• 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.

• Journal of the Mineralogical Society of Korea
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• v.17 no.4
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• pp.339-355
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• 2004

Locality of domestic high-Ca limestones can be divided into three districts, i.e., (1) the Jecheon-Danyang area, (2) the Samcheok-Taebaek-Jungsun area, and (3) the Uljin-Andong area, in accordance with their geologic background and type of the deposits. Except for some crystalline limestones from the Jecheon-Danyang area, domestic high-Ca limestones were mostly recrystallized and Ca-enriched by the effects of hydrothermal alteration and/or thermal metamorphism. The lime-stones can be also divided into crystalline limestone type, marble type, micro- and mega-crystalline calcite types on the basis of their composition, crystallinity, and mineral facies. An applied-mineralogical characterization of the high-Ca limestones was done through the systematic analyses and tests for the limestones. The high-Ca limestones from the area (1), which are megascopic ally close to the original limestone in lithology, display lower whiteness, higher contents of CaO (51 ～ 54 wt.%), low crystallinity, and fine-grained texture. Two typical hydrothermal types of the high-Ca limestones from the area (2), i.e., micro- (mostly 0.2～0.3 mm) and mega-crystalline (2～15 em) calcite types, have comparatively higher whiteness and rather variable CaO contents (50～55 wt.%) with exhibiting quite different crystallinity each other. The micro-crystalline calcite type is especially dominant in this area, and has comparatively uniform crystallinity and homogeneous composition. Compared to these limestones, the high-Ca limestones from the area (3) show remarkable differences in grade and quality according to their types of deposit and occurrence. Based on these mineral characters and chemical composition, a possible scheme for industrial uses of the domestic high-Ca limestones was suggested.