• Journal of the Korean Ceramic Society
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• v.32 no.4
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• pp.429-435
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• 1995

Al2O3-SiC-C(ASC) refractory materials were prepared from kaolin using thermit reaction. The mixed powder (A-K) for the thermit reaction was composed of Hadong kaolin, C(graphite) and Al. A-S(SiO2＋C＋Al) composition was also employed to compare with A-K in respect to reactability. As a result of XRD patterns of A-K sample after thermit reaction, and firing at 140$0^{\circ}C$ for 3hrs in Ar atmosphere, it was possible to use as a ASC refractory materials.

• Journal of the Korean Ceramic Society
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• v.19 no.2
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• pp.157-161
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• 1982

The possibility of extraction of alumina from domestic Ha-dong kaolin was studied by sulfuric acid treatment. Raw kaolin was calcined at various temperature (500-110$0^{\circ}C$) and calcined kaolin were treated with sulfuric acid. The tendency of extraction yield of alpha alumina have been investigated by relating reaction time, temperature, and acid concentration. After reaction, precipitates were analyzed by DTA, TGA, and identified alpha alumina by X-ray diffractometer with calcined sample at 120$0^{\circ}C$. The results were as follows; 1. The optimum calcination temperature was 800-86$0^{\circ}C$. 2. The most suitable extracting conditions of alpha alumina were 40 wt%-$H_2SO_4$, 2-3 hours acid-treating time and 8$0^{\circ}C$ acid-treating temperature. 3. Precipitates were composed of $(NH_4)_2SO_4$, $Al_2SO_4(OH)_4$ 5-7 $H_2O$ and $Al(OH)_3$.

• Journal of the Korean Ceramic Society
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• v.17 no.4
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• pp.188-196
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• 1980

To investigate the corrosion behavior of the clay-bonded kaolin chamotte by molten aluminum, the mixture of 20 wt% fire clay and 80 wt% kaolin chamotte was prepared and fired in the temperature range 900~120$0^{\circ}C$. The specimens fired at each temperature were reacted with molten aluminum at 90$0^{\circ}C$. The results obtained in this experiment are as followed. 1) It was confirmed through X-ray diffraction analysis that the clay-bonded kaolin chamotte exposed to molten aluminum suffered penetration by the reaction of aluminum with silica forming alumina and metallic silicon. 2) Penetration was independent whether the silica existed as free or one component of mullite. 3) Penetration of the specimen fired at 90$0^{\circ}C$ was negligible while the others fired above 100$0^{\circ}C$ showed remarkable penetration. 4) Penetration rate at 90$0^{\circ}C$ was parabolically increased with the holding time as in the case of metal oxidation.

• Proceedings of the Korean Geotechical Society Conference
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• 2010.03a
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• pp.649-655
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• 2010

Unsaturated compressive tests are performed to evaluate the effect of matric suction on the strength and the deformation characteristics for statically compacted natural kaolin in Korea. Under different conditions of the initial degree of saturation in kaolin, the relationship between suction and the degree of saturation at failure can be expressed by unique soil-water characteristic curve. These results demonstrate that the newly established constant water content type unsaturated shear strength test equipment can be used for estimating the relationship between suction and the compressive strength.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2010.05a
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• pp.89-90
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• 2010

As a result of physical characteristics of using meta-kaolin and alkali accelerator, it was found that higher curing temperature density is favorable to strength development at early age and the higher the age is, the higher, most of the compressive strength gets. Also, I was shown that more than atmospheric curing, steam curing was favorable for development of compressive strength. When the temperature of curing temperature was higher, most of the compressive strengths were higher. Thus, based on this study, it was understood that environmental-friendly chemically combined concrete using meta-kaolin and alkali accelerator can be utilized without using cement.

• Archives of Pharmacal Research
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• v.10 no.4
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• pp.228-231
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• 1987

Studies on the adsorption of four kinds of bacteria, Staphylococcus aureus, Sarcina lutea, Escherichia coli and Serratia marcescens by activated Korean Kaoline have been carried out to innovate utilization as adsosrbent preparations. In connection with particle size and size fraction, the adsorption was examined by colony counting and spectroscopy. Korean kaolin was purified from Hadong white species of preminum grade and three size fractions were derived from passage through BS # 100, #200 and # 325 mesh sieves, respectively. These were activated at $105^{\circ}$or $280^{\circ}$ for three hours and at $550^{\circ}C$ for one hours. The results indicated that the adsorbing power of Korean kaolin was superior for S. aureus and S. lutea, but E. coli and S. marcescens were not adsorbed by clays. The smaller the particle size, the greater was adsorbing power for Gram-positive bacteria. Threre appears to be justification for its investigations as an ingredient in intestinal adsorbent preparations.

• Journal of the Korean Ceramic Society
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• v.20 no.2
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• pp.123-128
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• 1983

This research is aimed to synthesize the mullite by adding Al powder of $Al_2O_3$ to kaolin. Specimens fired at 1400, 1450 and 150$0^{\circ}C$ were compared in their X-ray diffraction patterns quantitative analysis of mullite formed and fine microstructures with those containing reactive $Al_2O_3$ activated $Al_2O_3$ as alumina source The experiment of Al oxdiation was also performed by measuring the weight increase of specimens. Two different shapes of mullites acicular and chunky were observed by SEM and the yield of mullites were in-creased by the order of adding activated $Al_2O_3$ reactive $Al_2O_3$ and Al powder to kaolin.

• Proceedings of the Membrane Society of Korea Conference
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• 2002.11a
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• pp.166-169
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• 2002

• Journal of the Korean Ceramic Society
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• v.47 no.3
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• pp.223-231
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• 2010

The serious issue of tall building is to ensure the fire-resistance of high strength concrete. The fire resistant finishing method is necessarily essential in order to satisfy the fire resistance time of 3 h required by the law. The fire resistant finishing method is installed by applying a fire resistant material as a method of shotcrete or a fire resistant board to high strength concrete surface. This method can reduce the temperature increase of the reinforcement embedded in high strength concrete at high temperature due to the installation thickness control. This study is interested in identifying the effectiveness of inorganic alumino-silicate compounds including the inorganic admixture such as fly ash and meta-kaolin as the fire resistant finishing materials through the analysis of fire resistance and components properties at high temperature. The study results show that the fire resistant finishing material composed of fly ash and meta-kaolin has the thermal stability of the slight decrease of compressive strength at high temperature. These thermal stability is caused by the ceramic binding capacity induced by alkali activation reaction by the reason of the thermal analysis result not showing the decomposition of calcium hydrate. Inorganic compounds composed of fly ash and meta-kaolin is evaluated to be very effective as the fire resistance material for finishing to protect the concrete substrate by the reason of those simplicity in both application and manufacture. The additional study about the adhesion in the interface with concrete substrate is necessary for the purpose of the practical application.

• Journal of Korea Soil Environment Society
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• v.4 no.3
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• pp.17-24
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• 1999

The effects of hydrophobic chain length and its structure of nonionic surfactants on surfactant adsorption and contaminated diesel removal were studied in kaolin soil. Hydrocarbon chain length and double bond in hydrophobic tail group of nonionic surfactants affected surfactant adsorption and diesel removal efficiency from kaolin soil. The degrees of surfactant adsorption and diesel removal were closely related each other. Among nonionic surfactants we studied, surfactants with shorter hydrophobic chain length and higher HLB value showed lower degree of adsorption and higher efficiency of diesel removal. The existence of unsaturated carbons in the structure of hydrophobic chain enhanced diesel removal by reducing surfactant adsorption to kaolin soil. The best diesel removal was obtained after adsorption saturation was reached. If surfactant concentration was higher than a critical value, diesel removal was reduced probably because of precipitation. liquid crystal formation, or coacervation of surfactants at high concentration.