• Clean Technology
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• v.7 no.3
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• pp.187-194
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• 2001

The desulfurization process which belongs to the gas refining part is the unit process that eliminates $H_2S$ and COS in the coal gas formed by the coal gasification part in the integrated gasification combined cycle(IGCC). In this study, natural manganese ores were selected as the raw material of the desulfurization sorbent due to economical efficiency. Initial rates for the reactions between $H_2S$ and desulfurization sorbent using natural manganese ores were determined in a temperature range of $400{\sim}800^{\circ}C$ using a thermobalance reactor. All reactions were first order with respect to $H_2S$ and were in accord with the Arrhenius equations. When sulfidation reaction was controlled by diffusion, the temperature dependence of the effective diffusivity was given by the Arrhenius equation. Activation energies and frequency factors were obtained from the product layer diffusion coefficient of various sorbents by plotting as Arrhenius equation form.

• Journal of the Mineralogical Society of Korea
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• v.2 no.2
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• pp.90-99
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• 1989

Manganese deposits ar the Dongnam mine occur as vein in the Pungchon limestone of Ordovician age. Manganese ore veins consist of the hydrothermal manganese carbonate ores in the deeper part and the supergene manganese oxide ores in the shallow part. Manganese carbonate ores consist mainly of rhodochrosite, with minor amount of proxmangite, garnet, calcite, quartz, pyrite, galena and sphalerite. Manganese oxide ores consist of rancieite, buserite, birnessite, vernadite, todorokite, pydrolusite, nsutite, hydrohetaerosite and goethite. Manganese oxide minerals were formed in the following sequences; 1) rhodochrosite ${\rightarrow}$ vernadite ${\rightarrow}$ birnessite ${\rightarrow}$ nsutite ${\rightarrow}$ pyrolusite, 2) pyroxmangite ${\rightarrow}$ birnessite, 3) Buserite ${\rightarrow}$ ransieite. Todorokite, buserite and hydrohetaerolite were precipitated from solution in the later stage. The natural analogue of synthetic buserite has been discovered from the mine. It has been disclosed that buserite transforms to rancicite by dehydration, and that distinction between buserite and todorokite is possible by X-ray diffraction studies combined with dehydration experiment. Minerals identified from the mine have been characterized using various methods including polarizing microscopy, X-ray diffraction, thermal analysis, infrared spectroscopy, X-ray diffraction, thermal analysis, infrared spectroscopy, elecrton microscopy and dehydration experiment.

• Journal of the Mineralogical Society of Korea
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• v.2 no.1
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• pp.1-7
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• 1989

The terrestrial Ca-buserite has been found from Dongnam mine, Korea. It occurs in close association with rancieite in the manganese oxide ores which were formed by supergene weathering of hydrothermal rhodochrosite in veins. A study on this mineral using X-ray diffraction, infrared, polarizing and electron microscopes and dehydration experiment shows that the natural cabuserite (10$\AA$ phase) is more or less unstable, transforming partly to rancieite (7.5 $\AA$ phase) in the natural environment, and upon heating, its 10 $\AA$ line shifts to 7.5$\AA$ at 70-9$0^{\circ}C$. The Ca-buserite is the hydrate of rancieite.

• Journal of the Mineralogical Society of Korea
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• v.18 no.4 s.46
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• pp.259-266
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• 2005

X-ray diffraction (XRD), Electron microprobe analyses (EPMA) and heating experiments were used for mineralogical characterization of natural buserites collected from the Janggun and Dongnam mines. They are closely associated with $7-{\AA}$ phase (usually rancieite) in manganese oxide ores of the supergene oxidation zones of manganese carbonate deposits. Electron microprobe analyses give the average formula $(Ca_{0.78}Mg_{0.64}Mn^{2+}\;_{0.45})Mn^{4+}\;_{8.03}O_{18}\cdot13.2H_{2}O\;and\;(Zn_{0.81}Ca_{0.77}Mg_{0.26})Mn^{4+}\;_{8.00}O_{18}\cdot10.9H_{2}O$ for buserite from the Janggun and the Dongnam mine, respectively. The basal reflection of buserite from the Janggun mine shifts continuously from $9.86\;{\AA}\;at\;40^{\circ}C\;to\;7.60\;{\AA}\;at\;90^{\circ}C$, but the buserite from the Dongnam mine shows tendency of decreasing intensity in the $9.67^{\circ}C$ peak and of increasing intensity in the $7.53\;{\AA}$ peak in the range of $40\∼90^{\circ}C$, showing no gradual shifting of peaks.