• Proceedings of the Korean Geotechical Society Conference
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• 2008.03a
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• pp.920-925
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• 2008

In this presentation, a leaching experiment which is followed the pH changes(pH=4, pH=7) and the mixing rates(1%, 3%, 5%, 7%) was carried out to examine the arsenic reduction effects and the leaching characteristics on arsenic contaminated soil after stabilization treatment in which 5 materials were used as stabilization agencies, i.e. ZVI(zero valent iron), blast furnace slag, steel refining slag, quick lime, and oyster shell meal. Except for blast furnace slag, the arsenic removal rate increased as the mixing rate increases of stabilization agencies. Arsenic leaching concentration was indicated that pH=7 condition is higher than pH=4 condition. This result shows because arsenic immobilization reaction increases as pH decreases, and arsenic adsorption takes place as pH decreases.

• Journal of the Korean Wood Science and Technology
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• v.23 no.3
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• pp.66-72
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• 1995

The rate of fixation of the components were evaluated in CCA-Type B and CCFZ-treated radiata pine sapwood by quantitative analysis of solution expressed from the treated wood. The leaching characteristics of radiata pine blocks treated with CCA-Type B and CCFZ were also evaluated by the AWPA standard leaching test. Both fixation and leaching charactersistics of CCA-Type B were compared with CCA-Type C treated wood samples. The rate of CCA-Type B fixation was a little faster than that of CCFZ. However, significant amounts of arsenic was unfixed in the CCA-Type B treated samples and consequently leached. These significant quantities of arsenic liberated from the CCA-Type B treated wood during service may pose some environmental concerns. Arsenic was no longer detectable from CCA-Type C treated samples when fixation was complete, even though the fixation of CCA-Type C was slower in some degree than CCA-Type B. In summary, it could be said that CCFZ was much safer preservative than CCA-Type B by the criterion based on the relative hazard assessed by absolute amount of unfixed element present in the treated wood. Also the decision that CCA preservative has to move from Type B to Type C should be made sooner or later for continuous use of CCA preservative in the future.

• Journal of the Korean Wood Science and Technology
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• v.31 no.6
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• pp.55-59
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• 2003

The fixation and leaching characteristics of chromated copper arsenate (CCA Type C) and chromium- copper-fluoride-zinc (CCFZ) in domestic softwood (Japanese red pine, Korean pine, and Japanese larch) sapwood were investigated using the expressate method to follow chromium fixation and the American Wood-Preservers' Association (AWPA) leaching procedure to determine leaching properties after fixation. The rates of fixation were affected by preservative types; CCA was fixed much faster than CCFZ for all species evaluated. There were definite differences in the fixation rates of different species, with Korean pine requiring shorter to fix than the other species evaluated. Chromium fixation was greatly enhanced by elevated temperatures, and fixation time can be estimated according to fixation temperatures applied. The percentage of arsenic and zinc leached from domestic softwoods was relatively high compared to chromium and copper, indicating that there is still a relatively high unfixed arsenic and zinc components after complete chromium fixation in CCA-and CCFZ-treated samples, respectively.

• Analytical Science and Technology
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• v.19 no.1
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• pp.86-95
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• 2006

This study was carried out to estimate leaching characteristics of incineration residues from municipal solid waste incinerators, and determine organic compounds in raw ash, leaching water and leaching residue. A total of 44 organic compounds, which were analyzed by GC/MSD and identified by wiley library search, were contained in bottom ashes. A total of 17 organic compounds were contained in fly ashes. Bottom ash and fly ash were found to contain a wide range of organic compounds such as aliphatic compounds and aromatic compounds. Organic compounds such as Ethenylbenzene, Benzaldehyde, 1-Phenyl-Ethanone and 1,4-Benzenedicarboxylic acid dimethyl ester were detected in raw ash, leaching water and residues (from bottom ash). Organic compounds such as Naphthalene, Dodecane, 1,2,3,5-Tetrachlorobenzene, Tetradecane, Hexadecane and Pentachlorobenzene were detected in raw ash, leaching water and residues (from fly ash). Through the leaching characteristics of incineration residue, it was represented that the open dumping of incineration residue can contaminate the soil and undergroundwater. In order to prevent environmental contamination that derived from extremely toxic substances in the incineration residues, it is particularly important that the incineration residues should be treated before disposal the incineration residues. Further study and proper management about leaching characteristics of organic compounds might be required.

• Journal of the Korea institute for structural maintenance and inspection
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• v.22 no.2
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• pp.16-25
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• 2018

Concrete is a suitable construction material for long-term structure, however, it is needed to understand the calcium leaching damage caused by exposure to underground pure water for a long time. In this paper, it is experimentally investigated that the characteristics of flexural behavior in RC member damaged by calcium leaching degradation. From the test results, when calcium leaching is happened, yielding load and flexural rigidity is reduced, neutral axis depth and displacement is increased. That is, calcium leaching degradation adversely affects RC member performance. And, when the mineral admixture is used in the calcium leaching environment, it is considered that the optimal replacement ratio should be prepared according to the type of mineral admixture.

• Nuclear Engineering and Technology
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• v.55 no.10
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• pp.3617-3627
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• 2023

This study presents a method to solidify spent ion-exchange resin (IER) in a metakaolin-based geopolymer and shows results of mechanical strength, immersion, leaching, irradiation, and thermal cycling tests for waste acceptance criteria (WAC) to repository. The geopolymer waste form with 20 wt% of simulated spent IER met the WAC in South Korea (ROK), and the leaching tests of various sized-waste forms up to 15.0 × 30.0 cm and waste loadings up to 20 wt% for 1-5 d and 1-90 d achieved a leachability index, L_i > 6. In a leaching test for 5 d, the cumulative fraction leached (CFL) for Cs, which leached the most, was linearly correlated with the square root of leaching time for all waste forms, and L_i increased as the size of the waste form increased. The CFL was also correlated with elapsed time in the 90 d leaching test. The correlations among CFL, time, and volume-to-surface area ratio of waste forms used to estimate the L_i of Cs of a 200-L sized geopolymer with 15 wt% IER showed the L_i values as 14.73 (5 d) and 17.71 (90 d), respectively, indicating that the large-sized geopolymer waste form met the WAC.

• Proceedings of the International Microelectronics And Packaging Society Conference
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• 2002.05a
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• pp.130-133
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• 2002

Solder leaching resistance of the metal electrode is an important factor with regard to adhesion properties of ceramic substrate. In the Low Temperature Co-fired Ceramics (LTCC), Ag-Pd or Ag-Pt pastes are used instead of pure Ag paste to prevent leaching. Solder leaching behavior of the Ag-Pd paste in relation to LTCC raw material powder size was investigated. First fabrication of LTCC green tape with different particle size was done. LTCC substrates with Ag-Pd electrode were prepared using conventional multilayer ceramic process. Dipping test was performed to test solder leaching behavior of the electrode. Ag-Pd electrode on LTCC substrate with smaller particle size achieved higher solder leaching resistance.

• Journal of Environmental Science International
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• v.28 no.8
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• pp.689-700
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• 2019

The adsorption and leaching characteristics of five ionic pesticides including four acidic pesticides (2,4-D, dicamba, MCPA, and MCPP) and one amphoteric pesticide (imazaquin) in agricultural soils were investigated. Soils around spring waters that were heavily affected by pesticide run-off and soils around wells considering the regional characteristics in Jeju Island were collected at 24 stations. The Freundlich constant, $K_F$ value, which is a measure of the adsorption capacity, decreased in the order of 2,4-D > MCPA > MCPP > dicamba > imazaquin. The adsorption capacity of these ionic pesticides decreased with increasing pH owing to the effects of ionization of pesticides and different ionizable functional groups of soils. The leaching of ionic pesticides in the soil column showed a reverse relationship with their adsorption in soils, namely, the ionic pesticides were leached more quickly for the pesticides with lower adsorption capacity. The groundwater contamination potential of the ionic pesticides was evaluated in the order of imazaquin > MCPA > MCPP > dicamba > 2.4-D according to the groundwater ubiquity score based on soil Koc and the half-life of the pesticide.

• Journal of the Korean Wood Science and Technology
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• v.33 no.6 s.134
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• pp.87-94
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• 2005

This study was carried out to investigate the effect of soil types and soil properties on wood preservative leaching. Radiata pine (Pinus radiata Don.) sapwood stakes, which had been treated with 2.0%(w/v) CCA, were leached for 12 weeks by a common laboratory method in four different soils and for 14 days by the AWPA standard leaching method in water. The physical and chemical properties of the four soils were determined, and the percent leaching of the individual component of CCA was correlated with the various soil properties. The data show that leaching of preservative chemicals from treated wood exposed to soil is influenced by the type of soil. The preservative leaching was greater when wood was exposed to water than when the wood was in contact with water-saturated soil. The greatest chromium, copper and arsenic leaching from CCA-treated stakes were observed in the sandy loam, loam, and sand, respectively, and the least amount of leaching of CCA components occurred in the silty loam. The leaching of preservative components from treated wood is extremely complex and appears to be influenced differently by the soil properties. The extent of copper leaching from CCA treated wood appears to be related to exchangeable Mg and sum of bases. There is a reasonably good relationship between chromium leaching and exchangeable Mg, and between arsenic leaching and exchangeable K, soil Ni, Mn, Fe, Cr, or Cu content. Since this study was conducted based on laboratory leaching method using small cross-sectional dimensions; thus, data obtained from this experiment should not be used to predict leaching characteristics from commercial-size wood used in real situation. Accordingly, further studies are necessary using outdoor ground-contact leaching.

• Environmental Engineering Research
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• v.25 no.3
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• pp.335-344
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• 2020

This work describes highly efficient recovery and selective leaching of Zn from electric arc furnace dust (EAFD) with different physicochemical properties, induced by acid leaching at ambient conditions. The chemical compositions, mineralogical phases, and particle sizes of the EAFDs were analyzed and compared. The effects of leaching time, liquid/solid ratio, acid type, and acid concentration on the selective leaching of Zn were also studied. The EAFD with high Fe/Zn ratio (> 1, EAFD₃) was richer in ZnFe₂O₄ and exhibited larger particle size than samples with low Fe/Zn ratio (< 1, EAFD_1,2). ANOVA analysis revealed that the Fe/Zn ratios of the EAFDs also have a significant effect on Zn extraction (p < 0.005). Selective leaching of Zn with minimum Fe dissolution was obtained at pH > 4.5, regardless of other parameters or sample properties. The maximum Zn extraction rate obtained by the pH control was over 97% for EAFD₁ and EAFD₂, 76% for EAFD₃, and 80% for EAFD₄. The present results confirm that the Fe/Zn ratio can be used to identify EAFDs that permits facile and high-yield Zn recovery, and pH can be used as a process control factor for selective leaching of Zn regardless of any differences in the properties of the EAFD sample.