• Journal of the Korean Recycled Construction Resources Institute
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• v.7 no.2
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• pp.70-77
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• 2012

The Ladle Furnace Slag, about 20% of the electric arc furnace slag, has high content of free CaO and free MgO, which generates the expansion collapse by hydration reaction. Although many researchers have been endeavoring to recycle the EAF reducing slag in construction fields, there is not found the effective recycling method up to now. However, the LFS(Ladle Furnace Slag) contains mineral composition of the system of calcium aluminate with high-reactivity. Therefore, it is possible to developed the quick setting property and the high strength at the early age by the rapid cooling. This study aimed to check the reactive minerals and predict the reactivity with water on the LFS discharged from different steel product plants. The test results show that many types of LFS has hydration reactivity and can use in construction field as a inorganic binder with the rapid setting property.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2016.05a
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• pp.36-37
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• 2016

Among all the slags, ladle furnace slag (LFS) is reducing slag generated from electric arc furnace. After cooled rapidly by high-pressured air (atomizing technology), LFS has more amorphous phase than slow cooled slag. Therefore, it shows higher reactivity than another recycling slag. This material also is named by rapid cooling LFS (RC-LFS). Pulverized RC-LFS should be fully understood. This paper deal with the present some basic experimental properties and discussions about the setting time of pulverized RC-LFS with different gypsum under the various temperatures. According to the experimental results, the pulverized RC-LFS with gypsum can hydrate in a low-temperature environment, even though the initial and final setting time are delayed.

• Resources Recycling
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• v.26 no.1
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• pp.37-42
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• 2017

It has been reported that aqueous indirect carbonation process of calcium silicate mineral could be one of the most promising methods for $CO_2$ sequestration. The process consists of two main steps, extraction of Ca from calcium silicate and carbonation of the extracted solution by $CO_2$. Many types of acids such as HCl and $HNO_3$ can be used in the extraction step of the process. In the case of using aqueous acetic acid solution as the extraction solvent, acetic acid can be reproduced at the carbonation step of the extracted solution by $CO_2$ and recycled to extraction step for reuse it. Industrial by-products such as iron and steel slags are potential raw materials of the indirect carbonation process due to their high contents of calcium silicate. In this study, in order to examine the extraction efficiency of domestic electric arc furnace steel slag by aqueous acetic acid solution, extraction experiments of the slag were performed by using the aqueous acetic acid solutions of varying extraction conditions ; acetic acid concentrations, extraction temperatures and times.

• Proceedings of the IEEK Conference
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• 2001.10a
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• pp.381-386
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• 2001

The dust generated from the electric arc furnace steel making process is classified as hazardous material by Korean Environmental Protection Acts, mainly because of the existence of water teachable Pb, Zn and Cd. Thus the treatment of EAF dust is being carried out to fulfill both the environmental aspect and recovery of valuable metals. To establish the proper process for recovering the valuable metals (Fe, Zn, Pb and Cd) and producing the non-toxic slag from EAF dust, using RAPID-10 system, feasibility study have been carried out. To find out the scale-up factor for designing the commercial scale EAF dust treatment process(capacity 50,000 ton EAF dust per year) entitled RAPID-50 system. The design and construction of RAPID-50 (RIST Arc Plasma Industrial Device) system for treating 50,000 ton of EAF dust per year is now undergoing. Overall plan for treating EAF dust generated in KOREA will be setup after successful operation (December, 2002) of RAPID-50 system.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.29 no.3
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• pp.115-122
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• 2019

Electric arc furnace dust (EAFD), which is a dust waste generated in the steel manufacturing process, contains heavy metals. Recently, researches of recycling a large amount of valuable metals such as zinc and iron in EAFD are being actively carried out. In this study, EAFD is used as a substitute for cobalt in blue ceramic pigments without any pretreatment. Then, the synthesized blue ceramic pigment using EAFD was micronized and formulated as a ceramic ink for inkjet printer. The particle size distribution, crystal structure and color characteristics during the micronization process were investigated for the development of ceramic ink. $Co_{0.75}Zn(EAFD)_{0.25}Al_2O_4$ ceramic pigments showed excellent blue coloric properties and monomodal distribution through micronization process. The average particle size of $Co_{0.75}Zn(EAFD)_{0.25}Al_2O_4$ ceramic pigments after 3 hours of milling was $0.271{\mu}m$, which is smaller than $0.303{\mu}m$, which is the average particle size of $CoAl_2O_4$ ceramic pigments without EAFD after 5 hours of milling. Especially, it was confirmed that $Co_{0.75}Zn(EAFD)_{0.25}Al_2O_4$ ceramic pigments showed a color difference (${\Delta}E{^*}_{ab}$) value of 5.67, which smaller than ${\Delta}E{^*}_{ab}$ value of $CoAl_2O_4$ during micronization. These results show that EAFD can be used as a raw material for a blue ceramic pigment by replacing expensive cobalt without any pretreatment.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.20 no.1
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• pp.91-99
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• 2006

Large steel industries have nonlinear loads including electric arc furnaces and harmonic field measurements have shown that harmonic content of a waveform varies with time. Since the large loads are supplied from the power system grid, it must be recognized that not only will the system of utility be impacted, but neighboring customer system could be impacted as well. In this paper time-varying harmonics are evaluated by international harmonic standards IEEE Std. 519 and IEC 61000-3-6 using a cumulative probablistic approach.

• Journal of the Korean Recycled Construction Resources Institute
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• v.3 no.1
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• pp.15-21
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• 2015

Recently, attempts of replacing some of natural aggregate with mix of low quality aggregate are carried out for stable supply of aggregate. However, low quality aggregate such as recycled aggregate produced during the disposal process of construction wastes and by-product aggregate produced by industrial activities has problem of failing to comply to KS Standards. Therefore, we have compared fundamental properties of concrete by using granite crushed aggregate, recycled aggregate, blast furnace and electric arc furnace slag aggregate for effective utilization of lacking aggregate resources. As the result, slump in case of mixed use of aggregate was increased 0~10% compared to single use. Therefore, it is judged to be economically advantageous as it can expect effects in unit quantity or reduction of SP agent. Compressive strength in case of mixed use of aggregate was increased 0~10% compared to single use as it filled internal crevice of concrete with continuous particle size distribution. Accordingly, if we utilize by satisfying standard particle scope through mix of aggregate with different cause of formation in proper ratio, it was possible to confirm utility of mixed aggregate with demonstration of effects of increases of fluidity and compressive strength of concrete.

• Resources Recycling
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• v.23 no.1
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• pp.58-63
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• 2014

Variety of volatile materials is present in crude-Zinc oxide recovered from EAFD(Electric arc furnace steel dust). Commonly, it is purified by oxidizing roasting. In this study, spherical each specimen prepared crude-zinc oxide like 1~3 mm and 10 mm was tested in vertical tube furnace at the temperature range $600^{\circ}C$ to $1200^{\circ}C$ in oxidizing atmosphere. Oxidizing roasting properties of zinc oxide were investigated using XRD, XRF and ICP-OES. At temperature blow $950^{\circ}C$ volatilization rate were remarkably low. As the temperature increases, the concentration of Zn increased and the concentration and XRD peaks of impurities decreased. The result indicated that volatilization rate depended on specimen size and roasting temperature.

• Transactions of Materials Processing
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• v.15 no.8 s.89
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• pp.603-608
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• 2006

The main purpose of the present study has been placed on investigating the mechanical properties and microstructures of C-Si-Mn-V steels for cold forming manufactured by controlled rolling and cooling technology. The steels were manufactured in electric arc furnace (EAF) and casted to $160{\times}160mm$ billet. The billets were reheated in walking beam furnace and rolled to coil, the stocks were rolled by Controlled Rolling and Cooling Technology (CRCT), so rolled at low temperature by water spraying applied in rolling stage and acceleratly cooled before coiling. Rolled coils were cold drawed to the degree of 16%, 27% of area reduction respectively without heat treatment. Microstructual observation, tensile test, compression test and charpy impact tests were conducted. The mechanical properties of the steels were changed by area reduction of cold drawing and it is founded that there are optimum level of cold drawing to minimize compression stress for these steels. From the result of this study, it is conformed that $80kg_{f}/mm^{2},\;90kg_{f}/mm^{2}$ grade high strength microalloyed steel for cold forming are developed by accelerated cooling and optimum cold drawing.

• Resources Recycling
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• v.27 no.2
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• pp.68-76
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• 2018

EAF (Electric arc furnace) dust is an important secondary resource such as zinc, lead, and iron. Recycling of EAF dust is benefit to solving disposal and environmental problems caused by the heavy metals entrained in the dust. In this study, pyrometallurgical treatment technology of EAF dust reviewed for the improvement of conventional process and development of new process. The existing technologies categorized into four groups: those by rotary kiln process, rotary hearth furnace (RHF) process, shaft type process, and reduction smelting process. The product of these processes are ZnO and Fe or slag as a waste. Their mechanisms for the production of ZnO from EAF dust were carbothermic reduction and oxidation of zinc gas with air.