• Journal of the Korean institute of surface engineering
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• v.19 no.1
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• pp.13-19
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• 1986

Manganese in the Anode slime and the paste-positive material of waste-dry cell was recovered by leaching with the hydrochloric acid solution. The impurities (Zn, Fe, Pb), co-leached with manganese were removed from the leached solution prior to electrolysis by hydrometallurgical techniques such as the neutralization with ammonium hydroxide and cementation on manganese powder. The electrodeposition of manganese from the purified chloride solution with sodium selenate was performed. Cathode current efficiency was found to be affected significantly by the concentration of sodium selenate and ammonium chloride salt, bath temperate, current density and PH. The current efficiency of about 88.7% was obtained by electrolysis manganese chloride solution with sodium selenate (0.1/g) at 10$^{\circ}C$.

• Journal of Veterinary Clinics
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• v.19 no.3
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• pp.371-374
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• 2002

A female 8-year-old Pug weighing 7.3 kg and a female 10-year-old Maltese dog weighing 3.5 kg showing anorexia and vomiting for a few weeks were referred to Veterinary Medical leaching Hospital, Seoul National University. Radiographic findings were an enlarged right kidney in a pug dog and a radiopaque material on the right ureteral region lateral to the third lumbar vertebrae with indefinite right kidney contour in a Maltese dog, repectively. Excretory urography performed in a Pug dog revealed a poor opacified enlarged right kidney with absent of pelvic recesses and pelvic dilation with proximal ureteral dilation on contralateral kidney. Ultrasonographic findings were enlarged kidney with dilated pelvis and echogenic sediment within the medulla in both dogs and especially an engorged proximal ureter and a thin rim of functional renal tissue remains in a Maltese dog. Those diagnostic findings indicated high possibility of pyelonephritis and these were confirmed by pathologic examination. Radiography and ultrasonography, although not giving final diagnosis for pyelonephritis, are useful for assessment and diagnosis of pyelonephritis.

• Resources Recycling
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• v.26 no.4
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• pp.3-8
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• 2017

Oxidation-reduction reaction is one of the most important reactions occurring in the aqueous phase. Analysis of the equilibria related to these oxidation-reduction reactions is of great value in designing many unit operations in hydrometallurgy, such as leaching, separation and electrochemical reactions. The construction of Frost diagram was discussed in this work. The conditions at which disproportionation and proportionation reactions can occur were explained by analyzing Frost diagram together with Latimer table. The information which can be obtained from Frost diagram was discussed.

• Journal of Korean Society of Water and Wastewater
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• v.32 no.5
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• pp.399-409
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• 2018

Prussian blue is known as a superior material for selective adsorption of radioactive cesium ions; however, the separation of Prussian blue from aqueous suspension, due to particle size of around several tens of nanometers, is a hurdle that must be overcome. Therefore, this study aims to develop granule type adsorbent material containing Prussian blue in order to selectively adsorb and remove radioactive cesium in water. The surface of granular activated carbon was grafted using a covalent organic polymer (COP-19) in order to enhance Prussian blue immobilization. To maximize the degree of immobilization and minimize subsequent detachment of Prussian blue, several immobilization pathways were evaluated. As a result, the highest cesium adsorption performance was achieved when Prussian blue was synthesized in-situ without solid-liquid separation step during synthesis. The sample obtained under optimal conditions was further analyzed by scanning electron microscope-energy dispersive spectrometry, and it was confirmed that Prussian blue, which is about 9.7% of the total weight, was fixed on the surface of the activated carbon; this level of fixing represented a two-fold improvement compared to before COP-19 modification. In addition, an elution test was carried out to evaluate the stability of Prussian blue. Leaching of Prussian blue and cesium decreased by 1/2 and 1/3, respectively, compared to those levels before modification, showing increased stability due to COP-19 grafting. The Prussian blue based adsorbent material developed in this study is expected to be useful as a decontamination material to mitigate the release of radioactive materials.

• Journal of the Korean Wood Science and Technology
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• v.47 no.1
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• pp.21-32
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• 2019

In order to investigate the decay process of wood treated with preservative, waterproofing agent and their compound systems, a full-cell process was applied to impregnate the sapwood of poplar (Populus cathay) at paraffin wax emulsion concentrations of 0.5% and 2.0%, Copper Azole (CA) concentrations of 0.3% and 0.5%, and their four compound systems, respectively. Leaching tests and laboratory decay resistance against the white-rot fungus Corious versicolor (L.) Murrill for treated wood were carried out according to the America Standard E11-06 and China Standard GB/T 13942.1-2009. At certain time intervals during the decay test, samples were characterized by Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction technique (XRD) to investigate the time-dependent changes of chemical components and crystalline structure, thus clarifying the decay mechanisms. The results suggested that white-rot fungi degrade hemicellulose and lignin in the wood cell wall first, followed by a simultaneous degradation of polysaccharides and lignin. Besides, CA could not only slower the decomposition of both hemicellulose and lignin, but also reduce the degradation amount of hemicellulose. However, paraffin wax emulsion at high concentration had a negative effect on the impregnation of CA for the compound system treated wood.

• Resources Recycling
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• v.11 no.1
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• pp.3-8
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• 2002

In order to make the high purity Mn$_3$O$_4$powder for the raw material of soft ferrite, Mn is extracted from the dust and the extracted solution is refined. The dust is generated in producing a medium-low carbon ferromanganese and contains 90% Mn$_3$O$_4$. Mn$_3$O$_4$in the dust was reduced into MnO by roasting with charcoal. Injection of the 180g/L of the reduced dust into 4N HCI solution increased pH of the leaching solution higher than 5 and then a ferric hydroxide was precipitated. Because the ferric hydroxide co-precipitates with Si ion etc, Fe and Si ion was removed from the solution and the about 10% Mn solution was obtained. The solution was diluted with water to Mn-15000 ppm and $NH_4$F was injected into the diluted solution at $70^{\circ}C$ to the F-3000 ppm. As a result, Ca ion is precipitated as $CaF_2$and the residual concentration of Ca was 14 ppm. Injection of the equivalent (NH$1.5M_4$)$_2$$CO_3$solution as 2 L/min at $25^{\circ}C$ into the above solution precipitated a fine and high purity $MnCO_3$powder. The deposition was filtrated and roasted at $1000^{\circ}C$ for 2 hours. As a result, $MnCO_3$powder is converted into $Mn_3$$O_4$powder and it had $8.2\mu$m of median size. The final production is above 99% $Mn_3$$O_4$powder and it satisfied the requirement of high purity $Mn_3$$O_4$powder for a raw material of soft ferrite.

• Journal of the Korean GEO-environmental Society
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• v.10 no.6
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• pp.27-33
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• 2009

In this study, it was analysed physical characteristics, TS, moisture, C/N ratio, leaching test, and element analysis in landfill wastes of 10 years old without landfill pretreatment. The Organic material content was 7.2%~23.5% and soil was the main inorganic materials which it's rate was 54.1%~71.0%, in landfill wastes. The results of TS, VS, and moisture were represented 51.5%~68.1%, 23.6%~56.1%, 32.0%~48.4%, respectively. The analysis of hazardous materials did not indicate Hg, $Cr^{+6}$, CN, Organic Phosphorus, TCE and PCE, however the Pb of leaching materials showed 0.023~0.092 mg/L, which was the highest. As the result of the element analysis, C was 47.74%~56.72%, N was 4.09%~9.92%, the C/N ratio was 5.76~12.57 and the result of soils around landfill was the highest heavy material, Pb, 2.465 mg/kg~10.251 mg/kg. The objectives of this paper are to investigate states, stabilization of these closed landfills and to gain suitable data for post-closure care using some parameters through analysis of landfill environment.

• Journal of the Korean Ceramic Society
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• v.39 no.7
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• pp.680-686
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• 2002

The solidification/stabilization mechanism of each cementious material was investigated. It was found that when $C_3$S was hydrated , the Pb element could be transferred to the insoluble Ca[Pb(OH)$_3$.$H_2O$]$_2$and the Cr element to the CaCr $O_4$$H_2O$. The addition of heavy metal tends to delay the hydration until initial 7 days. The Pb element as also delayed the hydration and the Cr element was substituted for the ettringite. On the occasion of the hydration of $C_4$ $A_3$ $S^{S}$, the Pb and Cr ions were solidified/stabilized by the substitution into the ettringite and/or monosulfate. Leaching of the Pb, Cr and Zn elements in the solidified material was extremely little, indicating that heavy metals were effectively solidified/stabilized in the hydrated cementious materials. Solidification/stabilization of heavy metal ions in the industrial wastes such as the STS, BF and COREX sludge was investigated. In case of the mixing ratio of cement and slag was 3 : 7, leaching of hazardous heavy metal ions was very little, indications that the solidification and stabilization was very successful.l.

• Resources Recycling
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• v.29 no.3
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• pp.61-74
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• 2020

This study was conducted to improve the recycling process of waste fluorescent lamp, and investigate the possibility of using the waste fluorescent lamp glass as a raw material for glass beads, the leaching method of rare earth from the waste phosphor powder, and the possibility of solvent extraction of rare earth from the rare earth leaching solution. The waste phosphor contained 28.9% yttrium oxide, 3.46% cerium oxide, 1.95% europium oxide, 1.76% terbium oxide, and 1.43% lanthanum oxide. As a result of the trial production of glass beads using waste fluorescent lamp glass, it was judged that the production yield and quality were excellent, so that waste fluorescent lamp glass could be used as a raw material for glass beads. The soda roasted waste phosphor was leached in water and thereby the aqueous solution was blown with CO₂ to drop the pH to about 7, Then, Al, Si and residual N₂CO₃ were dissolved, and NaAlCO₃(OH)₂ and SiO₂ were precipitated in the aqueous solution. In the solvent extraction of cyanex272-hydrochloric acid, cyanex272-sulfuric acid, D2EHPA-hydrochloric acid, D2EHPA-sulfuric acid, Ionquest290-hydrochloric acid, Ionquest290-sulfuric acid, p507-hydrochloric acid using xylene as a diluent, the extraction yield of Y, Eu, Ce, La, and Tb are close to 100%. However, in this conditions, the difference in extraction yield for each element, that is, selectivity is 16% or less.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.29 no.5
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• pp.192-202
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• 2019

Physicochemical properties and sintering characteristics of pottery stone (Taebaek, Haenam, Aphae, Haengnam) were evaluated as a raw material for porcelain products. Due to acid leaching procedure, the concentration of iron oxide ($Fe_2O_3$) was decreased to < 1.0 wt%, which affects the whiteness of sintered samples. Mean particle size of acid leached samples is $5.7{\sim}10{\mu}m$ with narrow particle size distribution (PSD), which is lower than that of the pristine ($8{\sim}18{\mu}m$) with broad PSD. According to phase analysis by X-ray diffraction, most of pottery stones (PS) have Quartz phase as a main phase with Pyrophyllite as a second phase, however, Haenam PS shows halloysite phase. The absorption rate was in order of Taebaek (A, B, C)~Aphae (A, B) < Taebaek (Special A) < Haengnam < Haenam, and the samples sintered in reductive atmosphere showed lower absorption rate. This result might be due to the concentration of feldspar contained in PS, working as a flux in sintering process. Comparing the color of the sintered samples, the whiteness of refined PS (Taebaek special A, Haenam, Hangnam) is higher than acid leached PS (Taebaek A/B/C, Aphae A/B). The whiteness (L*) for refined PS is 95~97 %, which is higher than acid leached (82~96 %). This might be due to lower iron oxide concentration of the refined PS (0.11~0.58 %) than those of the acid leached PS (0.41~1.91 %) even though most of iron oxide was removed by acid leaching.