• Resources Recycling
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• v.28 no.2
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• pp.3-13
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• 2019

Aluminum is the most abundant metal and the second most plentiful metallic element in the earth's crust, after silicon. Aluminum is a light, conductive, and corrosion resistant metal with strong affinity for oxygen. However, the primary aluminum production process is highly energy intensive. The recycling of aluminum scrap reduces the energy consumption and environmental burden, comparing to the primary metal production. However, the amount of the recovered metal from scrap is limited because of the difficulties to remove the impurities in the scrap. This work provides an overview of the aluminum production and recycling process, from the preparation of alumina to the scrap upgrading and the melting process.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.32 no.2
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• pp.61-67
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• 2022

A metal salt solution was prepared from valuable metals (Ni, Co, Mn) recovered from a scrap of waste lithium secondary batteries, and an NCM811 precursor was synthesized from the solution. The effect on precursor formation according to reaction time was confirmed by SEM, PSA, and ICP analysis. Based on the analysis results, the electrochemical properties of the synthesized NCM811 precursor and the commercial NCM811 precursor were investigated. The Galvano charge-discharge cycle, rate performance, and Cycle performance were compared, and as a result, there was no significant difference from commercial precursors.

• Bulletin of Korea Environmental Preservation Association
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• s.399
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• pp.34-37
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• 2012

현대제철이 미래성장동력인 '저탄소 녹색성장'을 실현하기 위한 녹색경영에 앞장서고 있다. 인류사회의 소중한 자원인 철을 재활용해 모든 산업의 기초가 되는 철강제품을 생산해온 현대제철은 1953년 국내 최초의 철강업체로 출범한 이후 줄곧 환경을 최우선으로 하는 경영철학을 실천하며 친환경기업의 위상을 다져왔다. 무엇보다 자연에 버려진 채로 방치될 경우 환경오염을 일으키는 철스크랩을 연간 1,100만 톤이나 재활용해 산업의 쌀이라 불리는 철강제품으로 재탄생시키는 자원재활용업체로 녹색경영을 실천해 왔다. 현대제철은 이러한 녹색경영을 기반으로 지난 2006년 10월부터 종합철강업체로의 새로운 도약을 위해 충남 당진에 일관제철소를 건설했으며 현재 제3고로 건설이 2013년 9월 완공을 목표로 진행되고 있다. 제3고로 완공시 현대제철 일관제철소는 연산 1,200만톤 규모로 확대돼 전기로를 포함한 현대제철의 조강생산 능력은 연산 2,400만톤에 이르게 된다.

• Journal of the Korea Concrete Institute
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• v.24 no.3
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• pp.267-273
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• 2012

This study is performed to evaluate the flexural performance of reinforced concrete columns with electric arc furnace oxidizing slag aggregates. Electric arc furnace slag is a by-product obtained from the process of refining scrap steel. The electric arc furnace slag can be used as a concrete aggregate, because it mainly consists of CaO and $SiO_2$, similar to natural rocks and minerals. Three rectangular columns with various types of aggregate were cast to test in flexure. All of the test specimens had a cross-section of $250{\times}250$mm and a height of 1,500 mm in test region. The specimens were designed to apply reversed cyclic antisymmetric moment and constant axial force. The experimental results showed that the specimens with electronic arc furnace oxidizing slag aggregates had superior flexural performance than the specimen with natural aggregates.

• Resources Recycling
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• v.28 no.2
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• pp.40-45
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• 2019

During steelmaking in EAF, recycled scraps is used as a main material, melted by arc, and electricity use as a main energy. Slag foaming is an important technology for reducing electrical energy. CO gas generated by the reaction between injection carbon and (FeO), [C] and injection {$O_2$}. CO gas generated by this reaction is collected in slag, resulted in slag foaming. In general, the carbon materials used in the EAF process is anthracite and coke. This study investigated the effects of the carbon materials used on slag foaming in the steelmaking process. As a result of this study, the slag foaming height is increased by cokes rather than anthracite, and with an increase in the amount of particles samller than $500{\mu}m$. Based on these results, the application to the operation resulted in increase of slag forming height, reduction of injection carbon, and reduction of electrical energy.

• Resources Recycling
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• v.21 no.4
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• pp.26-34
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• 2012

Recently, the recovery of resources from waste material of manufacturing electric and electronic equipment has been investigated. It is very important to extract metallic components from electric and electronic manufacturing processes with the view point of recycling of the used resources as well as an environmental protection. In this paper, open/registered patents of US, JP, EP, and KR and SCI journal related to metal recovery technologies from wastes produced in the electric and electronic manufacturing processes between 1975~2011 were reviewed. Patents and papers were collected using key-words searching and filtered by filtering criteria. The trends of the patents and papers were analyzed by the years, countries, companies, and technologies.

• Journal of Korea Foundry Society
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• v.31 no.3
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• pp.130-136
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• 2011

Effects of GBF (gas bubbling filtration) treatment conditions and scrap ratio on the electric conductivity of a commercial pure aluminum for diecasting were investigated using by specific gravity and electrical conductivity measurement system, hydrogen gas analyzer, XRD, and EDS. Electrical conductivities of specimen mixed Al scrap ratio until 60% from 0% were decreased with increasing the precipitates amount and size of AlFeSi ternary intermetallic compound on the grain boundary as well as amount of porosity in the grain. On the other hand, electrical conductivities was reincreased gradually in spite of scrap ratio increase from 80% to 100%. Size of AlFeSi compound formed on the grain boundary were coarsened with the increament of scrap ratios untill 80% and GBF treatment time simultaneously.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2015.11a
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• pp.217-218
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• 2015

주석은 최근 첨단 전기, 전자 제품의 핵심 소재로써 지속적인 수요 증가가 예상되는 전략 금속이다. 국내의 수요량은 2011년 기준 약 17,000톤 으로 99% 이상 수입에 의존하고 있는 실정이다. 그러나, 국내의 주석 제련 산업은 전무한 상태이며 폐자원에서 재활용하는 회수 기술도 초보 단계이다. 이러한 폐자원 발생량은 12,000톤/year이며, 약 1200억원에 달하는 규모이다. 다양한 폐자원의 선별적 전처리 요소 기술 개발 및 회수 공정 시스템 개발이 절실히 요구된다. 본 연구에서는, 주석 폐자원 중 solder 용융물 및 공정 스크랩 Lead solder, Lead-free solder 등 뿐만 아니라, ITO target 제조 시 발생하는 ITO sludge 등의 고상 폐자원으로부터 페자원의 물성을 파악하여 금속/산화물과의 파/분쇄 및 분급공정을 통하여 고품위의 주석 금속을 회수하였다. 뿐만 아니라, 고순도 주석시 발생하는 양극 슬라임 침출액 등의 액상 폐자원으로부터 희소금속의 추출 및 회수를 위해 습식 전처리 공정을 수행하였다. 침출액은 주석, 구리, 납 등의 유가금속이 이온형태로 존재하고 있으며, Chlorine이 다량 함유되어 있다. 고품위의 주석 산화물을 회수하기 위하여 침출액 내의 구리 제거 공정, Chlorine 제거 공정 등을 순차적으로 수행하여 고품위의 산화물 회수를 수행하였다.

• Resources Recycling
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• v.26 no.6
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• pp.65-72
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• 2017

APT (Ammonium paratungstate) is widely used in various industries such as metal cutting tools, drill bits, mining tools, and military inorganic materials. In order to produce high purity APT(S), an impurity purification step in an aqueous $Na_2WO_4$ convert $H_2WO_4$ solution is required. It is difficult to remove impurity Na of 200 ppm or less when $H_2WO_4(S)$ is prepared by adding HCl(Aq) to an aqueous solution of $Na_2WO_4$, which is a well-known conventional wet method. However, in this study, a more economical and efficient method of removing Na through electrodialysis using a cationic membrane was studied. A large amount of Na in aqueous solution of $H_2WO_4$ due to $Na_2CO_3(S)$ which was added to dissolve waste tungsten carbide drill and scrap was removed to 20ppm or less through electrodialysis process, and it was confirmed that the effect of Na removal was great when using electrodialysis.

• Journal of the Microelectronics and Packaging Society
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• v.23 no.2
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• pp.11-18
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• 2016

This study focused on examining the possibility for recycling of Fe-Si electric sheet. We manufactured Fe-6.5Si mother alloy using by Fe-Si electric sheet scrap for transformer core materials. And then, soft magnetic alloy powder which diameter and shape were $45{\sim}150{\mu}m$ and sphere type was prepared by gas atomization process. As we compared to commercial Fe-6.5Si powder, its diameter distribution and microstructure of recycled powder was a similar. To investigate the possibility of reusing the soft magnetic composite sheet for electronics, recycled powder was treated to have a high aspect ratio (AR), and we finally obtained the 65~66 AR and $2.3{\mu}m$ thickness powder. To release the residual stress of powder, heat treatment was conducted under $300{\sim}400^{\circ}C$, $N_2$ gas. And then, soft magnetic sheet was made by tape casting process using by those powders. After the density and permeability of tape was measured, and we confirmed that the recycled Fe-Si electric sheet scrap was possible to reuse the soft magnetic materials of electronics.