• 한국지하수토양환경학회지:지하수토양환경
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• 제22권5호
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• pp.89-97
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• 2017

In this study, we evaluated effect of particle size on arsenic solid-state speciation and bioaccessibility in soils highly contaminated with arsenic from smelting and mining. Soils were partitioned into six particle size fractions ($2000-500{\mu}m$, $500-250{\mu}m$, $250-150{\mu}m$, $150-75{\mu}m$, $75-38{\mu}m$, <$38{\mu}m$), and arsenic solid-state speciation and bioaccessibility were characterized in each particle size fraction. Arsenic solid-state speciation was characterized via sequential extraction and XRD analysis, and arsenic bioaccessibility was evaluated by SBRC (Solubility Bioaccessibility Research Consortium) method. In smelter site soil, arsenic was mainly present as arsenic bound to amorphous iron oxides. Fine particle size fractions showed higher arsenic concentration, but lower arsenic bioaccessibility. On the other hand, arsenic in mine site soil showed highest concentration in largest particle size fraction ($2000-500{\mu}m$), while higher bioaccessibility was observed in smaller particle size fractions. Arsenic in mine site soil was mainly present as arsenolite ($As_2O_3$) phase, which seemed to affect the distribution of arsenic and arsenic bioaccessibility in different particle size fractions of the mine soil.

• 자원리싸이클링
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• 제25권4호
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• pp.68-79
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• 2016

타이타늄은 지각 구성원소 중 아홉 번째로 풍부한 원소이다. 또한 구조용 금속으로서는 알루미늄, 철, 마그네슘에 이어서 네 번째로 풍부한 원소이다. 일반적으로 이러한 타이타늄은 Kroll법에 의해 만들어지고 있다. 최근 전 세계의 많은 연구자들에 의해서 새로운 타이타늄 제련법이 개발되어 왔다. 본 연구에서는 상업화 되었거나 개발 중인 신 제련 프로세스를 $TiCl_4$의 금속 열환원법, $TiO_2$ 등의 전해환원법, 그리고 수소를 이용한 환원법으로 분류하였다. 이러한 새로운 제련 프로세스의 환원기구와 현황에 대하여 종합하고 상업화 가능성의 관점에서 정리하였다.

• 자원리싸이클링
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• 제16권2호
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• pp.3-11
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• 2007

최근 국내에서 자동차 부품산업 및 전자기기 산업에서 마그네슘 금속의 수요가 증가하고 있다. 본 고에서는 마그네슘 금속 제련에 관하여 원료 광석, 세계 생산량과 상용화 조업중인 기술들을 요약 정리하였으며, 국내 마그네슘 관련 시장현황과 기술동향들을 조사하였다. 마그네슘 제련은 크게 용융염 제련법과 열환원법 두가지로 대별할 수 있으며 이들 기술의 일반적인 현황을 살펴보았다. 또한, 국내에서 수행중인 마그네슘의 용융염 제련 연구에 대하여 간략히 기술하고, 용융염 제련시 발생되는 염소나 염화수소의 회수 및 처리 등 재활용 분야와 관련기술을 소개하고자 한다.

• 자원리싸이클링
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• 제21권4호
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• pp.53-59
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• 2012

본 연구에서는 비철제련의 공정 부산물에서 얻어진 Bi-Pb-Sb 3원계 합금 용탕의 산화반응에 따른 Sb과 Pb의 제거거동에 대하여 조사하였다. $N_2+O_2$ 가스를 침지 노즐을 통해 1173 K의 합금 용탕 중에 취입하여 Sb을 산화물과 금속상의 혼합물로 분리 회수할 수 있었다. 그리고 923 K의 Bi-Pb 2원계 용탕에 $N_2+O_2$ 가스를 취입하면 Pb가 산화되어 슬래그상으로 제거될 수 있으나, Bi도 동시에 산화되어 Bi를 정제할 수 없었다.

• 보존과학회지
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• 제3권1호
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• pp.13-18
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• 1994

Chemical analysis and metallographic observations of the iron slag were carried out in an attempt to estimate the old iron-making process. The slag containing $9.3\%\;TiO_2$ without Cu indicates that the ore used for smelting was sand iron, not rock ore. The phases identified in the slag were $ulv\ddot{o}spinel$, magnetite, $w\ddot{u}stite$, fayalite etc. This also supports the fact that the smelted ore was iron sand. The total amount of Fe and slag-making components$(=SiO_2+Al_2O_3+MgO+CaO)$ were $40.7\%\;and\;36.1\%$, respectively. These values were average ones found in the old slags formed in the ancient iron-making process. Assuming that $TiO_2$ in the ore combines with FeO, resulting in the formation of $ulv\ddot{o}spinel$, the estimated temperature of smelting was found to be about $1200^{\circ}C$.

• 자원리싸이클링
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• 제11권4호
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• pp.37-43
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• 2002

전기로 분진의 유해성을 제거하고 인공자원으로써의 가치를 활용하기 위하여 연구되고 있는 고온용융법을 이용한 전기로 분진의 처리공정에 있어서 유가금속 특히 아연의 환원 거동에 관한 연구를 속도론적인 측면에서 수행하였다. 전기로 분진의 구성 성분인 ZnO와 Franklinte의 환원 반응이 CO gas의 분압에 대하여 1차 반응인 chemical reaction에 의해 지배를 받음을 확인 할 수 있었다. ZnO와 Franklinite의 CO 가스에 의한 환원 반응에 있어서 활성화 에너지는 각각 44.95 kcal/mol, 4.9546 kcal/mol로 나타나 화학반응 단계가 전체 반응의 율속 단계임을 알 수 있었다.

• Nuclear Engineering and Technology
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• 제53권5호
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• pp.1619-1625
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• 2021

This paper demonstrates the possible nondestructive analysis of iron artifacts' metallurgical characteristics using neutron imaging. Ancient kingdoms of the Korean Peninsula used a direct smelting process for ore smelting and iron bloom production; however, the use of iron blooms was difficult because of their low strength and purity. For reinforcement, iron ingots were produced through refining and forge welding, which then underwent various processes to create different iron goods. To demonstrate the potential analysis using neutron imaging, while ensuring artifacts' safety, a sand iron ingot (SI-I) produced using ancient traditional iron making techniques and a sand iron knife (SI-K) made of SI-I were selected. SI-I was cut into 9 cm², whereas the entirety of SI-K was preserved for analysis. SI-I was found to have an average grain size of 3 ㎛, with observed α-Fe (ferrite) and pearlite with a body-centered cubic (BCC) lattice structure. SI-K had a grain size of 1-3 ㎛, α-Ferrite on its backside, and martensite with a body-centered tetragonal (BCT) structure on its blade. Results show that the sample's metallurgical characteristics can be identified through neutron imaging only, without losing any part of the valuable artifacts, indicating applicability to cultural artifacts requiring complete preservation.

• 한국분말재료학회지
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• 제28권4호
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• pp.342-351
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• 2021

Because of its unique properties, tungsten is a strategic and rare metal used in various industrial applications. However, the world's annual production of tungsten is only 84000 t. Ammonium paratungstate (APT), which is used as the main intermediate in industrial tungsten production, is usually obtained from tungsten concentrates of wolframite and scheelite by hydrometallurgical treatment. Intermediates such as tungsten trioxide, tungsten blue oxide, tungstic acid, and ammonium metatungstate can be derived from APT by thermal decomposition or chemical attack. Tungsten metal powder is produced through the hydrogen reduction of high-purity tungsten oxides, and tungsten carbide powder is produced by the reaction of tungsten powder and carbon black powder at 1300-1700℃ in a hydrogen atmosphere. Tungsten scrap can be divided into hard and soft scrap based on shape (bulk or powder). It can also be divided into new scrap generated during the production of tungsten-bearing goods and old scrap collected at the end of life. Recycling technologies for tungsten can be divided into four main groups: direct, chemical, and semi-direct recycling, and melting metallurgy. In this review, the current status of tungsten smelting and recycling technologies is discussed.

• 보존과학회지
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• 제37권1호
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• pp.34-42
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• 2021

This study analyzes six slags excavated from the iron making site in Gogi-ri, Namwon, Korea to understand the characteristics of the ruins, and to confirm the iron making process performed at the time. The chemical components of the iron making by-products from the Gogi-ri site were analyzed, and the findings indicate total Fe contents between 23.24% and 37.56%, which are lower than the typical total Fe content found in ancient iron making processes. The deoxidation agent contents of the slags ranged from 43.88% to 58.13%, which are higher than the typical deoxidation agent content of ancient iron making processes. The high content suggests smooth separation between iron and slags, and TiO₂ detected from the site suggests the use of materials with high titanium content in the iron making in the region. As for the microstructures of the slags, some slags have long pillar-shaped fayalites, while others have pillar-shaped wüstite along with ulvöspinel. Slags from the forging furnace show hammer scales created by both the earlier stages and later stages of forging work. The findings suggest that the iron making site in Gogi-ri, Namwon, Korea used to be an iron making facility where a full range of iron making process was carried out ranging from smelting to forging, and the ironmakers used a wide array of technologies to manufacture iron products.

• 방사성폐기물학회지
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• 제21권1호
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• pp.9-22
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• 2023

Spin-off pyroprocessing technology and inert anode materials to replace the conventional carbon-based smelting process for critical materials were introduced. Efforts to select inert anode materials through numerical analysis and selected experimental results were devised for the high-throughput reduction of oxide feedstocks. The electrochemical properties of the inert anode material were evaluated, and stable electrolysis behavior and CaCu generation were observed during molten salt recycling. Thereafter, CuTi was prepared by reacting rutile (TiO₂) with CaCu in a Ti crucible. The formation of CuTi was confirmed when the concentration of CaO in the molten salt was controlled at 7.5mol%. A laboratory-scale electrorefining study was conducted using CuTi(Zr, Hf) alloys as the anodes, with a Ti electrodeposit conforming to the ASTM B299 standard recovered using a pilot-scale electrorefining device.