XXXI International Mineral Processing Congress 2024 Proceedings/Washington, DC/Sep 29–Oct 3 2351
Thermodynamic theory predicts that collector adsorp-
tion onto a mineral surface will be greater if it occurs at
the solid-gas interface rather than at the more typical solid-
liquid interface (Laskowski, 2007). That is, it predicts that
more collector would be adsorbed onto mineral surfaces if
it were adsorbed from the surfaces of bubbles rather than
from the pulp, resulting in more hydrophobic particles and
consequently, better mineral recoveries. Studies ranging
from single particle/single bubble systems (Burdukova and
Laskowski, 2009, Klassen and Mokrousov, 1963) to simple
ideal mineral systems (Tchaliovska et al., 1990, Yaminsky
and Yaminskaya, 1995) to laboratory scale test using real
ores (Misra and Anazia, 1987, Nott and Manlapig, 1994,
Patil and Laskowski, 2008) appear to support the thermo-
dynamic theory by variously demonstrating higher contact
angles, lower induction times, higher recoveries, higher
concentrate grades and/or better mineral selectivity when
collector is presented to the mineral in the presence of air.
We know that recovery decreases with increasing par-
ticle size and decreasing mineral liberation (Bradshaw et al.,
2019, Jameson, 2012). The concept of critical contact angle
shows that the contact angle required to recover particles
increases with increasing particle size (Awatey et al., 2014,
Blake and Ralston, 1985). This means that coarse particles
need to be more hydrophobic than fine particles to float.
Therefore, the ability to render particles more hydrophobic
is of particular interest when attempting to recover coarse
particles.
STUDY OBJECTIVE
This paper explores the concept of aerosol collector addi-
tion with a focus on particle size using a real complex ore.
The study aims to:
• Determine whether aerosol collector dosing methods
produce a mineral recovery benefit in a conventional
flotation system
• Demonstrate that aerosol collector dosing methods
recover more coarser particles than conventional col-
lector dosing methods
MATERIALS AND METHODS
Ore Sample
A complex sulphide ore sample was sourced from Aeris
Resources’ Tritton Copper Operations in central New
South Wales, Australia. The sample is a blend from the
Tritton and Murrawombie deposits, which contains chal-
copyrite as the main valuable mineral, pyrite as the main
gangue sulphide mineral, as well as minor quantities of
sphalerite and pyrrhotite. The sample head grade is 1.24%
Cu, 11.1% Fe, 8.7% S and 0.19% Zn.
The bulk ore sample was crushed, homogenised and
split into 975±25g aliquots, which are stored frozen until
use. Immediately prior to flotation, each aliquot is milled
at 60% solids in process water to produce a coarse (P80 of
130µm) flotation feed.
Reagents
Analytical grade methyl isobutyl carbinol (MIBC) frother
(Sigma Aldrich) and industrial grade sodium isobutyl xan-
thate (SIBX) collector (Solvay) are used as reagents for the
flotation tests. Because the ore exhibits a high degree of nat-
ural floatability, collector dosage rates are lower than would
typically be expected. Collector is dosed at a high (5g/t)
rate close to what could be described as ‘overdosing’ and
low (1g/t) rate at a level that could be described as ‘starva-
tion’. Diluted collector solutions are stored refrigerated for
no more than 5 days.
All tests are performed using synthetic process water
modelled on the water chemistry at Mount Isa Mines.
Process water is made-up using the following analytical
grade metal salts: CaCl2, MgSO4, Na2SO4 (Sigma Aldrich),
KCl and Na2CO3 (Rowe Scientific). Frother is added to a
concentration of 23 ppm, and the water is stored in a closed
60L tank at room temperature (circa 24°C) for no longer
than 5 days.
Flotation Procedure
Flotation tests are performed in a 3L mechanically agitated
(bottom driven) flotation cell. The milled flotation feed
is transferred to the flotation cell where it is diluted using
process water to ~26.7% solids concentration. The slurry is
conditioned for 4 minutes at 1000 rpm prior to flotation
for all tests. If the test requires the batch dosing addition
method, collector is added at the beginning of the condi-
tioning period. After conditioning, the agitation speed is
reduced to 810 rpm, and air is added at a rate of 3.6 L/min
to begin flotation. If the test condition requires the aerosol
or zero dosing method, collector dosing is started simulta-
neously with air addition. The flotation cell is incrementally
topped-up with process water during the test to maintain
a constant cell level (10mm below the cell lip) throughout
the test. Three concentrates are collected at 1, 4 and 15
minutes where froth is scraped at 15 second intervals.
Collector Dosing Methods
Collector is dosed using three different methods to alter
the degree to which collector adsorbs onto the mineral
Thermodynamic theory predicts that collector adsorp-
tion onto a mineral surface will be greater if it occurs at
the solid-gas interface rather than at the more typical solid-
liquid interface (Laskowski, 2007). That is, it predicts that
more collector would be adsorbed onto mineral surfaces if
it were adsorbed from the surfaces of bubbles rather than
from the pulp, resulting in more hydrophobic particles and
consequently, better mineral recoveries. Studies ranging
from single particle/single bubble systems (Burdukova and
Laskowski, 2009, Klassen and Mokrousov, 1963) to simple
ideal mineral systems (Tchaliovska et al., 1990, Yaminsky
and Yaminskaya, 1995) to laboratory scale test using real
ores (Misra and Anazia, 1987, Nott and Manlapig, 1994,
Patil and Laskowski, 2008) appear to support the thermo-
dynamic theory by variously demonstrating higher contact
angles, lower induction times, higher recoveries, higher
concentrate grades and/or better mineral selectivity when
collector is presented to the mineral in the presence of air.
We know that recovery decreases with increasing par-
ticle size and decreasing mineral liberation (Bradshaw et al.,
2019, Jameson, 2012). The concept of critical contact angle
shows that the contact angle required to recover particles
increases with increasing particle size (Awatey et al., 2014,
Blake and Ralston, 1985). This means that coarse particles
need to be more hydrophobic than fine particles to float.
Therefore, the ability to render particles more hydrophobic
is of particular interest when attempting to recover coarse
particles.
STUDY OBJECTIVE
This paper explores the concept of aerosol collector addi-
tion with a focus on particle size using a real complex ore.
The study aims to:
• Determine whether aerosol collector dosing methods
produce a mineral recovery benefit in a conventional
flotation system
• Demonstrate that aerosol collector dosing methods
recover more coarser particles than conventional col-
lector dosing methods
MATERIALS AND METHODS
Ore Sample
A complex sulphide ore sample was sourced from Aeris
Resources’ Tritton Copper Operations in central New
South Wales, Australia. The sample is a blend from the
Tritton and Murrawombie deposits, which contains chal-
copyrite as the main valuable mineral, pyrite as the main
gangue sulphide mineral, as well as minor quantities of
sphalerite and pyrrhotite. The sample head grade is 1.24%
Cu, 11.1% Fe, 8.7% S and 0.19% Zn.
The bulk ore sample was crushed, homogenised and
split into 975±25g aliquots, which are stored frozen until
use. Immediately prior to flotation, each aliquot is milled
at 60% solids in process water to produce a coarse (P80 of
130µm) flotation feed.
Reagents
Analytical grade methyl isobutyl carbinol (MIBC) frother
(Sigma Aldrich) and industrial grade sodium isobutyl xan-
thate (SIBX) collector (Solvay) are used as reagents for the
flotation tests. Because the ore exhibits a high degree of nat-
ural floatability, collector dosage rates are lower than would
typically be expected. Collector is dosed at a high (5g/t)
rate close to what could be described as ‘overdosing’ and
low (1g/t) rate at a level that could be described as ‘starva-
tion’. Diluted collector solutions are stored refrigerated for
no more than 5 days.
All tests are performed using synthetic process water
modelled on the water chemistry at Mount Isa Mines.
Process water is made-up using the following analytical
grade metal salts: CaCl2, MgSO4, Na2SO4 (Sigma Aldrich),
KCl and Na2CO3 (Rowe Scientific). Frother is added to a
concentration of 23 ppm, and the water is stored in a closed
60L tank at room temperature (circa 24°C) for no longer
than 5 days.
Flotation Procedure
Flotation tests are performed in a 3L mechanically agitated
(bottom driven) flotation cell. The milled flotation feed
is transferred to the flotation cell where it is diluted using
process water to ~26.7% solids concentration. The slurry is
conditioned for 4 minutes at 1000 rpm prior to flotation
for all tests. If the test requires the batch dosing addition
method, collector is added at the beginning of the condi-
tioning period. After conditioning, the agitation speed is
reduced to 810 rpm, and air is added at a rate of 3.6 L/min
to begin flotation. If the test condition requires the aerosol
or zero dosing method, collector dosing is started simulta-
neously with air addition. The flotation cell is incrementally
topped-up with process water during the test to maintain
a constant cell level (10mm below the cell lip) throughout
the test. Three concentrates are collected at 1, 4 and 15
minutes where froth is scraped at 15 second intervals.
Collector Dosing Methods
Collector is dosed using three different methods to alter
the degree to which collector adsorbs onto the mineral
