• 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%.

• Journal of Korea Foundry Society
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• v.29 no.6
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• pp.270-276
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• 2009

After casting button-type small ingots of ternary Fe-Mn-S alloys which had three different Mn/S ratios (1, 5 and 70) in a vacuum arc furnace, the effect of the ratio on the sulfide formation was investigated. In case of the Mn/S ratio of 1, if alloy composition was located in an iron-rich corner on a Fe-Mn-S ternary phase diagram, only duplex MnS-FeS sulfide films were observed in the grain boundary. If the alloy composition was located in the miscibility gap area of the phase diagram, primary globular dendritic sulfides and dendritic sulfide slags were generated within the grain and tubular monotectic sulfides were also detected in the grain boundary. When the Mn/S ratio was 5, if the alloy composition was in the iron-rich corner, only bead-like sulfides were generated. On the other hand, if the composition was in the miscibility gap area, globular dendritic sulfides and dendritic sulfide slags were generated in the form of primary sulfide inclusions and rod-like eutectic sulfides were observed in the grain boundary. Especially, if the contents of Mn and S increased more in the miscibility gap area of the phase diagram, primary globular sulfides containing iron intrusions were observed. In case of Mn/S ratio of 70, if the contents of Mn and S was decreased in the Fe corner of the phase diagram, only bead-like sulfides were observed in the grain boundary. Despite the composition was outside the miscibility gap area of the phase diagram, if the contents of Mn and S increased, clusters of fine sulfide particles as well as fine spherical primary monophase sulfides were observed in the grain boundary.

• Korean Journal of Materials Research
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• v.12 no.5
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• pp.414-422
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• 2002

Three different multi-component white cast irons alloyed with Cr, V, Mo and W were prepared in order to study their as-cast and solidification structures. Three combinations of the alloying elements were selected so as to obtain the different types of carbides and matrix structures : 3%C-10%Cr-5%Mo-5%W(alloy No.1), 3%C-10%V-5% Mo-5%W(alloy No. 2) and 3%C-17%Cr-3% V(alloy No.3). The as-cast microstructures were investigated with optical and scanning electron microscopes. There existed two different types of carbides, $M_7C_3$ carbide with rod-like morphology and $M_6C$ carbide with fishbone-like one, and matrix in the alloy No. 1. The alloy No. 2 consisted of MC carbide with chunky and flaky type and needle-like $M_2C$ carbide, and matrix. The chunky type referred to primary MC carbide and the flaky one to eutectic MC carbide. The morphology of the alloy No. 3 represented a typical hypo-eutectic high chromium white cast iron composed of rod-like $M_7C_3$ carbide which is very sensitive to heat flow direction and matrix. To clarify the solidification sequence, each iron(50g) was remelted at 1723K in an alumina crucible using a silicon carbide resistance furnace under argon atmosphere. The molten iron was cooled at the rate of 10K/min and quenched into water at several temperatures during thermal analysis. The solidification structures of the specimen were found to consist of austenite dendrite(${\gamma}$), $ ({\gamma}+ M_7C_3)$ eutectic and $({\gamma}+ M_6C)$ eutectic in the alloy No. 1, proeutectic MC, austenite dendrite(${\gamma}$), (${\gamma}$+MC) eutectic and $({\gamma}+ M_2C)$ eutectic in the alloy No. 2, and proeutectic $M_7C_3$ and $ ({\gamma}+ M_7C_3)$ eutectic in the alloy No 3. respectively.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.3
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• pp.576-584
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• 2020

The extruder screw material is mainly SKD11, but the recent development of synthetic resins have increased the occurrence of chemical corrosion and wear. To solve this issue, high chromium cast iron is needed because of its good abrasion resistance and corrosion resistance, but its use is avoided because of its poor machinability. In this study, to improve the machinability of high chrome cast iron, 0, 0.5, 1.0, 1.5% of nickel, which has excellent workability, was added to high chromium cast iron with a composition of Fe-23Cr-2.5C-1.2Si-1.08Mn-0.48Mo-0.3V, and annealed after casting. Subsequently, the effect of nickel on the machinability and corrosion resistance was analyzed using a turning test and coin polarization test, and compared with SKD11. After casting using a high-frequency vacuum induction furnace, the annealing treatment was performed at 750 ℃ for five hours and then reheated at 1100 ℃ for five hours. A turning test after annealing at 750 ℃ showed that the machinability was improved remarkably when the nickel content was over 1.0%. In the potentiodynamic polarization test in a 5% NaCl solution, the corrosion resistance decreased with increasing nickel content in the as-cast and annealing treatment. On the other hand, after reheating, the corrosion resistance was best with a 1.5% nickel content.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2005.04a
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• pp.291-294
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• 2005

본 해석은 제철용 고로 구조물에 대해여 고로 내의 온도 분포를 이용한 열전도 유한요소 해석을 수행하고자한다. 해석모델인 고로는 내화벽돌, 냉각판, 내화재(castable), 철피의 복잡한 구조로 이루어져있다. 각각의 재료뿐만 아니라 고로에 사용되어지는 모든 내화벽들의 재료 물성치 값을 사용하여 보다 실직적인 해석을 수행하고자 하며 고로의 냉각 시스템인 냉각판과 냉각 pipe의 효과 규명하고자 한다. 어떠한 부분 모델이 아니라 고로 전체를 대상으로 열전도 해석을 수행한다.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2015.11a
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• pp.41-42
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• 2015

The concrete aggregate generates carbon dioxide in production but its demanding is gradually increased in accordance with the depletion of natural resources. Therefore we evaluated compatibility and basic physical properties of Silicon manganese slag generated in iron production as an applicable concrete aggregate. In our test, the silicon maganese slag shows 2.8g/㎥ of density in 10mm of maximum particle size similar to a natural aggregate, and its absorption rate was 0.3% similar to the electric furnace slag. Unit volume weight and ratio of absolute volume was respectively 2,001㎏/㎥ and 51%. Strength properties of Silicon manganese slag will be evaluated with further studies and experiments.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.12 no.1
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• pp.107-113
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• 1992

This paper is the part of fundamental study considering whether the unprocessed water cooled blastfurnace slag, by-product of iron works, can be useful for some fine aggregate of mortar and concrete. The acquired results in this study show that the qualities of the water cooled blastfurnace slag produced in the state of raw material in the country in not good for using as a fine aggregate of mortar and concrete. To be used as a fine aggregate of concrete the qualities need to be improved in the process of manufacture.

• 제어로봇시스템학회:학술대회논문집
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• 2001.10a
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• pp.174.6-174
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• 2001

Various raw materials from which iron and steel are made are unloaded from ship and then piled up at the designated yard. The equipment that piles up the raw materials is called Stacker and these materials are then dipped out and sent to unit factories such as blast furnace and cokes using the equipment called Reclaimer. The Reclaimer has an actual size of 16 meter high and 50 meter long and runs back and forth over the rail of about 1.2 km, carrying the materials to each unit factory. Until now, in most cases, Stacker and Reclaimer are manually operated. At POSCO, four workers on a shift basis sit in the operation room as shown in the picture, pile up and dip out the materials, checking them out with their own eyes ...

• 제어로봇시스템학회:학술대회논문집
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• 2001.10a
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• pp.114.2-114
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• 2001

In steel works, Locomotives and torpedo ladle cars are used to convey the smelted iron that comes out Blast Furnace to the steel-making mill. Above conveying vehicles are operated in all steel works area. And to trace their positions, after partitioned their areas, Automatic Vehicle Identification(RF-ID method) is installed on the railroad and identifies vehicle numbers. But AVI facilities have many problem that means that are too expensive, cost too much maintenance fee and inefficient management. This paper is to revamp those inefficient operations and state the status of operations of train positioning system, get to know what the problem is. And also when we use GPS to monitor and trace the vehicle position ...

• 제어로봇시스템학회:학술대회논문집
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• 2002.10a
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• pp.38.1-38
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• 2002

In steel works, Locomotives and torpedo ladle cars are used to convey the smelted iron that comes out Blast Furnace to the mill making mill. In this process, Identification of the vehicles position is very important because the area is broad and efficient operation affects a productivity and investment. At present condition, there are many ways to use to identify the vehicles number and position. This paper will present the new ways using GPS/DR based method. For this, we practiced the site test to gather the real data. First, we collect the velocity data at the wheel of the vehicles with the direction data via process computer. Second, after installing the gyroscope we gathered the data wit...