• Journal of the Korean Ceramic Society
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• v.41 no.1
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• pp.41-44
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• 2004

Hydrophilicity and hydrophobicity of pottery bodies can be controlled via chemical substitution of layered clay with hydrophilic and hydrophobic organics. In this study, organo-clay nanocomposites were prepared by ion-exchange of montmorillonite with dodecylamine and hexadecylamine, respectively. Substitution sites of organics and the interval changes of layered materials are characterized by FT-IR and WAXD and organics amounts loaded and water comtents contained by C/S analysis and TG-DSC. The organics were selectively intercalated so that increase layer interval from 12${\AA}\; to\;16{\AA}$. Organo-modified clay is changed to more hydrophobic comparing to clay itself.

• Proceedings of the KSEEG Conference
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• 2003.04a
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• pp.316-319
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• 2003

스멕타이트계 점토광물은 팽윤성, 양이온 교환, 층간삽입 (intercalation), 콜로이드 형성, 겔형성, 층간화합물 형성 등의 기능이 있으므로 옛날부터 다양한 산업분야에서 폭넓게 사용되었다. 대표적인 용도는 굴착용 니수, 주형점결제, 농약 증량제, 토목용, 유기 스멕타이트 등이 있다. 그러나, 천연에서 산출되는 스멕타이트는 산지별로 성능이나 특성이 다르고, 불순물 함유등에 의해 안정적인 품질을 얻을 수가 없어, 최종제품의 고품질화, 고기능화에서의 대응이 곤란한 경우가 많고, 또한 양질의 천연 스멕타이트의 매장양은 한정되어 있다. (중략)

• Korean Journal of Mineralogy and Petrology
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• v.35 no.1
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• pp.51-64
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• 2022

For effective preservation of the rocks, which bearing plant fossils at Gumkwangdong Formation, Pohang, the properties of rock and treatment of chemicals were examined in an artificial weathering test. The rocks are diatomaceous siliceous mudstone, which contain a small amount of smectite and has developed laminated layers. The rocks react with water, the d₀₀₁ spacing of smectite was increased. On the one hand, the physical properties of the rock samples, such as surface hardness, improved after the application of ethyl silicate-based stone strengthener. On the other hand, the spacing of interlayer of swelling clay minerals decreased and spacing of laminae layer increased. When the ethyl silicate-based stone strengthener was applied after pretreatment with a swelling inhibitor, interlayer and spacing of laminae changes were similar to those when only the stone strengthener was treated. The effect of the swelling inhibitor was almost negligible. When the rocks that have been conserved with chemicals react with water, spacing of laminae has widened much, whereas when the rocks was in contact with moisture only, there was little change. In addition, if it is placed in the outdoor after conservation treatment, although it occurs slightly slower than the untreated rock, the separation of the lamination layer and the pulverization of the rock occur within a very short time. Consolidation is required to improve the physical properties of fossil rock, but when exposed to rain and undergoing freeze-thaw process, the effect is lost very quickly. Therefore, regardless of the chemical treatment, it is a priority to prevent direct rainfall contact with the rock.

• Korean Journal of Environmental Agriculture
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• v.3 no.2
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• pp.50-54
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• 1984

For the development of slow releasing K-fertilizer, K-ion exchanged montmorillonite was evaluated and characterized by layer charge determination with n-alkylammonium method. By this method it was possible to discern inhomogenous charge distribution within the crystals and to estimate the upper and lower limit of the layer charge(layer charge limit for Young-il bentonite in Korea: ${\xi}=0.39-0.28$ $e/(SiAl)_4O_{10}$, ${\xi}=0.34$) and the mean value of interlayer cation exchange capacity of 0.915meq/100g.

• Journal of the Mineralogical Society of Korea
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• v.27 no.4
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• pp.293-299
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• 2014

The bentonite, a buffer material, is essential for the deep geological disposal of HLW (high-level radioactive waste), and it is important to know its characteristic long-term evolution in the underground environment. With an assumption that the concentration of aqueous copper ions will increase if copper-coated materials on a metal canister are corroded, we examined some characteristic ion-exchanges and cation release phenomena occurring in the bentonite clay (montmorillonite) interacted with aqueous Cu cations. During the interaction between dissolved copper and bentonite, Na rather than Ca cations in the expandable clay were preferentially replaced by Cu ions in the experiment. In addition, the Cu-exchanged montmorillonite was characterized by an asymmetric X-ray diffracted pattern with relatively collapsed interlayers compared to the raw sample. These results indicate that the gradual change of the original bentonite property may occur in a underground disposal condition. We are going to further study the characteristic chemical and mineralogical changes of the bentonite buffer to be used for the disposal site by conducting additional experiments.

• Journal of the Mineralogical Society of Korea
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• v.15 no.1
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• pp.1-10
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• 2002

The present study is focused on the granite weathering and soil formation, and the heavy metal contamination in soils in the Onsan industrial area. For profile study, soil sampling was conducted on each depth and experimental analyses have been conducted on those samples. X-ray diffraction analyses show that clay minerals consist mainly of kaolin minerals, vermiculite, and minor illite. Most of kaolin minerals in the lower kiwi of the profile consist of halloysite as confirmed by formamide intercalation, but the content of halloysite decreases gradually toward the surface since it has been transformed to kaolinite in the upper part of the profile. Thermal treatment by heating at $110^{\circ}C,\;300^{\circ}C,\;and\;550^{\circ}C$ shows a diffuse and broad peak the between 10 and $14\;{\AA}$ region in X-ray diffractograms. This suggests the possible existence of the hydroxy-Al interlayerecl vermiculite. Na-citrate extraction method reaconfirms this result showing transition of $14\;{\AA}$ peak to $10\;{\AA}$ In by removing the interlayer materials and restoring the vermiculite to its original state. The occurrence of hydroxy-Al interlayered vermiculite is also supported by soil pH distribution room 3.9 In the lower part to 3.6 in the upper part of the profile. Sequential extraction experiment was conducted to investigate the states of heavy metals in soils. The experiment shows that relatively high amounts of heavy metals are concentrated in the upper part of the profile and that most of them are bound to Fe/Mn oxides and organic matters while less concentration in clay minerals. The result indicates that most of heavy metal pollutants are concentrated in the surface soil and that the low concentrations of heavy metals in clays are mainly due to the low adsorption capacities of clay minerals such as kaolin minerals and hydroxy-Al interlayered vermiculite in acidified soil condition.

• Journal of the Mineralogical Society of Korea
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• v.23 no.4
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• pp.377-393
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• 2010

Pumiceous tuffs occurring in the Beomgockri Group are examined applied-mineralogical characteristics and their controling factors to evaluate their potentials as the adsorption-functional mineral resources. The pumiceous tuffs are diagenetically altered to low-grade zeolitcs and bentonites in the Janggi area. Compositional specialty due to the presence of pumice fragments induces the altered tuffs to exhibit the characteristic adsorption property combined with cation exchange capacity, specific surface area, and acidic pH. Unusual lower pH in the adsorption-functional mineral substances is turned out to be originated from the presence of H-smectite having $H^+$ in the interlayer site of the sheet structure. On account of disordered crystallinity resulting from the exchanged $H^+$ in the interlayer site, the smectite commonly forms crenulated edges in the planar crystal form and exhibits characteristic X-ray diffraction patterns showing comparatively lower intensities of basal spacings including (001) peak than conventional Ca-smectite. Based on the interpretation of paragenetic relations and precursor of the H-smectite, a genetic model of the peculiar clay mineral was proposed. The smectite formation may be facilitated resulting from the precipitation of opal-CT at decreasing pH condition caused by the release of H+ during diagenetic alteration of pumice fragments. Because of the acidic smectite, the low-grade mineral resources from the Beomgockri Group may be applicable to the adsorption industry as the raw materials of acid clays and bed-soil.

• Journal of the Mineralogical Society of Korea
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• v.19 no.4 s.50
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• pp.221-229
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• 2006

Mineralogical and chemical examinations were performed on interstratified illite-smectite (I-S) minerals that occur in the mudstones from a petroleum exploration well in the Tertiary marine basin, Japan. X-ray diffraction analysis shows that component layers of illite in the interstratified I-S increase with increasing burial depth while those of smectie decrease. In addition, the randomly (R=0) interstratified illite-smectite is changed into Rp1 ordered I-S at a depth of about 4,000 m, which corresponds to the result of organic analysis and indicates a burial temperature of about $100^{\circ}C$. However, the present geothermal gradient shows that the conversion of the random I-S to R=0 ordered I-S is likely to occur at 3,000 m. This discrepancy may be interpreted by the reverse fault at 2,500 m which resulted in a deeper burial of sediments up to 1,000 m. Chemical analysis also shows the compositional variation in I-S with increasing depth: a decrease in Si and an increases in Al and K, indicating that the substitution of Al for Si in tetrahedral sheets is compensated by the addition of K to interlayers. K may be derived from K-feldspar and micas, which is present in the mudstones.

• Economic and Environmental Geology
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• v.47 no.2
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• pp.87-96
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• 2014

The objectives of this study were to characterize the physicochemical properties and mineralogy of Hwangto (yellow residual soils) from the southwestern part of Korea and to understand the soil-forming processes of the residual soils from their parent rocks. Both the yellowish residual soils as well as the unweathered and weathered parent rocks were obtained from Jangdong-ri, Donggang-myun, Naju, Jeollanam-do, Korea. The soil samples were examined to analyze the said soil's physicochemical properties such as color, pH, and particle size distribution. A scanning electron microscopy (SEM) with energy dispersive X-ray (EDX) analysis, transmission electron microscopy (TEM) and X-ray diffraction (XRD) analysis were performed in order to understand the mineralogy, chemical composition, and morphology of the soils. Two thin sections of a parent rock were analyzed to study its mineral composition. A particle size analysis of the soils indicates that the residual soil consists of mainly silt and clay (approximately 95%) and that soil textures are silty clay or silt clay loam. The soil colors of the residual soil are dark brown (7.5YR 3/4) through yellowish red (5YR 4/6). The pH of the residual soil ranges from 4.3 to 5.1. The major minerals of the parent rocks were quartz, biotite, chlorite, and plagioclase. The mineralogy of the sand fraction of the residual soil was quartz, biotite, muscovite and sanidine. The mineralogy of the silt fraction of the residual soil was quartz, biotite, muscovite, Na-feldspar, K-feldspar, and sanidine. The clay mineralogy of the soil was goethite, kaolinite, ilite, hydroxy-interlayed vermiculite(HIV), vermiculite, mica, K-feldspar and quartz. The mineral composition of the residual soil and the parent rock indicates that feldspar and mica in the parent rock weathered into illite, vermiculite and hydroxy-interlayed vermiculite(HIV), and finally changed into kaolinite and halloysite in the yellowish residual soils.

• Korean Journal of Soil Science and Fertilizer
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• v.25 no.3
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• pp.202-212
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• 1992

This study reports on the genesis and mineralogical characteristics of the clay minerals in the soils derived from the five major parent rocks of granite, granite-gneiss, limestone, shale, and basalt in Korea. The investigation on the mineralogical aspects of primary and secondary minerals of the rocks and coarse fractions in the soils have been already reported. In this report, the identification of clay minerals in the soil clay fractions was done through the analyses of chemical, X-ray diffraction, and thermal methods. The studies showed clearly that much of the clay minerals was evolved by the weathering of primary minerals and some were further developed by the transformation of secondary minerals. Cation exchange capacity(CEC) of the clay fractions increased with higher amotunts of vermiculite, chlorite, and illite, however, decreased with higher hydroxy octahedral sheet within the interlayer spaces of vermiculite even if dominant clay with vermiculite. Feldspars in the granite and granite-gneiss might be completely transformed to kaolin mineral, Illite, chlolrite, and vermiculite formed by the alteration of micas, amphibole, augite, and primary chlorile seem to be subsequently transformed to the mixed layer minerals such as illite/vermiculite, illite/chlorite, and chlorite/vermiculite. These weathering products may be ultimately transformed into kaolin minerals. The smectite minerals in the clay fractions of the soils developed on the limestone are considerably present and they seem to be formed directly by the precipitation from high Mg solution and/or by the transformation of vermiculite from micas and chlorite in the parent materials. Abundant presence of illite in the soil clays developed on the shale is considered to have inherited from the fine particles and more resistant hydrous muscovite. The weathering sequences of the hydrous muscovite were as follows according to the degree of soil development ; hydrous muscovite ${\rightarrow}$ illite/vermiculite mixed layer(Inceptisols, Daegu series) and hydrous muscovite ${\rightarrow}$ illite/vermiculite mixed layer ${\rightarrow}$ vermiculite ${\rightarrow}$ kaolin mineral(Alfisols, Buyeo series). The plagioclase in the basalt might be mostly weathered to kaolin minerais. The augite in the basalt is likely to be transformed through progressive stage of weathering, augite ${\rightarrow}$ chlorite ${\rightarrow}$ chlorote/vermiculite mixed layer ${\rightarrow}$ vermiculite ${\rightarrow}$ kaolin. Another weathering sequence of augite could be expected, augite ${\rightarrow}$ chlorite ${\rightarrow}$ illite by the presence of illite and illite/vermiculite mixed layer in the clay fractions. Vermiculite and gibbsite were quantified from thermogravimetry(TG) and kaolin minerals, from both TG and differerential thermal analysis (DTA). Vermiculite in Jangseong series from the limestone was the dominant clay mineral of 21.7 percent and had a range in the order of 9.2 percent in Buyeo series to 5.4 percent in Daegu series from the shale. The rest soils ranged from 8.8 to 28.3 percent. Kaolin minerals were the dominant clay mineral of 32.7 percent in Asan series from the granite-gneiss and Gueom series of 32.0 percent from the basalt. The soils from the limestone ranged from 9.4 to 14.9 percent. The rest soils ranged from 8.9 to 28.6 percent. Gibbsite were 3.9 and 2.3 percent for Weoljeong and Chahang series from the granite, respectively. In Asan and Cheongsan series from the giranite-gneiss were 1.4 and 4.5 percent, respectively, and 3.6 percent in Jangpa series from the basalt.