• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2008.11a
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• pp.217-220
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• 2008

Slag mass deposition was required to predict accurate performance of kick motor (KM) system. Slag mass accumulation was analyzed through the aluminum oxide particle paths to predict slag mass deposition. Numerical analysis to solve both flow field and droplet accumulation was performed with Fluent 6.3 program. The effects for the acceleration and diameters of the aluminum oxide particles was analyzed, finally total slag mass accumulation was acquired. It confirmed that the slag mass deposition was agreed well with previously slag mass prediction based on KM ground test.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.3 no.2
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• pp.95-104
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• 2005

Effects of the aluminum melting temperature, melting time and a kind of flux agents on the distribution of surrogate nuclide were investigated in the electric furnace at the aluminum melting including surrogate radionuclides(Co, Cs, Sr) in order to establish the fundamental research of the melting technology for the metallic wastes from the decommissioning of the TRIGA research reactor. It was verified that the fluidity of aluminum melt was increased by adding flux agent but it was slightly varied according to the sort of flux agents. The results of the XRD analysis showed that the surrogate nuclides move into the slag phase and then they were combined with aluminum oxide to form more stable compound. The weight of the slag generated from aluminum melting test increased with increasing melting temperature and melting time and the increase rate of the slag depended on the kind of flux agents added in the aluminum waste. The concentration of the cobalt in the ingot phase decreased with increasing reaction temperature but it increased in the slag phase up to 90$\%$according to the experimental conditions. The volatile nuclides such as Cs and Sr considerably transferred from the ingot phase to the slag and dust phase.

• Aerospace Engineering and Technology
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• v.7 no.2
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• pp.131-143
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• 2008

Slag mass deposition was required to predict performance accurately of KSLV-I kick motor(KM) system. The validation of the numerical analysis was performed with mass flow rate measured at 4th ground test of the KM. The study described here included internal flow field of KM at various time steps during burning. Slag mass accumulation was computed through the aluminum oxide particle paths to deviate from the gas flow streamlines in flight. These numerical analysis was performed with Fluent 6.3 program The effects for the acceleration, origins and diameters of the aluminum oxide particles was analyzed, finally the total slag mass accumulation was acquired. We confirmed that the slag mass deposition was agreement well with predicted slag mass based on kick motor the grounded test.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2023.11a
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• pp.161-162
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• 2023

Limestone slag cement is a green and sustainable building material with huge market potential. However, its shortcoming of low early compressive strength needs to be improved. A method of using aluminum sulfate to improve the early strength of ternary mixed mortar was proposed, and its effect and optimal dosage were tested. Macroscopic properties such as mechanical properties and surface electrical resistivity were measured at different dosages (0%, 1%, 2%, 3%). The microstructure and products of the mixtures were tested in detail, including by scanning electron microscopy, thermogravimetric analysis, and X-ray diffraction. The results show aluminum sulfate enhances mechanical properties and significantly increases surface electrical resistivity. The 1% and 2% doses had no adverse effects on the 28-day mechanical properties, while the 3% dose reduced the 28-day strength. Considering the changes in mechanical properties and surface electrical resistivity, 1% aluminum sulfate is the optimal dosage.

• Journal of the Korean Society of Propulsion Engineers
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• v.13 no.4
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• pp.1-8
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• 2009

Accumulated slag mass was predicted to estimate accurate performance of kick motor (KM) system. The validation of numerical analysis was performed with mass flow rate measured at the 4th ground test of the KM. The study described here includes the internal flow field of KM at various time steps during burning. Slag mass accumulation was analyzed through the aluminum oxide particle paths to predict slag mass deposition. Numerical analysis to solve both flow field and droplet accumulation was performed with Fluent 6.3 program. Analysing the effects of the acceleration, starting position and diameters of the aluminum oxide particles, total slag mass accumulation was obtained.

• Journal of the Korean GEO-environmental Society
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• v.25 no.5
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• pp.39-47
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• 2024

In this study, the environmental implications of electric arc furnace steel slag, commonly used in road construction and soil reinforcement, were examined. Experiments were conducted to assess the leaching of heavy metals based on particle size and to investigate ion leaching from specimens with varying mixtures of steel slag and clay. The official waste test revealed no detectable heavy metals in the sample items. However, when subjected to leaching experiments and analyzed using ICP-OES, certain heavy metals were found. The reaction of steel slag with water, facilitated by free CaO within the slag, was identified as the cause of leaching. Results showed that aluminum, exhibiting the highest leaching rate, displayed an inverse relationship with particle size. In mixed soil containing steel slag and clay, higher steel slag content resulted in increased aluminum leaching. Nonetheless, the quantity of leached aluminum was notably lower in mixed soil compared to pure steel slag. Furthermore, leaching of other heavy metals remained within acceptable limits. These findings suggest that recycling mixed soil of steel slag and clay for road construction or soil stabilization presents reduced environmental risks compared to using steel slag alone. Utilizing such mixtures could offer an environmentally sustainable and safe alternative.

• Proceedings of the Korea Concrete Institute Conference
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• 2001.05a
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• pp.481-486
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• 2001

Ground granulated blast-furnace slag shows very high strength when proper alkali-activator exists. This paper deals with setting time, heat evolution rate and the strength development of alkali-activated slag cement activated by KOH, Ca(OH$)_{2}$, $Na_{2}$ $So_{4}$ , and alum(potassium aluminum sulfate). Alkali-activated slag mortar is studied by comparison with GGBF slag cement mortar. The experimental results indicate that for moisture curing at $25^{\circ}C$, the addiction of either 4% $Na_{2}$ $So_{4}$ or 4% alum increases the strength of GGBF slag cement mortar consisting of 50% GGBF slag and 50% portland cement at early age. Strength of activated GGBF slag cement mortars at 1, 3 and 7 days exceeded that of GGBF slag cement mortar. A conduction calorimeter was used to monitor early age hydration.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.4 no.1
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• pp.33-40
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• 2006

The characteristics of the aluminum waste melting and the distribution of the radioactive nuclides have been investigated for the estimation on the volume reduction and the decontamination of the aluminum wastes from the decommissioning of the TRIGA MARK it and III research reactors at the Korea Atomic Energy Research Institute(KAERI). The aluminum wastes were melted with the use of the fluxes such as flux $A:NaCl-KCl-Na_3AlF_6$, flux B:NaCl-NaF-KF, flux $C:CaF_2$, and flux $D:LiF-KCl-BaCl_2$ in the DC graphite arc furnace. For the assessment of the distribution of the radioactive nuclides during the melting of the aluminum, the aluminum materials were contaminated by the surrogate nuclides such as cobalt(Co), cesium(Cs) and strontium(Sr). The fluidity of aluminum melt was increased with the addition of the fluxes, which has slight difference according to the type of fluxes. The formation of the slag during the aluminum melting added the flux type C and D was larger than that with the flux A and B. The rate of the slag formation linearly increased with increasing the flux concentration. The results of the XRD analysis showed that the surrogate nuclide was transferred to the slag, which can be easily separated from the melt and then they combined with aluminum oxide to form a more stable compound. The distribution ratio of cobalt in ingot to that in slag was more than 40% at all types of fluxes. Since vapor pressures of cesium and strontium were higher than those that of the host metals at the melting temperature, their removal efficiency from the ingot phase to the slag and the dust phase was by up to 98%.

• Journal of Ceramic Processing Research
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• v.19 no.5
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• pp.378-382
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• 2018

It is a known fact that the cement production is responsible for almost 5% of total worldwide $CO_2$ emission, the primary factor affecting global warming. Geopolymers are valuable as ordinary Portland cement (OPC) substitutes because geopolymers release 80% less $CO_2$ than OPC and have mechanical properties sufficiently similar to those of OPC. Therefore, geopolymers have proven attractive to eco-friendly construction industries. Geopolymers can be fabricated from aluminum silicate materials with alkali activators such as fly ash, blast furnace slag, and so on. Integrated gasification combined cycle (IGCC) slag has been used for fabricating geopolymers. In general, IGCC slag geopolymers are fabricated with finely ground and sieved (<128 mesh) IGCC slag. The grinding process of as-received IGCC slag is one of the main costs in geopolymer production. Therefore, the idea of using as-received IGCC slag (before grinding the IGCC slag) as aggregates in the geopolymer matrix was introduced to reduce production cost as well as to enhance compressive strength. As-received IGCC slag (0, 10, 20, 30, 40 wt%) was added in the geopolymer mixing process and the mixtures were compared. The compressive strength of geopolymers with an addition of 10 wt% as-received IGCC slag increased by 19.84% compared to that with no additional as-received IGCC slag and reached up to 41.20 MPa. The enhancement of compressive strength is caused by as-received IGCC slag acting as aggregates in the geopolymer matrix like aggregates in concrete. The density of geopolymers slightly increased to $2.1-2.2g/cm^3$ with increasing slag addition. Therefore, it is concluded that a small addition of as-received IGCC slag into the geopolymer can increase compressive strength and decrease the total cost of the product. Moreover, the direct use of as-received IGCC slag may contribute to environment protection by reducing process time and $CO_2$ emission.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2011.11a
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• pp.554-557
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• 2011

One of the issues that occurs in development of a combustor using Metal Powder as a fuel is an alumina slag processing. A water film formed inside the combustor is expected to be able to solve this issue. The experiments about the formation of a water film were carried out as a preliminary study. As the tangential velocity of water jet is increasing, the angle derivation from horizontal is decreasing for the test model. Results of the experiments showed that the thin water film on the inner surface appeared at the velocity of 10~15 m/s.