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>

Effects of Ethanol Addition on the Efficiency of Subcritical Water Extraction of Proteins and Amino Acids from Porcine Placenta

Park, Sung Hee,Kim, Jae-Hyeong,Min, Sang-Gi,Jo, Yeon-Ji,Chun, Ji-Yeon Korean Society for Food Science of Animal Resource 2015 한국축산식품학회지 Vol.35 No.2

In a previous study, hydrolysates of porcine placenta were obtained and the extraction efficiency for proteins and amino acids was compared between sub- and super-critical water extraction systems; optimum efficiency was found to be achieved using subcritical water ($170^{\circ}C$, 10 bar). In this study, the effects of adding ethanol to the subcritical water system were investigated. The lowest-molecular-weight extraction product detected weighed 434 Da, and the efficiency of extraction for low-molecular-weight products was increased when either the concentration of ethanol was decreased, or the extraction time was lengthened from 10 min to 30 min. The highest concentration of free amino acids (approximately 8 mM) was observed following 30 min extraction using pure distilled water. The concentration of free amino acids was significantly lower when ethanol was added or a shorter extraction time was used (p<0.05). Color change of the solution following extraction was measured. There were no significant differences in color between lysates produced with different extraction times when using distilled water (p>0.05); however, using different extraction times produced significant differences in color when using 20% or 50% ethanol solution for subcritical extraction (p<0.05). The range of pH for the hydrolysate solutions was 6.4-7.5. In conclusion, the investigated extraction system was successful in the extraction of $\leq$ 500 Da hydrolysates from porcine placenta, but addition of ethanol did not yield higher production of low-molecular-weight hydrolysates than that achieved by DW alone.

Effects of Ethanol Addition on the Efficiency of Subcritical Water Extraction of Proteins and Amino Acids from Porcine Placenta

Sung Hee Park,Jae Hyeong Kim,Sang Gi Min,Yeon Ji Jo,Ji Yeon Chun 한국축산식품학회 2015 한국축산식품학회지 Vol.35 No.2

In a previous study, hydrolysates of porcine placenta were obtained and the extraction efficiency for proteins and amino acids was compared between sub- and super-critical water extraction systems; optimum efficiency was found to be achieved using subcritical water (170°C, 10 bar). In this study, the effects of adding ethanol to the subcritical water system were investigated. The lowest-molecular-weight extraction product detected weighed 434 Da, and the efficiency of extraction for low-molecular-weight products was increased when either the concentration of ethanol was decreased, or the extraction time was lengthened from 10 min to 30 min. The highest concentration of free amino acids (approximately 8 mM) was observed following 30 min extraction using pure distilled water. The concentration of free amino acids was significantly lower when ethanol was added or a shorter extraction time was used (p<0.05). Color change of the solution following extraction was measured. There were no significant differences in color between lysates produced with different extraction times when using distilled water (p>0.05); however, using different extraction times produced significant differences in color when using 20% or 50% ethanol solution for subcritical extraction (p<0.05). The range of pH for the hydrolysate solutions was 6.4-7.5. In conclusion, the investigated extraction system was successful in the extraction of ≤ 500 Da hydrolysates from porcine placenta, but addition of ethanol did not yield higher production of low-molecular-weight hydrolysates than that achieved by DW alone.

신질환 환아에서 Cyclosporine A의 약동학 특성 및 치료효과

전우성,박민수,이재승,유재은,박문성,배기수 대한소아과학회 2004 小兒科 Vol.47 No.2

초음파에 의한 수중통신

신재민,김천석 麗水水産大學校産業技術硏究所 1997 産業基術硏究所 論文集 Vol.6 No.-

The underwater acoustic channel is probably one of the most complicated environment for data communication. The unique characteristics of this channel, which include fading, extended multipath and refraction, fluctuation and unstable behavior, preclude direct application of standard communication techniques. In this paper, we derive methods for acoustic communication protocol and system.

간내 간충병에 대한 간절제술 1예

심민철,김홍진,권광보,노성균,이헌주,이태숙,장재천 영남대학교 의과대학 1990 Yeungnam University Journal of Medicine Vol.7 No.1

영남대학교 의과대학 외과학교실에서는 1989년 11월에 한국에서 발병한 간흡충병의 여섯 번째 증례로, 특히 간내 담관에 발생한 첫 증례를 우측 간엽 절제술 및 담낭 적출술로 좋은 결과를 얻었으며, 간내 담관에 발생한 경우에는 간암과의 구별이 요구되어야 한다는 점을 상기 시키면서 증례보고와 더불어 문헌적 고찰을 하였다. Human Fasciola hepatica infection is a rare entity involving infestation of the liver and biliary tree with adult flukes, which can result in hepatitis, cirrhos is and biliary tract inflammation, obstruction and lithiasis. The patient had the typical diagnostic tetrad of fever, eosinophilic leukocytos is, tender hepatomegaly and fluke ova in the stools. Theatment consistes of Emetine hydrochloride administration for hepatic involvement and common bile duct exploration for removal of flukes, with cholecystectomy for associated cholelithiasis. The combination of medical and surgical therapy cal be expected to produce an arrest of this infection. The removed liver revealed eggs of the fasciols species in the intrahepatic bile duct. The clinical history, pathological findings and treatment of this case were described.

산화구리 촉매담지 세라믹 캔들필터를 이용한 NO 제거

홍민선,문수호,이재춘,이동섭 한국대기환경학회 2004 한국대기환경학회지 Vol.20 No.3

The CuO/3Al₂O₃ㆍ2Si0₂ catalyst impregnated ceramic candle filters for nitrogen oxides removal were prepared by porous mullite(3Al₂O₃ㆍ2Si0₂) support and CuO catalyst deposited on this support to achieve uniformly dispersed CuO deposition, which arc impregnated into the pores of available alumino-silicate ceramic candle filter. The CuO/3Al₂O₃ㆍ2Si0₂ catalyst impregnated ceramic candle filters were characterized by XRD, BET, air permeability, pore size, SEM and catalytic tests in the reduction of NOx by NH₃. The observed effects of CuO/3Al₂O₃ㆍ2Si0₂ impregnated ceramic candle tilters in SCR reaction arc as follows: (1) when the content of CuO catalyst increased further, activity of NO increased. (2) NO conversion at first increased with temperature and then decreased at high temperatures (above 400℃), possibly due to the occurrence of the ammonia oxidation reaction. (3) In pilot plant test for 3 months, NO conversion was greater than 90%.

질소산화물 제거를 위한 디스크형 바나디아 촉매담지 세라믹필터의 특성

홍민선,문수호,이재춘,이동섭 한국대기환경학회 2004 한국대기환경학회지 Vol.20 No.4

The performance of disk-type catalytic fillers impregnated by TiO₂ or TiO₂-3Al₂O₃ㆍ2SiO₂ supports and V₂O_(5), catalyst was evaluated for selective catalytic reduction (SCR) of NO with ammonia as a reductant. XRD, FT-IR, BET and SEM were used to characterize the catalytic filters prepared in this work. Optimal V₂O_(5) loading and reaction temperature for V₂O_(5)/TiO₂ catalytic filters were 3~6wt.% and 350~400℃ at GHSV 14.300hr-¹ in the presence of oxygen, respectively. With increasing the V₂O_(5) loading from 0.5 to 6 wt.%, NO conversion increased from 24 to 96% at 400℃ and 14.300 hr-¹, and maintained at 80% over in the V₂O_(5) loading range of 3~6 wt.% and then dropped at V₂O_(5) loading of 7wt.% over. In comparing V₂O_(5)/TiO₂ and V₂O_(5)/TiO₂-3Al₂O₃ㆍ2SiO₂ catalytic fillers, which have same 3 wt.% V₂O_(5) loading, the V₂O_(5)/TiO₂-3Al₂O₃ㆍ2SiO₂ catalytic filter showed higher activity than V₂O_(5)/TiO₂ catalytic filter, but higher differential pressure drops owing to its low air permeability.

회귀분석법을 이용한 로타리 공구의 절삭 특성

심승천,장성민,맹민재,정준기 한국공작기계학회 2004 한국공작기계학회 춘계학술대회논문집 Vol.2004 No.-

This paper deals with the study of feasibility of rotary carbide tools in the machining of aluminium alloy. A rotary tool holder was designed and manufactured for this work. Experiments were performed using Taguchi methods and regression analysis to analyse the influence of various factors and their interactions on the cutting characteristics of rotary carbide tools during machining. The cutting force is influenced the most greatly at the inclination angle. The surface roughness is influenced distinctly at depth of cut. It deduced an equation to predict cutting force and surface roughness. Hence, it could be concluded here that the proposed model agrees with the experimental data satisfactorily.

서울의 Penicillinase Producing Neisseria Gonorrhoeae 발생빈도(1996)

김재홍,황동규,전재홍,김윤석,김중환,김용준,이창균,임동진,김현수,조창근,김경문,박상훈,전우형,김희성,이호정,차명수,김갑형,김형석,김석우,황지환,박병순,권오상,이민수,송기훈,성소영,이인섭,부태성 대한화학요법학회 1999 대한화학요법학회지 Vol.17 No.2

Background : In recent years, gonorrhea has been panedemic and remains one of the most commom STDs in the world, especially in developing countries. Objective & Methods: For the detection of a more effective therapeutic regimen and assessing the prevalence of PPNG, we have been trying to study the patients who have visited the VD Clinic of Choong-Ku Public Health Center in Seoul since 1980 by means of the chromogenic cephalosporin method. Results: In 1996, 139 strains of N. gonorrhoeae were isolated, among which 53(39.0%) were PPNG. Conclusion: Our results suggests that after a peak of 74.3% in 1993, the prevalence of PPNG in Seoul is gradually declining.