VANCOUVER, BC, June 29, 2021 /CNW/ - South Star Battery
Metals Corp. ("South Star" or the
"Company") (TSXV: STS) (OTCQB: STSBF), along with its
technological partner in the United
States ("US Lab"1), are pleased to announce that
South Star has successfully produced uncoated and coated spherical
purified graphite ("SPG") suitable for use as anode active material
for lithium-ion batteries ("LiB").
"We are pleased to continue announcing robust battery testing
results," commented Richard Pearce,
President and CEO of South Star. "The thermal purification process
resulted in 99.9993 wt % C without any of the environmental, health
and worker safety issues associated with application of
hydrofluoric and hydrochloric acids, which are the standard
chemicals used in conventional processing of battery grade
graphite. Excellent quality uncoated and coated SPG suitable for
LiB anodes was produced. Our spherical graphite testing resulted in
yields of approximately 74%, which is twice the standard industry
yield. The results indicate we would be very cost competitive with
a less costly micronization process and exceptional spherical
graphite yields. The latest testing highlights the high-quality,
high-purity and low-contaminate nature of South Star's concentrates
for value-add and purified graphite products. We will now be
constructing battery cells and performing long-term cycle testing
and optimizations."
Micronization Test Results
Purified graphite was successfully micronized using advanced
pilot scale mechanical milling system outfitted with two air
classification circuits. The latter technology was found to be
preferable over micronization in cascading air jet mills.
Specifically, Santa Cruz flake has
demonstrated nearly twice higher throughput rate during the
mechanical grinding and sizing, as compared to sizing rate in an
air-mill of the same nominal size. During sizing step, the size of
flakes was reduced to a range of 25 to 30 microns prior to
spheroidization. Geometries and shape factors are adjusted based on
the battery cell manufacturer's requirements and the inherent
physical characteristics of the graphite.
Mechanical milling was effective in sizing of its flake and
resulted in higher throughput, which translates into lower cost for
the same energy input. It should be noted that a reference sample
of flake graphite from Madagascar
was milled on the same mill concurrently. Santa Cruz flake material ground at 23% faster
than the reference material processed on the same mill to similar
particle size distribution.
Figure 1: Scanning Electron Microscopy Image of Micronized
South Star Flake
Uncoated SPG Test Results
Once the target sizing geometries have been achieved, uncoated
SPG was produced, the micronized graphite was rolled and rounded
into elliptical spheres in a specialized mill. The elliptical
shapes are a preferred morphology for higher active loading
densities in batteries. They are also preferred due to better rate
capacities, safer and generally longer-life LiBs.
The safety aspect of LiBs deserves a standalone comment. Passing
criteria for spherical uncoated graphite is defined by the BET
(Brunauer, Emmett and Teller) surface area value. The latter has to
be less than 10 m2/g for
graphite to be considered promising in anode applications. Many
uncoated graphites struggle to deliver such a BET surface area and
that requires the application of thick exterior coatings as a way
to mitigate this issue. By contrast, Santa Cruz spheroidal flake was determined to
have BET values of 6.7
m2/g, which is indicative of the fact that this
material will require rather thin surface coatings to make a
successful anode for LiBs. Moreover, as much as 47.11 wt % of
spheronized Santa Cruz graphite
was measured to have tap density in the range from 1.02 to 1.16
g/cm3. An additional 26.9 wt % of spheroidal particles
was harvested with the tap density of 0.9 g/cm3, which is a passing
criterion for LiBs. Therefore, a combined total of 74.01 wt% of
useable uncoated spheroidal purified graphite was harvested in the
process of spheroidization of Santa
Cruz natural flake. In contrast, typical yields of
spheroidal product synthesized in the cascade milling circuits by
Asian manufacturers of spherical graphite are 35-40 wt % spheres.
It is worth noting that higher yield is a prerequisite to the cost
leadership position of Santa Cruz
natural graphite on the worldwide markets of advanced graphite
products.
Figure 2: Scanning Electron Micrograph of Spherical Graphite
(Intermediate Product)
Coated SPG Test Results
Finally, uncoated SPG was coated with a nanolayer of soft carbon
and heat treated under a blanket of inert gas. The hardened
coating provides a layer of protection from exfoliation and general
degradation during the normal expansion and contraction cycles
associated with charging and discharging. The coating also reduces
ongoing reactions of electrolytes with the graphitic carbon, which
results in a reduced battery life. Coated SPG is the basic raw
material used to generate battery anodes by casting the coated SPG
onto copper foils.
For this round of testing a D50 of 18 microns of purified
graphite was produced. Future testing will include optimization of
particle size and determining the electrochemical performance of
Santa Cruz graphite in the battery
cell environment. The results of the Coated SPG testing indicate
excellent physiochemical properties for high-quality LiB anode
materials. A summary is presented in Table 1 and Figures 2 and 3,
below:
Table 1: Coated SPG Summary Characteristics (D50 = 18
microns)
Tap
Density
|
Scott
Volume
|
Surface
Area
|
(g/cc)
|
(g/cc)
|
m2/g
|
0.94
|
0.69
|
2.35
|
Figure 3: Coated SPG (D50 = 18 microns) Particle Size
Distribution
Figure 4: Scanning Electron Micrographs of Coated SPG
Figure 4: Scanning Electron Micrographs of Coated SPG
About South Star Battery Metals Corp.
South Star Battery Metals Corp. is Canadian Graphite developer
focused on the selective acquisition and development of near-term
production graphite projects in Brazil. South Star's Santa Cruz Graphite
Project, located in Southern Bahia, and is the first of a series of
industrial and battery metals projects that will be put into
production. Brazil is the
second-largest graphite-producing region in the world with more
than 80 years of continuous mining. Santa
Cruz has at-surface mineralization in friable materials, and
successful large-scale pilot-plant testing (>30t) has been
completed. The results of the testing show that approximately 65%
of Cg concentrate is +80 mesh with good recoveries and 95-99% Cg.
With excellent infrastructure and logistics, South Star is carrying
its development plan towards Phase 1 production projected in Q4
2022, pending financing. South Star trades on the TSX Venture
Exchange under the symbol STS, and on the OTCQB under the symbol
STSBF.
South Star is committed to a corporate culture, project
execution plan and safe operations that embrace the highest
standards of ESG principles based on transparency, stakeholder
engagement, ongoing education and stewardship.
To learn more, please visit the Company website at
www.southstarbatterymetals.com.
This news release has been reviewed and approved by Richard
Pearce, P.E., a "Qualified Person" under National Instrument 43-101
and President and CEO of South Star Battery Metals.
On behalf of the Board,
Mr. Richard Pearce
Chief Executive Officer
Twitter: https://twitter.com/southstarbm
Facebook:
https://www.facebook.com/southstarbatterymetals
LinkedIn:
https://www.linkedin.com/company/southstarbatterymetals/
CAUTIONARY STATEMENT
Neither the TSX Venture Exchange nor its Regulation Services
Provider (as that term is defined in policies of the TSX Venture
Exchange) accepts responsibility for the adequacy or accuracy of
this press release.
This news release and the Updated Technical Report contain
references to inferred resources. The Report is preliminary in
nature and includes inferred mineral resources that are considered
too speculative geologically to have the economic considerations
applied to them that would enable them to be categorized as mineral
reserves.
Forward-Looking Information
The information contained herein contains "forward-looking
statements" within the meaning of applicable securities
legislation. Forward-looking statements relate to information that
is based on assumptions of management, forecasts of future results,
and estimates of amounts not yet determinable. Any statements that
express predictions, expectations, beliefs, plans, projections,
objectives, assumptions or future events or performance are not
statements of historical fact and may be "forward-looking
statements".
Forward-looking statements are subject to a variety of risks
and uncertainties which could cause actual events or results to
differ from those reflected in the forward-looking statements,
including, without limitation: risks related to failure to obtain
adequate financing on a timely basis and on acceptable terms; risks
related to the outcome of legal proceedings; political and
regulatory risks associated with mining and exploration; risks
related to the maintenance of stock exchange listings; risks
related to environmental regulation and liability; the potential
for delays in exploration or development activities or the
completion of feasibility studies; the uncertainty of
profitability; risks and uncertainties relating to the
interpretation of drill results, the geology, grade and continuity
of mineral deposits; risks related to the inherent uncertainty of
production and cost estimates and the potential for unexpected
costs and expenses; results of prefeasibility and feasibility
studies, and the possibility that future exploration, development
or mining results will not be consistent with the Company's
expectations; risks related to commodity price fluctuations; and
other risks and uncertainties related to the Company's prospects,
properties and business detailed elsewhere in the Company's
disclosure record. Should one or more of these risks and
uncertainties materialize, or should underlying assumptions prove
incorrect, actual results may vary materially from those described
in forward-looking statements. Investors are cautioned against
attributing undue certainty to forward-looking statements. These
forward-looking statements are made as of the date hereof and the
Company does not assume any obligation to update or revise them to
reflect new events or circumstances. Actual events or results could
differ materially from the Company's expectations or
projections.
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SOURCE South Star Mining Corp.