XXXI International Mineral Processing Congress 2024 Proceedings/Washington, DC/Sep 29–Oct 3 1221
Lease in Australia, Nechalacho (Kursun et al., 2019) and
Thor Lake (Xia et al., 2015).
The primary challenge associated with beneficiation
of allanite deposits is separating the REE minerals from
gangue minerals, which can be chemically and physically
similar. Coupled with low head grades, achieving concen-
trate grades that conventional refinery treatments typi-
cally require (20% REEs) is difficult without sacrificing
recovery.
Examples of approaches taken by researchers in recent
times to beneficiate ores containing allanite, though not
necessarily the primary focus, are offered here:
• Flotation—Xia et al (2015) assessed flotation of Thor
Lake ore using hydroxamate collectors with addi-
tions of lead nitrate activator. Kursun et al (2019)
compared flotation of Isparta ore from Turkey with
EDA, an ethylene diamine acetate group collec-
tor more typically used for reverse flotation of silica
from magnetic iron ore concentrates, and R845N,
a sulfosuccinamate anionic collector used for barite
“pre-flotation” ahead of rare earths flotation.
• Magnetic separation—allanite, being a weakly
paramagnetic mineral, responds to high intensity
wet magnetic separation (WHIMS), which is in
widespread use in Chinese operations. WHIMS is
advantageous as a primary separation technique as
it enables rejection of non-magnetic minerals such
as silica, fluorspar and feldspar to be rejected prior
to “polishing” steps such as gravity separation or
flotation where similarities in SG or surface chem-
istry may make separation difficult otherwise. An
example of an operation employing WHIMS and
gravity separation is the Sichuan Maoniuping Rare
Earth Mine in China which achieved greater than
55% rare earth mineral recovery without the use of
flotation (Jordens et al., 2013). WHIMS forms an
integral part of the beneficiation flowsheet developed
for Halleck Creek, discussed later in this paper.
• Gravity separation—this technology is limited by
unit capacity and also by efficiency of recovery at
fine sizes. At industrial scale, spirals are commonly
used in mineral sands separation and are relatively
easy to assess at the design stage, allowing faithful
scale up. Shaking tables such as Wilfley and Holman
tables are a useful assessment tool to provide guid-
ance ahead of spirals testing but are not practical
at industrial scale. Continuous centrifugal mineral
separators are finding use in niche applications, par-
ticularly for high value commodities such as tin, but
also have limited capacity and are expensive. In the
development of the Nechalacho project in Canada,
both batch Knelson concentrators with a KD-3 flui-
dised bowl and Falcon C proxy testing with a non-
fluidised bowl were assessed for primary separation,
followed by LIMS to remove strongly ferromagnetic
minerals (Jordens et al., 2016).
PROGRAM OVERVIEW
The test material used in this work was composited from
HQ2 diamond drill core from both the Red Mountain
and Overton Mountain deposits of the Halleck Creek Rare
Earth Project. Drill core was initially crushed to minus
37.5 mm to select sub-samples for SMC comminution
testing, followed by crushing to minus 19 mm for Bond
abrasion index testing and finally to minus 3.35 mm for
Bond ball mill work index determination and beneficiation
testing, with work assigned as follows.
• SGS Advanced Mineralogy Facility (Montreal,
Canada)—feed mineralogy using the automated
TIMA analyser.
• Nagrom (Perth, Australia)—head analysis, commi-
nution and WHIMS
• Auralia Metallurgy (Perth, Australia)—direct and
reverse flotation testing on ore and WHIMS mag-
netics, sighter gravity separation.
• ALS Global (Perth, Australia)—mineralogy on
WHIMS magnetics.
• Mineral Technologies (Karara, Australia)—HLS and
electrostatic separation on WHIMS magnetics.
• Bureau Veritas (Perth, Australia)—Falcon C series
proxy testing of WHIMS magnetics.
RESULTS
Mineralogy
Mineralogical evaluation of ore feed sample by SGS was
conducted using the TIMA-X (Tescan Integrated Mineral
Analyzer), Electron Probe Micro-Analysis (EPMA), X-ray
diffraction analysis (XRD) and electron microscopy. The
objective of the analysis was to quantify the mineral assem-
blage of the sample and define degrees of liberation and
locking of key rare earth minerals ahead of beneficiation tes-
twork. A 500 g sample was crushed to a P80 of 250 microns
for mineralogical analysis and sub-samples mounted for
EPMA. A 20 g aliquot was pulverised and subjected for
XRD analysis using Rietveld refinement. A further 100 g
aliquot was pulverised and submitted for ICP-MS (REEs,
Th and U).
Lease in Australia, Nechalacho (Kursun et al., 2019) and
Thor Lake (Xia et al., 2015).
The primary challenge associated with beneficiation
of allanite deposits is separating the REE minerals from
gangue minerals, which can be chemically and physically
similar. Coupled with low head grades, achieving concen-
trate grades that conventional refinery treatments typi-
cally require (20% REEs) is difficult without sacrificing
recovery.
Examples of approaches taken by researchers in recent
times to beneficiate ores containing allanite, though not
necessarily the primary focus, are offered here:
• Flotation—Xia et al (2015) assessed flotation of Thor
Lake ore using hydroxamate collectors with addi-
tions of lead nitrate activator. Kursun et al (2019)
compared flotation of Isparta ore from Turkey with
EDA, an ethylene diamine acetate group collec-
tor more typically used for reverse flotation of silica
from magnetic iron ore concentrates, and R845N,
a sulfosuccinamate anionic collector used for barite
“pre-flotation” ahead of rare earths flotation.
• Magnetic separation—allanite, being a weakly
paramagnetic mineral, responds to high intensity
wet magnetic separation (WHIMS), which is in
widespread use in Chinese operations. WHIMS is
advantageous as a primary separation technique as
it enables rejection of non-magnetic minerals such
as silica, fluorspar and feldspar to be rejected prior
to “polishing” steps such as gravity separation or
flotation where similarities in SG or surface chem-
istry may make separation difficult otherwise. An
example of an operation employing WHIMS and
gravity separation is the Sichuan Maoniuping Rare
Earth Mine in China which achieved greater than
55% rare earth mineral recovery without the use of
flotation (Jordens et al., 2013). WHIMS forms an
integral part of the beneficiation flowsheet developed
for Halleck Creek, discussed later in this paper.
• Gravity separation—this technology is limited by
unit capacity and also by efficiency of recovery at
fine sizes. At industrial scale, spirals are commonly
used in mineral sands separation and are relatively
easy to assess at the design stage, allowing faithful
scale up. Shaking tables such as Wilfley and Holman
tables are a useful assessment tool to provide guid-
ance ahead of spirals testing but are not practical
at industrial scale. Continuous centrifugal mineral
separators are finding use in niche applications, par-
ticularly for high value commodities such as tin, but
also have limited capacity and are expensive. In the
development of the Nechalacho project in Canada,
both batch Knelson concentrators with a KD-3 flui-
dised bowl and Falcon C proxy testing with a non-
fluidised bowl were assessed for primary separation,
followed by LIMS to remove strongly ferromagnetic
minerals (Jordens et al., 2016).
PROGRAM OVERVIEW
The test material used in this work was composited from
HQ2 diamond drill core from both the Red Mountain
and Overton Mountain deposits of the Halleck Creek Rare
Earth Project. Drill core was initially crushed to minus
37.5 mm to select sub-samples for SMC comminution
testing, followed by crushing to minus 19 mm for Bond
abrasion index testing and finally to minus 3.35 mm for
Bond ball mill work index determination and beneficiation
testing, with work assigned as follows.
• SGS Advanced Mineralogy Facility (Montreal,
Canada)—feed mineralogy using the automated
TIMA analyser.
• Nagrom (Perth, Australia)—head analysis, commi-
nution and WHIMS
• Auralia Metallurgy (Perth, Australia)—direct and
reverse flotation testing on ore and WHIMS mag-
netics, sighter gravity separation.
• ALS Global (Perth, Australia)—mineralogy on
WHIMS magnetics.
• Mineral Technologies (Karara, Australia)—HLS and
electrostatic separation on WHIMS magnetics.
• Bureau Veritas (Perth, Australia)—Falcon C series
proxy testing of WHIMS magnetics.
RESULTS
Mineralogy
Mineralogical evaluation of ore feed sample by SGS was
conducted using the TIMA-X (Tescan Integrated Mineral
Analyzer), Electron Probe Micro-Analysis (EPMA), X-ray
diffraction analysis (XRD) and electron microscopy. The
objective of the analysis was to quantify the mineral assem-
blage of the sample and define degrees of liberation and
locking of key rare earth minerals ahead of beneficiation tes-
twork. A 500 g sample was crushed to a P80 of 250 microns
for mineralogical analysis and sub-samples mounted for
EPMA. A 20 g aliquot was pulverised and subjected for
XRD analysis using Rietveld refinement. A further 100 g
aliquot was pulverised and submitted for ICP-MS (REEs,
Th and U).