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RISS 인기검색어
- 검색키워드
- 저자 : Myoungwook Mun (검색결과 2 건)
- 무료
- 기관 내 무료
- 유료
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Study on characteristics of various extractants for mineral carbonation of industrial wastes
Mun, Myoungwook,Cho, Heechan,Kwon, Jihoe Elsevier 2017 Journal of environmental chemical engineering Vol.5 No.4
<P><B>Abstract</B></P> <P>In this research, blast furnace slag and waste cement were reacted with various acids at the same concentration (0.1M) under atmospheric conditions, in order to determine their efficiency for mineral carbonation. Based on maximum calcium concentration (2400mg/L) and selectivity (99%), waste cement was selected as a suitable material for mineral carbonation, and further experiments were conducted with HCl, CH<SUB>3</SUB>COOH), and NH<SUB>4</SUB>Cl as effective extractants. At low acid concentrations, the concentration of calcium was similar regardless of acid type used. Increasing acid concentration revealed a linear relationship with the maximum ratio of calcium extraction, but the ratio of increment depended on the type of acid. Although the yield of calcium extracted when using NH<SUB>4</SUB>Cl was lower than that extracted when using HCl and CH<SUB>3</SUB>COOH, vaterite was precipitated in carbonation without a basic reagent. Moreover, the NH<SUB>4</SUB>Cl regenerated during carbonation can be reused for calcium extraction. The reaction of waste cement and acids was analyzed using PHREEQC. Even though the initial pH of CH<SUB>3</SUB>COOH was higher than that of HCl for dissociation constants, the equilibrium pH and calcium concentration of extraction solution were similar for the two acids. NH<SUB>4</SUB>Cl showed a lower extraction rate, except at 0.1M. These results were similar to those obtained experimentally. In a periodic fashion, the amount of calcium in the NH<SUB>4</SUB>Cl solution fluctuated within specific values, unlike experimental results. There are two possible reasons for these deviations: (1) kinetics, and (2) lack of thermo-dynamic data of different types for the calcium carbonate polymorphs, with the latter requiring further study.</P>
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Coal and solvent properties and their correlation with extraction yield under mild conditions
Heechan Cho,Kihong Kim,Si Hyun Lee,Myoungwook Mun,Deayang Lee 한국화학공학회 2016 Korean Journal of Chemical Engineering Vol.33 No.7
Coal solvent extraction is a clean coal technology that involves the extraction of organic matter from coal using solvents. In this study, the effects of various coal and solvent properties on extraction yield were studied and their correlations were observed. Solvent extraction was performed for fifteen coal samples of different ranks with eight solvents under mild conditions. Statistical analyses were then conducted to find correlations between the extraction yields and the coal and solvent characteristics. The extraction yield was strongly correlated with the atomic H/C ratio or volatile matter content. Among the solvent properties, the correlation between the electron donor, acceptor number (DNAN) and yield was confirmed to be high. The results of multiple regression showed that positive correlations were found with the content of volatile matter of coal and polar force, DN-AN of solvent. Whereas negative correlations were found with the Ca/Mg content of coal and dispersion force, hydrogen bonding force of solvent. The regressionequation- calculated value was similar to the experimental value.
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