Development of in-situ electro-generated chlorine leaching and its application to the leaching of platinum

Kim Min-Seuk,Kim Rina,Chung Kyeong-Woo,Lee Jae-Chun 한국자원공학회 2022 Geosystem engineering Vol.25 No.4

An in-situ electro-generated chlorine leaching with a closed recycling unit of unconsumed gas was developed for precious metal dissolution and applied to the leaching of platinum from a spent automotive catalyst containing 0.13 wt% Pt. Cathodic current in a cathodic compartment of the chlorine generation cell reduces the unconsumed chlorine gas into chloride ions for further chlorine generation. The electro-reduction efficiency was 99.4% in alkaline 2 M NaCl solution, whereas 80.8% in 35% HCl solution at 0.62 mmol min−1 supply rate of unconsumed chlorine gas. The 98.3% platinum from the spent automotive catalyst leached without discharging the unconsumed chlorine gas into the air at 100 g L−1 solid/liquid ratio and 80°C in a 7 M HCl solution. Increasing the solid/liquid ratio to 400 g L−1 drastically decreased the leaching percentage to 16.5% in 90 minutes by possible adsorption of leached Pt to the porous surface of the automotive catalyst carrier.

물표면 방전을 이용한 클로로포름의 분해

유승민 ( Seung Min Ryu ),유승열 ( Seung Ryul Yoo ),박준석 ( Jun Seuk Park ),홍은정 ( Eun Jung Hong ),노태협 ( Tai Hyeop Lho ) 한국물환경학회 2013 한국물환경학회지 Vol.29 No.5

Chloroform is harmful volatile organics and representatives of Trihalomethane (THM). Well-known removal methods of Chloroform are photo oxidation or OH radical oxidation. Plasma on water surface at slightly vacuum condition (45 torr) can produce OH radical and it will help chloroform removal. 81.5% of chloroform is removed by vacuum and plasma in 10 min. Plasma can totally oxidize it till 2.8% and partially oxidize chloroform up to 18.5%. Water-surface plasma is good method to remove chloroform in short time.

Conversion of chalcopyrite to copper oxide in hypochlorite solution for selective leaching of copper in dilute sulfuric acid solution

Choubey, Pankaj Kumar,Lee, Jae-chun,Kim, Min-seuk,Kim, Hyung-Seok Elsevier 2018 Hydrometallurgy Vol.178 No.-

<P><B>Abstract</B></P> <P>In the present study, development of a novel oxidation route to convert chalcopyrite to tenorite for leaching of copper has been described. Initially chalcopyrite was converted into tenorite/copper oxide (CuO) under alkaline region using electro-generated chlorine as an oxidant. Various process parameters such as chlorine sparging rate, temperature, and reaction time were investigated. It was found that 93.8% chalcopyrite converted to tenorite at 60 °C in 300 min when chlorine sparging rate was 0.69 mmol min<SUP>−1</SUP> while, maintaining the pulp density of 10 g/L and pH of the solution between 11−12.7 using dilute sodium hydroxide solution. The oxidized sample containing tenorite phase was leached in dilute sulfuric acid solution at 30 °C and 10 g/L pulp density for 60 min. It was observed that pH of the solution plays a crucial role to enhance the selective recovery of copper. Almost 88% of copper along with 43.1% iron were leached out when pH of the leaching solution was varied between 0.9−1.2. However, negligible dissolution of iron with almost same percentage of copper leaching (88.2%) was observed with the solution having pH 2.7−3.2. Enhanced copper leaching efficiency of up to 99.3% was achieved in the same pH range (2.7−3.2) at 60 °C within 30 min.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Conversion of chalcopyrite to tenorite in alkaline medium was investigated. </LI> <LI> Electro-generated chlorine was used as an oxidant to assist the phase transformation. </LI> <LI> Subsequent leaching of tenorite yielding a selective recovery of copper. </LI> <LI> Linear relationship between degree of conversion to leaching efficiency was established. </LI> </UL> </P>

설악산 국립공원의 어류분포

장민호,조가익,하진용,정광석,박성배,주기재 한국어류학회 2002 韓國魚類學會誌 Vol.14 No.4

설악산 국립공원지역 산간계류의 17개 지점에서 2000년 6월부터 2001년 6월까지 어류상 및 이화학적 요인을 계절별로 총 4회에 걸쳐 분석하였다. 모든 조사지점은 1~3차의 하천으로 비교적 물리·화학적 교란이 적었으며 하천폭은 5~30 m 정도였다. 채집된 어류는 총 18과 42종 2,557개체였고, Cyprinidae는 16종으로 84.7%의 상대풍부도를 나타냈으며, Gobiidae 4종, 5.0?의 상대풍부도를 보였다. Cyprinidae는 전체 채입종의 37.2%를 나타냈다. 우점종은 Zacco temminck로 10개 지점에서 738개체가 채집되어 28.9%의 상대풍부도를 나타냈으며, 아우점종은 Rhynchocypris kumkangensis와 Z. platypus로 각각 4개 지점 648개체(25.3%)와 7개 지점 344개체(13.5%)로 나타났다. 한국고유종(Korean endemic species)은 모두 4과 11종 781개체로 30.5%의 상대풍부도를 나타냈으며, 고유화 빈도는 25.6%로 한국의 평균 고유화 빈도와 유사하게 나타났다. 본 조사에서 외래어는 채집되지 않았다. 국립공원 내에 서식하는 어류의 다양성 유지와 회복을 위해서는 공원 내는 물론 경계지역 하천의 체계적인 관리가 요구된다. The fish fauna of mountain streams in the Seorak National Park area was investigated from June 2000 to June 2001 (4 times). All 17 sites were relatively undisturbed 1st to 3rd order streams. A total of 2,557 individuals were collected and classified into 17 families and 43 species. Cyprinidae accounted for 37.2% (16 species) of the total fish species and 84.7% (2,165 ind.) of the total abundance. Subdominant families were Gobiidae (4 species, 5.0%) and Balitoridae (3 species, 3.4%). Zacco temmincki (RA 28.9%, 10 sites) dominated. Subdominant species were Rhynchocypris kumkangensis (25.3%, 4 sites) and Zacco platypus (13.5%, 7 sites). Eleven of the species are endemic to Korea (4 families, 30.5%). Exotic species were not collected in this survey. Fish diversity was higher in streams around the boundary area than in the national park. Therefore, management of streams in the boundary area to protect the fish biodiversity can be efficiently conducted. Habitat degradation should be reduced for the conservation and restoration of fish diversity.

신경회로망을 이용한 직류 서보 전동기의 위치제어용 적응형 자기동조 PID 제어기의 실현

이준탁,이민호,최우진,이상석 동아대학교 공과대학 부설 한국자원개발연구소 1994 硏究報告 Vol.18 No.2

In this paper, the design technique of AST NN PID controller with the newly proposed learning algorithm is presented. The proposed controller is implemented using a 80486 microprocessor and a DT-2801 data acquisition board and is applied to the accurate position control of unmodelled DC servo system with uncertainty. The computer simulation results and the related experimental ones at no-load and at full-load, shows that the implemented AST NN PID controller has the excellent dynamic responses against load disturbances.

흉통의 양상에 따라 분류한 불안정형 협심증 환자의 임상적 소견의 비교

김명수,김성구,정호석,온영근,신원용,김철현,최태명,현민수,권영주 순천향의학연구소 2001 Journal of Soonchunhyang Medical Science Vol.7 No.1

Background and aims : The clinical syndrome unstable angina pectoris that encompasses a variety of symptoms and clincal presentations of transient episode of myocardial ischemia, was devided to several subgroups. Also, it has variable pathophysiologic factors to cause myocardial ischemia. According to clincal presentation, coronary angiographic finding and prognostic factor, the result of unstable angina pectoris is variable. In fact, there were a few data reported on the prognosis of wide spectrum of patients with unstable angina. However, the precise risk of subgroups according to classitication has not been established because it was difficult to compare between studies. We classified unstable angina pectoris by clinical nature of chest pain, and performed to establish and compare the clinical presentations, coronary angiographic findings, treatement and prognosis of patients with unstable angina within subgroups of classification. Methods : Retrospenctive data for 164 unstable angina pectoris patients admitted to the Internal Cardiology Division of Soon Chun Hyang University Hospital from May 1996 to July 1999 was analyzed. The patients were classified into one of the following categories: Class I, new onset of severe angina; Class II, acceleration of previous chronic stable angina; Class III, angina at rest. Clinical presentations, echocardiographic findings, coronary angiographic findings, treatment and prognosis were compared. Results : From the total 164 patients, the subjects of classes were as follows : Class I, 46 cases (28.1%); Class II, 74 cases (45.1%); Class III, 44 cases (26.8%). In view of age distribution, the 7th decade had the highest incidence, and then, 6th, 8th decades were followed. There was no baseline differences among the 3 classes with respect to gender, number of risk factors. Significantly, class II showed more severe findings in abnormal Q wave 15 cases (20.8%), total occclusive lesion 10 cases (20.8%) and three vessel coronary disease 11 cases (22.9%) than other classes. The change of ST segment was significantly apparent (p<0.02) among class I 28 cases (60.8%), class III 26 cases (59.0%), comparing with class II 30 cases (40.5%). Class III had the higher incidence of one vessel coronary artery disease than class I and III. The heparin treatment was performed in 99 cases (60.1%). The incidence of nonfatal myocardial infarction was much more in class I and III, each 4 cases (8.7%, 9.8%) than in class II 1 cases (1.4%). In-Hospital death was occurred in class I and II, each 1 case. Conclusion : The patients with the acclerated angina from chronic stable angina had more severe coronary artery disease than other classes, but they had better in-hospital prognosis.

대기 중 휘발성 유기화합물의 Advanced Technology에 대한 실험비교

최금찬,안병주,김석택,김찬훈,정창훈,서정민,유수영 동아대학교 환경문제연구소 2000 硏究報告 Vol.23 No.1

Nowaday, Advanced technology has been applied to organic destruction technologies that are alternatives to incineration. Plasma, photolysis, and Photocatalytic oxidation processes are an emerging advanced technologies for the abatement of volatile organic compounds(VOCs) in atmospheric pressure air streams, so we has been used these technologies for destruction of VOCs. TCE, Benzene, Toluene, and Xylene were selected as objective materials. We have been studied each process and found many types of reaction parameters which effect on treatment efficiency. So combination processes, which are plasma-photocatalytic oxidation process and photolysis-photocatalytic oxidation process, have been used to increase destruction efficiency. Analysis of above materials and byproducts was carried out by GC-FID.

Unexpected pulmonary edema and cardiac arrest following wedge resection of spontaneous pneumothorax -A case report-

Han Woong,Kim Gyu Seong,Lee Jong Min,Lim Chang Mook,Yang Hong Seuk,Jeong Chang Yeong,박동호 대한마취통증의학회 2022 Anesthesia and pain medicine Vol.17 No.3

BackgroundReexpansion pulmonary edema is a rare but potentially lethal complication. We report a case of suspected reexpansion pulmonary edema that led to cardiac arrest.CaseA 16-year-old male patient underwent wedge resection due to right pneumothorax. The patient showed pink frothy sputum three hours following surgery, and a chest x-ray showed right unilateral pulmonary edema. Thirteen hours following surgery, the patient continuously showed pink frothy sputum and presented with severe hypoxemia, tachypnea, and tachycardia. After transferring to the intensive care unit (ICU), he developed ventricular tachycardia. Cardiopulmonary resuscitation was performed for 32 min. Chest X-ray showed diffuse bilateral pulmonary edema. Extracorporeal membrane oxygenation was performed. During the 65 days of ICU care, the patient became mentally alert. However, follow-up echocardiography revealed severe heart failure.ConclusionsRexpansion pulmonary edema can rapidly progress to diffuse bilateral pulmonary edema. Therefore, careful observation is required for the patients who show signs of pulmonary edema after reexpansion.

Efficient Recycling of WC-Co Hardmetal Sludge by Oxidation Followed by Alkali and Sulfuric Acid Treatments

Dong-hyo Yang,Rajiv Ranjan Srivastava,Min-seuk Kim,Dao Duy Nam,Jae-chun Lee,Hai Trung Huynh 대한금속·재료학회 2016 METALS AND MATERIALS International Vol.22 No.5

We present a process to recycle strategic metals, viz. tungsten and cobalt, from a WC-Co hardmetal sludge (WCHS) via oxidation followed by a two-step hydrometallurgical treatment with alkali and acid solutions. The oxidation of WCHS was investigated in the temperature range of 500 to 1000 °C and optimized at 600 °C to transform the maximum WC into an alkali-soluble WO3. The conditions for the selective dissolution of WO3 in stage-I were optimized as follows: 4.0 M NaOH, pulp density of 175 g/L, and temperature of 100 °C for 1 h, yielding maximum efficacy. Subsequently, in the second step, the optimal conditions for cobalt leaching from the alkali-treated residue were established as follows: 2.0 M H2SO4, 25 g/L pulp density, and 75 °C temperature for 30 min. Downstream processing of the obtained metal ions in solutions was also easier, as the only impurity of dicobaltite ions with the Na2WO4 solution was precipitated as Co(OH)3 under atmospheric O2; meanwhile, the CoSO4 solution obtained through the second step of processing can be treated via electrolysis to recover the metallic cobalt. The present process is simpler in operation, and the efficient use of eco-friendly lixiviants eliminates the previously reported disadvantage.

리튬이온전지 제조공정의 폐양극활물질로부터 습식제련공정에 의한 코발트의 회수

정진기,김민석,이재천,손정수,Jeong, Jinki,Kim, Min Seuk,Lee, Jae-chun,Sohn, Jeong-Soo 한국자원리싸이클링학회 2005 資源 리싸이클링 Vol.14 No.6

황산을 사용하여 폐양극활물질, $LiCoO_{2}$로부터 코발트를 침출한 뒤 용매추출법으로 분리하여 회수하는 습식제련공정을 개발하였다. 최적침출조건은 황산농도 2.0 M, 과산화수소수 첨가량 5 $vol.\%$, 침출온도 $75^{\circ}C$, 침출시간 30 min., 초기정액농도 100 g/L 이었으며, 코발트와 리튬의 침출율은 각각 $93\%$와 $94.5\%$이었다. 초기 pH 5.0, 유기상과 수용액상의 상비 1.6 : 1, 추출단수 1단의 조건에서 1.5 M Cyanex 272를 추출제로 사용하여 44.72 g/L 코발트와 5.43 g/L 리튬을 함유하는 황산침출액으로부터 $85\%$의 코발트를 추출하였다. 추출잔액에 남아있는 코발트는 Na-Cyanex 272농도 0.5M, 초기 pH 5.0, 유기상과 수용액상의 상비 1:1의 조건에서 완전히 추출되었다. 폐 $LiCoO_{2}$의 황산침출-Na-Cyanex 272에 의한 코발트의 용매추출-탄산소다용액에 의한 리튬의 세정-황산용액에 의한 코발트의 탈거 등 일련의 습식제련공정을 이용하여 폐$LiCoO_{2}$로부터 순도 $99.99\%$이상의 황산코발트용액을 회수할 수 있었다. A hydrometallurgical process to leach cobalt from the waste cathodic active material, $LiCoO_{2}$, and subsequently to separate it by solvent extraction was developed. The optimum leaching conditions for high recovery of colbalt and lithium were obtained: 2.0 M sulfuric acid, 5 $vol.\%$ hydrogen peroxide, $75^{\circ}C$ leaching temperature, 30 minutes leaching time and an initial pulp density of 100 g/L. The respective leaching efficiencies for Co and Li were $93\%$ and $94.5\%$. About $85\%$ Co was extracted from the sulfuric acid leach liquor containing 44.72 g/L Co and 5.43 g/L Li, using 1.5 M Cyanex272 as an extractant at the initial pH 5.0 and in organic to aqueous phase ratio of 1.6:1 under the single stage extraction conditions. The Co in the raraffinate was completely extracted by 0.5 M Na-Cyanex272 at the inital pH 5.0, and an organic to aqueous phase ratio of 1;1. The cobalt sulfate solution of higher than $99.99\%$ purity could be recovered from waste $LiCoO_{2}$, using a series of hydrometallurgical processes: sulfuric acid leaching of waste $LiCoO_{2}$- solvent extraction of Co by Na-Cyanex 271 - scrubbing of Li by sodium carbonate solution - stripping of Co by sulfuric acid solution.