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.

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>

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.

적응 퍼지 제어기를 이용한 유연성 빔의 위치제어

탁한호,이병로,김병철,전중창,황석순,정민우 진주산업대학교 산업과학기술연구소 2003 산업과학기술연구소보 Vol.- No.10

In this paper, applications of adaptive fuzzy controller to position control of flexible beam are considered. When a flexible beam is rotated by a motor through the fixed end, transverse vibration may occur. The architecture and learning underlying adaptive networks based fuzzy inference system (ANFIS) is presented, which is a fuzzy inference system implemented in the framework of adaptive networks. By using a hybrid learning procedure, the proposed ANFIS can construct an input-output mapping based on both human knowledge and stipulated input-output data pairs. Therefor, a dynamic model for a flexible beam is derived, and then a comparative analysis was made with before learning and after learning adaptive fuzzy controller through an simulation. The results are presented to illustrate the advantages and improved performance of the proposed position control cver the after learning adaptive fuzzy controller.

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.

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.

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.

국가 대표급과 제주도 고교 대표급 수영선수들의 그랩 스타트의 운동학적 분석

김철원,김승곤,오만원,임상용,김성찬,이창준,남사웅,이세형,류재청,신석종,김세민 濟州大學敎 體育科學硏究所 1998 체육과학연구 Vol.4 No.-

The purpose of the study was to undertaken to analysis the Grab starting technique between national representive team(3) and Cheju's representive team(3) with 3D cinematography. The conclusions obtained were as follows: Cheju's showed more elapsed time than national representive team on starting block. and more vertical than horizontal direction of COG position, more concentrated vertical velocity & acceleration than forward direction. Therefore It is necessory for cheju's to train balanced trust force in horizontal and vertical direction in grab starting technique.

Characterization of a New Commercial Cultivar ‘GARES-HM-17-1’ by Mono-mono Crossing in Hypsizigus marmoreus

Min-Keun Kim,Eun-Heui Han,Ya-El Kim,Jeong-Min Jeong,Dong-Seong Kim,Su-Won Seuk,Byeong-Jeong Lee,Kwang-Pyo Hong,Sang-Dae Lee 한국버섯학회 2017 버섯 Vol.21 No.2

A new commercial cultivar ‘GARES-HM-17-1’ of Hypsizigus marmoreus was developed by the method of mono-mono crossing between monokaryotic strains derived from Hae-Sal 3Ho. The parental strains are characterized by the property of high quality and a short period of time in cultivation. The optimum temperature of mycelial growth was 25°C and that of fruiting body development was 15~16°C. The period of harvesting including primordia formation was 23.0 days shorter than that of control strain Mangadak No. 2. The color of pileus and stipe surface was neutral-white, respectively. The yield was 82.0±5.8g/850cc plastic bottle. Analysis of the genetic characteristics of the new commercial cultivar ‘GARES-HM-17-1’ showed a different profile as that of the control strain, Mangadak No.2, when RAPD (Random Amplified Polymorphic DNA) primer was used. This new cultivar ‘GARES-HM-17-1’ of H. marmoreus is characterized by the improved quality and a short period of time in cultivation after scratching. It would be of much help to expand the cultivation area of H. marmoreus.

PⅢ-2 Characterization of a new commercial cultivar ‘GARES-HM-18-1’ by mono-mono crossing in Hypsizigus marmoreus

Min-Keun Kim,Soon-Ae Sim,Ji-Hye Park,Su-Won Seuk,Jeong-Min Jeong,Dong-Seong Kim,Byeong-Jeong Lee,Kwang-Pyo Hong,Sang-Dae Lee 한국버섯학회 2018 버섯 Vol.22 No.1