1578 XXXI International Mineral Processing Congress 2024 Proceedings/Washington, DC/Sep 29–Oct 3
industries (Penner, 1978). In 2015, global lithium usage
was primarily distributed between energy storage and/or
batteries (37%) and ceramics (30%). Lubricants and met-
allurgy accounted for 8% and 6% of global usage, respec-
tively (Gloaguen et al., 2018). The main lithium reserves
are located in Chile, Australia, and China (Tkachev et al.,
2018). Australia was the top lithium producer in 2017, with
11,000 tonnes of spodumene produced, followed by Chile
and China (Jaskula, 2017). The distribution and type of
lithium deposits, i.e., rock or brine, are well defined, which
may explain the high supply risk associated with this metal.
Lithium is present in very low concentrations in the
Earth’s crust, as evidenced by its Clarke value of approxi-
mately 20 ppm (Robb, 2005). Therefore, it is essential to
identify lithium occurrences. The main lithium deposits are
brines (also known as salars) and rock deposits (Kesler et
al., 2012). In the case of rock deposits, several types exist,
such as pegmatites, rare metal granites, or sedimentary
deposits (Alekseev et al., 2019). These deposits hold 32%
of the world’s Li resources. However, only LCT pegma-
tites (Lithium Cesium Tantalum) and rare metal granites
can contain economically viable concentrations of lithium
(Garrett, 2004). Rare metal granites typically contain lepid-
olite, zinnwaldite, and amblygonite, with lepidolite being
the primary lithium-bearing mineral. These deposits are
the main sources of lithium in Europe and are increasingly
under study, as evidenced by emerging research projects on
Keliber pegmatites and St-Austell, Cinovec/Zinnwald, and
Beauvoir granites.
A thorough understanding of rock lithium deposits
relies on a detailed characterization of the mineral phases
bearing this metal, their size and texture, as well as their
spatial distribution within the deposit. This knowledge
is essential for understanding the efficiency or challenges
related to mineral separations, especially in the case of
flotation, a separation method based on mineral surface
properties (Fandrich et al., 2007 Sutherland and Gottlieb,
1991). Moreover, the use of such methods has often led to
adaptation and improvement of deposit processing schemes
(Buchmann et al., 2018 Vanderbruggen et al., 2021). Since
lithium is both a lightweight element and concentrated in
complex mineral phases, this characterization is only partial
and costly in terms of time, energy, and capital. Therefore,
the present study focused, based on the Beauvoir granite
case study, on the development of an analytical method
overcoming these hurdles. This method combines innova-
tive analytical methods such as µXRF and µLIBS (Menzies
et al., 2022 Nikonow and Rammlmair, 2017). Such meth-
ods are suitable for detecting and quantifying light elements
present in the Beauvoir granite and improve the flexibility
of the developed automated mineralogy method.
MATERIALS AND METHODS
SEM and µXRF analysis were carried out at the Service
Commun de Miscroscopie Electronique et de Microanalyse
X (SCMEM) of the GeoRessources research center
(Université de Lorraine, Nancy, France).
Sample
Samples of cores were provided by the company Imerys.
The sampling campaign conducted aimed to collect repre-
sentative samples of the Beauvoir granite. In addition, rep-
resentative samples of the different degrees of alteration of
this granite were provided to identify the issues associated
with these facies for the valorization of the deposit. These
samples were used, on one hand, to prepare thin sections
and, on the other hand, for ore processing tests. Following
the ore processing tests, the separation concentrates were
sampled and cast in resin to produce polished sections.
These sections are used for characterization studies. The
resin used has a high viscosity, which limits the sedimenta-
tion of grains during resin curing.
Characterization
Optical Microscopy
The thin sections were observed under a transmitted light
optical microscope. Scans of the thin sections were per-
formed using a VHX A525 macroscope (Keyence, Japan),
in plane and cross polarized light.
SEM Analysis
The scanning electron microscope used is a Tescan VEGA3
(Bruker, Germany). Using Esprit 2.3 software (Bruker,
Germany), backscattered electron (BSE) imaging was con-
ducted using mapping routines. The acquired images were
5% overlaid using the software. The experimental condi-
tions for acquisition were approximately 15 kV voltage, 12
kV beam intensity, and approximately 30 seconds acquisi-
tion time per image. Prior to mapping, EDS measurements
were performed to assign the observed shades in BSE to the
various minerals in the sample.
X-Ray Fluorescence (XRF)
Micro X-ray fluorescence (µXRF). The samples were
mapped using micro-X-ray fluorescence (µXRF) with an
M4 Tornado spectrometer (Bruker, Germany), equipped
with a Rh tube and two 30 mm2 EDS detectors. The anal-
yses were conducted at a pressure of 20 mbar. Analytical
conditions were set with a 20 μm diameter X-ray beam
industries (Penner, 1978). In 2015, global lithium usage
was primarily distributed between energy storage and/or
batteries (37%) and ceramics (30%). Lubricants and met-
allurgy accounted for 8% and 6% of global usage, respec-
tively (Gloaguen et al., 2018). The main lithium reserves
are located in Chile, Australia, and China (Tkachev et al.,
2018). Australia was the top lithium producer in 2017, with
11,000 tonnes of spodumene produced, followed by Chile
and China (Jaskula, 2017). The distribution and type of
lithium deposits, i.e., rock or brine, are well defined, which
may explain the high supply risk associated with this metal.
Lithium is present in very low concentrations in the
Earth’s crust, as evidenced by its Clarke value of approxi-
mately 20 ppm (Robb, 2005). Therefore, it is essential to
identify lithium occurrences. The main lithium deposits are
brines (also known as salars) and rock deposits (Kesler et
al., 2012). In the case of rock deposits, several types exist,
such as pegmatites, rare metal granites, or sedimentary
deposits (Alekseev et al., 2019). These deposits hold 32%
of the world’s Li resources. However, only LCT pegma-
tites (Lithium Cesium Tantalum) and rare metal granites
can contain economically viable concentrations of lithium
(Garrett, 2004). Rare metal granites typically contain lepid-
olite, zinnwaldite, and amblygonite, with lepidolite being
the primary lithium-bearing mineral. These deposits are
the main sources of lithium in Europe and are increasingly
under study, as evidenced by emerging research projects on
Keliber pegmatites and St-Austell, Cinovec/Zinnwald, and
Beauvoir granites.
A thorough understanding of rock lithium deposits
relies on a detailed characterization of the mineral phases
bearing this metal, their size and texture, as well as their
spatial distribution within the deposit. This knowledge
is essential for understanding the efficiency or challenges
related to mineral separations, especially in the case of
flotation, a separation method based on mineral surface
properties (Fandrich et al., 2007 Sutherland and Gottlieb,
1991). Moreover, the use of such methods has often led to
adaptation and improvement of deposit processing schemes
(Buchmann et al., 2018 Vanderbruggen et al., 2021). Since
lithium is both a lightweight element and concentrated in
complex mineral phases, this characterization is only partial
and costly in terms of time, energy, and capital. Therefore,
the present study focused, based on the Beauvoir granite
case study, on the development of an analytical method
overcoming these hurdles. This method combines innova-
tive analytical methods such as µXRF and µLIBS (Menzies
et al., 2022 Nikonow and Rammlmair, 2017). Such meth-
ods are suitable for detecting and quantifying light elements
present in the Beauvoir granite and improve the flexibility
of the developed automated mineralogy method.
MATERIALS AND METHODS
SEM and µXRF analysis were carried out at the Service
Commun de Miscroscopie Electronique et de Microanalyse
X (SCMEM) of the GeoRessources research center
(Université de Lorraine, Nancy, France).
Sample
Samples of cores were provided by the company Imerys.
The sampling campaign conducted aimed to collect repre-
sentative samples of the Beauvoir granite. In addition, rep-
resentative samples of the different degrees of alteration of
this granite were provided to identify the issues associated
with these facies for the valorization of the deposit. These
samples were used, on one hand, to prepare thin sections
and, on the other hand, for ore processing tests. Following
the ore processing tests, the separation concentrates were
sampled and cast in resin to produce polished sections.
These sections are used for characterization studies. The
resin used has a high viscosity, which limits the sedimenta-
tion of grains during resin curing.
Characterization
Optical Microscopy
The thin sections were observed under a transmitted light
optical microscope. Scans of the thin sections were per-
formed using a VHX A525 macroscope (Keyence, Japan),
in plane and cross polarized light.
SEM Analysis
The scanning electron microscope used is a Tescan VEGA3
(Bruker, Germany). Using Esprit 2.3 software (Bruker,
Germany), backscattered electron (BSE) imaging was con-
ducted using mapping routines. The acquired images were
5% overlaid using the software. The experimental condi-
tions for acquisition were approximately 15 kV voltage, 12
kV beam intensity, and approximately 30 seconds acquisi-
tion time per image. Prior to mapping, EDS measurements
were performed to assign the observed shades in BSE to the
various minerals in the sample.
X-Ray Fluorescence (XRF)
Micro X-ray fluorescence (µXRF). The samples were
mapped using micro-X-ray fluorescence (µXRF) with an
M4 Tornado spectrometer (Bruker, Germany), equipped
with a Rh tube and two 30 mm2 EDS detectors. The anal-
yses were conducted at a pressure of 20 mbar. Analytical
conditions were set with a 20 μm diameter X-ray beam