• 펄프종이기술
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• 제43권1호
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• pp.65-73
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• 2011

The fibrous raw materials in packaging-grade paper production in Korea were mainly obtained from waste paper. The use of recycled paper has both positive and negative impacts in papermaking process. The primary positive impacts are the environmental protection and manufacturing cost reduction, and the negative impacts are the quality reduction in paper quality and the accumulation of heavy metals and other pollutants in wet- and dry-end process. This study was carried out to consider the optimum acid decomposition system with the highest recovery rate for the analysis of heavy metals in packaging-grade paper. The open digestion system using Kjeldahl apparatus and the closed digestion system using microwave oven for decomposing the organic materials in paper were compared. In both open and closed digestion method, the combination of nitric acid, hydrochloric acid and hydrogen peroxide showed higher recovery rate than using only nitric acid alone because the presence of Cl- ions in hydrochloric acid stabilizes ligand formation with metal ions. KOCC was observed to have the highest heavy metal content among the recycled paper samples. The heavy metal contents decomposed with the closed digestion system were relatively higher than with open digestion system.

• 한국산학기술학회논문지
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• 제16권1호
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• pp.906-913
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• 2015

알루미나를 생산하는 Bayer 공정에서 발생하는 레드머드는 환경과 인간에게 심각한 위험요인이 되고 있어, 알루미늄 산업에서 레드머드의 발생량을 줄이거나 또는 재활용 하는 것은 매우 시급한 문제이다. 본 연구에서는 초음파 강도, 반응온도, 반응시간 및 산성용액 농도 등 4가지 변수가 레드머드 내의 철과 알루미늄의 침출에 미치는 영향에 대해 연구하였다. 레드머드로부터 금속 성분의 용출에 미치는 가장 중요한 변수는 초음파 강도와 반응온도로 나타났다. 초음파를 조사할 경우, 철과 알루미늄의 회수율은 초음파를 조사하지 않은 경우보다 각각 1.72배와 1.28배 정도 증가하는 것으로 나타났다. 본 연구결과, 알루미나로부터 금속성분을 회수하기 위한 적정 조업조건은 초음파 강도 150 W, 황산 용액의 농도 4-6N, 반응온도 $70^{\circ}C$, 반응시간 2시간 등이었다.

• 한국자원리싸이클링학회:학술대회논문집
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• 한국자원리싸이클링학회 1993년도 EARTH 발표논문초록
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• pp.6.2-6
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• 1993

• Bulletin of the Korean Chemical Society
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• 제29권9호
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• pp.1787-1789
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• 2008

• 대한용접접합학회:학술대회논문집
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• 대한용접접합학회 2005년도 추계학술발표대회 개요집
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• pp.162-164
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• 2005

570MPa grade weldable steels were $CO_{2}$ welded with various heat input and interpass temperature using flux cored wires. Effects of heat input and interpass temperature on the strength and toughness of weld metal were investigated and interpreted in terms of microstructural change, recovery of alloying elements, and the amount of reheated weld metal.

• 한국막학회:학술대회논문집
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• 한국막학회 1994년도 추계 총회 및 학술발표회
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• pp.8-11
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• 1994

Disposal of hazardous ions in the aqueous streams is a significant industrial waste problem.. Waste streams from electronics, electroplating, and photographic industries contain metal ions such as copper, nickel, zinc, chromium(IV), cadmium, aluminum, silver, and gold, amongst others in various aqueous solutions such as sulfates, chlorides, fluorocarbons, and cyanides. Typical plating solutions having similar compositions are listed in Table 1. Spent process streams in catalyst manufacturing facilities also contain precious metals such as Ag, Pt, and Pd. Developing an effective recovery process of these metal ions for reuse is important.

• 한국환경과학회지
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• 제6권1호
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• pp.61-67
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• 1997

미생물에 의한 흡착법으로 중금속을 효과적으로 제거, 회수할 수 있다. 알콜 발효 후 부산물로 생성되는 폐 Saccharomyces cerevisiae는 비교적 가격이 저렴하고, 중금속 생체흡착에 유용한 자원으로 이용될 수 있다. 생체흡착 실험에 사용된 미생물은 부유 및 alginate에 고정화된 S. cerevisiae로 수행하였다. 회분식 실험에서 생체흡착량은 Pb > Cu > Cd의 순으로 이루어졌다. Pb 이온의 흡착 평형은 Freundlich와 Langinuir 모델로 설명하였고, Freundlich 모델이 실험자 료와 잘 부합되었다 고정화된 S. cerevisiae를 이용한 혼합용액( Pb, Cu, Cr 및 Cd )흡착 실험에서 각 중금속들은 선택적 흡착 특성을 나타내었다. 고정화 미생물을 고정층 반응기에 충진하여 혼합 중금속 용액의 생체흡착 실험을 수행한 결과 Pb 이온이 가장 많이 흡착을 하였다. 고정화된 미생물에 흡착된 Pb의 탈착실험에서 0.1M의 HCI 및 $H_2SO_4$가 효과적이었다.

• 대한화학회지
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• 제32권3호
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• pp.211-226
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• 1988

역상 액체 크로마토그래피에 의하여 몇 가지 금속-dithiocarbamate(DTC) 킬레이트의 용리거동을 Novapak $C_{18}$과 {\mu}$-Bondapak $C_{18}$ 분리관을 사용하여 연구하고, 아울러 동시 분리정량에 미치는 pH, 진탕시간, 흐름속도, 추출용매 종류 및 이동상의 세기등 여러가지 인자들의 영향을 조사 검토하였다. 미량 금속-DTC 킬레이트들은 Novapak $C_{18}$ 분리관에서 acetonitrile/methanol/water 또는 acetonitrile/water의 용리액을 사용하여 성공적으로 분리되었다. 모든 금속-DTC 킬레이트의 용매세기 인자는 $0{\leqq}log\;k'{\leqq}1$ 의 범위임을 확인하였고, 회수율을 97.0-106.7 %, coefficient of variation은 0.98-3.41%이었다. 최적 분석 조건에서 합성 시료중에 있는 혼합 금속 이온들은 상대 오차 ${\pm}$6.7 % 이내에서 동시 분리정량이 가능하였다.

• Fibers and Polymers
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• 제5권1호
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• pp.1-5
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• 2004

The ability of inherently conducting polymer (ICP) coated textiles to recover gold metal from aqueous solutions containing $[AuCl_4]^-$ was investigated. Nylon-lycra, nylon, acrylic, polyester and cotton were coated with a layer of polypyrrole (PPy) doped with 1,5-naphthalenedisulfonic acid (NDSA), 2-anthraquinonesulfonic acid (AQSA) or p-toluenesulfonic acid (pTS). Textiles coated with polyaniline (PAn) doped with chloride were also used. The highest gold capacity was displayed by PPy/NDSA/nylon-lycra, which exhibited a capacity of 115 mgAu/g coated textile, or 9700 mgAu/g polymer. Varying the underlying textile substrate or the ICP coating had a major effect on the gold capacity of the composites. Several ICP coated textiles recovered more than 90 % of the gold initially present in solutions containing 10 ppm $[AuCl_4]^-$ and 0.1 M HCl in less than 1 min. Both PPy/NDSA/nylon-lycra and PAn/Cl/nylon-lycra recovered approximately 60 % of the gold and none of the iron present in a solution containing 1 ppm $[AuCl_4]^-$, 1000 ppm $Fe^{3+}$ and 0.1 M HCl. The spontaneous and sustained recovery of gold metal from aqueous solutions containing $[AuCl_4]^-$ using ICP coated textiles has good prospects as a potential future technology.

• 한국자원리싸이클링학회:학술대회논문집
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• 한국자원리싸이클링학회 2003년도 추계정기총회 및 국제심포지엄
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• pp.22-34
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• 2003

Processing and smelting of copper containing sulphide concentrates result in the accumulation of impurities into various process streams. All primary copper smelters and refineries around the world produce significant amounts of slag, dust, sludge, residues and others, which contain copper and precious metals. The recovery of these valuable metals is essential to the overall economics of the smelting process. Physical, chemical and mineralogical characterization of particular slag and Cottrell dusts from primary smelters and Dore furnace (TBRC) slag and Pressure Leached Anode slimes from a copper refinery have been carried out to understand the basic behind the recovery processes. Various process options have been evaluated and adapted for the treatment of slag from different smelting furnaces and Cottrell dusts as well as the intermediate products from copper refineries. Besides the hydro- or pyre-metallurgical treatments, the above mentioned physical separation options such as magnetic, gravity separation, flotation and precipitation flotation processes have been successfully identified and adapted as the possible process options to produce a Cu-rich or precious metal-rich concentrates for in-house recycling and other valued by-product for further treatment. The results of laboratory, pilot plant and production operations are presented, and incorporation of several alternative flowsheet is discussed in this paper.