• Journal of Environmental Science International
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• v.7 no.5
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• pp.693-696
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• 1998

We tried to develope a desulfurization sorbent using eggshell for recycling, practicability, and economic development. The calcination character of the eggshell was examined by thermal gravimetric analysis and qualitative-quantitative character by X-ray diffractometer(XRD) and scanning electron microscope(SEM). The calcination was occurred easily in the case of eggshell and its form was changed from calcite($CaCO_3$) to lime(CaO). The grain and pore sizes of the calcined sample after base-treatment were larger and more crystallic. The adsorption ability of the eggshell was two- to six-times in the calcination temperature more than in the grain size. Therefore, the eggshell was thought to be usable as the desulfurization sorbent.

• Journal of the Mineralogical Society of Korea
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• v.21 no.2
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• pp.209-224
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• 2008

Various types of high-purity limestone, which occurred in the Pungchon Formation, are examined to understand applied-mineralogical factors controlling their calcination characters with respect to the ore characters. To do this work, systematic characterization and determination were carried out for the limestone ores and their calcination products in a fixed heating condition, and the results were correlated and discussed. During the calcination experiment, a phase transition from calcite to quicklime begins to occur selectively in the physical weak zones such as grain boundary, cleavage and twin planes. All the fabrics of original limestones are preserved in the resultant quicklime. In addition, crystallinity of the quicklime was advanced, as the aging time of calcination was increased. Major controlling factors on the calcination effects of the high-purity limestone are elucidated to be the degree of development of cleavage and twin, together with crystallinity and textures in the limestone ore. Especially, lower crystallinity and dense interlocking fabrics obviously play advantageous role in all the calcination characters. But the development of cleavage and twin affects negatively on the calcination characters on account of favoring decrepitaion of quicklime in the lime manufacturing. Thus, the high-purity limestones characteristic of marble fabrics and relatively lower crystallinity are comparatively advantageous for the uses of lime manufacture.

• Korean Journal of Materials Research
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• v.32 no.3
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• pp.125-131
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• 2022

Effect of sulfation processes on the physicochemical properties of ZrO₂ and TiO₂ nanoparticles were thoroughly investigated. SO₄/ZrO₂ and SO₄/TiO₂ catalysts were synthesized to identify the acidity character of each. The wet impregnation method of ZrO₂ and TiO₂ nanoparticles was employed using H2SO₄ with various concentrations of 0.5, 0.75, and 1 M, followed by calcination at 400, 500, and 600 ℃ to obtain optimum conditions of the catalyst synthesis process. The highest total acidity was found when using 1 M SO₄/ZrO₂-500 and 1 M SO₄/TiO₂-500 catalysts, with total acidity values of 2.642 and 6.920 mmol/g, respectively. Sulfation increases titania particles via agglomeration. In contrast, sulfation did not practically change the size of zirconia particles. The sulfation process causes color of both catalyst particles to brighten due to the presence of sulfate. There was a decrease in surface area and pore volume of catalysts after sulfation; the materials' mesoporous structural properties were confirmed. The 1 M SO₄/ZrO₂ and 1 M SO₄/TiO₂ catalysts calcined at 500 ℃ are the best candidate heterogeneous acid catalysts synthesized in thus work.

• Archives of design research
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• v.18 no.4 s.62
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• pp.35-44
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• 2005

In the world, most of the metal technologists were as called as adornment artists than other field of industrial arts strongly industrial characters functional materials and manufacturing technology many used in the present age. In the study, one of adornments researched and material character analyzed about Art Clay Silver. The shrinkage rate of shape was about 0.24%. A shrinking phenomenon drying time thought of evaporation of water linking bonding agents and powders. After calcination of Art Clay Silver, the EDX used that just Ag 100% analyzed a result from the surface assay in the room temperature. A binder with powder in the room temperature considered to disappear, because it was been fume and smoke at high calcined temperature. A study showed when handicrafted necklaces make by these characteristic as using in difficult and delicated operations rather than naturally and beautifully expressive products.

• Journal of the Korean Applied Science and Technology
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• v.26 no.2
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• pp.143-150
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• 2009

Today, wastes of much quantity by fast industrialization and increase in population, population concentration etc. of modem society are increasing. Much oyster shell is breeding by character and conduct of oyster-industry for a long time among them. Oyster shell which breed by-product in oyster cultivating industry that specific gravity of domestic seashore cultivating industry is high is causing environmental problem by problem and so on hindrance, nature spectacle's waste and health hygiene on administration if it is pollution of district along the coast fishing ground, number of public ownership being stored in open area in seashore. About new material just-in-time through recycling and he of oyster shell by these problem wide that study. Go forward more and investigate special quality that is oyster shell's physical chemistry red in this research and oyster shell oyster shell which cause several environmental problems developing ability agricultural chemicals that use this encapsulating micro by ability carrier that is environmentally application possibility examine wish to.

• Journal of Korean Society of Environmental Engineers
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• v.27 no.9
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• pp.932-938
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• 2005

[ $TiO_2$ ] nanoparticles were prepared from the precipitation in $TiCl_4$ and the sol-gel profess in $Ti(OC_3H_7)_4$ as starting materials with various synthetic conditions. The samples were characterized by XRD, SEM, and TEM testing techniques. The photocatalytic degradation of congo red has been investigated in $TiO_2/UV$ process to evaluate photocatalytic activities for the samples. $TiO_2$ nanoparticles calcined at $400^{\circ}C$ had the best photocatalytic activity with the rate constant of the degradation of congo red as $0.0319\;min^{-1}$. The rate constant of $TiO_2$ photocatalysts was increased with the calcination temperature under $400^{\circ}C$ and decreased with the calcination temperature upper $400^{\circ}C$. In the case of $TiO_2$ photocatalysts, the photocatalytic activity wasn't greatly affected by the frequencies of usage. In the similar synthesis condition, the degradation efficiency of the $TiO_2$ particle prepared by $TiCl_4$ was increased to 8.8%, when the rate was compared with the sample prepared by $Ti(OC_3H_7)_4$. The photocatalytic activities of $TiO_2$ photocatalysts synthesized by $Ti(OC_3H_7)_4$ with various conditions were also discussed.