Pan European Networks - Horizon 2020 - page 86

E
lcora’s intent is to develop a vertically integrated graphite/
graphene company that produces natural flake graphite for
the production of premium quality graphite and graphene
based on the client’s requirements. This is, in part, to address the
industry-wide poor graphene quality reproducibility caused, to an
extent, by uncontrolled variations in the source of graphite.
Graphite is sold by grade and crude particle size distribution
information, but it may have significant variability in characteristics
such as crystal area, depth or number of layers, source defects
and different contaminations.
Graphite can be characterised on a crystal basis by area (a and
b axis), depth (c axis, number of layers), imperfections within the
crystal and intimately, or in-grown associated contaminations. On
a bulk level graphite can also be characterised by additional
contaminants that are not part of the graphite itself. Many
graphite suppliers do not control or quantify one or more of these
characteristics. As changes within each of these characteristics
are a source of variability within a graphene product, they should
be held within an acceptable range in order to produce
consistent graphene.
Strategy
Elcora’s strategy is to optimise each stage of production for the
final graphene products in terms of both quality and consistency.
This involves control and careful engineering of the entire supply
chain to ensure quality control, i.e. integrated mining, processing
and refining.
The focus of the mining aspect of the company is on deposits that
lend themselves to conversion to high quality graphite as a
precursor for graphene. Various deposits have been prioritised
based on a suitable distribution of crystal sizes and the ability to
purify the product to values in excess of 99% while maintaining
the
in situ
flat crystal morphology, the presence of minimal crystal
imperfections, and the absence of source contaminants that are
inter-grown with the graphite. Elcora may perform the mining itself,
in partnership with other companies, or obtain the graphite
through off-takes as long as the quality control is maintained.
Development
The first stage of this development is the Ragedara graphite
deposit in Sri Lanka, where Elcora is the operator of a joint
venture. This is a former producing mine whose peak production
was approximately 18,000 tonnes per year using primitive
technology. Earlier mining extended only about 100 metres from
the surface and protracted much of the way along an 8km ridge
from Ragedara to the state-run mine of Kahatagaha. The state
mine is currently mining at about the 600m level. The graphite
veins are almost vertical and vary up to about two metres in
width, with needle-shaped aggregates of graphite forming on the
periphery of the vein and massive or sheets of closely packed
graphite crystals in the middle.
Native contaminations within the vein are centimetre-long or
larger pyrite and silica. There are zones of matte rather than
metallic lustre graphite that contains sand-sized silica. Blasting
results in the inclusion of pea-sized metamorphic host rock.
Current production at the mine is, for graphite samples, at about a
tonne a day as exploration and development work progresses.
Mining techniques are being developed to reduce the blasting
dilution and to leave the larger silica and pyrite in the mine.
Elcora is also investigating joint ventures with a number of other
companies on deposits outside of Sri Lanka wherein Elcora would
do the processing and refining. This will enable Elcora to blend
graphite from various sources to customise product characteristics
for specific clients and give them a consistent product that might
now be produced from a single source.
Construction
Elcora is currently constructing the processing plant specifically
designed for the Ragedara graphite deposit. This will be done
through equipment that has been selected, modified or designed
Graphene and graphite are in high demand; Elcora Resources provides quality
products suited to the needs of its clients
Elcora’s graphene strategy
86
I S S U E S I X
H O R I Z O N 2 0 2 0 P R O J E C T S : P O R TA L
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