 304 ± 15 mg/l의 트레할로스를 생산하였다. This study aimed to optimize the culture conditions of recombinant Escherichia coli expressing otsBA using crude glycerol for the enhanced production of trehalose. The effects of culture temperature and isopropyl β-D-1-thiogalactopyranoside (IPTG)-induction were investigated. Trehalose production and cell growth were highest when cells were cultured at 37℃ and induced with IPTG. The concentrations of IPTG, validamycin A, and NaCl were optimized using Box-Behnken design. Statistical analyses of the experimental data revealed that the concentrations of IPTG and NaCl had significant effects on trehalose production, but that of validamycin A did not. Contour plot analysis and model calculation showed that the highest amount of trehalose could be produced at 298 mM NaCl and 0.1 mM IPTG. Under these optimal conditions, the optical density at 600 nm and trehalose production were 5.4 ± 0.2 and 304 ± 15 mg/l, respectively.