2552 XXXI International Mineral Processing Congress 2024 Proceedings/Washington, DC/Sep 29–Oct 3
Figure 10(b) illustrates the C1s spectra, showing dif-
ferent peaks and their respective attributions. The fitted
peak at 284.84 eV was associated with adventitious C-C
contaminants introduced during the detection and sample
preparation procedures (Wang et al., 2020). The peak at
approximately 289.65 eV was attributed to carbon atoms
in CO32–, originating from bastnaesite. The disappear-
ance of this peak signified the removal of CO32– after the
reduction roasting (Liu et al., 2023). In the raw ore, a C=O
peak was observed at 285.78 eV, potentially originating
from functional groups in SHA (Wang et al., 2020). In the
roasted product, the presence of an amide group (−CON)
peak at 286.68 eV indicated the adsorption of SHA on the
roasted product surface, with a higher adsorption quantity
than on the raw ore surface. This adsorption quantity was
consistent with the flotation experiment results.
As labeled in Figure 10(c), the peaks labeled as ν were
attributed to the 3d5/2 photoemissions, and the peaks
labeled as μ with splitting of around 18 eV were associ-
ated with the 3d3/2 emissions (Anandan et al., 2013). The
two prominent peaks at 884.58 eV and 903.48 eV for
the raw ore, labeled as ν0-μ0 and ν'-μ′, respectively. The
ν0-μ0 spin-orbit doublet peaks corresponded to charac-
teristic Ce3d94f2O2p5 final state shake-down satellites,
whereas the higher binding energy ν'-μ' peaks belonged to
the main photoionization from Ce3d94f1O2p6 final state
(Anandan et al., 2013). A satellite peaks (ν"-μ") belong-
ing to Ce4+ were observed at 892.48 eV and 907.88 eV,
originating from Ce3d94f1O2p5 final states shake-down
satellite features (Fernandes et al., 2011). The presence of
a small amount of Ce4+ in the raw ore could be attributed
to detection and fitting errors, or the raw ore might have
contained Ce4+ minerals other than bastnaesite. The Ce3d
peaks exhibited distinct characteristics of Ce4+ species in the
roasted product, and quantitative analysis revealed a Ce4+
content of 76.7%. The spin-orbit double peaks, labeled as
ν-μ, corresponded to the Ce3d94f2O2p4 final states shake-
down satellite features, while the spin-orbit peaks, denoted
as ν’’’-μ’’’, were attributed to the primary photoionization
of the Ce3d94f0O2p6 final state (Anandan et al., 2013).
O1s reflects the Ce valence state from another perspec-
tive (Figure 10(c)). The lower binding energy of 528.0 to
530.5 eV exhibited the peak associated with lattice oxy-
gen, while the higher binding energy of 531.0 to 532.8 eV
was identified as oxygen vacancies (Ansari et al., 2014).
For the raw ore, a higher proportion of oxygen vacancies
indicates that the bastnaesite particles possess more surface
defects when the fresh surface was exposed through crush-
ing. In the roasted product, the coexistence of Ce3+ and
Ce4+ resulted in the observation of both lattice oxygen and
oxygen vacancies peaks. However, compared with the raw
ore, the proportion of lattice oxygen was notably increased.
Additionally, a peak around 532.58 eV was attributed to
the chemisorbed or dissociated oxygen species (X. Zhang et
al., 2014). This occurrence may be attributed to the forma-
tion of rare earth hydroxyl species on the surface during
flotation or the adsorption of SHA.
CONCLUSIONS
Bayan Obo ore is a typical refractory iron ore that is asso-
ciated and symbiotic with a variety of minerals. For its
efficient utilization, a hydrogen-based mineral phase trans-
formation technology has been proposed. The objective of
this study was to investigate the thermal decomposition
process and flotation behavior of bastnaesite, which is the
main rare earth mineral found in Bayan Obo ore. During
the reduction roasting process, bastnaesite decomposed
slowly at temperatures below 600°C. However, by increas-
ing the roasting temperature and extending the time within
the appropriate range, the decomposition of bastnaesite can
be significantly promoted. When SHA was used as a col-
lector for roasted products, it was possible to achieve the
same recovery as that of raw ore by increasing the SHA dos-
age. The decomposition products were mainly REOF, with
CeOF being rapidly oxidized upon contact with oxygen,
forming Ce7O12, CeF3, and other products. The structure
of the roasted particles was significantly destroyed, resulting
in the formation of numerous long, parallel cracks through-
out the particles and an obvious increase in particle poros-
ity. After roasting, Ce on the particle surface mainly existed
in the form of Ce4+. Additionally, SHA was adsorbed on the
surface of the sample, with a higher amount of adsorption
observed on the surface of the roasted product compared to
the raw ore. Although the recovery of roasted products can
still achieve around 90%, the development of new collec-
tors was necessary to adapt to the properties of the roasted
products.
CREDIT AUTHORSHIP CONTRIBUTION
STATEMENT
Qiang Zhang: Data curation, Formal Analysis, Validation,
Writing – original draft. Yongsheng Sun: Conceptualization,
Funding acquisition, Resources, Writing – review &edit-
ing. Yuexin Han: Funding acquisition, Project administra-
tion, Resources. Peng Gao: Resources, Supervision. Wenbo
Li: Resources, Supervision.
Figure 10(b) illustrates the C1s spectra, showing dif-
ferent peaks and their respective attributions. The fitted
peak at 284.84 eV was associated with adventitious C-C
contaminants introduced during the detection and sample
preparation procedures (Wang et al., 2020). The peak at
approximately 289.65 eV was attributed to carbon atoms
in CO32–, originating from bastnaesite. The disappear-
ance of this peak signified the removal of CO32– after the
reduction roasting (Liu et al., 2023). In the raw ore, a C=O
peak was observed at 285.78 eV, potentially originating
from functional groups in SHA (Wang et al., 2020). In the
roasted product, the presence of an amide group (−CON)
peak at 286.68 eV indicated the adsorption of SHA on the
roasted product surface, with a higher adsorption quantity
than on the raw ore surface. This adsorption quantity was
consistent with the flotation experiment results.
As labeled in Figure 10(c), the peaks labeled as ν were
attributed to the 3d5/2 photoemissions, and the peaks
labeled as μ with splitting of around 18 eV were associ-
ated with the 3d3/2 emissions (Anandan et al., 2013). The
two prominent peaks at 884.58 eV and 903.48 eV for
the raw ore, labeled as ν0-μ0 and ν'-μ′, respectively. The
ν0-μ0 spin-orbit doublet peaks corresponded to charac-
teristic Ce3d94f2O2p5 final state shake-down satellites,
whereas the higher binding energy ν'-μ' peaks belonged to
the main photoionization from Ce3d94f1O2p6 final state
(Anandan et al., 2013). A satellite peaks (ν"-μ") belong-
ing to Ce4+ were observed at 892.48 eV and 907.88 eV,
originating from Ce3d94f1O2p5 final states shake-down
satellite features (Fernandes et al., 2011). The presence of
a small amount of Ce4+ in the raw ore could be attributed
to detection and fitting errors, or the raw ore might have
contained Ce4+ minerals other than bastnaesite. The Ce3d
peaks exhibited distinct characteristics of Ce4+ species in the
roasted product, and quantitative analysis revealed a Ce4+
content of 76.7%. The spin-orbit double peaks, labeled as
ν-μ, corresponded to the Ce3d94f2O2p4 final states shake-
down satellite features, while the spin-orbit peaks, denoted
as ν’’’-μ’’’, were attributed to the primary photoionization
of the Ce3d94f0O2p6 final state (Anandan et al., 2013).
O1s reflects the Ce valence state from another perspec-
tive (Figure 10(c)). The lower binding energy of 528.0 to
530.5 eV exhibited the peak associated with lattice oxy-
gen, while the higher binding energy of 531.0 to 532.8 eV
was identified as oxygen vacancies (Ansari et al., 2014).
For the raw ore, a higher proportion of oxygen vacancies
indicates that the bastnaesite particles possess more surface
defects when the fresh surface was exposed through crush-
ing. In the roasted product, the coexistence of Ce3+ and
Ce4+ resulted in the observation of both lattice oxygen and
oxygen vacancies peaks. However, compared with the raw
ore, the proportion of lattice oxygen was notably increased.
Additionally, a peak around 532.58 eV was attributed to
the chemisorbed or dissociated oxygen species (X. Zhang et
al., 2014). This occurrence may be attributed to the forma-
tion of rare earth hydroxyl species on the surface during
flotation or the adsorption of SHA.
CONCLUSIONS
Bayan Obo ore is a typical refractory iron ore that is asso-
ciated and symbiotic with a variety of minerals. For its
efficient utilization, a hydrogen-based mineral phase trans-
formation technology has been proposed. The objective of
this study was to investigate the thermal decomposition
process and flotation behavior of bastnaesite, which is the
main rare earth mineral found in Bayan Obo ore. During
the reduction roasting process, bastnaesite decomposed
slowly at temperatures below 600°C. However, by increas-
ing the roasting temperature and extending the time within
the appropriate range, the decomposition of bastnaesite can
be significantly promoted. When SHA was used as a col-
lector for roasted products, it was possible to achieve the
same recovery as that of raw ore by increasing the SHA dos-
age. The decomposition products were mainly REOF, with
CeOF being rapidly oxidized upon contact with oxygen,
forming Ce7O12, CeF3, and other products. The structure
of the roasted particles was significantly destroyed, resulting
in the formation of numerous long, parallel cracks through-
out the particles and an obvious increase in particle poros-
ity. After roasting, Ce on the particle surface mainly existed
in the form of Ce4+. Additionally, SHA was adsorbed on the
surface of the sample, with a higher amount of adsorption
observed on the surface of the roasted product compared to
the raw ore. Although the recovery of roasted products can
still achieve around 90%, the development of new collec-
tors was necessary to adapt to the properties of the roasted
products.
CREDIT AUTHORSHIP CONTRIBUTION
STATEMENT
Qiang Zhang: Data curation, Formal Analysis, Validation,
Writing – original draft. Yongsheng Sun: Conceptualization,
Funding acquisition, Resources, Writing – review &edit-
ing. Yuexin Han: Funding acquisition, Project administra-
tion, Resources. Peng Gao: Resources, Supervision. Wenbo
Li: Resources, Supervision.