Jayarathna, S.P.B.L.Peries, C.M.Henegamage, A.P.2022-03-112022-03-112013http://www.erepo.lib.uwu.ac.lk/bitstream/handle/123456789/8488/28-MRT-Biocoagulation%20and%20Its%20Potential%20Application%20for%20Graphite%20Bioprocessing%20.pdf?sequence=1&isAllowed=ySri Lanka is famous for Graphite industry since ancient times around the world. There are three major Graphite mines which are located in Kahatagaha, Bogala and Ragedara. Vein type graphite deposits in Sri Lanka are considered as a unique occurrence of graphite because of its high purity, extensive mineralization and restricted occurrence. Graphite with 95-99% of carbon and gangue minerals such as pyrite, chalcopyrite, calcite, biotite and feldspars are found in each structural type depending on the mode of occurrences and nature of graphite vein (Amarweeraet al., 2013). Hence, removal of impurities from the graphite can increase the economic value of graphite. Flotation cell is common in Graphite industry to upgrade its carbon grade by removing impurities and it can be used to upgrade over 80 % Graphite in Sri Lanka However, efficiency of the flotation cell separation is not effective for Graphite with small particle sizes (Karr et al., 1990). Biocoagulation is the promising method, practiced in all over the world for sorting of small sized mineral particles with the use of microorganisms (Kuyumcuet al., 2009). Therefore, this study is focused to increase the carbon recovery in Graphite through the separation of fine particles using the biocoagulation with microorganisms. Methodology Three different particle sizes (40µm, 53µm and 72µm) of graphite samples were obtained from Bogala and Kahatagaha mines. Isolation of fungi was carried out from the obtained samples using dilution plate techniques with Potato Dextrose Agar (PDA) medium. Pure cultures of the isolated fungi were obtained using single spore isolation technique with the same medium. Isolated pure fungi cultures were inoculated in to 20 ml of Potato Dextrose Broth (PDB) and incubated for 48 hours at 30 C. Then the pH values of the each fungi broth cultures were measured separately. Two grams of each different graphite samples with different particle sizes were mixed with the incubated PDB and kept with continuous mixing for the coagulation. After four days of incubation, the number of coagulates in each broth cultures was counted using the light microscope and the fungal broth culture (F3) which was given the highest coagulates number was selected for the further processing. In order to determine the carbon grade of the sample, coagulates of the selected broth culture were carefully separated out from the broth medium and washed with distilled water for three times. Then the particles with the coagulates were kept in a muffle furnace at 500 C for two hours in order to remove microbial biomass from graphite particles followed by keeping the samples again in muffle furnace at 960 C for further digestion. Initial and the final weights of the sample were measured to calculate the percentage of carbon recovery. Three replicates were maintained for each treatment and data were analyzed using ANOVA with the confidence level of 95% using MINITAB statistical software.enMineral SciencesMineralScience and TechnologyGraphite IndustryGraphiteOther