3027
Impact of Platy Morphology in the Flotability of
Gangue Minerals: A Talc Case Study
Daniel Dodoo, Shane P. Usher, Peter J. Scales, Anthony D. Stickland
Department of Chemical Engineering, The University of Melbourne, Victoria 3010, Australia
ARC Centre of Excellence on Eco-Efficient Beneficiation of Minerals, Australia
Nathan A.S. Webster
ARC Centre of Excellence on Eco-Efficient Beneficiation of Minerals, Australia
CSIRO Mineral Resources, Victoria, Australia
Liza Forbes
ARC Centre of Excellence on Eco-Efficient Beneficiation of Minerals, Australia
Julius Kruttschnitt Mineral Research Centre, Sustainable Minerals Institute,
The University of Queensland, Queensland, Australia
ABSTRACT: The question of whether certain talcs have a different platy morphology that makes them more
“flotable” than others has persisted for quite some time. To resolve this, this study looked into the effect of
platy morphology on the flotation behaviour of talcs sourced from India and the United States. The X-ray
diffraction (XRD) technique was used to quantify the platy morphology of the Indian and US talc from their
XRD patterns. The XRD-morphological quantification indicated that the Indian talc was more platy than the
United States talc. A flotation test was then conducted on the talc ground to a particle size D80 of 75 µm with
different amounts of platy talc particles. As a result, the flotation of the talcs revealed that the highly platy talc,
Indian talc, was more flotable than the talc from the United States. This suggests that the flotability of various
talcs is affected by their varying degrees of platiness. Therefore, the morphological differences of different talcs
could be utilised in predicting their flotability in real ore and deciding which actions need to be carried out to
maximise the recovery of a valuable mineral in a flotation system.
Keywords: Talc Platy Morphology Aspect Ratio Flotation, X-ray diffraction (XRD)
INTRODUCTION
Particle morphology continues to be a significant factor
in mining operations as it largely results from the commi-
nution of ores prior to the flotation stage, which in turn
affects the flotability of minerals (Ulusoy 2023 Xia 2017).
Particles entering a flotation cell after comminution can
assume many shapes, including nearly spherical, cuboi-
dal, platy, acicular, or rod-like (Ulusoy 2023 Verrelli
et al. 2014). The flotability of a mineral particle is most
significantly impacted by platy morphology, which is
characterised by a high aspect ratio. Minerals with platy
morphologies have been the subject of much research for

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Extracted Text (may have errors)

3027
Impact of Platy Morphology in the Flotability of
Gangue Minerals: A Talc Case Study
Daniel Dodoo, Shane P. Usher, Peter J. Scales, Anthony D. Stickland
Department of Chemical Engineering, The University of Melbourne, Victoria 3010, Australia
ARC Centre of Excellence on Eco-Efficient Beneficiation of Minerals, Australia
Nathan A.S. Webster
ARC Centre of Excellence on Eco-Efficient Beneficiation of Minerals, Australia
CSIRO Mineral Resources, Victoria, Australia
Liza Forbes
ARC Centre of Excellence on Eco-Efficient Beneficiation of Minerals, Australia
Julius Kruttschnitt Mineral Research Centre, Sustainable Minerals Institute,
The University of Queensland, Queensland, Australia
ABSTRACT: The question of whether certain talcs have a different platy morphology that makes them more
“flotable” than others has persisted for quite some time. To resolve this, this study looked into the effect of
platy morphology on the flotation behaviour of talcs sourced from India and the United States. The X-ray
diffraction (XRD) technique was used to quantify the platy morphology of the Indian and US talc from their
XRD patterns. The XRD-morphological quantification indicated that the Indian talc was more platy than the
United States talc. A flotation test was then conducted on the talc ground to a particle size D80 of 75 µm with
different amounts of platy talc particles. As a result, the flotation of the talcs revealed that the highly platy talc,
Indian talc, was more flotable than the talc from the United States. This suggests that the flotability of various
talcs is affected by their varying degrees of platiness. Therefore, the morphological differences of different talcs
could be utilised in predicting their flotability in real ore and deciding which actions need to be carried out to
maximise the recovery of a valuable mineral in a flotation system.
Keywords: Talc Platy Morphology Aspect Ratio Flotation, X-ray diffraction (XRD)
INTRODUCTION
Particle morphology continues to be a significant factor
in mining operations as it largely results from the commi-
nution of ores prior to the flotation stage, which in turn
affects the flotability of minerals (Ulusoy 2023 Xia 2017).
Particles entering a flotation cell after comminution can
assume many shapes, including nearly spherical, cuboi-
dal, platy, acicular, or rod-like (Ulusoy 2023 Verrelli
et al. 2014). The flotability of a mineral particle is most
significantly impacted by platy morphology, which is
characterised by a high aspect ratio. Minerals with platy
morphologies have been the subject of much research for

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3028 XXXI International Mineral Processing Congress 2024 Proceedings/Washington, DC/Sep 29–Oct 3
example, Bhambhani et al. (2023) and Farrokhpay et al.
(2018) found that concentrate grades were drastically lower
when platy clay minerals like talc and mica, respectively,
were present during the flotation of an ore. According to
another recent study by Triffett and Bradshaw (2008), the
surface hydrophobicity of molybdenite particles with a
higher aspect ratio is significantly higher than that of round
particles, which causes them to float more rapidly than par-
ticles with a lower aspect ratio. This, according to the same
authors (Triffett &Bradshaw, 2008), is because hydropho-
bic sulphur species are more concentrated along the basal
planes of the plate-like molybdenite structure.
Platy morphology is a major concern because it is more
commonly found in gangue minerals than valuable min-
erals, which causes significant problems in mineral pro-
cessing operations (Bhambhani et al. 2023 Farrokhpay
et al. 2018 Xia 2017). A difficult platy gangue is talc
(Mg3Si4O10(OH)2), a magnesium silicate mineral that is
frequently encountered in low-grade ore deposits, particu-
larly sulphide-type deposits. Talc, an exceptionally hydro-
phobic mineral, is amenable to flotation concentrates, a
process that reduces the grade of valuable minerals by utilis-
ing its principal surfaces, or basal surfaces, which comprise
approximately 90% of its overall surface area (Nalaskowski
et al. 2007 Tarasevich &Aksenenko 2014). The quantity
of platy talc particles present in a talc ore varies in accor-
dance with the talc’s geographical origin, as noted and
documented by Holland and Murtagh (2000). Therefore,
additional research is needed to determine whether the
flotation behaviour of talc is affected by the amount of
platy particles present. This could potentially provide an
explanation for the divergence in flotation characteristics
among various talcs, and the resulting data could be utilised
to construct predictive models that accurately depict their
flotability.
A major hurdle in gaining understanding of the flota-
tion behaviour of talc through the quantification of its platy
morphology is the need for precise and consistent methods
of characterising its shape. It is common practice to deter-
mine the platy morphology of talc by calculating the aspect
ratio of talc platelets (Forssberg et al., 1988 Hiçyilmaz et
al., 2004 Ulusoy &Kursun, 2011). Th aspect ratio is cal-
culated by dividing the maximum Feret diameter by the
minimum Feret diameter, where Feret diameter is the dis-
tance between two parallel tangents of the particle oriented
at a certain angle (Wiese et al., 2015). Several methods have
been used to calculate the aspect ratio of talc from a 2D
image, which does not accurately represent the platy mor-
phology of talc.
This study used X-ray diffraction (XRD) to determine
the platy morphology of talcs originating from various geo-
graphic locations. The platy morphology, as determined
by XRD, was compared with the results obtained through
image analysis and scanning electron microscopy (SEM).
To investigate the effect of platy morphologies on talc flo-
tability, a flotation test was performed on two different talcs
with varying platy morphologies.
MATERIALS AND METHODS
Materials
Talc lump ores were obtained from mining operation
sites located in India (Table 1(a)) and the United States
(Table 1(b)). The large lump ores were crushed and sieved
through a series of sieves arranged in descending order from
2,000 µm down to 1 mm. Table 2 presents the chemical
analysis of the talc sample determined by X-ray fluores-
cence (XRF). The main chemical constituents of the talcs
were SiO2 of about 57 – 62% and MgO of 26 – 31%.
All instruments used in the current research were located
Table 1. Images of (a) India and (b) United States talc
India (a) USA (b)

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Extracted Text (may have errors)

3028 XXXI International Mineral Processing Congress 2024 Proceedings/Washington, DC/Sep 29–Oct 3
example, Bhambhani et al. (2023) and Farrokhpay et al.
(2018) found that concentrate grades were drastically lower
when platy clay minerals like talc and mica, respectively,
were present during the flotation of an ore. According to
another recent study by Triffett and Bradshaw (2008), the
surface hydrophobicity of molybdenite particles with a
higher aspect ratio is significantly higher than that of round
particles, which causes them to float more rapidly than par-
ticles with a lower aspect ratio. This, according to the same
authors (Triffett &Bradshaw, 2008), is because hydropho-
bic sulphur species are more concentrated along the basal
planes of the plate-like molybdenite structure.
Platy morphology is a major concern because it is more
commonly found in gangue minerals than valuable min-
erals, which causes significant problems in mineral pro-
cessing operations (Bhambhani et al. 2023 Farrokhpay
et al. 2018 Xia 2017). A difficult platy gangue is talc
(Mg3Si4O10(OH)2), a magnesium silicate mineral that is
frequently encountered in low-grade ore deposits, particu-
larly sulphide-type deposits. Talc, an exceptionally hydro-
phobic mineral, is amenable to flotation concentrates, a
process that reduces the grade of valuable minerals by utilis-
ing its principal surfaces, or basal surfaces, which comprise
approximately 90% of its overall surface area (Nalaskowski
et al. 2007 Tarasevich &Aksenenko 2014). The quantity
of platy talc particles present in a talc ore varies in accor-
dance with the talc’s geographical origin, as noted and
documented by Holland and Murtagh (2000). Therefore,
additional research is needed to determine whether the
flotation behaviour of talc is affected by the amount of
platy particles present. This could potentially provide an
explanation for the divergence in flotation characteristics
among various talcs, and the resulting data could be utilised
to construct predictive models that accurately depict their
flotability.
A major hurdle in gaining understanding of the flota-
tion behaviour of talc through the quantification of its platy
morphology is the need for precise and consistent methods
of characterising its shape. It is common practice to deter-
mine the platy morphology of talc by calculating the aspect
ratio of talc platelets (Forssberg et al., 1988 Hiçyilmaz et
al., 2004 Ulusoy &Kursun, 2011). Th aspect ratio is cal-
culated by dividing the maximum Feret diameter by the
minimum Feret diameter, where Feret diameter is the dis-
tance between two parallel tangents of the particle oriented
at a certain angle (Wiese et al., 2015). Several methods have
been used to calculate the aspect ratio of talc from a 2D
image, which does not accurately represent the platy mor-
phology of talc.
This study used X-ray diffraction (XRD) to determine
the platy morphology of talcs originating from various geo-
graphic locations. The platy morphology, as determined
by XRD, was compared with the results obtained through
image analysis and scanning electron microscopy (SEM).
To investigate the effect of platy morphologies on talc flo-
tability, a flotation test was performed on two different talcs
with varying platy morphologies.
MATERIALS AND METHODS
Materials
Talc lump ores were obtained from mining operation
sites located in India (Table 1(a)) and the United States
(Table 1(b)). The large lump ores were crushed and sieved
through a series of sieves arranged in descending order from
2,000 µm down to 1 mm. Table 2 presents the chemical
analysis of the talc sample determined by X-ray fluores-
cence (XRF). The main chemical constituents of the talcs
were SiO2 of about 57 – 62% and MgO of 26 – 31%.
All instruments used in the current research were located
Table 1. Images of (a) India and (b) United States talc
India (a) USA (b)

3026 XXXI International Mineral Processing Congress 2024 Proceedings/Washington, DC/Sep 29–Oct 3
copper recovery and solve the Cu/Zn selectivity problems.
The results showed that the total copper recovery was calcu-
lated as 83.53% (58.10% Leach +25.43% flotation) in the
hybrid flowsheet option. The copper from the leach solu-
tion can be recovered in the form of Cu2S precipitate using
the SART process. A significant portion of cyanide is also
recovered and recycled with this process.
The leach residue can either be blended with the stan-
dard sulfide ore or treated separately in campaign mode in
the flotation circuit.
A high-grade zinc concentrate was produced assaying
52.14% Zn at 77.51% recovery.
The problematic enriched type ores can be treated with
the hybrid leach-flotation process. The economics of the
process depends on the ore grade and tonnage.
REFERENCES
Bulatovic, S.M., 2007. Handbook of Flotation
Reagents. Elsevier Science and Technology, 449p,
ISBN:0444530290.
Fernando Medina Ferrera,b,c,*, Bernhard Doldd,e, Oscar
Jerez., 2021. Dissolution kinetics and solubilities of
copper sulfides in cyanide and hydrogen peroxide
leaching: Applications to increase selective extractions.
Journal of Geochemical Exploration, 230, doi: 10.1016/j.
gexplo.2021.106848.
Fisher, W.W., 1994. Comparison of chalcocite dissolution
in the sulfate, perchlorate, nitrate, chloride, ammo-
nia, and cyanide systems. Miner. Eng. 7, 99–103. doi:
10.1016/0892-6875(94)90150-3.
Fisher, W.W., Flores, F.A., Henderson, J.A., 1992.
Comparison of chalcocite dissolution in the oxygen-
ated, aqueous sulfate and chloride systems. Miner. Eng.
5, 817–834. doi: 10.1016/0892-6875(92)90248-8.
Hu, Y., Sun, W., Wang, D., 2009. Electrochemistry of
Flotation of Sulphide Minerals. Tsinghua University
Press, Beijing and Springer-Verlag Berlin Heidleberg,
304p.
Kettanah, Y.A., 2019. Copper mineralozitaion and altera-
tions in Gercus Basal within the Gercus Formation,
northern Iraq., Ore Geology Reviews, 111, doi:
10.1016/j.oregeorev.2019.102974.
Sikka, D.B., Petruk, W., Nehru, C.E., Zhang, Z.
1991. Geochemistry of secondary copper min-
erals from Proterozoic porphyry copper depos-
its, Malanjkhand, India., Reviews, 6, 2–3. doi:
10.1016/0169-1368(91)90026-4.

Previous Page Next Page

Extracted Text (may have errors)

3026 XXXI International Mineral Processing Congress 2024 Proceedings/Washington, DC/Sep 29–Oct 3
copper recovery and solve the Cu/Zn selectivity problems.
The results showed that the total copper recovery was calcu-
lated as 83.53% (58.10% Leach +25.43% flotation) in the
hybrid flowsheet option. The copper from the leach solu-
tion can be recovered in the form of Cu2S precipitate using
the SART process. A significant portion of cyanide is also
recovered and recycled with this process.
The leach residue can either be blended with the stan-
dard sulfide ore or treated separately in campaign mode in
the flotation circuit.
A high-grade zinc concentrate was produced assaying
52.14% Zn at 77.51% recovery.
The problematic enriched type ores can be treated with
the hybrid leach-flotation process. The economics of the
process depends on the ore grade and tonnage.
REFERENCES
Bulatovic, S.M., 2007. Handbook of Flotation
Reagents. Elsevier Science and Technology, 449p,
ISBN:0444530290.
Fernando Medina Ferrera,b,c,*, Bernhard Doldd,e, Oscar
Jerez., 2021. Dissolution kinetics and solubilities of
copper sulfides in cyanide and hydrogen peroxide
leaching: Applications to increase selective extractions.
Journal of Geochemical Exploration, 230, doi: 10.1016/j.
gexplo.2021.106848.
Fisher, W.W., 1994. Comparison of chalcocite dissolution
in the sulfate, perchlorate, nitrate, chloride, ammo-
nia, and cyanide systems. Miner. Eng. 7, 99–103. doi:
10.1016/0892-6875(94)90150-3.
Fisher, W.W., Flores, F.A., Henderson, J.A., 1992.
Comparison of chalcocite dissolution in the oxygen-
ated, aqueous sulfate and chloride systems. Miner. Eng.
5, 817–834. doi: 10.1016/0892-6875(92)90248-8.
Hu, Y., Sun, W., Wang, D., 2009. Electrochemistry of
Flotation of Sulphide Minerals. Tsinghua University
Press, Beijing and Springer-Verlag Berlin Heidleberg,
304p.
Kettanah, Y.A., 2019. Copper mineralozitaion and altera-
tions in Gercus Basal within the Gercus Formation,
northern Iraq., Ore Geology Reviews, 111, doi:
10.1016/j.oregeorev.2019.102974.
Sikka, D.B., Petruk, W., Nehru, C.E., Zhang, Z.
1991. Geochemistry of secondary copper min-
erals from Proterozoic porphyry copper depos-
its, Malanjkhand, India., Reviews, 6, 2–3. doi:
10.1016/0169-1368(91)90026-4.