• Journal of Korea Foundry Society
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• v.30 no.6
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• pp.231-234
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• 2010

The effect of $C_2Cl_6$ for preventing to the surface oxidation and ignition of molten Mg alloy was studied with metallographic analysis, X-ray diffraction, scanning electron microscopy and energy dispersive spectroscopy. The alloy used for this study was AM100A Mg casting alloy with high strength. In order to investigate the surface protective characteristic of this molten alloy by $C_2Cl_6$ addition, we added them into molten AM100A alloy at $700^{\circ}C$ and then the melts were slowly cooled under a protective atmosphere of air containing Ar gas and $C_2Cl_6$ flux addition. The result found that the surface oxidation and ignition reaction of molten AM100A Mg alloy by adding $C_2Cl_6$ flux was more slowly occurred than that of the only a protective atmosphere of containing Ar gas with increasing time. This result was due to a dense protective film formed containing $MgCl_2$ on surface of molten Mg alloy during casting and solidification. The $MgCl_2$ was formed by a reaction of $C_2Cl_6$ with molten Mg.

• Journal of Korea Foundry Society
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• v.20 no.1
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• pp.38-45
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• 2000

The remelting for recycling or thin aluminum scrap, such as aluminum chip generally involves melting of these pieces submerged in molten salt flux. In this study, the effects of salt flux compositions and alloying elements on the aluminum dropletscoalescence and oxide film removal were studied in 99.8%Al, Al-1.01%Cu, Al-1.03%Si, and Al-1.38%Mg alloys as a function of holding time at $740^{\circ}C$ Salt fluxes based on NaCl-KCl(1:1) with addition of 5wt.% fluorides(NaF, $Na_3AlF_6$, $CaF_2$) or 5 wt.% chloride($MgCl_2$, $AlCl_3$) were used. The experimental results show that NaCl-KCl(1:1) with addition of 5 wt.% fluorides exhibits better coalescence ability than that with chlorides. The oxide film is not removed by NaCl-KCl(1:1) with addition of 5 wt.%chlorides, while it is removed by NaCl-KCl(1:1) with addition of 5 wt.% fluorides. The aluminum droplets coalescence and oxide film removal by salt fluxes are related to interfacial tension tension between metal and salt flux.

• Electrical & Electronic Materials
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• v.6 no.6
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• pp.537-544
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• 1993

기본조성이 0.5[Pb(Ni$_{1}$3/Nb$_{2}$3/)O$_{3}$]-0.5[0.65PbTiO$_{3}$ -0.35PbZrO$_{3}$] (PNN-PT-PZ)인 압전세라믹스를 NaCl-KCI를 사용한 flux의 양 및 소결온도에 따른 생성반응과 소결특성, 유전 및 압전특성을 조사하였다. 이때 1몰의 산화물에 대한 flux의 양은 0.1, 2 및 5mole로 하였으며 소결온도는 1000-1200.deg.C로 하였다. 본 연구의 flux법은 고상반응법에 비해 낮은 하소온도에서 pyrochlore상을 현저히 줄일수 있었으며 고상반응법보다 낮은 온도에서 치밀화가 이루어질뿐 아니라 유전 및 압전특성을 개선할 수 있었으며 소결온도도 낮출 수 있었다. Flux의 양이 증가할수록 결정의 입성장이 빨랐으며 유전 및 압전특성이 가장 좋은 flux의 첨가량의 조건은 1mole이었다.

• Resources Recycling
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• v.6 no.1
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• pp.5-10
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• 1997

The aluminum was recovered from the middle size (Q1.0-12.0 mm) aluminum drosses using NaCl and KC1 mixuture as a basic salt flux. The maximum aluminum recovery was about 76.9% when 40% basic salt flux was added to aluminum dross at 850$^{\circ}$C for two hours. Also, aluminum remvery increased with increasing fluoride (1%-5%) addition to basic salt flux. But, there was no considerable effect due ta the increasing of viscosity when the fluorides were added over 5%, respectively. E s p d y , the most aluminum recovery was about 83.5% when 5% cryolite was added to 40% basic salt flux.

• 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%.

• Membrane Journal
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• v.28 no.5
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• pp.368-377
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• 2018

The n-nitrilotris(methylene) phosphonic acid (NTPA) potassium salt was synthesized as a draw solute for forward osmosis. NTPA-4K, NTPA-5K and NTPA-6K were synthesized by varying the content of KOH added to NTPA and confirmed by $^1H$-NMR and $^{13}C$-NMR. The osmotic pressure, viscosity, water flux and reverse salt flux were measured to characterize the draw solute. In the forward osmosis process when distilled water was used as a feed solution and 0.5 M of NTPA-4K, NTPA-5K and NTPA-6K were used as a draw solution, the water flux was 35.8, 38.8 and 42.2 LMH, the reverse salt flux was 5.4, 6.9 and 7.4 gMH, respectively. It was confirmed that the water flux was lower than the conventional NaCl draw solution, but the reverse salt flux was much lower. In order to recover the diluted draw solution, nanofiltration was conducted. The results showed that the draw solute could be retained by above 90%.

• Clean Technology
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• v.6 no.1
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• pp.61-69
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• 2000

In this study, generation process and properties of inorganic industrial waste which can be used in cement industry were investigated. The scheme of recycling to use the selected waste as raw materials, mineralizer and flux, admixture and raw materials for special cement was decided and then various experiments were carried out. The experimental results were as follows ; In the use of industrial waste as raw materials, ferrous materials could be substituted by Cu-slag, Zn-slag, electric arc furnace or convertor furnace slag etc., and a siliceous material could be substituted by sand from cast-iron industry. By-products from sugar or fertilizer industry, which has $CaF_2$ as the main component, and jarosite from Zn refinery enabled clinker phases to be formed at lower temperature by $100{\sim}150^{\circ}C$. Adding Cu slag and STS sludge in proper proportion to cement improved properties of cement. Fly ash and limestone powder as admixture had the same effect on cement. As a raw material for special cement, aluminium waste sludge could be used in making ultra early strength cement, which had the compressive strength of $300kg/cm^2$ within 2hours. And two different ashes from municipal incinerator could be raw materials of the cement which was mainly composed of $C_3S$ and $C_{11}A_7{\cdot}CaCl_2$ as clinker phases.

• Membrane Journal
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• v.28 no.5
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• pp.361-367
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• 2018

In this study, the nanofiltration (NF) composite membranes for the low pressure use were prepared using polyvinylidene fluoride (PVDF) hollow fiber membrane as a supporter. Poly styrene sulfonic acid (PSSA) and polyethyleneimine (PEI) were coated onto the PVDF membrane by both layer-by-layer and salting-out methods. To characterize the prepared NF membranes in terms of the flux and salt rejection, 100 mg/L feed solutions of NaCl, $MgCl_2$, and $CaSO_4$ were used at the flow rate of 1 L/min and the operating pressure of 2 bar at room temperature. The NF membranes coated with 20,000 ppm PSSA (ionic strength 1.0) solution for 3 minutes and then 30,000 ppm (ionic strength 0.1) solution for 1 minute were observed the best performance. The permeability and salt rejection were 38.5 LMH, 57.1% for NaCl, 37.9 LMH and 90.2% for $MgCl_2$ and 32.4 LMH and 54.6% for $CaSO_4$, respectively.

• Membrane and Water Treatment
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• v.6 no.3
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• pp.173-187
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• 2015

The goal of present work is the preparation of a novel positively charged nanofiltration (NF) membrane and its development for the cation removal of aqueous solutions. This NF membrane was fabricated by the surface modification of polysulfone (PSf) ultrafiltration support. The active top-layer was formed by interfacial cross-linking polymerization of poly(ethyleneimine) (PEI) with p-xylylene dichloride (XDC) and then quaternized with methyl iodide to form a perpetually positively charged layer. In order to improve the efficiency of nanofiltration membrane, the concentration of PEI, XDC and methyl iodide solutions, PEI coating and cross-linking time have been optimized. As a result, a high water flux and high $CaCl_2$ rejection (1,000 ppm) was obtained for the composite membrane with values of $18.29L/m^2.h$ and 93.62% at 4 bar and $25^{\circ}C$, respectively. The rejections of NF membrane for different salt solutions followed the order of $Na_2SO_4$ < $MgSO_4$ < NaCl < $CaCl_2$. Molecular weight of cut off (MWCO) was calculated via retaining of PEG solutions with different molecular weights that finally, it revealed the Stokes and hydrodynamic radius of 1.457 and 2.507 nm on the membrane selective layer, respectively. The most efficient positively charged nanofiltration membrane exhibited a $Ni^{2+}$ rejection of 96.26% for industrial wastewater from Shamse Hadaf Co. (Kashan, Iran).

• Proceedings of the KIEE Conference
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• 2003.10a
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• pp.322-325
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• 2003

BST thin films were etched with inductively coupled plasmas. A chemically assisted physical etch of BST was experimentally confirmed by ICP under various gas mixtures. After a 20 % addition of $BCl_3$ to the $Cl_2/Ar$ mixture, resulting in an increased the chemical effect. As a increases of RF power, substrate power, and substrate temperature, and decrease of working pressure, the ion energy flux and chlorine atoms density increased. The maximum etch rate of the BST thin films was 90.1 nm/min at the RF power, substrate power, working pressure, and substrate temperature were 700 W, 300 W, 1.6 Pa, and 20 $^{\circ}C$, respectively. It was proposed that sputter etching is dominant etching mechanism while the contribution of chemical reaction is relatively low due to low volatility of etching product.