3352
Recovery of Lithium From Lepidolite by Mechanical Activation
and Acid Leaching
Yuik Eom, Laurence Dyer, Richard Diaz Alorro
Western Australia School of Mines: Minerals, Energy and Chemical Engineering, Curtin University
Aleksandar N. Nikoloski
College of Science, Health, Engineering &Education, Murdoch University
ABSTRACT: Lepidolite, one of the major lithium (Li) hard rock minerals, was mechanically activated in
a planetary ball mill (Restch PM 100) and leached using 20% concentration of sulfuric acid. In this study,
the mechanical activation process was investigated as a pre-treatment method before extracting Li from the
lepidolite concentrate under mild leaching conditions, including atmosphere pressure and room temperature.
The effect of mechanical activation was identified through the leaching efficiencies of alkaline metals and silica
(Si) by treatment time.
Keywords: Mechanical Activation, Lepidolite, Lithium Leaching, Sulfuric Acid Leaching
INTRODUCTION
Lepidolite (K(Li,Al)3(Al,Si)4O10(F,OH)2) is one of the mica
group minerals, which contain lithium (Li) from 1.39% Li
to a theoretical maximum grade of 3.58% Li (Luong et al.,
2013 Rosales et al., 2017 Setoudeh et al., 2019). Since
lepidolite does not require the calcination step for phase
transformation, a one-step roasting process is preferred for
lepidolite processing to reduce operation time and energy
consumption (Luong et al., 2013 Vieceli et al., 2016
Setoudeh et al., 2019). The existing methods are able to
achieve high Li extraction from lepidolite concentrate, but
the energy required to reach high operation temperatures
and the use of corrosive reagents may impact the environ-
ment (Vieceli et al., 2016). The direct leaching of lepidolite
using fluorine-based acids is proposed (Rosales et al., 2017
Wang et al., 2020 Guo et al., 2021), but these acids form
the insoluble fluoride with valuable elements and lower the
metal’s leaching efficiency. Therefore, an appropriate treat-
ment method is required for the remaining fluoride (F–)
in the leaching solution (Rosales et al., 2017 Wang et al.,
2020 Guo et al., 2021).
The mechanochemical-assisted process in extractive
metallurgy is known to improve the reactivity of miner-
als and mitigate the drawbacks of the conventional process
(Viecelie et al., 2016 Setoudeh et al., 2019). There are two
modes for mechanochemical processing, mechanical activa-
tion and mechanochemical activation (Warris et al., 1997
Baláž et al., 2014). Mechanical activation enhances the
reactivity of feed material without change in chemical com-
position, and mechanochemical reaction brings changes
in chemical composition (e.g., mechanochemical synthe-
sis) (Warris et al., 1997 Baláž et al., 2014). The mecha-
nochemical-assisted process in lepidolite processing has
been mainly introduced as the pre-treatment method for
the subsequent extraction process, including roasting-water
Recovery of Lithium From Lepidolite by Mechanical Activation
and Acid Leaching
Yuik Eom, Laurence Dyer, Richard Diaz Alorro
Western Australia School of Mines: Minerals, Energy and Chemical Engineering, Curtin University
Aleksandar N. Nikoloski
College of Science, Health, Engineering &Education, Murdoch University
ABSTRACT: Lepidolite, one of the major lithium (Li) hard rock minerals, was mechanically activated in
a planetary ball mill (Restch PM 100) and leached using 20% concentration of sulfuric acid. In this study,
the mechanical activation process was investigated as a pre-treatment method before extracting Li from the
lepidolite concentrate under mild leaching conditions, including atmosphere pressure and room temperature.
The effect of mechanical activation was identified through the leaching efficiencies of alkaline metals and silica
(Si) by treatment time.
Keywords: Mechanical Activation, Lepidolite, Lithium Leaching, Sulfuric Acid Leaching
INTRODUCTION
Lepidolite (K(Li,Al)3(Al,Si)4O10(F,OH)2) is one of the mica
group minerals, which contain lithium (Li) from 1.39% Li
to a theoretical maximum grade of 3.58% Li (Luong et al.,
2013 Rosales et al., 2017 Setoudeh et al., 2019). Since
lepidolite does not require the calcination step for phase
transformation, a one-step roasting process is preferred for
lepidolite processing to reduce operation time and energy
consumption (Luong et al., 2013 Vieceli et al., 2016
Setoudeh et al., 2019). The existing methods are able to
achieve high Li extraction from lepidolite concentrate, but
the energy required to reach high operation temperatures
and the use of corrosive reagents may impact the environ-
ment (Vieceli et al., 2016). The direct leaching of lepidolite
using fluorine-based acids is proposed (Rosales et al., 2017
Wang et al., 2020 Guo et al., 2021), but these acids form
the insoluble fluoride with valuable elements and lower the
metal’s leaching efficiency. Therefore, an appropriate treat-
ment method is required for the remaining fluoride (F–)
in the leaching solution (Rosales et al., 2017 Wang et al.,
2020 Guo et al., 2021).
The mechanochemical-assisted process in extractive
metallurgy is known to improve the reactivity of miner-
als and mitigate the drawbacks of the conventional process
(Viecelie et al., 2016 Setoudeh et al., 2019). There are two
modes for mechanochemical processing, mechanical activa-
tion and mechanochemical activation (Warris et al., 1997
Baláž et al., 2014). Mechanical activation enhances the
reactivity of feed material without change in chemical com-
position, and mechanochemical reaction brings changes
in chemical composition (e.g., mechanochemical synthe-
sis) (Warris et al., 1997 Baláž et al., 2014). The mecha-
nochemical-assisted process in lepidolite processing has
been mainly introduced as the pre-treatment method for
the subsequent extraction process, including roasting-water
