• Journal of the Korea Safety Management & Science
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• v.15 no.2
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• pp.185-192
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• 2013

This research identified approachable management innovation technique from SCM point of view, and analyzed sales/logistics, integrated production planning, phenomenon of cooperation and suggested an innovation model over this for strengthening competitiveness of a case company. Process innovation model with an enterprise viewpoint is designed and suggested to solve the previous ares for improvement, and suggested various models of an ordering management model, available delivery management model, logistics operation model based on planning and S&OP model.

• Korean Journal of Materials Research
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• v.27 no.5
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• pp.263-269
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• 2017

Fe-Si-Cr ferroalloy is predominantly produced by carbothermic reduction. In this study, silicothermic and carbothermic mixed reduction of chromite ore to produce Fe-Si-Cr alloy is suggested. As reductants, silicon and silicon carbide are evaluated by thermochemical calculations, which prove that silicon carbide can be applied as a raw material. Considering the critical temperature of the change from the carbide to the metallic form of chromium, thereduction experiments were carried out. In these high temperature reactions, silicon and silicon carbide act as effective reductants to produce Fe-Si-Cr ferroalloy. However, at temperatures lower than the critical temperature, silicon carbide shows a slow reaction rate for reducing chromite ore. For the proper implementation of a commercial process that uses silicon carbide reductants, the operation temperature should be kept above the critical temperature. Using equilibrium calculations for chromite ore reduction with silicon and silicon carbide, the compositions of reacted metal and slag were successfully predicted. Therefore, the mass balance of the silicothermic and carbothermic mixed reduction of chromite ore can be proposed based on the calculations and the experimental results.

• Resources Recycling
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• v.17 no.4
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• pp.47-56
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• 2008

The aim of this study is to produce cokes which can be used for the production of ferroalloy, for this purpose, domestic anthracite mixed with plastic was sintered at various condition. The combustion and physical properties of anthracite and plastic, coal separation, and the influence of factors on the strength of coke were investigated. The results of this study are as follows: 1. The three kinds of anthracite from the Samcheok region contained 25 to 30% ash of $100{\mu}m$ over size, and have the caloric value of 5,205 cal/g(TaeAn), 4,893 cal/g(JangSung), 4,873cal/g(KyongDong). 2. The recommendable conditions for heavy-fluid separation of the Samcheok coal are to set the specific gravity of heavy fluid to 2.4 and control the size of coal to $35{\sim}140mesh$. 3. It is concluded that phenolic resin powder, liquefied phenolic resin, SAN, and melamine resin can be used as a binder for the anthracite cokes, from the thermal analysis of various plastics. Especially, the liquefied phenolic resin was considered as the most suitable binder as it would simplify the process.

• Resources Recycling
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• v.17 no.6
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• pp.57-61
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• 2008

The aim of this study is to produce the coke which can be used for the production of ferroalloy, by mixing phenolic resin and anthracite and sintering it. The influence of factors on the strength of coke were investigated. The results of this study are as follows: It is found that the anthracite coke of $100{\sim}150\;kgf/cm^2$ strength for ferroalloy can be made by a series of process as follows; Mixing homogeneously 6% liquefied phenolic resin and 6% water with $35{\sim}325$ mesh anthracite of low ash content. Making pellet by press the mixture in $10-50\;kgf/cm^2$ pressure. Dehydrating the pellet for 6 hrs at $50^{\circ}C$, and hardening it for 180 min at $200^{\circ}C$. Sinter the mixture for 6 hrs at $1,200^{\circ}C$.

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2006.09b
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• pp.824-825
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• 2006

Homogeneous microstructures of the PM compacts are difficult to attain when mixed elemental powders are used. This study examined the microstructures of pressed-and-sintered and MIM products that contain Ni and Mo.Ni-rich areas, which were lean in carbon and were soft and were found easily in regular specimens. Gaps or cracks near the Ni-rich or Mo-rich areas were also frequently observed. This problem worsened when Ni and Mo particles were large and were irregular in shape. By using ball milling treatment and ferroalloy powders, the microstructure homogeneity and mechanical properties were improved. The addition of 0.5wt%Cr further improved the distribution of Ni because Cr reduced the repulsion effect between nickel and carbon. With the elimination of Ni-rich areas, more bainites and martensites were formed and mechanical properties were significantly improved.

• Safety and Health at Work
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• v.4 no.3
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• pp.123-135
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• 2013

Exposure to manganese (Mn) is associated with neurobehavioral effects. There is disagreement on whether commonly occurring exposures in welding, ferroalloy, and other industrial processes produce neurologically significant neurobehavioral changes representing parkinsonism. A reviewof methodological issues in the human epidemiological literature onMnidentified: (1) studies focused on idiopathic Parkinson disease without considering manganism, a parkinsonian syndrome; (2) studies with healthy worker effect bias; (3) studies with problematic statistical modeling; and (4) studies arising from case series derived from litigation. Investigations with adequate study design and exposure assessment revealed consistent neurobehavioral effects and attributable subclinical and clinical signs and symptoms of impairment. Twenty-eight studies show an exposure-response relationship between Mn and neurobehavioral effects, including 11 with continuous exposure metrics and six with three or four levels of contrasted exposure. The effects of sustained low-concentration exposures to Mn are consistent with the manifestations of early manganism, i.e., consistent with parkinsonism. This is compelling evidence thatMnis a neurotoxic chemical and there is good evidence that Mn exposures far below the current US standard of $5.0mg/m^3$ are causing impairment.

• 한국지구물리탐사학회:학술대회논문집
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• 2009.05a
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• pp.57-65
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• 2009

Selection of good mineralized area is a combination of the integration of all the available geo-scientific (i.e., geological, geochemical, and geophysical) information, extrapolation of likely features from known mineralized terrenes and the ability to be predictive. The time-space relationships of the hydrothermal deposits in the East Asia are closely related to the changing plate motions. Also, two distinctive hydrothermal systems during Mesozoic occurred in Korea: the Jurassic/Early Cretaceous deep-level ones during the Daebo orogeny and the Late Cretaceous/Tertiary shallow geothermal ones during the Bulguksa event. Both the Mesozoic geothermal system and the mineralization document a close spatial and temporal relationship with syn- to post-tectonic magmatism. The Jurassic mineral deposits were formed at the relatively high temperature and deep-crustal level from the mineralizing fluids characterized by the relatively homogeneous and similar ranges of ${\delta}^{18}O$ values, suggesting that ore-forming fluids were principally derived from spatially associated Jurassic granitoid and related pegmatite. Most of the Jurassic auriferous deposits (ca. 165-145 Ma) show fluid characteristics typical of an orogenic-type gold deposits, and were probably generated in a compressional to transpressional regime caused by an orthogonal to oblique convergence of the Izanagi Plate into the East Asian continental margin. On the other hand, Late Cretaceous ferroalloy, base-metal and precious-metal deposits in the Taebaeksan, Okcheon and Gyeongsang basins occurred as vein, replacement, breccia-pipe, porphyry-style and skarn deposits. Diverse mineralization styles represent a spatial and temporal distinction between the proximal environment of sub-volcanic activity and the distal to transitional condition derived from volcanic environments. However, Cu (-Au) or Fe-Mo-W deposits are proximal to a magmatic source, whereas polymetallic or precious-metal deposits are more distal to transitional. Strike-slip faults and caldera-related fractures together with sub-volcanic activity are associated with major faults reactivated by a northward (oblique) to northwestward (orthogonal) convergence, and have played an important role in the formation of the Cretaceous Au-Ag lode deposits (ca. 110-45 Ma) under a continental arc setting. The temporal and spatial distinctions between the two typical Mesozoic deposit styles in Korea reflect a different thermal episodes (i.e., late orogenic and post-orogenic) and ore-forming fluids related to different depths of emplacement of magma (i.e., plutonic and sub-volcanic) due to regional changes in tectonic settings.

• Economic and Environmental Geology
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• v.40 no.5
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• pp.517-535
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• 2007

Two distinctive Mesozoic hydrothermal systems occurred in South Korea: the Jurassic/Early Cretaceous(ca. $200{\sim}130$ Ma) deep-level ones during the Daebo orogeny and the Late Cretaceous/Tertiary(ca. $110{\sim}45$ Ma) shallow hydrothermal ones during the Bulgugsa event. The Mesozoic hydrothermal system and the metallic mineralization in the Korean Peninsula document a close spatial and temporal relationship with syn- to post-tectonic magmatism. The calculated ${\delta}^{18}O_{H2O}$ values of the ore-forming fluids from the Mesozoic metallic mineral deposits show limited range for the Jurassic ones but variable range for the Late Cretaceous ones. The orogenic mineral deposits were formed at relatively high temperatures and deep-crustal levels. The mineralizing fluids that were responsible for the formation of theses deposits are characterized by the reasonably homogeneous and similar ranges of ${\delta}^{18}O_{H2O}$ values. This implies that the ore-forming fluids were principally derived from spatially associated Jurassic granitoids and related pegmatite. On the contrary, the Late Cretaceous ferroalloy, base-metal and precious-metal deposits in the Taebaeksan, Okcheon and Gyeongsang basins occurred as vein, replacement, breccia-pipe, porphyry-style and skarn deposits. Diverse mineralization styles represent a spatial and temporal distinction between the proximal environment of subvolcanic activity and the distal to transitional condition derived from volcanic environments. The Cu(-Au) or Fe-Mo-W deposits are proximal to a magmatic source, whereas the polymetallic or the precious-metal deposits are more distal to transitional. On the basis of the overall ${\delta}^{18}O_{H2O}$ values of various ore deposits in these areas, it can be briefed that the ore fluids show very extensive oxygen isotope exchange with country rocks, though the ${\delta}D_{H2O}$ values are relatively homogeneous and similarly restricted.