XXXI International Mineral Processing Congress 2024 Proceedings/Washington, DC/Sep 29–Oct 3 2545
rare earth ores by converting weakly magnetic iron miner-
als into strongly magnetic ones, which can then be effec-
tively beneficiated by magnetic separation (Q. Zhang et
al., 2022). The REEs minerals in the magnetic separation
tailings can be further enriched via flotation (Ning et al.,
2024). The magnetization roasting-magnetic separation-
flotation process presents a promising method for the
efficient utilization of iron-containing rare earth ores.
Experiments were carried out by our research team utilizing
a fluidized semi-industrial equipment based on hydrogen-
based mineral phase transformation (Ning et al., 2024).
The results demonstrated the successful production of iron
concentrate with an iron grade of 63.60% and a recovery of
92.99%. Additionally, rare earth concentrate was obtained,
exhibiting an REO grade of 60% and a recovery of 73%.
Moreover, a fluorite concentrate was achieved, surpassing
90% in CaF2 grade with a recovery of 32%.
However, a comprehensive understanding of the reac-
tion mechanisms of rare earth minerals during the roasting
process, as well as the surface physicochemical properties
and flotation behavior after roasting, has yet to be thor-
oughly investigated. In this study, reduction roasting was
conducted on bastnaesite concentrate samples, and subse-
quent flotation tests were performed on the roasted prod-
ucts. X-ray diffraction (XRD) analysis was employed to
investigate the phase composition of the roasted products.
The particle morphology and pore structure were analyzed
using scanning electron microscopy-energy dispersive spec-
troscopy (SEM-EDS) and Brunauer-Emmett-Teller (BET)
analysis, respectively. Furthermore, X-ray photoelectron
spectroscopy (XPS) was employed to analyze the surface
elemental composition.
MATERIALS AND METHODS
Materials and Reagents
The bastnaesite samples are magnetic and gravity separa-
tion concentrates. Its chemical composition and XRD pat-
tern are shown in Figure 1. As shown in Figure 1(a), the
rare earth elements contained are mainly cerium, followed
by lanthanum. The rare earth content (REO equivalent)
is about 72%, and the sample purity is above 95% (the
theoretical REO content is about 75%) (Ren et al., 2000).
The impurity component is mainly CaO. From the XRD
pattern in Figure 1(b), it is found that it was because, in
addition to the main bastnaesite in the sample, there was
also a small amount of parisite.
The flotation collector is salicylhydroxamic acid (SHA,
mass concentration 0.5%), and the frother is methyl isobu-
tyl carbinol (MIBC, mass concentration 1%). Hydrochloric
acid and sodium hydroxide (mass concentration 1%) were
used as the pH regulators. The above reagents were all
chemically pure and purchased from Shanghai Aladdin
Biochemical Technology Co., Ltd., China.
Experimental Apparatus and Procedure
The reduction roasting and flotation of bastnasite was car-
ried out in the device shown in Figure 2, and the flotation
process was also given. The roasting system (OTF-1200X-
S-VT) was supplied by Hefei Kejing Materials Technology
Co., LTD. China., and the flotation equipment (XFGCII)
was supplied by Jilin Prospecting Machinery Plant, China.
The reducing gases were H2 and CO, and N2 was used to
adjust the reducing gas concentration. The gas flow rate
during the roasting process was 500 mL/min. The mass
of bastnaesite was 15 g for each roasting. Before reduction
10 20 30 40 50 60 70 80 90
72.43
8.76 5.41
1.42
0.46 0.2 0.06 0.3 0.07 0.03 0.07 0.06
REO F C CaO S TFe MgO Ba Al
2
O
3
P SiO
2
Sr
0
1
2
3
4
20
40
60
80
Component
(a) • Bastnaesite
Parisite
•
•
••
•
•
•
•
•
•
•
• • • • •
•
••• •
•
•
•
•
(b)
2θ/(°)
Bastnaesite: (Ce
0.5 La
0.5 )CO
3 F #96-900-0140
Figure 1. The chemical composition (a) and XRD pattern (b) of the bastnaesite sample
Content/ Intensit
•
rare earth ores by converting weakly magnetic iron miner-
als into strongly magnetic ones, which can then be effec-
tively beneficiated by magnetic separation (Q. Zhang et
al., 2022). The REEs minerals in the magnetic separation
tailings can be further enriched via flotation (Ning et al.,
2024). The magnetization roasting-magnetic separation-
flotation process presents a promising method for the
efficient utilization of iron-containing rare earth ores.
Experiments were carried out by our research team utilizing
a fluidized semi-industrial equipment based on hydrogen-
based mineral phase transformation (Ning et al., 2024).
The results demonstrated the successful production of iron
concentrate with an iron grade of 63.60% and a recovery of
92.99%. Additionally, rare earth concentrate was obtained,
exhibiting an REO grade of 60% and a recovery of 73%.
Moreover, a fluorite concentrate was achieved, surpassing
90% in CaF2 grade with a recovery of 32%.
However, a comprehensive understanding of the reac-
tion mechanisms of rare earth minerals during the roasting
process, as well as the surface physicochemical properties
and flotation behavior after roasting, has yet to be thor-
oughly investigated. In this study, reduction roasting was
conducted on bastnaesite concentrate samples, and subse-
quent flotation tests were performed on the roasted prod-
ucts. X-ray diffraction (XRD) analysis was employed to
investigate the phase composition of the roasted products.
The particle morphology and pore structure were analyzed
using scanning electron microscopy-energy dispersive spec-
troscopy (SEM-EDS) and Brunauer-Emmett-Teller (BET)
analysis, respectively. Furthermore, X-ray photoelectron
spectroscopy (XPS) was employed to analyze the surface
elemental composition.
MATERIALS AND METHODS
Materials and Reagents
The bastnaesite samples are magnetic and gravity separa-
tion concentrates. Its chemical composition and XRD pat-
tern are shown in Figure 1. As shown in Figure 1(a), the
rare earth elements contained are mainly cerium, followed
by lanthanum. The rare earth content (REO equivalent)
is about 72%, and the sample purity is above 95% (the
theoretical REO content is about 75%) (Ren et al., 2000).
The impurity component is mainly CaO. From the XRD
pattern in Figure 1(b), it is found that it was because, in
addition to the main bastnaesite in the sample, there was
also a small amount of parisite.
The flotation collector is salicylhydroxamic acid (SHA,
mass concentration 0.5%), and the frother is methyl isobu-
tyl carbinol (MIBC, mass concentration 1%). Hydrochloric
acid and sodium hydroxide (mass concentration 1%) were
used as the pH regulators. The above reagents were all
chemically pure and purchased from Shanghai Aladdin
Biochemical Technology Co., Ltd., China.
Experimental Apparatus and Procedure
The reduction roasting and flotation of bastnasite was car-
ried out in the device shown in Figure 2, and the flotation
process was also given. The roasting system (OTF-1200X-
S-VT) was supplied by Hefei Kejing Materials Technology
Co., LTD. China., and the flotation equipment (XFGCII)
was supplied by Jilin Prospecting Machinery Plant, China.
The reducing gases were H2 and CO, and N2 was used to
adjust the reducing gas concentration. The gas flow rate
during the roasting process was 500 mL/min. The mass
of bastnaesite was 15 g for each roasting. Before reduction
10 20 30 40 50 60 70 80 90
72.43
8.76 5.41
1.42
0.46 0.2 0.06 0.3 0.07 0.03 0.07 0.06
REO F C CaO S TFe MgO Ba Al
2
O
3
P SiO
2
Sr
0
1
2
3
4
20
40
60
80
Component
(a) • Bastnaesite
Parisite
•
•
••
•
•
•
•
•
•
•
• • • • •
•
••• •
•
•
•
•
(b)
2θ/(°)
Bastnaesite: (Ce
0.5 La
0.5 )CO
3 F #96-900-0140
Figure 1. The chemical composition (a) and XRD pattern (b) of the bastnaesite sample
Content/ Intensit
•