The mineralogical characteristics of the ultrafine calcite (UFC) in the Namsan karst cave were studied. The UFC formed in the cave comes in the form of a gel with white or light yellow very fine mineral particles containing water. Chemical composition of UFC is CaO 55.62%, MgO 0.3%, SiO2 0.09%, Al2O3 0.01%, Fe2O3 0.03% and ignition loss 43.78%. The minimum particle size of UFC was 0.12 μm, the maximum size was 5.25 μm, and it was characterized in that the average particle size (1.39 μm was very small and the size distribution was narrow by a result of laser particle size analysis. The pyrolysis temperature (630 ~ 900 °C) was much lower than the theoretical that of calcite. Infrared absorption curves with a wavelength of 711.8, 873.9, 1423.6 and 1797.9/cm agree very well with the curve of typical carbonate minerals. Microscopic observation showed that almost round individual particles were formed into a net shape by being formed into a chain shape. The crystal particle size of UFC by X-ray diffraction (XRD) analysis was 149.3 μm The crystal structure of UFC was in agreement with the crystal structure of the chain-like calcium carbonate produced by the synthetic method and is confirmed as a chain-like UFC not known in nature hitherto by a result of XRD. The pH of UFC was 7.3, the covering power 56.8 g/m2, and the predicted specific surface area 1989.19 m2/kg. In Namsan karst cave, the UFC were basically divided into 20 ~ 30 cm thickness on the ceiling of the cave and 30 ~ 50 cm thickness on the middle of the cave bottom sediment layer. UFC in the Namsan karst cave was very important in not only mineralogy but also resources.

中文翻译：

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朝鲜民主主义人民共和国南山溶洞形成的超细方解石

研究了南山溶洞中超细方解石(UFC)的矿物学特征。在洞穴中形成的 UFC 以凝胶的形式出现，带有白色或浅黄色的非常细的含水矿物颗粒。UFC的化学成分为CaO 55.62%、MgO 0.3%、SiO2 0.09%、Al2O3 0.01%、Fe2O3 0.03%和烧失量43.78%。UFC 的最小粒径为 0.12 μm，最大粒径为 5.25 μm，激光粒度分析结果表明其平均粒径（1.39 μm 很小，粒径分布窄）温度（630～900℃）远低于方解石的理论值，波长为711.8、873.9、1423.6和1797.9/cm的红外吸收曲线与典型碳酸盐矿物的曲线非常吻合。显微镜观察表明，几乎圆形的单个颗粒通过形成链状而形成网状。通过 X 射线衍射 (XRD) 分析，UFC 的晶体粒径为 149.3 μm UFC 的晶体结构与合成方法生产的链状碳酸钙的晶体结构一致，证实为链状迄今为止，根据 XRD 的结果，UFC 在自然界中未知。UFC的pH值为7.3，覆盖力为56.8 g/m2，预测比表面积为1989.19 m2/kg。在南山溶洞中，UFC基本分为洞顶20～30cm厚和洞底沉积层中部30～50cm厚。南山岩溶洞中的UFC不仅在矿物学上而且在资源上都非常重要。