• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.23 no.4
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• pp.365-371
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• 2013

The purpose of this study is to develop a sound absorbing material for indoor which manufactured by a clay and binding material. The seven kind of sound absorbing specimens which sintered through a mold process at high temperature were manufactured for the purpose of testing sound absorption performance. The random and normal sound absorption coefficients were measured for the sintered clay sound absorbing specimens with different particle size, density and mixture ratio. From the experimental results, it was found that its particle size was closely related to the sound absorption performance. It was shown that the sintered clay sound absorbing specimen had the sound absorption properties of a fiber-type or a resonance-type sound absorbing material depending on the particle size.

• Journal of the Korean Ceramic Society
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• v.32 no.9
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• pp.1027-1032
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• 1995

SiC had been widely applied for mechanical sealing as a sealing material. SiC sintering is commonly made of reaction sintering, presureless sintering, and hot isostatic pressing (HIP) sintering. In this investigation, however, clay bonded sintering was used to avoide any complications of the special sintering methods as mentioned above. In order to prevent harmful SiC oxidation in the clay bonded sintering, clay and frit were used to form the SiC oxidation protecting layer and graphite was added to provide high solid lubricity. As a result, the material with 6% clay (clay 5.4% and frit 0.6%) and 2~4% graphite (45 mesh) sintered at 140$0^{\circ}C$ for 3 hours, showed the following physical properties; porosity 6%, static friction coefficient 0.15, kinematic coefficient 0.1,. and specific wear rate 4.8$\times$10-8 $\textrm{mm}^2$kgf-1. On the other hand, the flexural strength was 900kgf/$\textrm{cm}^2$. This tribological characteristic properties were similar to those of the reaction sintered SiC except the flexural strength.

• Journal of the Korean Ceramic Society
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• v.33 no.7
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• pp.771-778
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• 1996

Utilization of fly ash by-produced from coal fired power plants and classified as general waste became very important problem to solve in the environmental protection and recycling of waste materials. The possibility of large scale substitution of fly ash as a raw material for bricks and wet tiles was highly expected because the chemical compositions of fly ash were mostly Al2O3 and SiO2 and the properties of it were very similar with clay. Accordingly in order to investigate the substitutional limit these specimens were substituted from 0 to 100 wt% fly ash by 20wt% increment for clay. Fly ash-clay bodies were fired at 1200, 1250 and 130$0^{\circ}C$ and then their properties were measured, It was found that these specimens sintered at 125$0^{\circ}C$ had a good bending strength. Especially when these sintered bodies were added to 20, 40 and 60 wt% fly ash the bending strength of those were 201 , 205 and 191kg.cm2 respectively with the water absorption below 1%, This showed that fly ash could be substituted ab 60 wt% in this experiment.

• Journal of the Korean Ceramic Society
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• v.51 no.5
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• pp.492-497
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• 2014

Artificial fine aggregates (denoted AFA) were fabricated using spent bleaching clay (denoted SBC) generated from processed vegetable oil and stone sludge (denoted SS) produced from crushed aggregate manufacturing materials for use as functional construction materials. Each raw material was crushed to particle size finer than $150{\mu}m$, and fine spherical pellets of approximately 1 ~ 4 mm in diameter were prepared by a pelletizing process. The physical properties of the AFA were measured with different types of sintering equipment. A new type of vertical furnace that sinters fine aggregates in a fluidized bed at high temperatures was designed and tested. AFA sintered in a rotary kiln at $1125^{\circ}C$ showed a bulk density of $1.5g/cm^3$ and a water absorption of 16%. AFA sintered in the vertical furnace at $1125^{\circ}C$ showed a bulk density of $1.9g/cm^3$ and water absorption of 8.5%. The bulk density of the AFA sintered in the vertical furnace showed a bulk density 27% higher and water absorption 47% lower than those of AFA sintered in the rotary kiln.

• Journal of Industrial Technology
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• v.20 no.A
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• pp.239-245
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• 2000

Sintered $Al_2TiO_5$ has a very low thermal expansion and an infrared radiative selectively emitting large amounts of far infrared rays. However, it is week in mechanical strength. Spectral infrared emittance, thermal expansion coefficient, and mechanical strength of $Al_2TiO_5$-clay composites were studied to develop a material for far infrared radiators. The composites containing 10~50 mass% Jungsan clay had high emittance in the range of 2,000~500cm-1. The bending strength of the $Al_2TiO_5$-clay composites increased with increasing clay content. The $Al_2TiO_5$-clay composites with a clay content of 50mass% and heat-treated at $1,200^{\circ}C$ had a large strength for infrared radiators ; 86MPa. The average linear thermal expansion coefficient from $200{\sim}1,000^{\circ}C$ of the 50mass% jungsan clay containing compo sited heat-treated at $1,200^{\circ}C$ was lower than $3.87{\times}10-6/^{\circ}C$.

• Journal of the Korean Ceramic Society
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• v.44 no.10
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• pp.568-573
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• 2007

For the manufacturing lightweight fine aggregate, clay and waste material was formed by pelletizer. The fine aggregate of 1-5 mm diameter was formed by diameter 76 cm pelletizer disc. Pelletization variables were : (1) pelletizer disc angle, (2) speed of revolution of pelletizer, (3) added pelletization time. Green and sintered aggregate were measured specific gravity, absorption rate and average size. The optimum condition were found that the pelletization variables were angle at $70^{\circ}$, speed of revolution of pelletizer at 23.2 rpm, and water/solid ratio at 1/5. At these conditions, it was formed that fine aggregate green whose average size was $2.0{\sim}3.35mm$. Specific gravity and average size are increased with low angle of disc and fast revolution speed of disc. Specific gravity and average size were not distinctly influenced by added pelletization time. Sintered aggregate was distinctly influenced by properties of green.

• Proceedings of the Korea Concrete Institute Conference
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• 2000.10a
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• pp.339-344
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• 2000

The purpose of this study is to evaluate qualities of lightweight aggregate for structural concrete according to mixing proportions, pelletizer condition, sintering condition and to choose the suitable main and sub material. Main material used paper sludge ash(PSA) and sub material used clay, fly-ash and paper sludge. The aggregates are sintered after granulating at the various condition. As the result of test, quality difference of aggregate showed clear according to the mixing proportions and sintering conditions. It was possible to manufacture lightweight aggregate for structural concrete that dry specific gravity was ranged about 0.9 to 1.4 also the test results of the aggregates showed same physical properties compared with abroad product as 10% granules crushing value from 5 or 10% and absorption percentage from 10 to 20%.

• Journal of the Korean Ceramic Society
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• v.47 no.5
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• pp.445-449
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• 2010

The purpose of this study is to improve recycling rate of the waste glasses by investigating bloating mechanism. In this study, we use waste glass(W/G) and hard clay(H/C) as raw materials. The artificial lightweight aggregates were formed by plastic forming($\phi$=10 mm) and sintered by fast firing method at different temperatures(between 700 and $1250^{\circ}C$). The physical properties of the aggregates such as bulk specific gravity, adsorption and microstructure of surface and cross-section are investigated with the sintering temperature and rate of W/G-H/C contents. As the result of the bulk specific gravity graphs, we can found out the inflection point at content of W/G 60 wt%. From the microstructure images, we considered the artificial lightweight aggregates content of W/ G over 60wt% are distributed numerous micro-pores by organic oxidation without Black Core and the artificial lightweight aggregates of W/G below 60 wt% are distributed macro-pores with Black Core.

• Journal of the Korean Applied Science and Technology
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• v.30 no.4
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• pp.575-585
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• 2013

This research was performed to evaluate the recycling feasibility as a construction material of dredged harbor soil mixed with clay and glass frit. Concentration of heavy metals of the dredged soil from D harbor was severly high, showing Zn of 526.0~13,150.1 mg/kg. The dredged soil was maily composed of 48.30 wt% $SiO_2$, 16.60 wt% $Al_2O_3$, 10.10 wt% CaO, 7.75 wt% $Fe_2O_3$. The clay and the glass frit contained 70.82 wt% $SiO_2$ and $Al_2O_3$ 18.78 wt%, and 71.75 wt% $SiO_2$, 13.99 wt% CaO, 8.51 wt% $Na_2O$, respectively. After adding 10~40 wt% to the clay and sintering them at $1,000^{\circ}C$ or $1,100^{\circ}C$, the compressive strength of the sintered specimens showed $132.6{\sim}178.5kgf/cm^2$ or $581.2{\sim}793.7kgf/cm^2$, respectively. In case of SC46 with the addition 40 wt% of the dredged soil to the clay, the compressive strength ($793.7kgf/cm^2$) of specimen sintered at $1,100^{\circ}C$ was over 5 times higher than that at $1,000^{\circ}C$. The specimen mixed with 40 wt% of dredged soil, 60 wt% of clay and 1 wt% of glass frit satisfied the 1st grade standard for clay brick by KS L 4201. The results of all specimens by Korean Standard Leaching Test also satisfied the standard criteria.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.20 no.3
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• pp.147-152
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• 2010

In this study, the artificial coarse aggregate was manufactured by using coal ash and low grade clay. The characteristics of a coal ash-clay system were investigated using XRD, XRF, TG-DTA, SEM and Dilatometer with various coal ash contents. The chemical compositions are the fly ash, bottom ash and clay, $Al_2O_3$ are 28.5 wt%, 32.4 wt% and 18.1 wt%, and $SiO_2$ are 33.0 wt%, 53.7 wt% and 68.4 wt% in weight ratio, respectively. The shrinkage of specimens started at around $850^{\circ}C$ and changed little up to $1100^{\circ}C$, but increased markedly at above $1100^{\circ}C$. The shrinkage rate is strongly related to the decarbonization amount of coal ash. At the sintering temperature $1150^{\circ}C$, it was found that quartz, mullite, anorthite and albite phase exist in all specimens. It was found that bottom-clay system specimen sintered at $1150^{\circ}C$ had a good compressive strength of 87.5 kg/$cm^2$, and the compressive strength of bottom-clay specimen was higher than that of fly-clay system specimen. The reusability of coal ash as a raw material in the process of shotcrete resources such as artifical coarse aggregate is highly expected.