2660 XXXI International Mineral Processing Congress 2024 Proceedings/Washington, DC/Sep 29–Oct 3
Zinnwaldite has a similar zeta potential profile to that
of lepidolite (Ney 1973), it is, therefore, a good candidate
for flotation with cationic collectors.
Flotation of Petalite
Bulatovic (2015) and Tadesse et al. (2019) agree that little
research work has been done on the flotation of petalite.
The available data indicates that petalite can be success-
fully floated, with cationic collectors (Jessup et al., 2000)
including primary amines, ether amines and quaternary
ammonium salts. It has also been shown that the flotation
of petalite is insensitive to pH changes and can be done at
any pH between 2.0 and 11.0. Jessup et al. (2000) describe
a successful process to float petalite using a quaternary
ammonium salt at a pH between 2 and 3 in a 10% brine
solution comprised of a 1:1 ratio of NaCl and KCl. Critical
to the process was the activation of petalite with hydroflu-
oric acid (HF) dosed at up to 1,000g/t.
Challenges in Lithium Flotation
The choice of collectors plays an important role in the flo-
tation of lithium-bearing ores and, typically, mineralogy
dictates the collectors to be used. Cationic, anionic and
mixed collectors have all been used, however, they also have
associated challenges. Cook and Gibson (2023) explain in
detail the challenges associated with the predominant use of
fatty acids for the flotation of spodumene, viz. poor solubil-
ity, poor selectivity, sensitivity to pH, excessive foaming/
froth stability issues etc. The cationic collectors used for the
reverse flotation of spodumene and the direct flotation of
lepidolite, petalite and zinnwaldite are also associated with
the following limitations: the need for low pH (needed to
enhance collector adsorption to particle surfaces) which
results in high costs of corrosion protection (Lui, 2023),
some traditional amine collectors have a strong propensity
to foam (Chen et al., 2023), low selectivity for lepidolite
because adsorption is driven by electrostatic interaction,
some are sensitive to the presence of slimes. Furthermore,
some cationic collectors have a negative environmental
effect due to toxicity and low biodegradability. Collector
mixtures or the addition of defoamers have been used as
possible means of improving the recovery of lithium-bear-
ing minerals and overcoming some of these limitations e.g.,
Bulatovic (2015), Chen et al. (2023) etc.
This paper focuses on evaluating the flotation perfor-
mance of a new range of collectors and collector blends for
the flotation of lithium-bearing minerals. These collectors
were specially designed to reduce some of the challenges/
limitations associated with currently available collectors.
Specifically, the collectors will be tested on the direct
flotation of spodumene, reverse flotation of spodumene
(mica pre- flotation) and direct lepidolite flotation.
MATERIALS AND METHODS
Flotation Collectors
The direct flotation of spodumene was done with tall oil
fatty acid (TOFA, with an acid number 194 mg KOH/g
and Rosin acids content approx. 2.5%), Berol ® 8305,
Berol ® 8313 products and a mixture of TOFA plus Atrac ®
2600 as collectors. Atrac ® 2600 product is a specially for-
mulated and patented anionic surfactant based on complex
amino acid chemistry. It is a label-free product, which is
highly selective and maintains performance in hard process
water. Berol ® 8305 and Berol ® 8313 products are also fatty
acid-based complex formulations containing fatty alcohol
alkoxylates and fatty acid derivatives among other additives.
The cationic collectors used in this work include Armeen ®
T Tallowalkylamine, Armeen ® C Cocoalkylamine and a
blend of the two. These were compared to the new alkyl-
esteramine class of cationic collectors with different chain
lengths i.e., Armoflote ® 940 and Armoflote ® 945 products.
These collectors are less toxic and readily biodegradable.
Ore
Three different types of ores were used in this work. For the
direct flotation of spodumene, an ore with the composition
shown in Table 1 (Sample A) and a P80 =212μm was used,
for the reverse flotation of spodumene (mica pre flotation),
the ore shown in Table 2 (Sample B) with P80 of 105μm
was used, and lepidolite flotation was done using an ore
with a P80 of 50μm (Sample C- composition unavailable)
with an average feed grade of 0.85% Li2O. While samples
A and B were floated as received, sample C was milled
before flotation.
Flotation Procedure
Spodumene Flotation
Direct spodumene flotation tests were done using sam-
ple A with the composition shown in Table 1. Tests were
divided into two sets with different objectives. The first set
of tests were baseline rougher flotations designed to study
the impact of the new label-free anionic collector when
blended with a fatty acid. The second set was detailed
in multistage flotation tests to assess the performance of
the blend against known and efficient spodumene collec-
tors. All tests were performed in a Denver D12 flotation
machine. The rougher tests were done in a 2.5 litre flotation
cell while the cleaner and recleaner were performed in 1.5
and 1 litre flotation cells respectively. In all the tests, the pH
Zinnwaldite has a similar zeta potential profile to that
of lepidolite (Ney 1973), it is, therefore, a good candidate
for flotation with cationic collectors.
Flotation of Petalite
Bulatovic (2015) and Tadesse et al. (2019) agree that little
research work has been done on the flotation of petalite.
The available data indicates that petalite can be success-
fully floated, with cationic collectors (Jessup et al., 2000)
including primary amines, ether amines and quaternary
ammonium salts. It has also been shown that the flotation
of petalite is insensitive to pH changes and can be done at
any pH between 2.0 and 11.0. Jessup et al. (2000) describe
a successful process to float petalite using a quaternary
ammonium salt at a pH between 2 and 3 in a 10% brine
solution comprised of a 1:1 ratio of NaCl and KCl. Critical
to the process was the activation of petalite with hydroflu-
oric acid (HF) dosed at up to 1,000g/t.
Challenges in Lithium Flotation
The choice of collectors plays an important role in the flo-
tation of lithium-bearing ores and, typically, mineralogy
dictates the collectors to be used. Cationic, anionic and
mixed collectors have all been used, however, they also have
associated challenges. Cook and Gibson (2023) explain in
detail the challenges associated with the predominant use of
fatty acids for the flotation of spodumene, viz. poor solubil-
ity, poor selectivity, sensitivity to pH, excessive foaming/
froth stability issues etc. The cationic collectors used for the
reverse flotation of spodumene and the direct flotation of
lepidolite, petalite and zinnwaldite are also associated with
the following limitations: the need for low pH (needed to
enhance collector adsorption to particle surfaces) which
results in high costs of corrosion protection (Lui, 2023),
some traditional amine collectors have a strong propensity
to foam (Chen et al., 2023), low selectivity for lepidolite
because adsorption is driven by electrostatic interaction,
some are sensitive to the presence of slimes. Furthermore,
some cationic collectors have a negative environmental
effect due to toxicity and low biodegradability. Collector
mixtures or the addition of defoamers have been used as
possible means of improving the recovery of lithium-bear-
ing minerals and overcoming some of these limitations e.g.,
Bulatovic (2015), Chen et al. (2023) etc.
This paper focuses on evaluating the flotation perfor-
mance of a new range of collectors and collector blends for
the flotation of lithium-bearing minerals. These collectors
were specially designed to reduce some of the challenges/
limitations associated with currently available collectors.
Specifically, the collectors will be tested on the direct
flotation of spodumene, reverse flotation of spodumene
(mica pre- flotation) and direct lepidolite flotation.
MATERIALS AND METHODS
Flotation Collectors
The direct flotation of spodumene was done with tall oil
fatty acid (TOFA, with an acid number 194 mg KOH/g
and Rosin acids content approx. 2.5%), Berol ® 8305,
Berol ® 8313 products and a mixture of TOFA plus Atrac ®
2600 as collectors. Atrac ® 2600 product is a specially for-
mulated and patented anionic surfactant based on complex
amino acid chemistry. It is a label-free product, which is
highly selective and maintains performance in hard process
water. Berol ® 8305 and Berol ® 8313 products are also fatty
acid-based complex formulations containing fatty alcohol
alkoxylates and fatty acid derivatives among other additives.
The cationic collectors used in this work include Armeen ®
T Tallowalkylamine, Armeen ® C Cocoalkylamine and a
blend of the two. These were compared to the new alkyl-
esteramine class of cationic collectors with different chain
lengths i.e., Armoflote ® 940 and Armoflote ® 945 products.
These collectors are less toxic and readily biodegradable.
Ore
Three different types of ores were used in this work. For the
direct flotation of spodumene, an ore with the composition
shown in Table 1 (Sample A) and a P80 =212μm was used,
for the reverse flotation of spodumene (mica pre flotation),
the ore shown in Table 2 (Sample B) with P80 of 105μm
was used, and lepidolite flotation was done using an ore
with a P80 of 50μm (Sample C- composition unavailable)
with an average feed grade of 0.85% Li2O. While samples
A and B were floated as received, sample C was milled
before flotation.
Flotation Procedure
Spodumene Flotation
Direct spodumene flotation tests were done using sam-
ple A with the composition shown in Table 1. Tests were
divided into two sets with different objectives. The first set
of tests were baseline rougher flotations designed to study
the impact of the new label-free anionic collector when
blended with a fatty acid. The second set was detailed
in multistage flotation tests to assess the performance of
the blend against known and efficient spodumene collec-
tors. All tests were performed in a Denver D12 flotation
machine. The rougher tests were done in a 2.5 litre flotation
cell while the cleaner and recleaner were performed in 1.5
and 1 litre flotation cells respectively. In all the tests, the pH