Abstract:
Sri Lankan vein graphite comprises extraordinary purity, exceeding 99+% and occurs substantially
as veins in colossal, underground sedimentary rocks. This carbon rich resource comes up with a unique
potentiality to produce high quality graphene nevertheless, a number of obstacles are recognized to
hamper the large scale production. Underground mining process at the boundary of the vein consistently
brings about graphite lumps, consist of stone pieces hence, a substantial aggregate of graphite has been
disposed off while hammering. In this study, it was intended to explore promising approaches to recover
these graphite lumps and subsequently, to synthesize graphene from recovered graphite more efficiently.
Lumps of graphite consist pieces of stones were treated with a dispersion of conc.H2SO4 and conc.HNO3 in
the way that 1:8 volume ratio in room temperature thus, the leaching of dispersion in to graphite layers
facilitates the stripping off and obtains delaminated graphite together with stone pieces. Subsequently,
the delaminated graphite was filtered and after several washing steps the sample is heated at 6000C to
acquire expanded graphite; the precursor for scalable synthesis of graphene. Hummers method with a few
modifications enables a feasible production route concurrently, the expanded graphite enables the obvious
penetration of the intercalating agent (conc. H2SO4) together with amenable oxidation. The spontaneous
expansion of graphite influences in the way that, achieving the milestone of the study by acquiring yield of
graphene about two times more than manipulating ball milled graphite as the precursor. The results give
an insight into large scale, cost effective and industrially viable synthesis of graphene thus, pave the way
towards massive production of enormously important graphene applications.
