Somarathna, R.M.U.M.Balasooriya, N.W.B.2022-02-082022-02-0820159789550481088http://www.erepo.lib.uwu.ac.lk/bitstream/handle/123456789/8314/56-MRT-Purification%20of%20Surface%20Graphite%20from%20Passyala%2c%20Sri%20Lanka%20.pdf?sequence=1&isAllowed=yFlake graphite occurs as isolated, flat plate-like particles disseminated in lenses or pockets in metamorphic rocks. Less frequently it occurs in massive accumulations in veins. This is the geologically most common variety of natural graphite. Surface graphite (flake graphite) deposits occur at South Western region of Sri Lanka. There were large number of shallow pits in Sri Lanka had historically been sunk in to the weathered rock or top soil and believed more than 2500 graphite pits and mines were located in the west and central highlands. Graphite exploration from Matugama, Warakapola, Passyala and Deniyaya are in progress as new sites. Even though there are various studies on Sri Lankan vein graphite, limited attention was drawn to study the distribution, chemistry, origin and geology setting of surface graphite deposits in Sri Lanka. (Wijayananda N.P.,1987).Froth Flotation is versatile mineral processing technique, that utilizes the difference in surface properties of the valuable minerals and the unwanted gangue minerals to achieve specific separations from complex ores. Graphite have non-polar surface that do not readily attach to the water dipoles. Therefore in the separation graphite can be effectively collected into the froth. (Wills B.A.,2006). considering the chemical purification, recent studies on flake graphite with alkali roasting proven that the purity can be upgraded over 95%. ( Lu, X.J., et al,2002 ) Present research was aimed to study the purification of Sri Lankan flake graphite by using both chemical and physical purification techniques. Materials and methodology Initially collected samples were crushed into chips and prepared powder samples (<250 µm) for both sample no-01(taken from Wawehena mine) and 02 (taken for Kaluaggala mine). 200g from each samples were taken into froth flotation. Separated froth was washed to remove the effect of phenol and dried at 60 C for 24 hours. 3g from each graphite sample was take into alkali roasting, mixed with 10,20,30,40,50,60 vol. % NaOH (solid: liquid, 1:2) separately and roasted at 250 C under air for one hour. The roasted sample was acid-leached in 10 vol. % H2SO4 and filtered. The residue was washed to neutral and vacuum dried at 100 C for 15 hours . (Lu, X.J., et al,2002).Carbon percentage of graphite was determined according to ASTM - 561 and weighing the residues. Both initial and froth floated graphite matrix was characterized by Fourier Transform infrared (FTIR) spectrophotometer in 500 - 4000 cm-1 region (Nicolet 6700). The electrical characterization was performed on the dense graphite pellets by four probe d.c. conductivity in air. Results and discussion Table - 4.1 shows the measured carbon content for both sample 01 and 02, before and after froth flotation. Forth flotation was able to achieve averagely 35% purity enhancement for the collected flake graphite samples. Therefore it clearly evident that the forth flotation technique is much effective as an initial purification technique before moving to the chemical or any other purification method.enMineral SciencesMaterials SciencesGraphiteGraphite IndustryChemicalChemistryPhysical ChemistryOther