• Proceedings of the KSEEG Conference
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• 2002.04a
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• pp.327-328
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• 2002

• Journal of the Mineralogical Society of Korea
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• v.22 no.4
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• pp.371-383
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• 2009

Crystallinity and textural relations, which are crucial in terms of the quality concept of high-purity limestone, have not been effectively applicable to the limestone evaluation as crude ore due to the difficulties in precise measurements. To overcome the above, as a new method of ore characterization, a measurement of shape factor and grain boundary frequency utilizing the image analysing system was adopted in this study. Some domestic limestones used for lime manufacturing were investigated by such a quality evaluation method, and its results are discussed and correlated each other samples. As the result, even though calcite contents of crude ore, i.e., limestone grade and its crystal size are similar, quality of manufactured lime is remarkably different depending on the degree of shape factor and grain boundary frequency. In other words, as the more irregular in crystal shape and the higher the grain boundary frequency, the manufactured quick lime became more superior in all terms of lime quality such as rate of calcination, porosity, reactivity, sintering and decrepitation effect. However, because the quick lime become easily overheated in case of relatively higher degree in shape factor and grain boundary effect, a technology minimizing heating time is necessary for the manufacturing of high quality lime. In limestone industry, such a ore characterization method will be much more reasonable than the conventional method by measurement of mean size, because the method may collectively comprise crystal shape and other textural factors which can not be numerically evaluated in the past.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2004.04a
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• pp.139-142
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• 2004

본 논문은 광산산성배수(AMD)에서 철 및 알루미늄 제거 효과가 입증된 인회석을 이용하여 ARD (Acid Rock Drainage)에서의 비소저감 능력을 알아보고 고품위 석회석과 정화효율을 비교하기 위하여 실내실험을 실시하고 그 결과를 이용 인회석 배수로를 설계하는 것을 연구목적으로 하고 있다. 실험결과, pH, 비소제거율 및 석회석/인회석의 용해량은 유속이 증가함에 따라 감소하는 것으로 나타났으며 유속이 0.6 ml/min/kg 정도에서 인회석은 침출수 중 비소를 100% 제거하는 것으로 확인되었다. 유속에 따른 용해율은 인회석이 석회석보다 10배 정도 높은 것으로 나타났다.

• Journal of the Mineralogical Society of Korea
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• v.20 no.2 s.52
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• pp.71-81
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• 2007

The marble-type dolomite from the Jasung Mine, which was farmed by duplicated affects of contact metamorphism and subsequent hydrothermal alteration, corresponds to a high-purity dolomite ranging up to above 98wt.% in dolomite contents. The dolomite contain minor impurities such as quartz, muscovite, and pyrite. It is characteristic that the dolomite is fairy Fe-rich corresponding to 0.4 wt.% due to the presence of pyrite of possible hydrothermal origin. The dolomite is nearly white-colored and constituting with subhedral crystals ranging $0.35{\sim}0.46mm$M in size, forming equigranular texture. Compared to the typical high-Ca limestone from the Pungchon Formation, the powder characteristics of dolomite is rather superior in milling efficiency, yields of fine particles, and size distribution. In addition, except for iron contents, the dolomite powder is no less superior than the limestone in quality and characteristics as fillers with respects to not only whiteness, oil absorption, and specific surface area but also shape characters such as elongation ratio, aspect ratio, and sphericity. This good characteristics of dolomite powder seem to be originated basically from comparatively higher grade and crystallinity of dolomite. Higher iron contents and the presence of sulfides prevents the dolomite from application for uses by thermal treatment, except for metallic manufacture. However, if proper ore separation procedure is available, the dolomite can be sufficiently utilized as substitutes for high-Ca limestone in most fields of filler industries.

• Economic and Environmental Geology
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• v.52 no.1
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• pp.107-118
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• 2019

Two assertions about the process the formation of the high-purity limestone in the Taebaeksan Basin, categorized into syngenetic and epigenetic origin, are verified on the basis of its oxygen-carbon stable isotopic characteristics. The carbonate rocks sampled from the selective six high-purity limestone mines and several outcrops in the Daegi formation are featured by various colors such as the gray, light gray and dark gray. They show a wide range of oxygen stable isotope ratios (4.5 ~ 21.6 ‰), but a narrow range of carbon stable isotope ratios (-1.1 ~ 0.8 ‰, except for vein calcite), which means that they had not experienced strong hydrothermal alteration. In addition, there is no difference in the range of the oxygen stable isotope ratios by mine and color, and it is similar to the range from surrounding outcrop samples. These results indicate that the effect of the hydrothermal alteration were negligible in the generation of high-purity limestone in deposit scale. Whereas, the carbonate rocks can be divided texturally into two groups on the basis of an oxygen isotope ratio; the massive-textured or well-layered samples (>15 ‰), and the layer-disturbed (or layer-destructed) and showing over two colors in one sample (<15 ‰). In the multi-colored samples, the bright parts are characterized by the very low oxygen stable isotope ratios, compared to the dark parts, implying the increase in brightness of the carbonate rocks could be induced by the interaction between hydrothermal fluid and rock. However, these can be applied in a small scale such as one sample and are not suitable for interpretation of the generation of high-purity limestone as a deposit scale. In particular, the high oxygen isotope ratios from the recrystallized white limestone suggest that hydrothermal fluids are also rarely involved during recrystallization process. In addition, the occurrences of the high-purity limestone orebody strongly support the high-purity limestone in the area are syngenetic rather than epigenetic; the high-purity limestone layers in the area show continuous and almost horizontal shapes, and is intercalated between dolomite layers. Consequently, the overall reinterpretation based on the sequential stratigraphy over the Taebaeksan basin would play an important role to find additional reserves of the high-purity limestone.

• Resources Recycling
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• v.26 no.6
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• pp.10-19
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• 2017

It is studied the effect of crystal structure of domestic High-Ca limestones using absorbent for desulfurization on the grinding characteristics and dissolution rates in wet flue gas desulfurization process of domestic coal fired power plant. It compared the crystal structure, grinding work index and dissolution rates with 4 Limestones from Jecheon-Danyang with different crystal structure, and we found that grinding work index differ in crystal size and crystal structure of limestones : The lower the value of the grinding work index is, the higher the dissolution rates of limestones. Confirmed that we have important indicators of grinding characteristics for crystal structure with CaO content of limestones.

• Economic and Environmental Geology
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• v.55 no.1
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• pp.77-95
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• 2022

The Gonamsan gabbroic complex in the Pocheon area, northwestern region of South Korea consists of a variety types of gabbroic rocks and associated Fe-Ti oxide deposits caused by magmatic differentiation. Post-magmatic intrusions (i.e., gabbroic pegmatite and pyroxene-apatite-zircon rocks) partly intruded into the gabbroic rocks. The gabbroic pegmatite occurs in monzodiorite and oxide gabbro of the complex, intimately and spatially associated with high-grade lenticular Fe-Ti oxide mineralization. The pegmatite can be subdivided into plagioclase-amphibole and pyroxene-olivine pegmatite, in which the contact surface is sharp. The plagioclase-amphibole pegmatite comprises plagioclase and amphibole, with lesser amount of pyroxene, ilmenite, sphene, apatite, and biotite. The pegmatite shows plagioclase-amphibole intergranular texture, in which the open space formed by large plagioclase laths (An_2-26Ab_72-98Or_0-2) are infilled by amphibole. The pyroxene-olivine pegmatite is dark gray to black in color and also contains magnetite, ilmenite, spinel, apatite, and calcite as a minor component. The pyroxene (En_35-36Fs_8-9Wo₅₅) and olivine (Fo_84-85Fa_15-16) partly show a poikilitic texture defined by smaller euhedral olivine enclosed by coarser clinopyroxene. Fe-Ti oxide minerals consist mainly of magnetite and ilmenite that are found interstitially to earlier formed silicates. Subsequently, they are encompassed by reaction rim (almost of amphibole and biotite) along the boundary with surrounding silicate minerals. Under the microscope, magnetite contains a lot of oxyexsolved ilmenite (trellis type) and spinel, and thereby is weakly enriched in magnetite-compatible elements such as Ti, Al, Mg, and V. The structure and textures at the contact zone as well as mineralogical disequilibrium between gabbroic pegmatite and the host gabbroic rocks suggest that the pegmatite may form as a result of accumulation from Fe-rich melt (or liquid) that occurred somewhere rather than in situ form from the host gabbroic rock during the magmatic differentiation. Consequently, the preliminary study suggests that further study on the post-magmatic activities can not only help us improve our understanding on magmatic fractionation but also provide critical information on Fe-Ti oxide mineralization in gabbroic rocks resulting from the magmatic differentiation.