• Economic and Environmental Geology
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• v.41 no.5
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• pp.587-595
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• 2008

The geology of the Capim region in Brazil is composed of Ipixua Formation in Mesozoic-Tertiary(Miocene), sedimentary rocks in Miocene, Barreiras Formation(sedimentary rocks) in Pleistocene and sediments in Holocene. Kaolin deposit consists of Barreiras Formation(average depth in 120m) composed of sandstone, clay, fine sand of Miocene to Pliocene age. Kaolin of the high grade is white in color and its thickness averages 7m. The orebody formed by kaolinite was confirmed by XRD, is shape of hexagonal, SK is above 33 degree. It is class A also suit for producing a paper without filtration. According to the CPRM report, the reservation of kaolin ore is amounts of 566,819,164 tons.

• Journal of the Korean Ceramic Society
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• v.32 no.6
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• pp.735-747
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• 1995

The synthesis of clay mineral through the hydrothermal reaction of the anorthite, which is distributed in San Chung-District of Korea and called as the ground rock for halloysite-kaolin, has been investigated. It was observed that this anorthite sample was easily converted into clay mineral with 0.5 wt% HCl solution at a temperature below 20$0^{\circ}C$ under a pressure about 15 atm. The conversion reaction was promoted by adding aluminum chloride under the condition concerned. Aluminum chloride was considered to supply the insufficient aluminum ion during the conversion reaction and to reprepare the acid solution-condition by adding the HCl-component as a by-product. According to the electron micrographs, it was confirmed that fine tubular or needle-shaped halloysite-kaolin minerals with the crystal length shorter than about 1.1${\mu}{\textrm}{m}$ could be obtained by the hydrothermal reaction for 5 days under those conditions.

• Proceedings of the Korean Geotechical Society Conference
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• 2006.03a
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• pp.1142-1147
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• 2006

Cement-stabilized clay has widespread applications in Deep Mixing projects, whereby soft deep clay deposits are improved through the addition of cement. While much research on this subject has taken place over the past decade, the strength and deformation behaviour of cement-stabilized clay is still not well understood. An extensive laboratory program was conducted on kaolin stabilized with up to 10% cement. Water curing was employed for durations up to 112 days. To study the microstructure of raw and stabilized soil, use is made of SEM. Micrographs of selected raw and stabilized soil were obtained. These micrographs were closely analyzed for any change in the microstructure of the soil as a result of stabilization.

• Geomechanics and Engineering
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• v.14 no.3
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• pp.247-255
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• 2018

Soil stabilization can make the soils becoming more stable by using an admixture to the soil. Lime stabilization enhances the engineering properties of soil, which includes reducing soil plasticity, increasing optimum moisture content, decreasing maximum dry density and improving soil compaction. Silica fume is utilized as a pozzolanic material in the application of soil stabilization. Silica fume was once considered non-environmental friendly. In this paper, the materials required are kaolin grade S300, lime and silica fume. The focus of the study is on the determination of the physical properties of the soils tested and the consolidation of kaolin mixed with 6% silica fume and different percentages (3%, 5%, 7% and 9%) of lime. Consolidation test is carried out on the kaolin and the mixtures of soil-lime-silica fume to investigate the effect of lime stabilization with silica fume additives on the consolidation of the mixtures. Based on the results obtained, all soil samples are indicated as soils with medium plasticity. For mixtures with 0% to 9% of lime with 6% SF, the decrease in the maximum dry density is about 15.9% and the increase in the optimum moisture content is about 23.5%. Decreases in the coefficient of permeability of the mixtures occur if compared to the coefficient of permeability of kaolin soft clay itself reduce the compression index (Cc) more than L-SF soil mix due to pozzolanic reaction between lime and silica fume and the optimum percent of lime-silica fume was found to be (5%+6%) mix. The average coefficient of volume compressibility decreases with increasing the stabilizer content due to pozzolanic reaction happening within the soil which results in changes in the soil matrix. Lime content +6% silica fume mix can reduce the coefficient of consolidation from at 3%L+6%SF, thereafter there is an increase from 9%L+6%SF mix. The optimal percentage of lime silica fume combination is attained at 5.0% lime and 6.0% silica fume in order to improve the shear strength of kaolin soft clay. Microstructural development took place in the stabilized soil due to increase in lime content of tertiary clay stabilized with 7% lime and 4% silica fume together.

• 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.

• Korean Journal of Soil Science and Fertilizer
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• v.27 no.3
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• pp.168-178
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• 1994

Acid sulfate soils occur extensively in Gimhae area where they have been formed from the brackish alluvial sediments along the sea coast and river estuary. The strong acid environment enhances silicate weathering and thus affects the soil clay minerals. The minerals were identified through chemical, X-ray diffraction and thermal methods. The ratio of $SiO_2$ and $Al_2O_3$ in the clay fractions ranged from 3.14 to 3.77, indicating that the distribution of the clay minerals were 1 : 1 and 2 : 1 minerals. Cation exchange capacity in the clay fractions was low due to high contents of 1 : 1 minerals and hydroxy interlayered vermiculite(HIV). The B and C horizon rich in jarosite have large amounts of yellow streaks which reflect high content of $Fe_2O_3$ and $K_2O$. Vermiculite and illite were quantified from thermogravimetry(TG), kaolin minerals from both TG and differential thermal analysis(DTA), and HIV from X-ray diffraction analysis. The dominant clay minerals were kaolin minerals, vermiculite, illite and HIV. HIV considered to be formed, especially, in acid soil environments. The minor minerals were quarts, feldspar, jarosite, pyrite, hematite and goethite. Kaolin minerals were the most abundant clay minerals throughout the acid sulfate soil. Kaolin minerals, however, increased towards the top of horizons throughout the soils and HIV decreased towards the top of horizons in the soil of Gimhae series and Haecheog series. Alteration of HIV to kaolin minerals during weathering of low pH condition in deep soil horizons may explain the high quantities of kaolin minerals and the relatively low quantities of HIV in the soil at top horizons.

• Journal of the Korean Ceramic Society
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• v.14 no.4
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• pp.215-225
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• 1977

In this study, we are observe to the sagger which is composed of cordierite-mullite system. And especialy, we investigated the characteristics of the body which composed of Chamotte-Kaolin-Plastic clay-Talc (or Clinochlore) system and Chamotte-Kaolin-Plastic clay-Agalmatolite-Talc (or Clinochlore) system. The obtained results are as follows. 1. Modulus of rupture and apparent porosity were improved by particle size of talc and clinochlore in order that -16 mesh, -6 mesh, 6-16 mesh. 2. When the body composed of talc, the modulus of rupture was increased as firing temperature was rising up but composed of clnochlore, it was reversed. 3. When added to the agalmatolite, firing shrinkage, modulus of rupture and apparent porosity were improved. 4. Mineral phases of samples fired at 125$0^{\circ}C$ above consist of cordierite, mullite and $\alpha$-cristobalite.

• Advances in Computational Design
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• v.5 no.2
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• pp.195-207
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• 2020

The present study focuses on the application of artificial neural network (ANN) and Multiple linear Regression (MLR) analysis for developing a model to predict the unconfined compressive strength (UCS) and split tensile strength (STS) of the fiber reinforced clay stabilized with grass ash, fly ash and lime. Unconfined compressive strength and Split tensile strength are the nonlinear functions and becomes difficult for developing a predicting model. Artificial neural networks are the efficient tools for predicting models possessing non linearity and are used in the present study along with regression analysis for predicting both UCS and STS. The data required for the model was obtained by systematic experiments performed on only Kaolin clay, clay mixed with varying percentages of fly ash, grass ash, polypropylene fibers and lime as between 10-20%, 1-4%, 0-1.5% and 0-8% respectively. Further, the optimum values of the various stabilizing materials were determined from the experiments. The effect of stabilization is observed by performing compaction tests, split tensile tests and unconfined compression tests. ANN models are trained using the inputs and targets obtained from the experiments. Performance of ANN and Regression analysis is checked with statistical error of correlation coefficient (R) and both the methods predict the UCS and STS values quite well; but it is observed that ANN can predict both the values of UCS as well as STS simultaneously whereas MLR predicts the values separately. It is also observed that only STS values can be predicted efficiently by MLR.

• 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.

• Economic and Environmental Geology
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• v.21 no.1
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• pp.1-15
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• 1988

This is a study on the mineral compositions, SK numbers of refractoriness and the genesis of the clay mineral deposits in Cheonnam Province and Handong area. 1. Jindo kaolin deposits: Chief clay minerals of the deposits are kaolinite, quartz and alunite. The SK number of the ore is from $34^+$(the highest) to 27(the lowest). On the genesis of the deposits some geologists believe that the deposits were formed by the alteration of the siliceous tuff. But the deposits seems to be formed by the hydrothermal alteration of the rhyolite lava beds. This area is formed by alternative beds of tuff; and kaoline deposits. 2. Hadong area: Chief mineralogy of Hadong kaolin area is $10{\AA}$ halloysite and kaolinite. The SK number of some of the ore is up to $36^+$. The theoretic SK number of kaolinitic composition is 35. So one of the highest alumina minerals of gibbsite is formed in the ores of $36^+$ SK numbers. 3. Hampyong kaolin deposits: Most of kaolin has black color. The chief minerals are kaolinite, quartz and muscovite. Some of the kaoline contains rutile crystals. SK number ranges from 30 to 17. The kaolin deposit is formed by the transported sedimentation in lower part of the seashore. 4. Jangsan kaoline deposits: Chief minerals of the kaolin is kaolinite, quartz and muscovite. Some kaoline contains small crystals of pyrite. This area consists almost of the tuffs. Kaolin deposits also would be formed by the alteration of the tuffs. 5. Nohwado pyrophyllite deposits: Quartz and pyrophyllite are chief minerals. SK number of the ore ranges from 32 to 30. The pyrophyllite deposits would be formed by the hydrothermal alteration of the rhyolitic lava beds. This area consists of alterative beds of tuffs and rhyolitic lavas. 6. Songsuk pyrophyllite deposits: Chief minerals are quartz, kaolinite, pyrophyllite and iron oxides. In the pyrophyllite deposits egg-like inclusions of diaspore and kaolinite in composition. This area almost consists of tuffs. Several faults are developed and along the fault the tuff would begin to alter to pyrophyllite and some parts to diaspore and kaolinite nodules by the acts of hydrothermal solution.