• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2005.04a
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• pp.167-170
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• 2005

대부분의 폐광산 주변 농경지 토양은 비소 및 여러 중금속으로 오염되어 있으며, 이러한 중금속들의 지속적인 용출에 의해 주변 지하수 오염과 재배 농산물의 중금속 축적이 우려되고 있다. 오염토양에서의 중금속 용출에 의한 오염을 막기 위하여 본 연구에서는 개량제를 이용한 안정화 공법을 선택하여 하부로 배출되는 중금속의 용출율을 감소시키는 실험을 실시하였다. 생석회(CaO)를 개량제로 이용하여 실제 오염 농경지 현장과 비슷한 대형칼럼을 제작한 후 인공강우를 주입, 하부로 용출되는 중금속의 농도를 측정함으로써 생석회 첨가에 의한 용출율 감소를 규명하였다. 개량제를 비오염토와 혼합하여 오염토양 상부에 복토한 것과 오염토와 혼합하여 객토한 칼럼을 각각 제작하였으며 투입되는 생석회의 양도 $2{\sim}10%$로 다양하게 적용 하였고, 첨가된 개량제의 성상도 분말과 입상으로 나누어 실험하였다. 주입하는 인공강우는 연구지역 주변의 10년간의 연 평균 강수량을 토대로 산정하였으며, 복토와 객토를 하지 않은 오염토양도 같은 조건에서 용출을 실시하였다. 실험결과 생석회의 성상에 따른 중금속 용출율의 차이는 없었으며, 개량제 함량은 5%가 적당한 것으로 나타났다. 복토와 객토를 비교하였을 때 용출되는 중금속의 농도는 객토가 복토에 비해 낮아 중금속 용출율 감소효과가 매우 큰 것으로 나타났으며, 중금속의 종류에 따라 용출율 감소의 차이를 나타내었다. 복토법의 경우 As의 용출율은 분말 생석회를 5% 복토한 경우 용출율이 10배 감소하고 Cd의 경우 2%와 5% 복토한 경우 각각 25배와 161배 감소하는 것으로 나타났다. Pb의 경우 생석회로 5%로 복토한 경우 10배정도의 용출율 감소를 보였고 Zn의 용출율은 분말, 입상 생석회를 5% 복토한 경우 80배$\sim$155배 감소하는 것으로 나타났다. 객토법의 경우 입상생석회를 5% 복토한 경우 Cd과 Zn 각각 200배에서 400배의 용출율 감소를 나타내었다.

• Journal of Korean Society of Environmental Engineers
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• v.29 no.9
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• pp.1003-1012
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• 2007

In this study, we analyzed the release differences for some critical pollution compounds according to the surrounding conditions in order to predict water quality due to the sedimental releases and the release characteristics at different sedimental locations in Lake Leewon, in Tae-An area. COD, nitrogens and phosphates were analyzed using the standard methods for water quality, based on high chloride ion concentration(greater than 2,000 ppm). For COD, the release rate increased in the anoxic basin but almost the same in the oxic basin. For $NH_3$-N, the release rate decreased in the oxic basin as you go A through C point meanwhile, for $NO_3$-N and T-N, the tendency was reversed because of nitrification of them. In the anoxic basin, the release rates of $NH_3$-N and $NO_3$-N went up with A through C path. However, the release rate of T-N was found to decrease. Also, for $PO_4$-P and T-P, the release rates in the oxic basin were lowest at B point mainly because the phosphates were at less released in the highly $O_2$ concentrated environment. In the anoxic reactor, $PO_4$-P was released similarly regardless of the sampling points. In summary, the release rates in the oxic reactor were greater than those in the anoxic reactor for COD and $NO_3$-N. For the other components, the anoxic basin generated the higher release rates.

• Korean Journal of Soil Science and Fertilizer
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• v.35 no.5
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• pp.264-271
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• 2002

Nitrogen releasing characteristics of polymer-coated urea(PCU) that made acrylic synthetic resins were studied in incubated soil, water and paddy soil. Also, their correlations and degradation patterns of coating material were tested. Releasing rate of nitrogen from PCU decreased with increasing coating rate. N001(coating rate 8.5%) and N003(coasting rater 6.3%) were low releasing amount at the early stage, whereas N005(coating rate 4.8%) was released over 80% within 20 days. Relationship of the releasing rate between incubated soil($25^{\circ}C$) and paddy soil could be described as follows : $Y=-0.0011X^2+2.2931X-50.264(R^2=0.9884)$ for N001, $Y=-0.0016X^2+1.1587X+5.5064(R^2=0.9805)$ for N003 and $Y=-0.03X^2+6.499X-243.22(R^2=0.9422)$ for N005, respectively (Y: release rate at field condition, X: experiment period). Relationship of the releasing rate between incubated water($30^{\circ}C$) and paddy soil can be described as follows : $Y=0.0011X^2+2.2601X-25.329(R^2=0.9884)$ for N001, $Y=-0.0306X^2+4.4994X-76.307(R^2=0.955)$ for N003 and $Y=-0.0164X^2+3.7764X-108.22(R^2=0.9422)$ for N005. After 150 days, coating materials of N001, N003, and N005 in incubated soil were degraded approximately 23%, 22% and 15%, respectively. Also The scanning electron microscope examination of coating material revealed that particle surface became gradually shattered with the time after the soil treatment.

• Journal of the Mineralogical Society of Korea
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• v.26 no.1
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• pp.1-8
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• 2013

This study was carried out to test the possibility of using an environmentally friendly method of leaching silver concentrate from the Samjo mine. The Samjo mine ore contained minerals such as pyrite, chalcopyrite, galena, arsenopyrite, and sphalerite. The concentrate samples tested with the thiourea solution were roasted at $750^{\circ}C$. The results of different experimental conditions showed that the highest silver leaching rate was obtained when the concentration of thiourea was at 0.8 g with ferric sulfate at 0.425 g and the leaching temperature at $60^{\circ}C$. The Ag leaching rate obtained was 91.5% at a pulp density of 10%. However, in the XRD analysis, peaks of pyrite, galena, and hematite were still found in the leached solid residues in which the Ag leaching rate was the highest. it is expected that the unrecovered silver in the solid residue can be lost.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2004.09a
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• pp.342-345
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• 2004

국내에 산재해 있는 휴ㆍ폐광산은 주변의 하천이나 농경지에 지속적인 중금속 오염원을 제공하면서 많은 문제점을 발생시키고 있다. 여러 종류의 중금속으로 오염된 토양에 대하여 안정화 공법의 적용가능성을 알아보기 위한 실험을 실시하였다. 오염토양에 적절한 복토첨가제로 생석회와 석회석을 사용하여 첨가제를 넣지 않은 dh염토양과 중금속 용출율을 비교 ㆍ분석하였다. 이 결과 안정화 첨가제들이 Cd, Pb, Zn등의 중금속 용출을 억제하는데 높은 효율을 보여줌을 확인할 수 있었으며, 첨가제를 넣지 않은 토양과 비교한 결과 약 40배 이상의 용출율 감소를 보였다. 또한 실험 시에 첨가제 각각의 함량을 1%, 2%, 5%로 설정하여 현장 적용시 복토에 첨가할 적절한 양을 산출해 낼 수 있도록 하였다. 첨가제 주입으로 인한 용출율 감소는 하나의 중금속에 국한되는 것이 아니라 여러 원소를 동시에 효과적으로 안정화시킬 수 있는 것으로 나타났다. 본 연구 결과는 오염토양에 토양안정화공법을 적용 시에 중요한 자료로 이용될 수 있을 것으로 판단된다.

• Applied Chemistry for Engineering
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• v.9 no.4
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• pp.574-578
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• 1998

Electrochemical Ion Exchang(EIX) electrode containing Amberlite IRP-64 as a cation ion exchange resin and Stylene-Buthylene-Rubber(SBR) as a binder was fabricated by the compressed diecasting method. The adsorption and elution characteristics in copper sulfate solution were investigated at the various electrode potentials and electrolyte pHs. In the adsorption process, it was found that the maximum adsorption rate of copper was obtained at -1800 mV and the ratio of adsorption was 92% during 90 min. In the elution process, the elution rate of copper was increased in proportion to anodic potential in the present experimental range and the ratio of elution was 88% during 50 mins at 3600 mV. The adsorption and elution processes were significantly affected by the variation of local pH in the vicinity of electrochemical ion exchange electrode. The higher performances of adsorption and elution were elution were obtained at basic and acidic eletrolytes.

• Korean Journal of Mineralogy and Petrology
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• v.33 no.3
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• pp.243-250
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• 2020

The purpose of this study is to find out the possibility of applying microwave-hypochlorous acid leaching to effectively leaching Au in hydrothermal minerals on board. The comparative leaching experiment were confirmed that the leaching rate of Au with(T1)/with out(T2) of microwave nitric acid leaching. In addition, the leaching rate of Au on the conventional leaching by mechanical agitation(T3) and microwave leaching was compared. The result of microwave nitric acid leaching(solid-liquid ratio; 10%, leaching temperature; 90 ℃, leaching time; 20 min) confined that the metal leaching rate was high in the order of As>Pb>Cu>Fe>Zn, and the content of Au in the leaching residue was increased from 33.77 g/ton to 60.02 g/ton. As a result of the comparative leaching experiment using a chloride solvent, the dissolution rate of Au was high in the order of T1(61.10%)>T3(53.30%)>T2(17.30%). Therefore, chloride, which can be manufactured using seawater and that can be recycled by collecting chlorine gas generated in the leaching process, is expected to be an optimal solvent for Au leaching. In addition, the application of microwaves is believed to be effective in terms of time, efficiency and energy.

• Proceedings of the Korean Society of Dyers and Finishers Conference
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• 2008.10a
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• pp.55-56
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• 2008

본 연구에서는 국내 기업에서 개발된 Nyoln P 입자첨가 마스터배치를 이용하여 방사공정에서의 방사온도와 Nylon sheath와 PET core 비율을 변화시켜 용출형 Nylon 중공사를 방사하여 용출온도, 용출시간 등 용출조건의 변화에 따라 Nylon 중공사의 중공율에 미치는 영향에 대해 분석하였고, 또한 용출된 상태를 보기 위해 용출형 나일론 중공사의 SEM 사진을 측정하였다. 이러한 결과를 토대로 개발된 나일론 용출형 중공사를 이용하여 고부가가치의 나일론 용출형 중공사 제품의 상품화 기술을 개발하는데 도움을 주는데 본 연구의 목적이 있다.

• Journal of the Mineralogical Society of Korea
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• v.25 no.3
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• pp.123-130
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• 2012

Leaching experiments of gold and silver from roasted concentrate were carried out using a chlorine-hypochlorite solution. The leaching rate of gold was 75% at 1.5:1 ratio of chlorine and hypochlorite and increased to 81% with adding 1 M NaCl. However, at 1% pulp density and at $65^{\circ}C$, the leaching rates of Au were close to 100%. XRD analysis identified quartz in the solid residues after digestion of roasted concentrate with aqua regia or chlorine-hypochloride leaching solution. This suggests that the gold may not be leached out of the quartz in aqua regia or chlorine-hypochlorite solution. In order to leach the gold from the quartz, the concentrate will have to be pre-treated through ultra-fine grinding or treated with stronger oxidative agents.

• Korean Journal of Food Science and Technology
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• v.18 no.2
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• pp.168-172
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• 1986

The swelling and hydration properties of Korean red ginseng tails and yield of total solids in extract were studied during extraction with ethanol solution having a concentration of 0-90% at $60-100^{\circ}C$. Extraction was carried out 5 times which was taken 8 hours per each time of extraction. The swelling, hydration and total solids yield were increased as the ethanol concentration decreased and as the extraction temperature raised. The cumulative value of solids yield suggested that three times of extractions with water or 70% ethanol were effective to recover more than 84%. Linear regression analysis on the properties investigated and extraction conditions showed a linear logarithmic relationship .