• Journal of the Korean Ceramic Society
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• v.52 no.6
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• pp.467-472
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• 2015

The effect of $SrCO_3$ content on the microstructure, porosity, flexural strength, and pore size distribution of clay-based membrane supports was investigated. Green compacts prepared from low cost materials such as kaolin, bentonite, talc, sodium borate, and strontium carbonate were sintered at $1000^{\circ}C$ for 8 h in air. It was possible to control the porosity of the clay-based membrane supports within the range of 33% to 37% by adjusting the $SrCO_3$ content. The flexural strength of the clay-based membrane supports was found to strongly depend on their porosity. In turn, the porosity was affected by the $SrCO_3$ content. The average pore size and flexural strength of the clay-based membrane supports containing 4 wt% $SrCO_3$ were $0.62{\mu}m$ and 33 MPa at 34% porosity.

• Economic and Environmental Geology
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• v.25 no.4
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• pp.397-416
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• 1992

In the present study, three clay deposits, named the Seongsan, Ogmaesan and Haenam deposits, were investigated. The altered zones are recognized in the hydrothermally altered rocks of the clay deposits from the center of the alteration to the margin: Kaolin, Kaolin-Quartz, Quartz, Sericite and Chlorite zones in the Seongsan deposits; Quartz zone, Alunite zone, Kaolin zone, Sericite zone and Chlorite zone in the Ogmaesan deposits; Quartz zone, Pyrophyllite zone, Sericite zone and Chlorite zone in the Haenam deposits. These zones can be grouped into two types of alteration: Acidic alteration such as Pyrophyllite zone, Alunite zone, Quartz zone, Kaolin zone, Kaolin-Quartz zone and a part of Sericite zone; Propylitic alteration such as Chlorite zone and a part of Sericite zone. All clay deposits belong to high-sulfidation (acid-sulfate) system. The rocks of the acidic alterations are composed of pyrophyllite, alunite, kaolin minerals, sericite, quartz and pyrite. On the basis of bulk chemical compositions, it was found that some components such as $SiO_2$, $TiO_2$, $Fe_2O_3$, FeO, MgO, CaO, $K_2O$ and $Na_2O$ were mobilized considerably from the original rocks. The mobility of these major elements is related to, and controls, mineral assemblages in each altered zone. Polytypes of sericite are determined as $2M_1$ and 1M by X-ray diffraction method. The amount of $2M_1$ is nearly equal to that of 1M in the Seongsan deposits whereas $2M_1$ is less and higher than that of 1M in the Ogmaesan and the Haenam deposits. These facts indicate that formation temperature of sericite is relatively high in the Haenam deposits, moderate in the Seongsan deposits, and low in the Ogmaesan deposits. The ratios of Na/(K+Na) for alunite in the Ogmaesan deposits determined by electron microprobe analyzer (EPMA) are higher than those in the Seongsan deposits. Thus, the alunite of the Ogmaesan deposits must have been formed from the solutions with relatively high aqueous Na/(K+Na) ratios and low pH at a high temperature rather than that of the Seongsan deposits. From all data, it is clarified that alunite is hypogene in origin, and has been formed by oxidation of hydrogen sulfide in the steam-heated environment, and that alunite has been produced by the spectacular solfataric alteration observed at the surface of some present-day hydrothermal systems.

• Journal of the Mineralogical Society of Korea
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• v.5 no.1
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• pp.22-31
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• 1992

The Sancheong kaolin was fractionated into 9 size fractions by wet sieving, sedimentation, and centrifugation. The systematic X-ray diffraction combined with electron microscopy shows that the clay mineral composition of each size fraction is related to the original fabric of kaolin. Minerals such as halloysite (10${\AA}$), kaolinite, illite, and goethite which were formed by procipitation from solution are generally concentrated in the finer fractions, whereas verniculite which was formed by pseudomorphic transformation from other primary minerals are concentrated in the coarser factions. Kaolinits of various types which were formed by precipitation or transformation show a wide size range but they are generally concentrated in the coarser fractions. Halloysite or halloysite-kaolinite clusters in coarse fractions are the fragmentation products of the walls of original boxwork clusters in coarse fractions are the fragmentation products of the walls of original boxwork kaolin which escaped the complete dispersion even through the grinding, ultrasonic agitation, and chemical treatment. Separation of fully hydrated halloysite and kaolinite was possible by systematic wet size fractionation. The coarse-grained minerals such as vermiculite and kaolinite are usually removed during the preparation of clay fraction smaller than 2${\mu}m$, whereas the fine-grained minerals such as illite and goethite are overlooked in X-ray diffraction of the bulk samples because of their minor contents. The systematic wet size fractionation is needed for understanding of the exact mineralogy of kaolin of weathering origin.

• Economic and Environmental Geology
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• v.19 no.spc
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• pp.43-52
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• 1986

Kaolin-pyrophyllite are locally abundant in the three hydrothermal areas at Yangsan-Tongnae area, Hadong-Sancheong area and Haenam area, deposits are originally composed of acidic volcanic rocks and anorthositic rocks in Hadong-Sancheong area. The clay deposits are formed in the near shallow depths environment through acid hydrothermal alteration. Hadong-Sancheong halloysite deposits are formed by alteration of anorthosite. These differences are mainly on the various country rocks, geological structure and properties of hydrothermal solutions. Country rock is mostly underlain by rhyolitic tuffaceous and anorthositic rocks and a large number of clay deposits were formed during volcanic activity through upper Cretaceous-lower Tertiary. Intrusive rocks is broadly distributed in this area and clay deposits are variable in shapelayer and funnel typed. Zonal pattern of mineral assemblage is as follows, Yangsan-Tongnae deposits-kaolinite, pyrophyllite, dumortierite, andalusite and sericite, Hadong-Sancheong-mostly halloysite, and Haenam-dickite, pyrophyllite, alunite and diaspore. The difference in the zonal pattern of altered rock is considered to depend on differences in the initial acidity of related hydrothermal solution, initial acidity was controlled by the oxygen fugacity.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2002.09a
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• pp.362-365
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• 2002

토양의 물리/화학적 특성에 따른 토양의 유기오염물 흡착능 변화를 규명하기 위하여, 토양 내 clay 함량 및 유기물 함량변화, 수용액 내 TCE 농도변화에 따른 TCE 의 토양내 흡착량 변화를 측정하였다. 수용액의 pH와 실내온도는 일정하게 유지시켰으며 clay는 표면적이 다른 Ca-montmorillonite, Na-montmorillonite, kaolin을 이용하였고, 유기물질로는 활성탄을 사용하였다. 일정한 토양성분과 실제토양에 대해 수용액 내 TCE의 농도를 변화시켜 농도변화에 따른 흡착량 변화를 측정하였다. 실험결과 유기물과 점토함량의 증가에 따라 흡착량은 모두 증가하였으나 활성탄에 의한 TCE 흡착량이 점토에 비해 매우 높았으므로 유기물에 의한 TCE 흡착영향이 점토에 의한 흡착 영향보다 큰 것으로 나타났다. TCE 농도변화에 따른 흡착결과는 실제토양과 모사토양에서 모두 농도가 증가함에 따라 흡착 증가율이 증가하다가 감소하는 Langmuir isotherm 형태를 보여 주었다.

• Proceedings of the Korean Society of Agricultural Engineers Conference
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• 2000.10a
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• pp.451-457
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• 2000

A series of consolidated undrained triaxial tests for compacted short fiber reinforced clay were performed to increase the field applications, e.g. retaining wall, waste landfill, soft ground etc. of soil admixtures mixed with short fiber. Kaolin clay and three types of fiber were selected. To acquire reliable length of fibers, an auto cutter was used and a helical mixer was also used to avoid floating of fibers during mixing soil and fibers. It is found that reinforcing effect by aspect ratio and mixing ratio of short fiber decreases as confining pressure is increased. Reinforcing effect has a maximum value at the aspect ratio of 120 and the fiber content of 0.6%∼1.2% and low confining pressure like 50kPa.

• Journal of Animal Science and Technology
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• v.53 no.2
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• pp.133-138
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• 2011

Two experiments were conducted to determine the effects of supplementing different levels of kaolin (Exp. 1) and effects of age of layers and levels of kaolin (Exp. 2) on the performance, egg and shell quality parameters of laying hens. In Exp.1, 64 laying hens of 58 wks age were randomly allotted to 4 treatments of 16 hens in each. Dietary treatments were basal diet supplemented with 0.0, 0.2, 0.4 and 0.6% kaolin. In Exp. 2 96 laying hens were divided into 6 groups of 16 hens each in a 2 ${\times}$ 3 factorial arrangement (two different ages, 30 and 58 wk and three levels of kaolin, 0.0, 0.2 and 0.4%). In both the experiment there were linear decreases in feed intake (P<0.001), improvement in FCR (P<0.05), and egg production (P<0.05), with increasing dietary kolin level. Supplementation of kaolin had no effect on the egg and shell quality parameters in both experiments. Thus, it is concluded that kaolin may improve performance, and 0.2% level showed the best laying performance.

• Korean Journal of Food Science and Technology
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• v.37 no.1
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• pp.23-29
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• 2005

To investigate potential characteristics of clay minerals (illite, kaolin, zeolite, vermiculite, and bentonite) for food industry application, antioxidative properties of clay minerals, electron-donating ability (EDA), peroxide value (POV), and thiobabituric acid (TBA) were measured, and antimicrobial activity against several food spoilage microorganisms were evaluated by minimum inhibition concentration (MIC) method. Changes in components by cooking clay minerals added to stored rice were measured by GC-MS. DPPH (1,1-diphenyl-2-picrylhydrazyl) analysis results revealed bentonite has strongest EDA at 20.6%. Antioxidant activities measured based on POV were similar to DPPH results. Induction period of linoleic acid with vermiculite was longest among. TBA results revealed zeolite hasstrongest antioxidant ability. Growth inhibition against E. coli and S. aureuswas observed in illite, vermiculite, and zeolite. Aroma components indicated decrease in hex anal, pent anal, non anal, linoleate, stearic acid, and oleic acid when clay minerals were added to stored rice. These results indicate that several clay minerals have antioxidative and antimicrobial abilities and improve flavor profiles in stored rice.

• Economic and Environmental Geology
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• v.29 no.4
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• pp.439-446
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• 1996

Clay minerals are locally abundant in two hydrothermal areas at Tongnae-Yangsan and Miryang, Gyong-sang-namdo, Korea. This study is done to access the clay forming processes, particularly hydrothermal alteration. Pyrophyllite-kaolin in the Zone is accompanied by sericite, diaspore mixed-layer mica/smectite, alunite, dumortierite and silica minerals. Small nodular diaspore and disseminated fine radiac dumortierite are present in the pyrophyllite-kaoline deposits, the northemly trending belt of rhyolite flows and pyroclastic rock near the intruded by granite rock of Bulkusa Series. Hydrothermal action has formed many clay deposits with a zone containing over 80~90% pyrophyllite, kaolinite, muscovite with a little amount of dumortierite, boehmite, andalusite. Most of the clay deposits occur as irregular, lenticular, massive and assosiated dumortierite was found to coexist with clay deposits. Dumortierite data are as follows: lattice constant a=11.783, b=20.209, c=4,7001, axial ratio a:b:c=0.5835 : 1 : 0.2327, XRD $d{\AA}$ 2.549, 5.89, 5.09.

• Journal of the Korean Geotechnical Society
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• v.18 no.1
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• pp.113-125
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• 2002

Ground improvement technique of cement stabilization via Deep Soil Mixing with dry cement is gaining popularity, particularly in Japan and other parts of Southeast Asia and in Scandinavia. Cement can be mixed with deep soft clay deposits, typical of marine environments, to improve the bearing capacity and/or reduce the compressibility of the material so that an otherwise poor site can be developed. However, the strength/deformation behaviour and resulting soil structure of the clay-cement mixture is presently not well understood with respect to both dry and wet mix methods. An extensive laboratory test was carried out to determine the mechanical characteristics of kaolin-cement, with some brief examination of the effects of curing environment. Laboratory tests include triaxial tests, unconfined compression tests, isotropic consolidation testis and oedometer tests. Cement contents up to 10 percent were considered and water curing was employed. Samples were cured for 7 to 112 days while submerged in distilled water. Conventional laboratory tests were also performed. In this paper, the laboratory testing program is described and various sample preparation techniques are discussed. Preliminary triaxial compression test results and trends at varying moisture contents, cement contents, confining pressures and curing times will be presented.