• Title/Summary/Keyword: Iron-making

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Fuzzy optimization for the removal of uranium from mine water using batch electrocoagulation: A case study

  • Choi, Angelo Earvin Sy;Futalan, Cybelle Concepcion Morales;Yee, Jurng-Jae
    • Nuclear Engineering and Technology
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    • v.52 no.7
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    • pp.1471-1480
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    • 2020
  • This research presents a case study on the remediation of a radioactive waste (uranium: U) utilizing a multi-objective fuzzy optimization in an electrocoagulation process for the iron-stainless steel and aluminum-stainless steel anode/cathode systems. The incorporation of the cumulative uncertainty of result, operational cost and energy consumption are essential key elements in determining the feasibility of the developed model equations in satisfying specific maximum contaminant level (MCL) required by stringent environmental regulations worldwide. Pareto-optimal solutions showed that the iron system (0 ㎍/L U: 492 USD/g-U) outperformed the aluminum system (96 ㎍/L U: 747 USD/g-U) in terms of the retained uranium concentration and energy consumption. Thus, the iron system was further carried out in a multi-objective analysis due to its feasibility in satisfying various uranium standard regulatory limits. Based on the 30 ㎍/L MCL, the decision-making process via fuzzy logic showed an overall satisfaction of 6.1% at a treatment time and current density of 101.6 min and 59.9 mA/㎠, respectively. The fuzzy optimal solution reveals the following: uranium concentration - 5 ㎍/L, cumulative uncertainty - 25 ㎍/L, energy consumption - 461.7 kWh/g-U and operational cost based on electricity cost in the United States - 60.0 USD/g-U, South Korea - 55.4 USD/g-U and Finland - 78.5 USD/g-U.

Prediction of Combustion and Heat Transfer in the Sintering Bed of Iron Ore (제철 소결공정의 철광석-코크스 베드에서의 연소와 열전달 해석)

  • Yang, Won;Ryu, Chang-Kook;Choi, Sang-Min
    • 한국연소학회:학술대회논문집
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    • 2001.11a
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    • pp.161-168
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    • 2001
  • Sintering bed of iron ore in the steel making process is one of typical applications of solid fuel bed, which has relatively uniform progress of fuel and simple processes of combustion. The sintering bed was modelled as an unsteady one-dimensional progress of fuel layer containing the two phases of solid and gas. Cokes added to the raw mix of which the amount is about 3.5% of the total weight was assumed to form a single particle with other components. In the early predition results presented in this paper, the flame propagation within the bed was not sustained after the top surface of the bed was ignited with hot gas. It suggests that the model should be extended to consider the multiple solid phase, which can treat the ore particles and the coke particles separately.

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The Optical Characteristics of Low Iron Glass for Photovoltaic Module Fabrication (태양전지모듈용 저철분 투과 유리의 광특성 평가)

  • Kim, Kyung-Soo;Kang, Gi-Hwan;Yu, Gwon-Jong
    • Proceedings of the KIEE Conference
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    • 2008.07a
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    • pp.1114-1115
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    • 2008
  • In this paper, we study the optical characteristics of low iron glass for photovoltaic modules fabrication. Tow types of glasses are examined by optical transmittance and reflection measurement. Also, by making laminated glass, we analyze the difference between glass maker. Mini-PV module is fabricated to compare optical reflectance through lamination process. Anti-reflection and catalyst-coated glasses are suggested for advanced technology to obtain high electrical generation output. The specific analysis is shown in the following paper.

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Morphology of the Inclusion as the Al Deoxidation Product of Molten Iron (용융철에서 알루미늄 탈산 생성 개재물의 형상)

  • Lee, Bong-Ok;Lee, Kyung-Ku
    • Journal of Korea Foundry Society
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    • v.19 no.6
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    • pp.466-471
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    • 1999
  • To investigate inclusions(oxides) which cause some trouble in the quality of the metal and a steel-making process, samples were manufactured. The molten irons were deoxidized using Al deoxidizer, and the morphology of the deoxidation products and the process of deoxidation were investigated by optical microscope, scanning electron microscope (SEM) and energy dispersive X-ray spectrometer(EDS). The reactions between Fe melt and Al deoxidizer formed deoxidation product, and those reaction may accelerates the reduction of oxide in Fe melt. According to the results of SEM analysis after deoxidizing treatment, it was found that deoxidation products had spherical cluster shape when 1% Al was added and dendritic shape with $2{\sim}3%$ A1 addition. The deoxidation products were globular, dendritic, polygonal(square) and cluster shape.

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Magnetic field detwinning in FeTe

  • Kim, Younsik;Huh, Soonsang;Kim, Jonghyuk;Choi, Youngjae;Kim, Changyoung
    • Progress in Superconductivity and Cryogenics
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    • v.21 no.4
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    • pp.6-8
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    • 2019
  • Iron-based superconductors (IBSs) possess nematic phases in which rotational symmetry of the electronic structure is spontaneously broken. This novel phase has attracted much attention as it is believed to be closely linked to the superconductivity. However, observation of the symmetry broken phase by using a macroscopic experimental tool is a hard task because of naturally formed twin domains. Here, we report on a novel detwinning method by using a magnetic field on FeTe single crystal. Detwinning effect was measured by resistivity anisotropy using the Montgomery method. Our results show that FeTe was detwinned at 2T, which is a relatively weak field compared to the previously reported result. Furthermore, detwinning effect is retained even when the field is turned off after field cooling, making it an external stimulation-free detwinning method.

Recyling of Waste Materials for Iron Ore Sintering (제철소내 폐기물의 소결공정에서의 이용기술)

  • 문석민;이대열;정원섭;신형기
    • Resources Recycling
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    • v.3 no.3
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    • pp.12-20
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    • 1994
  • Difficulties lies on using the dust from iron making process as a raw material for sintering process mainly because of high amount of Zn or alkali content and its ultra fine characteristics. To eliminate these toxic influence, new fluxing materials were tested and could get a very successful results. This fluxing materials, Calcium-ferrite of magnesio-ferrite were made from various waste materials such as lime stone sludge, bag filter dust, waste EP dust and dolomite sludge by simple way of pre-sintering. Sintering behavior as a fluxing materials was revealed to be good in any aspects and new concept of total recycling system could be established.

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The Study on Material Characteristics of Slags Excavated from Iron Making Site (제철 유적 출토 철재(鐵滓)의 재료학적 특성 연구)

  • Kang, Yoon-Hee;Cho, Nam-Chul;Song, Hyeon-Jeong;Go, Hyeong-Sun
    • Journal of Conservation Science
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    • v.26 no.2
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    • pp.171-182
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    • 2010
  • The slag excavated from Gyesil-ri in Gongju, Yeonje-ri in Cheongwon and Beopcheonsaji (temple) site in Wonju are analyzed by X-ray Fluorescence Analyzer, metallurgical microscope, SEM-EDS etc., for chemical composition and microstructure to figure out the raw material and the iron manufacturing technique. First of all, as a result of principal component analysis, the total Fe-content of slag from Gyesil-ri is 39 to 44% and the modified rate is 15 to 21%, which is common in ancient iron slag. Yeonje-ri site is found the ancient iron-smelting furnace. The total Fe-content of slag from Yeonje-ri is 41 to 43% and modified rate is 18~30%, which is also the general value in the ancient slag. However only slag is excavated in the residential area at Beopcheonsaji site and there is no iron making relic. In addition, the result of principal component analysis contains that the total Fe-content of Beopcheonsaji site is 52 to 57%, and modified rate is 8 to 14%. It shows that the total Fe-content of Beopcheonsaji site is higher than relic from Gyesil-ri and Yeonje-ri and the modified rate is lower than other sites. This results mean that recollecting rate of Fe in Beopcheonsaji site is lower than other sites. Also, as a result of minor elements analysis, the slag from Gyesil-ri has the higher level of Ti, V and Zr than other sites and the microstructure are observed as magnetite and ulvospinel, so that the raw material of slag is iron sand. But the slag from Yeonje-ri and Beopcheonsaji site are identified to use iron ore. As a result of microstructure observation, fayalite, gray-columnar crystal, is found in the slag from Yeonje-ri and big wustite as main phase is observed in the slag from Beopcheonsaji site. This study show that the slag from Yeonje-ri is made of smelt ash produced during smelting works and the slag from Beopcheonsaji site is made of forging ash produced during forging work concerning the excavated location and the microstructure.

The Changing Patterns of Demand-Supply and Role of Mineral Resources in Economic Growth during Industrialization of the Republic of Korea (한국공업화과정(韓國工業化過程)에서의 광물자원(鑛物資源)의 수급구조변화(需給構造變化)와 경제성장(經濟成長)에 있어서의 역할(役割))

  • Yun, Suckew
    • Economic and Environmental Geology
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    • v.18 no.1
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    • pp.65-92
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    • 1985
  • A total of 12 mineral commodities significant in domestic output, economy and/or strategy of the Republic of Korea are chosen to examine the structural changes in production and demand-supply of these minerals during the last two decades of her industrialization. These include iron and manganese ores as the raw materials for iron and steel making, copper, zinc and tungsten ores among other non-ferrous metallic minerals, limestone (cement), kaolin, talc, pyrophyllite and graphite among other non-metallic minerals, and anthracite coal as the only domestic source of fossil energy. These are reviewed historically in time-series based on the statistical data which are tabulated and graphed in terms of domestic output, export, import, apparent demand-supply, its increasing rate, and self-sufficiency rate of each commodity. The increasing rates of demand-supply (IRDS) of some more important commodities are compared with those of Gross Domestic Production (GDP) and Economic Growth Rate (EGR) to evaluate how the IRDS contributed to the GDP and EGR. The major results revealed are as follows: Among the 12 commodities, the domestic output of 8 commodities appeared to have grown with steady upward trends: they are ores of lead, zinc and tungsten, limestone (cement), kaolin, talc, pyrophyllite and anthracite coal. Two commodities, ores of iron and copper, continued with unchanging or slightly declining trends and varied fluctuations, in spite of their cardinal importance to the heavy industry and strategy of Korea. The remaining two, graphite and manganese ore, have gradualy declined in domestic output in which the former has still enough resource potential but the latter has not and virtually ceased its domestic output. Trade patterns for mineral commodities in the Republic of Korea during the last two decades have changed greatly, being marked by a shift from mineral-exporting to mineral importing, mainly because of increasing consumption of mineral raw materials for industrialization rather than beceuse of decreasing output of domestic mineral commodities in quantity. In terms of trade patterns, the 12 commodities concerned in this study can be classified into the following four groups. The 1st group - ores of lead and tungsten have only been exported without imports. The 2nd group - amorphous graphite, and pyrophyllite have mainly been exported but partly been imported. The 3rd group - kaolin, talc and crystalline graphite have equally been exported and imported, but quantity of imports have rapidly been increased with time. The 4th group - ores of iron, manganese and zinc have shifted from exports to imports during the industrialization, particularly owing to the initiation of iron and steel making by the Pohang Iron and Steel Company in the middle 1970' s and the new establishment of the Onsan Zinc Refinery in the late 1970' s. All of the 12 commodities under considerations were far above 100% in self-sufficiency rate before or in the early 1960' s. Recently, however, most of them have been declined to below 100% except for those of limestone (cement) and pyrophyllite. It is particularly serious to identify that the self-sufficiency rates of the three important metallic minerals, iron, copper and manganese ores in 1982 appeared to be 5.1%, 0.5%, and 0.01%, respectively. The average self-sufficiency rate of the total domestic minerals produced in 1982 was 14.4% (in value) for that year. Mining industry appeared to be extremely high in its intermediate demand rate whereas its intermediate input rate to be quite low indicating that mineral raw materials have been exerted strong forward linkage effects upon the other industries rather than backward linkage effects. In comparing the curves of increasing rates of demand-supply of several major minerals - iron ore, manganese ore, copper ore, limestone (cement), kaolin, and anthracite coal - with those of Gross Domestic Production and Economic Growth Rate drawn on every graph, it is clearly shown that the curves of increasing rates of demand-supply comprise around 6 to 7 periods of cycles which roughly harmonious with those of the curves of GDP and EGR, except for the curve of anthracite coal of which the configuration seems to have resulted from the (artificial) government's mineral policy rather than from economic free market mechanism. The harmonic feature of these curves well suggests that the increasing rates of demand-supply of major minerals have been significantly contributed to the GDP and EGR. In addition, the wider amplitudes of the iron, manganese and copper curves than those of the limestone (cement) and kaolin curves indicate that the contribution of the former, metallic commodities, has been greater than that of the latter, non-metallic commodities.

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Metallurgical Study on the Iron Artifacts Excavated from Sudang-ri Site in Geumsan (금산 수당리유적 출토 철제유물의 금속학적 연구)

  • Park, Hyung-ho;Cho, Nam-chul;Lee, Hun
    • Korean Journal of Heritage: History & Science
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    • v.46 no.3
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    • pp.134-149
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    • 2013
  • The Sudang-ri Site in Geumsan is considered the historic site where Baekje dominated the inland traffic route to Gaya through Geumsan and Jinan in the 5th Century. This study identified the production techniques of iron by conducting an analysis of metallographical microstructure of the artifacts such as an iron sword and an iron sickle that were excavated in Sudang-ri Site, Geumsan, one of the regions ruled by Baekje, and tried to figure out the characteristics and the technical systems of Baekje's ironmaking around the 5th Century by comparing them with other iron artifacts produced around the same time. The analysis showed that various production techniques were applied to the artifacts excavated in Sudang-ri Site, Geumsan. Depending on the production techniques, they can be divided largely into three methods: the simple shape-forging method, the steel manufacture method after forging, and the steel manufacture & heat-treatment method after forging. The iron sickle from the stone chamber tomb No. 1, which was produced only through forging, is mostly composed of soft ferrite at both edges of the blade and at the rear making the use of the weapon impractical. From this fact, it is presumed that they were produced as burial objects or ceremonial accessories for the person buried. The iron axe from the outer stone coffin tomb No. 1 and the iron swords and sickle from the outer stone coffin tomb No. 12, which were produced through the steel manufacture method after forging such as carburizing, did not go through the heat treatment such as quenching, but applied different production processes to each part. Therefore, it is deemed that they were produced as daily tools for cultivation rather than burial objects or ceremonial accessories. The production techniques following the forging process - carburizing and heat treatment - can be found on the iron swords from the outer stone coffin tomb No. 5 and the outer stone coffin tomb No. 12. The sturdy structure of the blade part and the durable structure of the rear processed with heat are deemed to have been produced as weaponry and used by the person buried. Based on the analysis of the iron artifacts excavated from Sudang-ri Site in Geumsan, the characteristics of iron production techniques were investigated by comparing them with the artifacts from Yongwon-ri Site in Cheonan, Bongseon-ri Site in Seocheon, and Bujang-ri Site in Seosan that were made around the same time as the cluster of Baekje tombs examined by the metallographical microstructure analysis of this study. For the iron artifacts analyzed here, the changes in the techniques were investigated using the iron swords common in all of the tombs. In the case of the iron swords, it was identified the heat treatment technique called tempering was applied from the 4th Century.

Report on the Conservation Treatment for the Artifacts Exhibited in the newly-opened Kimhae National Museum (국립김해박물관(國立金海博物館) 개관(開館) 전시유물 보존처리 보고(報告))

  • Kwon, Hyuk-nam;Ahn, Byong-chan
    • Conservation Science in Museum
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    • v.1
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    • pp.15-26
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    • 1999
  • More than 200 objects selected for the newly-opened Kimhae National Museum were treated for conservation. The objects which represent ancient Kaya culture, were mainly composed of metallic such as gilt bronze, silver, copper alloy and iron. The corrosion products on gilt bronze and copper alloy objects were preserved or removed according to their stability. Minimum treatment was done for preserving the original state of the objects. For silver objects and iron objects with silver-plate decorations, silver surfaces were revealed after treatment of corrosion products and treatments to prevent corrosion of silver and iron were done emphatically. For iron objects, which were stabilized, the original shape of objects was restored and acrylic coating was applied to prevent further corrosion. For the objects which were being corroded, 2-step de-chloride treatments were undertaken. The first step was immersing the objects in a solution of 0.3M sodium hydroxide and the second was the pressure de-chloride treatment using borax-distilled water. The main purpose of those treatments was to get rid of the causes of corrosion. Besides, conservation treatments for potteries, making of special mounting board for exhibition and amendment of various modeling were done too.