• Advances in materials Research
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• v.13 no.2
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• pp.103-114
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• 2024

Zeolites are microporous materials that find applications in different fields due to their numerous interesting properties. This research investigated the effect of leaching on unheated Ifon kaolin in dilute hydrochloric acid and sulphuric acid. The hydrothermal method synthesized zeolite-X type, and the resulting sample was characterized using different techniques. The silica/alumina ratio in the synthesized sample was approximately 5.6, while Infrared spectra confirmed that the synthesized material was Zeolite-X. Based on the X-ray diffraction patterns, other phases were also formed in addition to zeolite-X crystals. Thermogravimetry results indicated that the synthesized zeolite was relatively stable below 500℃, so its weight loss was only 13% after heating to about 200℃. A differential thermal analyzer confirmed this amount of weight loss, and endothermic and exothermic reactions were also observed for the samples calcined respectively at 700 and 900℃. Based on Brunauer-Emmett-Teller (BET) analyses, samples at 700℃ showed slower adsorption-desorption isotherms, pore volume, and sizes than those at 900℃. These results have shown that leaching and calcination temperature significantly affect the type of zeolite produced.

• Journal of the Mineralogical Society of Korea
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• v.29 no.4
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• pp.179-190
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• 2016

X-ray diffraction analysis, chromaticity measurement, execution and evaluation by Dancheong artisan, accelerated weathering test, and fire resistance test were conducted to test the applicability as a Dancheong pigment raw materials of Korean low grade kaolin in cultural properties. The ores that feldspar rich and composed of fine particles (< $38.1{\mu}m$) showing advantageous for the inherent purpose of the white pigment than that of high grade kaolin. And the test of whiteness, concealment force, outdoor exposure durability and fire resistance shows similar or better result than existing products (Hobun and Sanhwa jidang). In conclusion, it is expected that the use of fine feldspar rich white soil and low-grade kaolin can be used as a white pigment raw materials which have similar to better material properties and economic efficiency than existing products.

• Journal of the Korean Ceramic Society
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• v.29 no.1
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• pp.15-22
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• 1992

The reason for permanent shrinking of recycled castable refractories from alumino-silicate waste refractories was investigated and the method to control shrinking is suggested in order to increase maximum service termperature. The porosity of castable refractories with waste material as large aggregate decreases after heat treatment because the porosity of waste refractories is greater than the of green material, in which CaO around large aggregate penetrates into aggregate and promotes liquid phase sintering. The shrinking of recycled castable refractories resulted in the decrease in porosity can be controled by addition of green kaolin chamotte as large aggregate. The shrinking of recycled castable refractories caused by the differences in densities of mineral phases before and after heat treatment can be controled by addition of kyanite. The use of green kaolin chamotte and kyanite increases the service temperature of recycled castable refractories up to 1500$^{\circ}C$.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.08a
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• pp.123-127
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• 2002

This paper presented the results of evaluation of artificially contaminated suspension insulators for transmission lines. The suspension insulators were contaminated with kaolin and clay which were included various amount of natural salt. The degree of contamination were evaluated by measuring equivalent salt deposit density(ESDD). Then, the leakage currents were measured as a function of applied voltage, degree of contamination, humidity.

• Journal of the Korea Concrete Institute
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• v.20 no.1
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• pp.89-97
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• 2008

By replacing the meta-kaolin with cement and the waste tire chip with fine aggregate separately, the high strength concrete is protected from the spalling in fire and the method to constrain the temperature increase of steel bar within the concrete and the basic properties of the high strength concrete mixed with the material are reviewed. As the result, meta-kaolin increases the self fire proof characteristics of the concrete, the waste tire chip can share the internal expanding pressure so it can be deleted. In detail, using the meta-kaolin about the cement in 4$\sim$8% of weight ratio about the cement and the waste tire chip under the grade scope of 0.6$\sim$3 mm in 5$\sim$10% of weight ratio about the sand is very effective to prevent the spalling.

• Journal of the Korean Ceramic Society
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• v.47 no.3
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• pp.216-222
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• 2010

Portland cement has been restricted in applications to ecological area because of its environmental harmfulness and the $CO_2$ emission during a production process. Geopolymer materials attract some attention as an inorganic binder due to their superior mechanical and eco-friendly properties. In this study, geopolymer-based cement was prepared by using aluminosilicate minerals (flyash, meta-kaolin) with alkaline-activators and its compressive strength with concentration of alkaline-activators was investigated. Aluminosilicate-based geopolymers were obtained by mixing aluminosilicate minerals, alkaline solution (NaOH or KOH with different concentration) and water-glass under the vigorous stirring for 20 min. Compressive strength after curing at $30^{\circ}C$ for 3 days increased with the concentration of alkaline-activator due to the enhanced polymerization of the aluminosilicate materials and dense microstructure. Aluminosilicate-based geopolymer cement using KOH as an alkaline-activator showed high compressive strength compared with NaOH activator. In addition, geopolymer cement using fly-ash as a raw material showed higher compressive strength than that of meta-kaolin.

• Polymer(Korea)
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• v.26 no.6
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• pp.803-811
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• 2002

In this study the wear behavior of ultra high molecular polyethylene (UHMWPE) filled with kaolin particles by different methods was investigated. UHMWPE/kaolin composites were prepared by two different methods: polymerization-filling and powder mixing. Particularly in a powder mixing method. Particle dispersion and wear property according to powder mining method were examined. It was found from wear test that filling of inorganic filler into UHMWPE by polymerization filling was more effective way than by powder mixing method in improving Wear resistance of UHMWPE. It was also confirmed that abrasive wear was dominant wear mechanism and particle dispersion in the composite as well as interface property was an important factor in controlling the wear behavior of the resulting composites.

• Proceedings of the Korea Concrete Institute Conference
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• 2008.11a
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• pp.333-336
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• 2008

As the high-rise building increase due to the gravitation of population to big cities recently, it requires high quality and high performance of Concrete. As a result, people are keenly interested in Meta-kaolin as new admixture favorable from an economic perspective, which has strength and endurance with admixture at the same level like Silicafume. Accordingly, as to Meta-kaolin, this study was to set by three levels like domestic one, foreign one, and Silicafume, the waterbinding material ratio 25%, and four level substitute like 0, 10, 20, and 30(%) in order to compare and analyze the quality characteristics of high-strength concrete according to the substitute of Meta-kaolin applicable with replacement of Silicafume. As a result of performing experiment, as to the higher the additive amount of Superplasticizing agents in order to secure target liquidity was, the more the substitute in each admixture increased. This study had a tendency that the Silicafume increased the additive amount of Superplasticizing agents with high fineness compared with Meta-kaolin. In addition, the higher the substitute in each admixture was, the more its strength increased On the strength property, the higher the substitute in each admixture was, the more its strength increased. This study has found out that the Meta-kaolin has shown the better strength than the one of Silicafume. On the other hand, the relationship between the Compressive strength and Elastic coefficient has shown the similar formula suggested from ACI363.

• 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.

• Journal of the Korean Recycled Construction Resources Institute
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• v.10 no.3
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• pp.252-260
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• 2022

In Korea, low-quality kaolin has significantly greater reserves and superior economic efficiency than high-purity kaolin. However, the utilization is low because it does not match the demand conditions of the market, and it is difficult to find a suitable source of demand. The purpose of this study is to derive the possibility and optimal calcination temperature of domestic low-quality kaolin that can be used as a raw material for limestone plastic clay cement (LC³). Isothermal calorimetry, X-ray diffraction analysis, Thermogravimetric Analysis, and compressive strength tests were conducted to evaluate hydrate generation and mechanical properties of LC³ paste according to calcination temperatures (600 ℃, 700 ℃, 800 ℃, 900 ℃). As a result, although 50 % of the clinker was replaced, the domestic low-quality kaolin clay produced calboaluminate hydrate and C(A)SH from the 3rd day of hydration, showing almost equal or higher strength to OPC, and there was a big difference in strength depending on the firing temperature.