• Resources Recycling
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• v.13 no.2
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• pp.39-46
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• 2004

The amount of electric furnace dust has been steadily increasing due to the increase of iron scraps which are usually recycled by electric furnace melting process. To date, this electric furnace dust has usually been treated by landfilling, however, because of shortage of landfill sites and heavy metal leaching more desirable treatment schemes are urgently needed. Among several possible schemes for the proper treatment of electric furnace dust, its recycling can be said to be most desirable. In present study, the triboelectrostatic separation of zinc and zinc-containing components from electric furnace dust was attempted based on its physicochemical properties such as particle shape, size distribution, and chemical assay. The dust was found to be mixed with spherical and non-spherical shaped particles and its major component materials were $ZnFe_2$$O_4$, ZnO, Fe, Zn, and FeO. The content of zinc-containing components in the entire dust was observed to be in the range of 15～30 wt%, which reasonably justified that zinc is recyclable. The triboelectrostatic characteristic of each component material was found to be different each other since their work functions were different, and based on this characteristic zinc and zinc-containing component could be flirty separated from the dust. After selecting a proper tribo-elec-trification material, the separation features of zinc and zinc-containing component were examined by taking the distance of electrodes, electric field strength, and scavenging as the experimental variables. The highest zinc-content obtained under the optimal separating condition was found to be up to 50wt%.

• Proceedings of the Korean Information Science Society Conference
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• 1999.10b
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• pp.24-26
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• 1999

본 논문에서는 용해로 이상감시를 위한 실시간 유리 용해로 운전 전문가시스템을 구축한 결과를 소개한다. 유리 용해 공정에서는 운전자의 경험지식에 의해 내부의 상황을 판단하게 되고, 이는 용해로 수명과 제품의 품질에 중요한 영향을 준다. 이를 전문가 시스템으로 구현하기 위하여, 먼저, 기존 운전자의 지식을 취합, 분석한다. 그 후, 취합된 각 지식들의 특성에 부합하도록 이진 룰(Crisp Rule)과 퍼지 룰(Fuzzy Rule)로 구분한다. 이 때, 선형 회귀분석을 통하여 퍼지 룰의 입력을 결정함으로써 보다 정확한 운전 지식의 표현이 가능하도록 하였다. 설계된 알고리즘은 젠심 (Gensym)사의 실시간 전문가 시스템 개발 툴인 G2를 사용하여 구현하였다. 제시된 퍼지 전문가 시스템은 삼성코닝(주) 수원사어장의 실제생산 용해 공정에 직접 적용하여 그 효율성이 검증되었다.

• Journal of the Korean Society of Safety
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• v.25 no.3
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• pp.28-33
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• 2010

Ni alloy steel is able to use during long time because of good acid and corrosion resistance. So, it's research has focused on developing the alternative alloy which is economically feasible. Recently, consumption of Kovar steel is gradually increased in field of the jet engine and the gas turbine because of its low thermal expansive characteristics. The specimens of Kovar steel(29%Ni-17%Co) contain 0.00%C, 0.03%C, 0.06%C, 0.10%C and 0.20%C, respectively. Ingots are manufactured by VIM(vacuum induction melting furnace) and then specimens are made by automatic hot rolling after heat treatment. Strength of Kovar steel according to carbon contents is estimated by hardness, tensile and impact test. Hardness of the 0.20%C specimen is more improved approximately 14.4% than one of base metal. Its strength increases 32.4% of a base metal, and its impact energy is also enhance 11.5%.

• Journal of Korea Foundry Society
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• v.22 no.4
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• pp.160-166
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• 2002

The structure and properties of Fe-29Ni-17Co alloy which had been melted using induction furnace in air atmosphere and than electroslag-remelted were investigated. The oxygen content was reduced to 0.03% when the ingot was refined from $0.09{\sim}0.12%$ of that air melted. The amounts of spheroidal oxides inclusions and gas porosities of ingot were markedly reduced by the ESR process. CTE of ESR ingot contained small amount of oxides and porosities was found to be lower than that of AIM ingot, and tensile properties of ESR ingot and plate were found to be superior than that of AIM ingot and plate.

• Korean Journal of Materials Research
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• v.16 no.5
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• pp.336-340
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• 2006

Fluorspar has been essential flux in steelmaking process. The main effects of fluorspar addition are lowering of the viscosity and melting temperature of slag. In recent years, due to the increasing price and environmental problem of fluorspar, various types of fluorspar substitute have been investigated. In this study, iron oxide by-products such as sinter dust, basic oxygen furnace (BOF) sludge and mill scale were developed as a substitute in terms of waste recycling. Several plant trials were carried out by addition of briquetted substitutes of $4{\sim}6$ kg/ton to compare with the fluorspar of $0.7{\sim}1$ kg/ton. The substitutes showed a similar behavior of slag formation, phosphorus removal and MgO saturation content.

• Journal of the Korean Ceramic Society
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• v.31 no.7
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• pp.767-771
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• 1994

In a salb-preheating furnace of steel-making industry, the oxidation/degradation behavior of Cr3C2 ceramic composited dkid button reaction with scale in Fe-oxide system occurs and was thermodynamically examined. The reaction of scale with Cr3C2 skid button produces Cr3C2(s) and C(s), and Co gas is then evolved from the reaction of C(s) with Fe-scale. Cr3C2(s) from oxidation of Cr3C2(s) reacted with Fe-oxide(s) becomes high-melting chromite. The chromite acts as protection layer against further oxidation and improves resistance of the reaction of Cr3C2 skid button with Fe-scale.

• The Journal of the Korean dental association
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• v.23 no.7 s.194
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• pp.577-583
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• 1985

The purpose of this investigation was to evaluate scanning electron micrographs of repeatedly cast base metal alloy. For this study two Ni-Cr-Be alloys were used; Rexillium III and Verabond. They were repeatedly cast without addition o new alloy melting with an electric resistant furnace (Castron 8, Yoshida dental equipment Mfg.Co.). They were etched with 10% H₂SO₄ Sol. at 300mA/㎠ for 3 minutes with the use of metal etching unit Oxyetch (OXY dental product Inc.), and ultrasonic cleaning in 18% HC1 Sol. was done. Etched surfaces were examined under a SEM at x 200 and x 750. The surfaces are shown in legends.

• Proceedings of the International Microelectronics And Packaging Society Conference
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• 1999.11a
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• pp.111-115
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• 1999

The $Li_2O-MgO-MgF_2-SiO_2$glasses with addition of $B_2O_3$ were investigated in order to make glass-ceramics for low temperature firing substrate. Glasses were made by melting at $1450^{\circ}C$ in the electronic furnace and crystallized at $750^{\circ}C$. After the crystallization, crystal phases and microstructure were observed. The crystal phases were polycrystalline of lithium boron fluorphlogopite and lithium fluorhectorite. The crystal shape was changed to grande type from needle type with the increase in $B_2O_3$ contents. Average particle size of the glass-ceramics aftar water swelling was $3.77{\mu}{\textrm}{m}$. The optimum sintering temperature and sintering shrinkage of the substrate were $900^{\circ}C$ and 13.4vol%, respectively.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 1997.06a
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• pp.148-159
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• 1997

In this study, microstructure, size of primary $\alpha$, solid fraction and hardness of A356 Al alloy, were investigated. Semi-solid A356 allos were obtained by semi-solid continuous casting apparatus consists of melting furnace, formation apparatus of granular primary $\alpha$ and continuous casting apparatus. Size of promary $\alpha$ and fraction solid were decreased with decreasing temperature, and with increasing volume of cooling water. At the cooling water temperature of 15$^{\circ}C$ and cooling water volume of 18.2$\ell$/min, the sizes of primary $\alpha$ phases were decreased up to 40${\mu}{\textrm}{m}$, and fraction solid was 0.68.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2014.11a
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• pp.186-186
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• 2014

In this study, corrosion behaviors of Ti-xNb alloys for biomaterials. The Ti-xNb binary alloys contained from 10 wt. % to 50 wt. % contents were manufactured by vacuum arc-melting furnace. Microstructures of the alloys were examined by optical microscope (OM) and field emission scanning electron microscope (FE-SEM). In order to identify the phase constitutents of the Ti-xNb alloys, X-ray diffractometer (XRD) with a Cu K radiation was used. The corrosion behaviors were investigated using potentiostat (Model2273,EG & GCo, USA) in NaCl solution at $(36.6{\pm}1.0)^{\circ}C$.