Abstract: In order to investigate the process mineralogy of a cryptocrystalline graphite ore in North Korea， analysis methods of chemical analysis， X-ray diffraction （XRD）， and scanning electron microscope （SEM） were used to systematically study the chemical composition， mineral composition， particle size distribution， carbon phase and ore structure of the raw ores， and the preliminary process exploration was carried out. The results showed that: ①the fixed carbon content is 70.29%， which is the main valuable element， indicating the raw ores belonging to low-carbon graphite. Carbon mainly exists in the form of graphite， carbonate and organic carbon， and contents are 70.29%， 4.21% and 2.80%， respectively. The ore is steel-gray， with fine crystalline scaly metamorphic structure， dense block structure， reticulated vein structure， and white reticulated calcite， quartz veinlets and speckled and scattered calcite-quartz aggregate can be seen. The contents of graphite， quartz， calcite， sericite， pyrite are 70%， 15%， 8.0%， 5.0% and 1.0%， respectively. The relationship between graphite and gangue mineral inlay is complex. ②Based on the process mineralogy and the separation and purification process of cryptocrystalline graphite， the stage grinding and stage separation process is preliminarily adopted with emulsion kerosene as collector， MIBC as foaming agent and sodium silicate as inhibitor. The graphite concentrate with fixed carbon content of 87.40% and recovery rate of 93.11% was obtained by "two roughing， seven cleaning and one scavening". In order to obtain high quality graphite concentrate， the combined process of "flotation and chemical purification" was considered to be adopted.

Key words: cryptocrystalline graphite, process mineralogy, floatability, fixed carbon content