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

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.

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.

신질환 환아에서 Cyclosporine A의 약동학 특성 및 치료효과

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

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.

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%.

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.

서울의 PPNG 발생 빈도(1990)

김재홍,김한중,노영석,김영태,김중환,황규홍,이정덕,백승철,김건우,조상현,김준영,김석민,김영호,김상순,이승한,김방순,전덕규,하상근 대한화학요법학회 1992 대한화학요법학회지 Vol.10 No.2

The prevalence of PPNG among pretreated gonorrhoeae cases isolates at the VD clinic of Choong-ku Public Health Center in Seoul has been studied and reported annually since 1981. In 1990, 162 strains of N.gonorrhoeae were isolated, among which 80 were PPNG. The prevalence of PPNG in Seoul showed increased tendency till 1987, thereafter, it has been stationary.

디스크형 산화구리 촉매담지 세라믹필터의 제조와 물성

홍민선,문수호,이재춘,이동섭,임우택 한국대기환경학회 2004 한국대기환경학회지 Vol.20 No.2

A catalyst with CuO ceramic filter for simultaneous treatment of dust and HAP was prepared and characterized. Catalytic ceramic tilter can not only potentially achieve the substantial savings in energy but provide with effective optimization and integration of process for simultaneous removal of S0₂ㆍ NOx and particulates from flue gases. Catalytic ceramic filters remove simultaneously particulates on exterior surface of filters and reduce NO to N₂and H₂O by SCR (Selective Catalytic Reduction) process. Preparation of catalyst impregnated ceramic filter with disk shape (Ψ50) follow the processing of alumino-silicate ceramic filter, support impregnation and catalyst impregnation(copper oxide). Preparation routes of alumino-silicate catalyst carrier suitable for production of catalytic filters practically were studied and developed using the sol-gel and colloidal processing, homogeneous precipitation and impregnation method. Characterization of the catalyst, catalyst carrier catalytic filter materials have been performed the using various techniques such as BET, XRD, TGA, SEM. Combination of the sol-gel and colloidal processing and impregnation method is recommended to prepare catalyst carriers economically for catalytic filter applications.

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.