• Journal of the Korean Ceramic Society
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• v.32 no.1
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• pp.71-82
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• 1995

The weathered two-mica granite is widely distributed in Korea and called a kind of ground rock for kaolin. The major minerla compositions are consist of this quartz, feldspar, mica and clay mineral. At present, only a small portion of this granite is used as the material for the low-grade tile industry due to the low S.K. value and the high contents of impurities such as Fe2O3 and FeO. The low S.K. value is caused by feldspars not weathered to clay minerals. The refinement of this thus has been required for the recent shortage of the resources of high-grade one. This paper concerns an optimum hydrothermal treatment condition to refine the low-grade weathered two-mica granite of which impurities are feldspar mineral and Fe2O3. FeO components in using for the main material of ceramic industry. And then, from this result, we tried to fine out the basic formation mechanism of clay mineral from feldspar etc and develope the effectual utilization method of this.

• Economic and Environmental Geology
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• v.22 no.4
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• pp.315-326
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• 1989

The pottery stone diposits of the Cheongsong area consist of abundant quartz with clay minerals such as mica/smectite interstratified mineral, tosudite, kaolinite and sericite. The occurrence and mineralogical properties of the clay minerals were investigated by X-ray diffraction method, chemical analysis, DTA and IR. The mineral transformation by hydrothermal alteration was also discussed. Tosudite occurs in the Beopsoo pottery stone deposit, it seem to be Li-beraing tosudite. Mica/smectite interstratified minerals with less than about 20% expandable layers are commonly observed in the pottery stone deposits of the area. The mica/smectite interstratified minerals tend to increase the expandable layers as the progress of alteration. The pottery stones from this area seem to be altered from rhyolite or welded tuff by hydrothermal solution.

• Journal of the Mineralogical Society of Korea
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• v.18 no.3 s.45
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• pp.215-225
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• 2005

Numerous clay veins along fractures such as fault, joints, cracks and small fissures are found in granitic rocks in the Korean Peninsula. Granitic rocks of three geological stages (Jurassic, Cretaceous and Paleogene) occur in the Korean Peninsula, and are known as the Daebo, Bulguksa and Hoam granites, respectively. Specimens from clay veins composed or mainly mica clay mineral (illite) were dated using the K-Ar method with the hosted granitoids. The respective ages were as follows. Jurassic: granites 143.7 Ma and 160 Ma, clay mineral veins 104 Ma and 107 Ma: Cretaceous: granite 133.2 Ma, clay mineral veins 93.6 Ma, 84.2 Ma and 84.3 Ma: Paleogene: granite 39.7 Ma and 35.4Ma, clay mineral veins 27.1 Ma and 23.9 Ma. The ages of the clay veins in the Korean Peninsula are clearly much younger than those of their hosted granitoids. This contrasts with data for similar clay veins in Cretaceous and Paleogene granitoids in southwest Japan, where the K-Ar ages of mica clay minerals are slightly younger than their host rocks, or are almost the same.

• Journal of the Korean Geotechnical Society
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• v.15 no.1
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• pp.113-125
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• 1999

In this study the occurrence and mineralogical characteristics of clay minerals from the Munhyun-dong landslide area in Pusan city were examined by XRD, SEM, and chemical analyses. Several types of clay minerals such as halloysite, vermiculite, mica/vermiculite interstratified mineral, vermiculite/smectite interstratified mineral, kaolinite and illite are found abundantly in the area. The occurrence of clay minerals suggest that they have been formed by weathering of andesite which is the bedrock of the area. It is believed that halloysite was formed in the early stage of weathering, and vermiculite, mica/vermiculite interstratified mineral and mica/vermiculite interstratified mineral were formed in the middle stage, and finally, kaolinite was formed. The clay minerals occurring in the central part of the landsliding area and within the slip surface are dominated by expandable minerals such as halloysite, vermiculite and vermiculite/smectite interstratified mineral. These clay minerals expand by absorbing water and effectively decrease the shear resistance of the rock mass, and therefore, they could be an important factor for the landslide. The analyses of geology and mineralogical characteristics of the area suggest that the landslide was caused by combination of various factors including steep slope, heavy rainfall, abundant joints, alteration of the rocks, and occurrence of expandable clay minerals. The result of this study suggests that the investigation for the prevention of possible landslide must include the examination of clay mineralogy as well as the site geology.

• The Journal of Engineering Geology
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• v.19 no.3
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• pp.287-294
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• 2009

To be design the slope, the area distributed the mica schist which was metamorphosed by shale or mudstone must carefully consider the stability. Mica schist is another unstable rock for slope by schistosity, cleavage, axial plane of a fold etc. In general mica schist contains the swelling clay minerals such as smectite, vermiculite and montmorillonite. These minerals make the slope unstable. At OO tunnel construction area for the rail way of the Kyungbu high speed train, the slope of mica schist is very unstable by the distribution phenomena of the discontinuous plane such as joints which are 1-5 cm spacing and thrust and strike-slip fault. By the drilling core of this area, most RQD have 0-20%.

• Korean Journal of Soil Science and Fertilizer
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• v.49 no.1
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• pp.53-59
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• 2016

This study deals with the distribution of the clay minerals separated from clay fractions of ranch pastures in Korea and their chemical and mineralogical properties. Crystalline phases of the clay minerals were identified by powder X-ray diffraction (XRD) pattern and FT-IR spectra, and their relative chemical compositions were also analyzed by X-ray flourescence spectrometry (XRF). Primary minerals consisted mainly of quartz and mica and chlorite and kaolinite along with a trace of swelling micas were identified as secondary clay minerals. However, the relative content of these clay minerals was different with the locations, which led to significant effects on physical and chemical properties of soils like inorganic elemental composition. In particular, $SiO_2$ content was higher in Gochang ranch pasture than in other ranch pasture. Infrared (IR) spectra did not indicate any significant differences in organic functional groups among the locations. This study clearly showed that ranch pastures had different relative content of clay minerals and chemical properties depending on the location and consequently that those properties are worthy to be taken into account for soil amendment.

• Korean Journal of Soil Science and Fertilizer
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• v.49 no.6
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• pp.813-818
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• 2016

Distribution of clay minerals separated from clay fraction of corn fields in Korea has been investigated along with their characterization. Crystalline phases of the clay minerals were identified by powder X-ray diffraction (XRD) pattern, and their relative chemical compositions were analyzed by X-ray fluorescence spectrometry (XRF). The soils were found to have pH 6.4, organic matter $37.2g\;kg^{-1}$, available $P_2O_5$ $599mg\;kg^{-1}$, respectively, and exchangeable K, Ca and Mg were 1.2, 7.3 and $1.8cmol_c\;kg^{-1}$, respectively. Major primary minerals consisted mainly of quartz and mica, and kaolinite and chlorite were identified as major secondary clay minerals. For most of soils, mica phase was identified to be muscovite rather than biotite. The average contents of $SiO_2$, $Al_2O_3$ and $Fe_2O_3$ were 43.7, 23.6 and 8.8%, respectively, although they were different with the locations.

• Korean Journal of Soil Science and Fertilizer
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• v.10 no.3
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• pp.135-151
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• 1977

The present paper summerizes the studies on clay mineralogical characteristics of Korean soil, relationship between potassium and clay minerals, potassium release pattern of clay minerals and utilization of clay minerals for soil conditioner and fertilizers, which have been carried out in this laboratory. 1. The red yellow podzolic soil is mostly abundant in the upland of Korea and mainly consists of halloysite and weathered intermediates of mica such as illite and vermiculite. 2. With regard to soil parent material, kaolin mineral occurs abundant in soils derived from granite and granite gneiss. Mica is dominant in basaltic soil. The main clay mineral of the soil, originated from the Tertiary, is found montmorillonite and the volcanic soil of Jeju Island has plenty of allophane as its main clay mineral. 3. It is confirmed that the soil fertility depends on the composition of clay minerals. The red yellow podzolic soil, containing lot of kaolin, shows low productivity while the montmorillonite soil has higher productivity. 4. The release rate of solid phase potassium (micas and fixed potassium) follows the 1st order reaction equation in the equilibrium solution of $IN-NH_4OAc$. The potassium release constant is positively correlated with the mica content of the clay but negatively correlated with the content of $14.5{\AA}$ minerals. On the other hand, the potassium release constant has very high correlation with the ratio(Kex/Kt) of exchangeable potassium(Kex) to total potassium(Kt). 5. It is also found that Kex/Kt has rather high correlation with the content of mica and $14.5{\AA}$ minerals existed in the clay as well as the mica content of the soil.

• Polymer(Korea)
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• v.37 no.2
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• pp.225-231
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• 2013

Poly(vinyl alcohol) (PVA) hybrid films containing 5 wt% pristine clay mineral were synthesized in the water solution. The various PVA hybrid films were synthesized from structurally different pristine clays: saponite (SPT), montmorillonite (MMT), hectorite (SWN), hydrophilic bentonite (PGV), and mica (Mica). The thermo-optical properties and morphologies of the PVA hybrid films were evaluated with various pristine clays. The nanostructure of the hybrid films was observed using transmission electron microscopy, which showed that the clay layers were well dispersed into the matrix polymer, although some clusters or agglomerated particles were also detected. The addition of pristine clay was more effective with regard to improving the thermal properties and gas barrier characteristics, whereas the optical transparency of the PVA hybrid films deteriorated with pristine clay.

• Journal of the Mineralogical Society of Korea
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• v.1 no.1
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• pp.40-47
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• 1988

Mineralogy of sand, silt and clay fractions from the five chronosequence soils of Jeju Island is studied with the X-ray, TEM and SEM techniques. Soils of Songag and Donghong situated at lower elevations are generally developed on relatively of ash or alluvial deposits and contain mainly ferromagnesian minerals and feldspars, with some quartz, mica and volcanic glass. Crystalline minerals are dominant in the clay fraction; halloysite and vermiculite are abundant but small amounts of allophane are present. Clay migration results in well developed ferrigargillan, Soils of Pyeongdae and Heugag located at higher elevations are developed on relatively young volcanic ash with some contamination of continental aeolian dust probably containing quartz which may be come from acid ash shower. The absence of clay illuivation is due to the dominance of allophane. This clay mineral is associated with some gibbsite, imogolite and halloysite.