XXXI International Mineral Processing Congress 2024 Proceedings/Washington, DC/Sep 29–Oct 3 2551
materials (Bardestani et al., 2019). As shown in Figure 9(b),
the raw ore demonstrated a small pore volume with no dis-
tinct peak in the pore diameter distribution, indicating the
almost absence of pores. Conversely, the roasted product
exhibited a significant increase in pore volume, primar-
ily distributed around 2.5 nm pore diameter. Figure 9(c)
represents the specific surface area of the raw ore was only
0.48 m2/g, but after roasting it increased about 70 times
to 33.65 m2/g. Simultaneously, the pore volume increased
from 0.0005 cm3/g to 0.04 cm3/g, and the average pore
diameter increased from 1.48 nm to 5.25 nm. These BET
analysis results corroborate the SEM analysis, confirm-
ing that reduction roasting significantly enhanced parti-
cle porosity and induced the formation of numerous slits
within the particles.
XPS Analysis
The surface analysis of flotation concentrates of raw ore and
roasted product are shown in Figure 10. The XPS spectral
peaks were corrected by C1s before fitting.
As shown in Figure 10(a), after the reduction roasting,
a decrease in the peak intensity of O1s (531.08 eV) and
C1s (284.08 eV) was observed, indicating a reduction in
the contents of C and O elements. Conversely, the con-
tents of F and Ce elements increased. This was because of
the decomposition of bastnaesite, which generated CO2
during the reduction roasting (Q. Zhang et al., 2023a).
Additionally, an observed peak corresponding to N1s
(399.08 eV) indicated the presence of the collector SHA
adsorbed on the surface (Yao et al., 2018). The adsorption
amount of SHA on the roasted product was higher, which
aligned with the flotation experiments.
(a) XPS survey spectra (b) C1s
292 290 288 286 284 282 280
(c) Ce3d (d) O1s
536 534 532 530 528 526
1000 800 600 400 200 0
Binding Energy (eV)
O1s
N1s
F1s C1s
Ce3d
Raw ore
Roasted
product
Raw ore
Raw ore
Binding Energy (eV)
C-C/C-H
C=O CO
3
2-
Roasted product
C-C/C-H C-O/CON
/C=O
925 920 915 910 905 900 895 890 885 880 875
Binding Energy (eV)
0
0
Roasted product
Raw ore
Binding Energy (eV)
Chemisorbed or dissociated oxygen (I
3
)
Lattice oxygen (I
1
)
Oxygen vacancy (I
2
)
Roasted product
Figure 10. XPS analysis of the flotation concentrates of raw ore and roasted product, (a) XPS survey spectra, (b) high-
resolution XPS spectra of C1s, (c) high-resolution XPS spectra of Ce3d, (d) high-resolution XPS spectra of O1s
Counts
(s)
Counts
(s)
Counts
(s)
Counts
(s)
materials (Bardestani et al., 2019). As shown in Figure 9(b),
the raw ore demonstrated a small pore volume with no dis-
tinct peak in the pore diameter distribution, indicating the
almost absence of pores. Conversely, the roasted product
exhibited a significant increase in pore volume, primar-
ily distributed around 2.5 nm pore diameter. Figure 9(c)
represents the specific surface area of the raw ore was only
0.48 m2/g, but after roasting it increased about 70 times
to 33.65 m2/g. Simultaneously, the pore volume increased
from 0.0005 cm3/g to 0.04 cm3/g, and the average pore
diameter increased from 1.48 nm to 5.25 nm. These BET
analysis results corroborate the SEM analysis, confirm-
ing that reduction roasting significantly enhanced parti-
cle porosity and induced the formation of numerous slits
within the particles.
XPS Analysis
The surface analysis of flotation concentrates of raw ore and
roasted product are shown in Figure 10. The XPS spectral
peaks were corrected by C1s before fitting.
As shown in Figure 10(a), after the reduction roasting,
a decrease in the peak intensity of O1s (531.08 eV) and
C1s (284.08 eV) was observed, indicating a reduction in
the contents of C and O elements. Conversely, the con-
tents of F and Ce elements increased. This was because of
the decomposition of bastnaesite, which generated CO2
during the reduction roasting (Q. Zhang et al., 2023a).
Additionally, an observed peak corresponding to N1s
(399.08 eV) indicated the presence of the collector SHA
adsorbed on the surface (Yao et al., 2018). The adsorption
amount of SHA on the roasted product was higher, which
aligned with the flotation experiments.
(a) XPS survey spectra (b) C1s
292 290 288 286 284 282 280
(c) Ce3d (d) O1s
536 534 532 530 528 526
1000 800 600 400 200 0
Binding Energy (eV)
O1s
N1s
F1s C1s
Ce3d
Raw ore
Roasted
product
Raw ore
Raw ore
Binding Energy (eV)
C-C/C-H
C=O CO
3
2-
Roasted product
C-C/C-H C-O/CON
/C=O
925 920 915 910 905 900 895 890 885 880 875
Binding Energy (eV)
0
0
Roasted product
Raw ore
Binding Energy (eV)
Chemisorbed or dissociated oxygen (I
3
)
Lattice oxygen (I
1
)
Oxygen vacancy (I
2
)
Roasted product
Figure 10. XPS analysis of the flotation concentrates of raw ore and roasted product, (a) XPS survey spectra, (b) high-
resolution XPS spectra of C1s, (c) high-resolution XPS spectra of Ce3d, (d) high-resolution XPS spectra of O1s
Counts
(s)
Counts
(s)
Counts
(s)
Counts
(s)