• Journal of Korean Society of Environmental Engineers
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• v.32 no.2
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• pp.185-192
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• 2010

The objective of this study was to investigate the effectiveness of stabilization for army firing range soil highly contaminated with Pb (total Pb: 29,000 mg/kg) using calcined waste oyster shells. The calcination was conducted to activate quicklime from calcite. In order to evaluate the effectiveness of calcination, both natural oyster shells (NOS) and calcined oyster shells (COS) were applied to the Pb contaminated soil. Stabilization was conducted by mixing the contaminated soil with oyster shell media at 5-20 wt% and cured for 28 days. Following 28 days of curing, Pb leachability was measured based on the Korean Standard Test method (0.1 N HCl extraction). The treatment results showed that the COS treatment outperformed the NOS treatment. All of the NOS treatments failed to meet the Korean warning standard of 100 mg/kg. However, the Pb concentrations were significantly reduced to 47 mg/kg and 3 mg/kg upon 15 wt% and 20 wt% COS treatments, respectively which passed the Korean warning standard. Moreover, -#20 mesh materials were more effective than the -#10 mesh materials in effectively reducing Pb leachability. The scanning electron microscopy (SEM)-energy dispersive X-ray spectroscopy (EDX) results indicated that Pb immobilization was strongly linked to Al and Si.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2020.06a
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• pp.75-76
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• 2020

Use fire resistant construction methods, of which fire resistant boards are used to protect buildings and structures from fire. However, in the case of fire resistant boards, the unit price of the main raw material is high and the cost efficiency is low. There have been studies to apply oyster shells to fire resistant boards to solve these problems. On the other hand, egg shells are also considered to be applicable to fire-resistant boards with components like oyster shells, but there is no case of using egg shells as building materials. Therefore, in this study, we confirmed the physical properties of egg shell powers used as mortar filler and compared them with the fire resistant board flexural strength standard. As a result, it was judged that the powder of egg shells could be used as a building material, because the standards for the flexural strength of fire resistant boards were satisfied except for a part.

• Korean Journal of Mineralogy and Petrology
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• v.33 no.3
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• pp.185-193
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• 2020

There have been many studies on the calcination of oyster shells in the perspective of recycling of resources. The quicklime made by the calcination of oyster shells is used either as it is or after reacting with water to transform to liquid lime before being used. However, the liquid lime made from calcined oyster shells show slightly different properties from that of limestone. In this study, to compare these properties of oyster shell with those of limestone, the samples were calcined and reacted with water at various temperatures to transform to a liquid lime and filtered using 150 ㎛ sieves to calculate the transform rate to liquid lime. The calcined limestone was transformed to liquid lime at all temperatures, but calcined oyster shell did not show any transformation at 30℃ and 50℃ under the experimental conditions of this study, and rather increased the weight for the remaining after filtration due to the presence of Ca(OH)₂ produced by the reaction with water, Even at 90℃, the transformation rate of calcined oyster shell to liquid lime was lower than that of limestone. This difference in oyster shell can be explained partly by the preventing calcined one from reacting with water by conchiolin which is protein found in the prismatic and pearl layers of oyster shell. Conchiolin is also known to be stable and does not decompose even at high temperature. However, even the calcined chalk layer without conchiolin shows lower transformation rate than that of calcined limestone, probably due to the small amount of Na in oyster shell, which may cause additional reaction including eutectic melt during calcination process.

• Korean Journal of Materials Research
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• v.13 no.4
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• pp.246-250
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• 2003

Calcium phosphate was prepared by chemical reaction formula using Oyster shells and $H_3$$PO_4$solutions. After added to 0.1 M∼0.9$ M H_3$$PO_4$ solution for oyster shell, prepared powders were investigated for heating properties and formation phase with heat treatment temperatures. As the results of XRD analysis of heated powders at $500^{\circ}C$∼$1200^{\circ}C$,$ CaCO_3$ phases were observed at the temperature of below 900 TEX>$^{\circ}C$ and in the condition of 0.1 M∼0.9 M $H_3$$PO_4$ solutions. However, $CaCO_3$, $CaPO_3$(OH) and $Ca_3$($PO_4$)$_2$ phases were appeared at the temperature range between $500∼900^{\circ}C$ and in the solution of 0.7 M to 0.9 M $H_3$$PO_4$. $Ca_{ 5}$($PO_4$)$_3$(OH) and CaO phases due to the decarbonation of oyster shells($CaCO_3$) were appeared at above $1000^{\circ}C$ and in the solution of below 0.5 M $H_3$X$PO_4$. However in the case of above 0.7 M $H_3$$H_4$ solutions, $Ca_{5}$ ($PO_4$)$_3$(OH) was decomposed into $Ca_3$($PO_4$)$_2$ at more higher 100$0^{\circ}C$. Thus $Ca_3$(X$Ca_4$)$_2$ phases were appeared at higher than 100$0^{\circ}C$.

• Korean Journal of Materials Research
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• v.12 no.9
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• pp.747-749
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• 2002

Hydroxyapatite powders were prepared after heating at $1250^{\circ}C$ by the direct reaction using oyster shells and $H_3$$PO_4$. Properties of hydroxyapatite powders were investigated as XRF, XRD, DTA, FT-IR, SEM. Only hydroxyapatite was observed in XRD powders which was heated at $1250^{\circ}C$ for 2 hours and there was no remained CaO in that sample. And the results of FT-IR of sample was confirmed hydroxyapatite. Sample was agglomerated together, but needle shape morphology was observed in powders heated at $1250^{\circ}C$.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2022.11a
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• pp.75-76
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• 2022

In the event of a fire in the lower space, a high temperature of 1000℃ or more and an explosive fire may occur due to the closed structural features and combustible materials. On the other hand, more than 90% of oyster shells are made of CaCO₃, and when heated to about 700℃ or higher, CaO and CO₂ is generated due to decarboxylation reaction. In this study, we try to infer the amount generated by CO₂ changing the weight of mortar using oyster shells as fine aggregates after heating. in conclusion It is considered that the smaller the particle, the greater the decarboxylation reaction and the greater the weight change.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2023.11a
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• pp.37-38
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• 2023

The purpose of this study is to manufacture mortars incorporating oyster shells and install them in the form of shaped, shaped butt joints, and flat boards to see what difference there is in the back temperature depending on the joint method and the type of installation. Based on the fact that similar backside temperatures were measured regardless of the presence or absence of a joint It is judged that the joint will not affect the backside temperature if it is constructed closely, In the case of ㄱ shaped, it is believed that the backside temperature higher than the backside temperature of the flat board was measured because heat accumulates on the backside during heating.

• Journal of the Korea Institute of Building Construction
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• v.14 no.6
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• pp.523-529
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• 2014

Large amounts of waste shells have been produced each year from shellfish raising industries located in Korean costal areas. Due to the limited space for the waste shell disposal, the related environmental problem has been a serious issue. It is believed that using the waste shells as a source of aggregate for mortar, concrete or bricks can be a good solution. In this research, possibility of utilizing waste shells as an aggregate of mortar is investigated. Waste shells of manila clam, cockle, clam, sea mussel, and oyster were properly crushed, sieved, and sorted to meet the requirements of the grading of standard fine aggregate. After that, the waste shells were used as partial and total replacement of the fine aggregate, and their absorption and 28-day compressive strengths of mortar were measured. In general, replacement of waste shells increased the absorption and decreased the strength. However, one specimen with cockle increased compressive strength as replacement ratio increased. Mortar with cockle of 50% and 100% replacement showed higher compressive strength than that of control mortar. This increase of compressive strength was found to be affected by the strong interfacial bonding properties of the cockle and a cement matrix.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2017.11a
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• pp.26-27
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• 2017

Oyster packs generate about 150,000 tons a year. Various studies are under way to utilize this oyster shell. Ca is the main component of oyster shell and is used as a raw material of refractory board. Studies on application of refractory board using oyster shell are also continuing. It is expected that the refractory characteristics will be improved as the mass of oyster shell, that is Ca, increases. In this study, mortar specimens and board specimens were fabricated by increasing the mass ratio of oyster shells classified below 0.6mm, 1.2 ~ 0.6mm, 2.5 ~ 1.2mm and 5.0 ~ 2.5mm, and the strength and fire resistance characteristics were examined.

• Journal of the korean society of oceanography
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• v.31 no.1
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• pp.32-36
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• 1996

The oyster shell bed (more than 47 cm thick) atop the Gaipri Point (granite coastal bluff) in the Hampyung Bay, southwest coast of Korea which is a coastal area of southeastern margin of the Yellow Sea basin has been interpreted as unique typhoon deposit formed at about 3610 yr BP or later. The unconformable boundary between the oyster shell bed by typhoon and the granitic soil horizon of the Gaipri Point is 820 cm high above the mean high-tide water level (MHWL). The $^{14}C$ age of the oyster shells is 3610${\pm}$70 yr BP.