Mineralogical and petrographic analysis on the flake graphite ore from Saba Boru area in Ethiopia

The mineralogy and petrography of natural graphite in Saba Boru of Ethiopia indicate that there exists flake graphite with a slightly oval structured fine size according to our study on thin and polished sections. Herein, for estimating the carbon content in graphite, the ASTM-0561, the test method for ash in a graphite sample, was used. For characterizing graphite, x-ray diffraction, x-ray fluorescence, inductively coupled plasma mass spectroscopy, and scanning electron microscopy were also used. Chemical analysis of ore samples determined that the average compositions are 63.35% SiO2, 15.45% Al2O3, 2.36% Fe2O3, 2.07% K2O, less than1% others, and loss-on-ignition (LOI) in the range of similar to 4.74%-37.42%. The total carbon content of graphitic ore ranged from 4.11% to 33.14%. Importantly, when graphite is concentrated through floatation, its average purity and recovery are 92.97% and 90.82%, respectively. Furthermore, once the graphite concentrates are treated with hydrofluoric acid, the average value attains a high grade of 96.48% C. Moreover, the average ash content is 81.93% (pre-flotation) and 3.1% (post-flotation), respectively. Finally, after beneficiation, a silica is identified as a major gangue (85.88%), usable as a raw material for other purposes such as cement. Hence, these graphite-bearing rocks seem to be worth exploring for commercialization opportunities. (C) 2020 Published by Elsevier B.V. on behalf of China University of Mining & Technology.