XXXI International Mineral Processing Congress 2024 Proceedings/Washington, DC/Sep 29–Oct 3 2641
Sensor-Based Sorting
A representative subsample of the belt-cut limestone sam-
ple was screened into three size fractions, based on its suit-
ability for SBS:
• A coarse fraction with particles sizes between 1 inch
and the top size of the sample, 2 inches (labelled as
C)
• A fine fraction with particle sizes between ¾ inches
and 1 inch (labelled as F)
• An under size fraction with particles sizes below ¾
inch
The C fraction (238 rocks, 6,199 g) and the F fraction
(406 rocks, 3,368 g) were directed towards the SBS pro-
cess. The rocks were washed one by one with tap water to
avoid any interference produced by fine particles attached
to the surface.
The rocks were separated by SBS utilizing a Thermo
Scientific Niton XL2 x-ray fluorescence analyzer as the sen-
sor. Measurements were performed on four faces of each
rock from fraction C, and on two faces for fraction F. All
measurements were performed in the “mining mode Cu/
Zn” with a counting time of 40 s. Elemental composition is
reported as percentages by weight (%wt/wt).
Based on a previous work performed by the authors
(Tomey, Seiler, de Amores, &Sánchez, 2023), the rocks
from subfraction C and F were classified into: CL, CM,
CH and FL, FM, FH, where L, M, and H stands for high,
medium, and low calcite grade respectively. A representa-
tive subfraction of each product was pulverized, dried, and
analyzed by XRF. The LOI of the products were quanti-
fied by weighing the samples before and after calcination
at 500°C and 1000°C. Values are reported as the percentile
mass loss between 1000°C and 500°C to focus the determi-
nation on the mass loss due to the carbonate decomposi-
tion (Siva, Muralidharan, Sathiyanarayanan, Manikandan,
&Jayachandran, 2017 Al Omari, 2016).
Froth Flotation
The six products from SBS (CL, CM, CH, FL, FM, FH)
were then floated individually. The products were crushed in
a cone crusher and then ground in a ball mill. The ball mill
processing times were 5 and 10 min to evaluate the effect
of grinding time on recovery and grade. Froth flotation
experiments were conducted in a 2 L Denver D12 with a
20% solids suspension. The agitation was set at 1250 RPM
and the air flow was set at 5 L/min for all experiments.
The flotation flowsheet followed in all the experiments is
presented in Figure 2. Both concentrate and tailings prod-
ucts were pulverized, dried, and analyzed by XRF and their
LOI was measured. Subsamples of the feed sample and the
under size sample were processed directly by froth flotation
for comparison following the same flowsheet.
Figure 1. X-ray diffraction pattern of the belt-cut limestone sample from Queguay
Formation. Peaks associated with calcite (C) and quartz (Q) are identified
Sensor-Based Sorting
A representative subsample of the belt-cut limestone sam-
ple was screened into three size fractions, based on its suit-
ability for SBS:
• A coarse fraction with particles sizes between 1 inch
and the top size of the sample, 2 inches (labelled as
C)
• A fine fraction with particle sizes between ¾ inches
and 1 inch (labelled as F)
• An under size fraction with particles sizes below ¾
inch
The C fraction (238 rocks, 6,199 g) and the F fraction
(406 rocks, 3,368 g) were directed towards the SBS pro-
cess. The rocks were washed one by one with tap water to
avoid any interference produced by fine particles attached
to the surface.
The rocks were separated by SBS utilizing a Thermo
Scientific Niton XL2 x-ray fluorescence analyzer as the sen-
sor. Measurements were performed on four faces of each
rock from fraction C, and on two faces for fraction F. All
measurements were performed in the “mining mode Cu/
Zn” with a counting time of 40 s. Elemental composition is
reported as percentages by weight (%wt/wt).
Based on a previous work performed by the authors
(Tomey, Seiler, de Amores, &Sánchez, 2023), the rocks
from subfraction C and F were classified into: CL, CM,
CH and FL, FM, FH, where L, M, and H stands for high,
medium, and low calcite grade respectively. A representa-
tive subfraction of each product was pulverized, dried, and
analyzed by XRF. The LOI of the products were quanti-
fied by weighing the samples before and after calcination
at 500°C and 1000°C. Values are reported as the percentile
mass loss between 1000°C and 500°C to focus the determi-
nation on the mass loss due to the carbonate decomposi-
tion (Siva, Muralidharan, Sathiyanarayanan, Manikandan,
&Jayachandran, 2017 Al Omari, 2016).
Froth Flotation
The six products from SBS (CL, CM, CH, FL, FM, FH)
were then floated individually. The products were crushed in
a cone crusher and then ground in a ball mill. The ball mill
processing times were 5 and 10 min to evaluate the effect
of grinding time on recovery and grade. Froth flotation
experiments were conducted in a 2 L Denver D12 with a
20% solids suspension. The agitation was set at 1250 RPM
and the air flow was set at 5 L/min for all experiments.
The flotation flowsheet followed in all the experiments is
presented in Figure 2. Both concentrate and tailings prod-
ucts were pulverized, dried, and analyzed by XRF and their
LOI was measured. Subsamples of the feed sample and the
under size sample were processed directly by froth flotation
for comparison following the same flowsheet.
Figure 1. X-ray diffraction pattern of the belt-cut limestone sample from Queguay
Formation. Peaks associated with calcite (C) and quartz (Q) are identified