• Journal of the Korean Recycled Construction Resources Institute
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• v.6 no.4
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• pp.112-118
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• 2012

Steel industry produces many by-products and wastes such as blast furnace slag, electric arc furnace slag, and converter slag. As in the case of rock, the main component of steel slag are CaO and $SiO_2$ ; further, steel slag is as alkaline as portland cement or concrete. Electric arc furnace oxidizing slag is possible to use as an aggregate for concrete ; however, it has been reclaimed because of it's expansibility caused by free CaO. Recently, a innovative rapid cooling method for melting steel slag has been developed in Korea, which reduces free lime content to minimum level and increases the stability of iron oxide. Therefore, this study describes the results of a series of research to utilize globular shape of electric arc furnace oxidizing slag fine aggregates made by rapidly cooled method for the construction industry by cooling rapidly melted slag from the steel industry. First of all, an experiment was carried out to investigate the quality characteristics of rapidly cooled electric arc furnace oxidizing slag fine aggregates in order to determine whether they can be applied to the construction industry. Then, by applying them to concrete of various particle sizes, we explored experimentally the desired condition to apply rapidly cooled electric arc furnace oxidizing slag fine aggregates to concrete.

• Bulletin of the Korean Chemical Society
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• v.33 no.10
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• pp.3177-3183
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• 2012

The carbon nanofibers (CNFs) used in this study were synthesized with an iron catalyst and ethylene as a carbon source. A concentration of 30 wt % iron(III) acetylacetonate was dissolved in resol type phenol resin and polyurethane foam was put into the solution. The sample was calendered after being cured at $80^{\circ}C$ in air for 24 h. Stabilization and carbonization of the resol type phenol resin and reduction of the $Fe^{3+}$ were completed in a high-temperature furnace by the following steps: 1) heating to $600^{\circ}C$ at a rate of $10^{\circ}C/min$ with a mixture of $H_2/N_2$ for 4 h to reduce the $Fe^{3+}$ to Fe; 2) heating to $1000^{\circ}C$ in $N_2$ at a rate $10^{\circ}C/min$ for 30 minutes for pyrolysis; 3) synthesizing CNFs in a mixture of 20.1% ethylene and $H_2/N_2$ at $700^{\circ}C$ for 2 h using a CVD process. Finally, the structural characterization of the CNFs was performed by scanning electron microscopy and a synthesis analysis was carried out using energy dispersive spectroscopy and X-ray photoelectron spectroscopy. Specific surface area analysis of the CNFs was also performed by $N_2$-sorption.

• Journal of Powder Materials
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• v.17 no.3
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• pp.223-229
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• 2010

Iron(Fe)-Molybdenum(Mo) alloyed nanoparticles and nanowires were produced by the chemical vapor condensation(CVC) process using the pyrolysis of iron pentacarbonyl($Fe(CO)_5$) and Molybdenum hexacarbonyl($Mo(CO)_6$). The influence of CVC parameter on the formation of nanoparticle, nanowire and size control was studied. The size of Fe-Mo alloyed nanoparticles can be controlled by quantity of gas flow. Also, Fe-Mo alloyed nanowires were produced by control of the work chamber pressure. Moreover, we investigated close correlation of size and morphology of Fe-Mo nanoparticles and nanowires with atomic quantity of inflow precursor into the electric furnace as the quantitative analysis. Obtained nanoparticles and nanowires were investigated by field emission scanning electron microscopy, energy dispersive spectroscopy and X-ray diffraction.

• Transactions of the Korean hydrogen and new energy society
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• v.30 no.2
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• pp.111-118
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• 2019

Greenhouse gas emissions have a profound effect on global warming. Various environmental regulations have been introduced to reduce the emissions. The largest amount of greenhouse gases, including carbon dioxide, is produced in the steel industry. To decrease carbon dioxide emission, hydrogen-based iron oxide reduction, which can replace carbon-based reduction has received a great attention. Iron production generates various by-product gases, such as cokes oven gas (COG), blast furnace gas (BFG), and Linz-Donawitz gas (LDG). In particular, COG, due to its high concentrations of hydrogen and methane, can be reformed to become a major source of hydrogen for reducing iron oxide. Nevertheless, continuous COG cannot be supplied under actual operation condition of steel industry. To solve this problem, this study proposed to use two alternative COG-based fuel mixtures; one with natural gas and the other with biogas. Reforming study on two types of mixed gas were carried out to evaluate catalyst performance under a variety of operating conditions. In addition, methane conversion and product composition were investigated both theoretically and experimentally.

• Journal of Powder Materials
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• v.21 no.5
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• pp.371-376
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• 2014

In this study, modified catalytic chemical vapor deposition (CCVD) method was applied to control the CNTs (carbon nanotubes) growth. Since titanium (Ti) substrate and iron (Fe) catalysts react one another and form a new phase ($Fe_2TiO_5$) above $700^{\circ}C$, the decrease of CNT yield above $800^{\circ}C$ where methane gas decomposes is inevitable under common CCVD method. Therefore, we synthesized CNTs on the Ti substrate by dividing the tube furnace into two sections (left and right) and heating them to different temperatures each. The reactant gas flew through from the end of the right tube furnace while the Ti substrate was placed in the center of the left tube furnace. When the CNT growth temperature was set $700/950^{\circ}C$ (left/right), CNTs with high yield were observed. Also, by examining the micro-structure of CNTs of $700/950^{\circ}C$, it was confirmed that CNTs show the bamboo-like structure.

• Resources Recycling
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• v.15 no.4 s.72
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• pp.44-51
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• 2006

Most electric arc furnace dust (EAFD) treatment processes to recover zinc from EAFD employ carbon as a reducing agent for the zinc oxide in the EAFD. In the present work, the reduction reaction of zinc oxide with carbon in the present of iron oxide was kinetically studied. The experiments were carried out at temperatures between 1173 K and 1373 K under nitrogen atmosphere using a weight-loss technique. From the experimental results, it was concluded that adding the proper amount of iron oxide to the reactant accelerates the reaction rate of zinc oxide with carbon. This is because iron oxide in the reduction reaction of zinc oxide with carbon promotes the carbon gasification reaction. The spherical shrinking core model for a surface chemical reaction control was found to be useful in describing kinetics of the reaction over the entire temperature range. The reaction has an activation energy of 53 kcal/mol (224 kJ/mol) for ZnO-C reaction system, an activation energy of 42 kcal/mol (175 kJ/mol) for $ZnO-Fe_{2}O_{3}-C$ reaction system, and an activation energy of 44 kcal/mol (184 kJ/mol) for ZnO-mill scale-C reaction system.

• Journal of Preventive Medicine and Public Health
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• v.30 no.4 s.59
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• pp.752-763
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• 1997

To evaluate the effect of manganese on the respiratory system, we investigated the respiratory symptoms of 63 male workers exposed to, fume containing manganese (Mn), iron (Fe) and silica (Si), and compared them with those of 66 male workers not exposed to the fume in a manganese alloy smelting factory. The prevalence ratios of the seven respiratory symptoms were not different between two groups. The presence of any respiratory symptom was not related with the age, duration of employment, smoking status of workers, and exposure to fume. In furnace workers, it was not related with the airborne Mn, Fe, and Si concentration in the total or respirable fume. Airborne Mn concentrations of all 4 furnaces in the respirable fume were below $1mg/m^3$. There were two suspicious cases of pneumoconiosis among furnace workers and one definite case(1/2) among casting workers who were not exposed to fume. The above results suggest that the exposure to the low airborne Mn concentration is not related with respiratory symptoms and pneumoconiosis. However, it is necessary to study the respiratory effects of Mn using the symptom questionnaire with consideration of the severity and persistence, of symptoms and the time interval from exposure.

• Journal of Conservation Science
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• v.36 no.5
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• pp.421-429
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• 2020

This study examined the manufacturing process of a furnace wall excavated from the Songdu-ri Site in Jincheon, and the difference in material composition between the 11 layers of the wall using physicochemical analyses. Based on microstructure observations, these layers could be largely divided into three groups: an undercalcined first layer, calcined second to ninth layer with evidences of partial heat, and non-fired soil layers from the tenth to the eleventh layer. Particle size analyses revealed that the fired layer constituted a relatively higher content of coarse sand than the non-fired layer. This difference was further confirmed by the results of the curvature coefficient analysis. An analysis of the constituent minerals showed similar overall XRD diffraction patterns between the different layers, but variations in the intensity of the low-temperature and high-temperature minerals. This indicates that the degree of heat was different. The thermal analysis results demonstrated that the heating peak of mullite was only reached in the first and second layers of the wall, thus implying these as the layers to be finally used. Consequently, no significant difference could be observed between the materials of the various layers of the wall. Thus, it can be suggested that the furnace wall was constructed using clay, which had a composition similar to that of the soil present in the area. However, the shape and characteristics of the constituent particles between the layers displayed partial variations, and it is possible that some external materials might have been added.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.14 no.4
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• pp.721-728
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• 1994

The objective of this research is to analyze whether the ground granulated blast furnace (GGBF) slag, by-product of industry in domestic iron-foundary, can be useful as a mineral admixture for concrete by investigating physical and chemical property. In addition, according to making an fundamental experiment on mortar and concrete mixed with GGBF slag to some grade, examining the consistency, the compressive strength and the resistance to sulfate attack of concrete and mortar, the acquired results are that the compressive strength was increased and the resistance to sulfate attack was predominant.

• 제어로봇시스템학회:학술대회논문집
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• 2005.06a
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• pp.1431-1434
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• 2005

In the steel production line, the molten metal of a furnace is transformed into billet and then moves to the heating furnace of the hot rolling mill. This paper describes about the development of recognition system for the characters, which was marked at the billet material by use template-marking plate and hand written method, in the steel plant. For the recognition of template-marked characters, we propose PSVM algorithm. And for the recognition of hand written character, we propose combination methods of CCD algorithm and PSVM algorithm. The PSVM algorithm need some more time than the conventional KLT or SVM algorithm. The CCD algorithm makes shorter classification time than the PSVM algorithm and good for the classification of closed curve characters from Arabic numerals. For the confirmation of algorithm, we have compared our algorithm with conventional methods such as KLT classifier and one-to-one SVM. The recognition rate of experimented billet characters shows that the proposing PSVM algorithm is 97 % for the template-marked characters and combinational algorithm of CCD & PSVM is 95.5 % for the hand written characters. The experimental results show that our proposing method has higher recognition rate than that of the conventional methods for the template-marked characters and hand written characters. By using our algorithm, we have installed real time character recognition system at the billet processing line of the steel-iron plant.