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48 results on '"Kim, Kyeong Ho"'

2. Regeneration of used sand with sodium silicate binder by wet method and their core manufacturing

Author

Min A Bae, Kim Kyeong Ho, Jae Ho Baek, Hung-Suck Park, and Man Sig Lee

Subjects
Materials science, Metallurgy, 0211 other engineering and technologies, Sodium silicate, 02 engineering and technology, Molding (process), 010501 environmental sciences, 01 natural sciences, Hazardous air pollutants, Grinding, law.invention, chemistry.chemical_compound, chemistry, Mechanics of Materials, law, Casting (metalworking), Sand casting, Molding sand, 021108 energy, Waste Management and Disposal, 0105 earth and related environmental sciences
Abstract

Organic binders that are used in sand casting emit high amounts of hazardous pollutants and volatile organic compounds during the casting process. Inorganic binders do not emit harmful gases and are widely used in aluminum casting processes. However, there is a paucity of studies on the reuse of waste sand using inorganic binders in casting processes. In the study, waste sands using an inorganic binder and a powder were recycled via wet regeneration and the effects of residual powder on regenerated sand were analyzed. The wet regeneration of molding and casting sands was performed by cleaning, followed by grinding in a 0.2-M KOH solution and then removing the residual binder using water. The molding sand was regenerated to the same level as the raw sand via the 0.2-M KOH solution followed by water cleaning twice. The casting sand removed most of the binder via additional water cleaning for the regeneration condition of the molding sand. Although the powder was completely removed from the regenerated molding sand, the regenerated casting sand remained used powder; the residual powder had a 78% performance. Thus, the regenerated casting sand was reusable only when adding binder without powder.

Published
2020

4. Synthesis of Zn/Al mixed-oxide catalyst for carbonylation of glycerol with urea

Author

Young Bok Ryu, Kim Kyeong Ho, Ji Sun Kim, Man Sig Lee, and Yangdo Kim

Subjects
010405 organic chemistry, Coprecipitation, Inorganic chemistry, General Chemistry, 010402 general chemistry, 01 natural sciences, Hydrothermal circulation, 0104 chemical sciences, Catalysis, chemistry.chemical_compound, chemistry, Urea, Glycerol, Carbonate, Mixed oxide, Carbonylation
Abstract

Zn/Al mixed oxide was prepared by the coprecipitation or the hydrothermal method under different conditions and used as catalyst for synthesis of glycerol carbonate by carbonylation of glycerol with urea. The physical properties of the prepared Zn/Al mixed oxide particles were investigated, as well as their activity as catalyst in the mentioned synthesis. The dried Zn/Al mixed-oxide particles prepared by the coprecipitation method showed higher activity in synthesis of glycerol carbonate than those prepared by the hydrothermal method. The Zn/Al mixed oxide prepared by the coprecipitation method without NaNO3 showed the highest catalytic activity in synthesis of glycerol carbonate.

Published
2015

43. Chemical constituent ofAloe capensis

Author

Park, Man Ki, primary, Park, Jeong Hill, additional, Shin, Young Geun, additional, Choi, Yong Seok, additional, Kim, Kyeong Ho, additional, Cho, Tae Hyeong, additional, and Lee, Seung Ki, additional

Published
1997
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44. Chemical constituents inAloe barbadensis

Author

Park, Man Ki, primary, Park, Jeong Hill, additional, Shin, Young Geun, additional, Choi, Su Mi, additional, Choi, Yong Seok, additional, Kim, Kyeong Ho, additional, and Lee, Seung Ki, additional

Published
1997
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