• Journal of Korean Society for Atmospheric Environment
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• v.21 no.6
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• pp.699-708
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• 2005

To characterize the elemental composition of fine particles in urban area, $PM_{2.5}$ was collected by a 3-stage DRUM impactor at Gwangju during spring and summer. Time and size resolved concentrations for 19 trace elements were obtained by synchrotron X-Ray fluorescence analysis. Trace elements in summer were distributed in smaller size range compared to those in spring. Almost trace element concentrations in fine particles were highly increased during the Asian dust. In spring, soil elements such as Si, K, Ca, Ti and Fe had low enrichment factors indicating the dominant influence of soil dust. However, all elements had high enrichment factors in summer implying that these elements could be emitted from the anthropogenic sources. Factor analysis was conducted with the elemental composition data in order to identify anthropogenic sources of aerosols in urban area during spring and summer. Fine particles in spring have several sources such as soil dust originating from China continental region, coal and oil combustion, biomass burning, sea salt, ferrous and nonferrous metal sources. On the other hand, fine particles in summer were influenced by road dust, gasoline vehicle as well as coal and oil combustion, sea salt, ferrous and nonferrous metal sources.

• Journal of the Korea Institute of Building Construction
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• v.24 no.2
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• pp.169-180
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• 2024

In this study, to suggest an efficient method of using coal gasification slag(CGS), a byproduct from integrated gasification combined cycle(IGCC), as a combined fine aggregate for concrete mixture, the diverse performances of concrete mixtures with combined fine aggregates of CGS, river sand, and crushed sand were evaluated. Additionally, using CGS, the reduction of the hydration heat and the strength developing performance were analyzed to provide a method for reducing the heat of hydration of mass concrete by using combined fine aggregate with CGS and replacing fly ash with cement. The results of the study can be summarized as follows: as a method of recycling CGS from IGCC as concrete fine aggregate, a combination of CGS with crushed sand offers advantages for the concrete mixture. Additionally, when the CGS combined aggregate is used with low-heat-mix designed concrete with fly ash, it has the synergistic effect of reducing the hydration heat of mass concrete compared to the low-heat-designed concrete mixture currently in wide use.

• Carbon letters
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• v.28
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• pp.38-46
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• 2018

Modified pitch A (MPA) and modified pitch B (MPB) were prepared by oxidative polymerization and thermal polycondensation reaction with refined pitch as the raw material, respectively. The toluene soluble components (TS-1 and TS-2) were obtained by solvent extraction from MPA and MPB, separately. The Flynn-Wall-Ozawa method and Kissinger-Akahira-Sunose method were used to calculate the pyrolysis activation energy of TS. The Satava-Sestak method was used to investigate the pyrolysis kinetic parameters of TS. Moreover, the optical microstructure of the thermal conversion products (TS-1-P and TS-2-P) by calcination shows that TS-1-P has more contents of mosaic structure and lower contents of fine fiber structure than TS-2-P. The research result obtained by a combination of X-ray diffraction and the curve-fitting method revealed that the ratios of ordered carbon crystallite (Ig) in TS-1-P and TS-2-P were 0.3793 and 0.4417, respectively. The distributions of carbon crystallite on TS-1-P and TS-2-P were calculated by Raman spectrum and curve-fitting analysis. They show that the thermal conversion product of TS-2 has a better graphite crystallite structure than TS-1.

• Proceedings of the Korea Concrete Institute Conference
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• 2003.05a
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• pp.19-24
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• 2003

Recently, the by-product of coal ash has been increased by increase of consumption of electric power. So in view of environmental aspect, it is important to secure a reclaimed land and treatment utility for coal ash. This is an experimental study to compare and analyze the properties of high volume coal-ash concrete using the bottom ash. For this purpose, the mix proportions of concrete according to the replacement ratio of bottom ash(l0, 20, 35, 50%). And then air content, slump, compressive strength, durability test were performed. According to test results, it was found that the compressive strength of bottom ash concrete was similar to that of plain concrete(BA0). And the carbonation depth of bottom ash concrete increased as the replacement ratio of bottom ash.

• Journal of Industrial Technology
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• v.15
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• pp.175-185
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• 1995

Under the new environmental regulations announced by the government, utilities will have to cut their sulfur dioxide emissions by 60% from 1991 levels by the year of 1999. Sulfur dioxide emissions can be reduced prior to combustion by physical, chemical or biological coal cleaning. The new technology of high gradient magnetic separation (HGMS) offers the potential of economic separatoins of a variety of fine, weakly magnetic minerals including inorganic sulfur and many ash-forming minerals from coals. In the present paper, magnetic separation tests have been conducted on Korean anthracite and high-sulfur Chinese coal to investigate the feasibility of these techniques for reducing sulfur content from coals. In wet magnetic separation, the studied operating parameters include particle size, pH, matrix types, feed solids content, feed rate, number of cleaning stages and etc. The results shows that for wet separation, 60~70% of total sulfur was removed from coals with over 80% combustible recovery, on the other hand, for dry separation, 47.6% of total sulfur was removed from coals with 75% recovery.

• Proceedings of the Korea Concrete Institute Conference
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• 2003.05a
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• pp.1017-1022
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• 2003

The hydraulic structures such as aqueduct tunnels and the drainage canal of the hydroelectric power plant in Japan are almost old. Therefore, the concrete surface of the aqueduct tunnel has received damage by wear-out and the crack, etc. This study was to develop repair mortar mixed a coal ash coarse powder by using two kinds of high early strength cements. As a result, the repair mortar was obtained by substituting the EF cement (maid in Japan) and the MT cement (maid in South Korea) at a rate of 60:40, and substituting the coal ash 30% and the mixing rate 35% of the artificial aggregate for natural fine aggregate.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2019.11a
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• pp.79-80
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• 2019

This study was intended to examine the possibility of reducing hydration heat by FA substitution and combination of slag (CGS) from coal gasification power generation (IGCC) with mixed aggregate for concrete. The analysis results showed good results if liquidity increases as the ratio of CGS increases, air volume decreases, and compressive strength is mixed up to 25% in the residual aggregate. The results showed that the heat of hydration was reduced compared to plain due to the boron content of CGS as the CGS substitution rate increased, but it was larger due to the combination with FA substitution. It was found that the heat of hydration was reduced.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2021.11a
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• pp.63-64
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• 2021

In this study, Coal gasification slag(CGS) was replaced with fine aggregate to verify the physical properties of the concrete according to the change in cement types. As a result of the study, the use of CGS resulted in a decrease of superplasticizer and an decrease of AE agent. In addition, when 50% of mixed cement and CGS were replaced, the initial strength expression was delayed, and the strength enhancing effect was judged to be weak.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2021.11a
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• pp.182-183
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• 2021

In this study, This is the result of thermal characteristics analysis to suggest an efficient method of using coal gasification slag(CGS) of byproduct from integrated gasification combined cycle(IGCC). In Specific Heat characteristics, CGS and CS showed similar values. Isothermal Conduction Calorimetry showed that the hydration reaction of cement was retarded when CGS was used. Therefore, it is expected that CGS will be used as an efficient alternative to reducing the hydration heat of mass concrete as a functional aggregate combination.

• Clean Technology
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• v.19 no.4
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• pp.464-468
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• 2013

In this study, in order to increase solid content of coal water fuel (CWF), various experimental parameters (i.e., coal type, additive, particle size distribution, drying method) were evaluated. To investigate the drying method, specimen is compared to using flash dry, fluidized bed dry and oil deposit stabilized coal. Difference of the solid content between low rank coal and high rank coal in this case indicate that high rank coal exhibits more higher than 20% of the solid cotent. And specimen for dispersibility was prepared by using dispersing agent of 4 types. As a result, using the dispersing agent was shown 5% higher in sold content than the case of not using the dispersing agent. Efficiency of CWF was improved by using fine coal of 80% in the particle size distribution of coal. Result of CWF using drying methods of 3 types, oil deposit stabilized (ODS) coal dried and stabilized was effective 12% higher in sold content than raw coal.