• Bulletin of the Korean Chemical Society
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• 제24권2호
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• pp.209-218
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• 2003

Ecosystems in the Keweenaw Peninsula region of Lake Superior, USA, were disturbed by over 500 million tons of copper-rich mine tailings during the period 1850-1968. Metals leaching from these mine residues have had dramatic effects on the ecosystems. Vast acreages of exposed tailings that are over 100 years old remain unvegetated because of the combination of metal toxicity, absence of nutrients, and temperature and water stress. Therefore, it is important to characterize and fractionate solid copper phases for assessing labile forms of copper in soils and sediments contaminated by the mining wastes. X-ray diffraction analyses indicate that calcite, quartz, hematite, orthoclase, and sanidine minerals are present as major minerals, whereas cuprite,tenorite, malachite, and chalcopyrite might be present as copper minerals in the mining wastes. Sequential extraction technique revealed that carbonate and oxide fractions were the largest pools of copper (ca. 50-80%) in lakeshore and wetland stamp sands whereas the organic matter fraction was the largest reservoir (ca. 32%) in the lake sediments. The concentrations of iron and copper were inversely correlated in the oxide fraction suggesting that copper may occur as a surface coating on iron oxides. As particle size and water contents decrease, the percent of the copper bound to the labile carbonate fraction increases.

• Journal of the Korean Wood Science and Technology
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• 제23권3호
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• pp.66-72
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• 1995

The rate of fixation of the components were evaluated in CCA-Type B and CCFZ-treated radiata pine sapwood by quantitative analysis of solution expressed from the treated wood. The leaching characteristics of radiata pine blocks treated with CCA-Type B and CCFZ were also evaluated by the AWPA standard leaching test. Both fixation and leaching charactersistics of CCA-Type B were compared with CCA-Type C treated wood samples. The rate of CCA-Type B fixation was a little faster than that of CCFZ. However, significant amounts of arsenic was unfixed in the CCA-Type B treated samples and consequently leached. These significant quantities of arsenic liberated from the CCA-Type B treated wood during service may pose some environmental concerns. Arsenic was no longer detectable from CCA-Type C treated samples when fixation was complete, even though the fixation of CCA-Type C was slower in some degree than CCA-Type B. In summary, it could be said that CCFZ was much safer preservative than CCA-Type B by the criterion based on the relative hazard assessed by absolute amount of unfixed element present in the treated wood. Also the decision that CCA preservative has to move from Type B to Type C should be made sooner or later for continuous use of CCA preservative in the future.

• 한국환경보건학회지
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• 제19권2호
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• pp.46-54
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• 1993

This study was carried out on the stabilized/solidified treatment for the reducing leachability of hazardous heavy metals copper, lead, chromium and cadmium in the hazardous sludge which treated to be unleached heavy metals by sodium diethyl dithiocarbamate. Cement matrix was analyzed for the leachability of 24 hrs and dynamic leaching test, structure and the optimum condition for the stabilization and solidification of the hazardous sludge. In 28 days of curing time the unconfined compressive strength was 21.5 kg/cm$^2$ at the ratio of portland cement (0.5)+fly ash (0.25) and 23.5 kg/cmz at the ratio of portland cement (0.5)+fly ash (0.25) + cake (0.25). High concentration of Pb, Cr and Cd in the sea water and Cu in the distilled water were leached at the dynamic leaching test. The concentration of leaching heavy metals for specimens which were tested 24 hrs were found low leachability with decreasing pH of leachant. According to dynamic leaching test, the low level of copper, lead, cadmium and chromium were leached in the cement matrix with sodium diethyl dithiocarbamate. But the effective diffusion coefficient of unleached cement matrix which was treated sodium diethyl dithiocarbamate was decreased above 2 times than that of cement matrix. The relation of leachant renewal period (Y) and cumulative fraction ion leached (X) was the following regression equations. Solidification with unleached agent. Y$_{Cu}$ = 1413752X + 247, Y$_{Pb}$ = 223501IX + 214, Y$_{Cr}$ = 8310601X - 472, Y$_{Cd}$ = 168787X + 1061 The structure of' solidified matrix with X-ray diffraction analysis was composed more Ca(OH)$_2$, Si, Mg(OH)$_2$ and Al in the unleached cement matrix than those in cement matrix.

• 한국지하수토양환경학회지:지하수토양환경
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• 제9권4호
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• pp.15-23
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• 2004

제설제를 살포하는 것은 도시지역에서 자동차가 겨울철에 운행하는 동안 안전한 운전을 가능하게 한다. 하지만 많은 양의 제설제 (염화칼슘과 소금)를 사용하는 것은 심각한 환경문제를 발생시키고 도로변 퇴적물에 함유된 중금속의 거동을 변화시키게 되며, 결과적으로 염소이온과의 착이온형성에 기인된 중금속의 이동성을 증가시키게 될 것이다. 제설제의 농도가 중금속 (카드뮴, 아연, 구리, 납, 비소, 니켈, 크롬, 코발트, 망간 및 철)의 용출특성과 이동성에 미치는 영향을 연구하기 위하여, 서울시 주요 도로변에서 채취한 퇴적물을 대상으로 제설제의 농도 (0.01-5.0M)를 변화시켜 용출실험을 수행하였다. 연구결과, 도로변 퇴적물에 함유된 아연, 구리 및 망간은 쉽게 용해되어 이동되는 반면, 크롬과 코발트는 도로변 퇴적물에 강하게 고정되어 있음을 관찰하였다. 이번 용출실험에서 검출된 아연 (최대 $118.6{\mu}g/g$). 구리 (최대 $44.9{\mu}g/g$) 및 망간 (최대 $42.2{\mu}g/g$)의 함량은 상대적으로 높은 함량이었다. 제설제는 흡착 (또는 침전)된 금속과 용해된 금속 사이의 분배를 감소시키며, 이는 제설제가 용해된 눈 녹은 물에 용존 중금속 함량을 증가시키게 되어 결과적으로 지표수의 수질을 악화시키게 된다. 또한, 도로에 제설제를 살포하는 것에 의해 중금속이 지하수까지 침투되어 지하수를 오염시키게 될 것이다.

• 분석과학
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• 제37권1호
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• pp.47-62
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• 2024

Abu Gurdi area is located in the South-eastern Desert of Egypt which considered as volcanic massive sulfide deposits (VMS). The present work aims at investigating the ore mineralogy of Abu Gurdi region in addition to the effectiveness of the hydrometallurgical route for processing these ores using alkaline leaching for the extraction of Zn, Cu, and Pb in the presence of hydrogen peroxide, has been investigated. The factors affecting the efficiency of the alkaline leaching of the used ore including the reagent composition, reagent concentration, leaching temperature, leaching time, and Solid /Liquid ratio, have been investigated. It was noted that the sulfide mineralization consists mainly of chalcopyrite, sphalerite, pyrite, galena and bornite. Gold is detected as rare, disseminated crystals within the gangue minerals. Under supergene conditions, secondary copper minerals (covellite, malachite, chrysocolla and atacamite) were formed. The maximum dissolution efficiencies of Cu, Zn, and Pb at the optimum leaching conditions i.e., 250 g/L NaCO₃ - NaHCO₃ alkali concentration, for 3 hr., at 250 ℃, and 1/5 Solid/liquid (S/L) ratio, were 99.48 %, 96.70 % and 99.11 %, respectively. An apparent activation energy for Zn, Cu and Pb dissolution were 21.599, 21.779 and 23.761 kJ.mol^-1, respectively, which were between those of a typical diffusion-controlled process and a chemical reaction-controlled process. Hence, the diffusion of the solid product layer contributed more than the chemical reaction to control the rate of the leaching process. High pure Cu(OH)₂, Pb(OH)₂, and ZnCl₂ were obtained from the finally obtained leach liquor at the optimum leaching conditions by precipitation at different pH. Finally, highly pure Au metal was separated from the mineralized massive sulfide via using adsorption method.

• 대한지하수환경학회지
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• 제6권3호
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• pp.120-125
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• 1999

충북 단양에 위치한 조일 광산에서 채취한 구리와 아연으로 오염된 광미(광산 폐기물로서 금속 추출 후 남은 찌꺼기) 처리방안으로서 생물학적 용출기법(bioleaching)의 효율 증진에 관한 연구를 수행하였다. 기본 배지 조성(9 K medium) 중 미생물의 성장 및 증식에 영향을 미치는 에너지원, 인, 질소원의 농도를 변화시켜가며 배지 조성에 따른 중금속의 생물학적 용출 특성을 관찰하였다. 먼지, 배지조성 중 인의 농도를 0 mM. 3.0 mM, 6.0 mM 각각 조절하여 중금속의 용출효율을 관찰한 결과. 인을 첨가하지 않았을 때 아연. 구리 각각 98.8%와 47.5%의 용출효율을 보인 반면 인의 농도가 6.0mM 로증가 시켰을 경우. 오히려 중금속의 용출효율이 감소하였다. 배지내 질소원의 농도를 0 mM. 45 mM, 90 mM로 조절하여 중금속의 용출정도를 알아본 결과. 45 mM 농도로 주입하였을 때 아연. 구리 각각 85%,와46.4%로 90 mM 농도에보다 더 높은 용출효율 나타내었다. 에너지원 변화에서는 아연의 경우 에너지원을 첨가하지 않았을 때 93%의 용출효율을 보였고. 구리의 경우는 160 mM 첨가했을 때 46.4%로 가장 높은 중금속 용출효율을 보였다.

• Membrane and Water Treatment
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• 제7권6호
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• pp.555-571
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• 2016

Heavy metal contamination has attracted considerable attention during recent decades due to the potential risk brought about for human beings and the environment. Several adsorbent materials are utilized for the purification of contaminated water resources among which chitosan is considered as an appropriate alternative. Copper is a heavy metal contaminants found in several industrial wastewaters and its adsorption on porous and macroporous chitosan membranes is investigated in this study. Membranes are prepared by phase inversion and particulate leaching method and their morphology is characterized using SEM analysis. Batch adsorption experiments are performed and it is found that copper adsorption on macroporous chitosan membrane is higher than porous membrane. The iso-steric heat of adsorption was determined by analyzing the variations of temperature to investigate its effect on adsorption characteristics of macroporous chitosan membranes. Furthermore, desorption experiments were studied using NaCl and EDTA as eluants. The mechanism of copper adsorption was also investigated using XPS spectroscopy which confirms simultaneous occurrence of chelation and electrostatic adsorption mechanisms.

• Environmental Analysis Health and Toxicology
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• 제22권4호
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• pp.339-348
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• 2007

A laboratory experiment was conducted to study the characteristics of leaching of Cr, Cu, and As from chromated topper arsenate (CCA)-treated wood. The wood species tested was hemlock spruce ($10\;cm\;{\times}\;10\;cm\;{\times}\;10\;cm\;tube$). The leaching experiment was conducted over 60 days using I L of leachants whose pHs were adjusted to 2.0, 3.7, and 1.6, respectively with nitric acid, and also using lake water, according to the OECD guideline. Each leachate was analyzed for Cr and Cu using flame-AAS, and for As using vapor generation-AAS. Three metals were loathed at the highest levels at pH 2.0 but almost at similar levels at the other conditions. Cumulative quantifies over 60 days of a leaching period were in order of As>Cu>Cr. As was predicted to leach with an increase in flux over a 10 year period, while Cr and Cu fluxes were predicted to decrease with time. This result suggest that arsenic can pose a health risk to humans over a long period of time, when CCA-treated wood is used for building facilities (e.g., playgrounds, residential purposes, etc.) with which humans frequently contact.

• 자원리싸이클링
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• 제17권1호
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• pp.51-58
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• 2008

Cu-Ni-Co-Fe 함금상에 황의 원료로서 pyrite 또는 chalcopyrite를 첨가하여 매트상을 제조하는 방법에 대하여 검토하였다. 두 매트상 모두 주성분은 $(FeSi)_9S_8$, $CuFeS_2$, FeS, $Co_4S_3$, $Ni_3S_2$ 그리고 $Cu_2S$의 금속황화물 이었으며, chalcopyrite를 첨가한 매트의 경우 구리의 함량이 높아 $Cu_2S$의 피크가 더 높게 나타났다. 제조한 매트상의 침출 결과 모두 구리는 95%이상, 니켈과 코발트는 90% 이상의 침출율을 보였다. Pyrite와 chalcopyrite 첨가량이 증가할수록 침출액의 pH는 낮아지고, 용해되어 있는 철이온의 농도와 잔사량은 증가하였다. 한편 매트 중 황의 함량변화에 따른 유가금속의 침출율은 모든 시료에 대해 크게 변하지 않았으며, 다만 pyrite를 이용하여 제조한 매트의 경우에 Ni과 Co가 황 함량 증가에 따라 다소 증가하는 경향을 나타내었다.

• 자원리싸이클링
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• 제24권4호
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• pp.12-21
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• 2015

일반적으로 구리제련 슬래그내 구리함량은 0.5-3.7% 혹은 그 이상의 높은 비율로 포함되어 있며, 슬래그내 구리회수에 대한 대표적인 방법으로는 부유선별, 침출 그리고 배소가 있다. 본 연구에서는 부유선별법에 의한 구리 회수방법을 검토하였으며, 잔세이트포수제를 이용한 황화부선을 수행하였다. 산성과 알칼리 조건에서 부유선별 특성을 관찰하였으며, pH 4 에서 구리회수율 50%, pH 11 에서 구리회수율 67%로 나타났으며, 특히 pH 11에서는 $100{\mu}m$ 이상의 입자가 정광으로 부유되어 회수율이 상대적으로 높게 나타나는 경향을 보였다. 슬래그 입도를 200 mesh 이하로 분쇄하여 단체분리도를 향상시켜 pH조건별 부유선별 실험을 수행한 결과, 회수율이 78 - 83%까지 향상되는 것을 확인할 수 있었다.