XXXI International Mineral Processing Congress 2024 Proceedings/Washington, DC/Sep 29–Oct 3 2549
This occurrence can be attributed to the susceptibility of
REOF to oxidation, resulting in the formation of REF3 and
Ce7O12 during XRD detection (Q. Zhang et al., 2023a).
At 750°C, the main product was predominantly REOF,
which aligned with the cerium oxidation degree analysis in
Section 3.1. This is due to the higher crystallinity observed
in the product at increased temperatures.
SEM-EDS Analysis
Figure 8 presents the surface and internal microstructure
analysis of the raw ore and the product roasted at 650°C
for 8 min. In Figure 8(a), it is evident that before roasting,
the bastnaesite particles possessed a complete structure with
no notable surface pores or cracks. Figure 8(b) reveals that
there were no apparent cracks present within the particles
of the raw ore, and EDS analysis confirms that bastnae-
site was its main phase. After roasting, the surface of the
bastnaesite particles exhibited numerous cracks, as depicted
2 4 6 8 10
6
7
8
9
10
11
12
Time (min)
pH value
La
Ce
0
5
10
15
20
25
(a)
0 50 100 150 200 250 300 350
0
20
40
60
80
100
Raw ore
2 min
4 min
6 min
8 min
10 min
(b)
Figure 6. (a) initial pH value of slurry and concentration of main rare earth ions in slurry (b) Recovery at different roasting
temperatures with different SHA dosages
Bastnaesite Parisite REF
3
Ce
7
O
12
REOF
10 20 30 40 50 60 70 80 90
2 (°)
Raw ore
550°C
600°C
650°C
700°C
750°C
Figure 7. XRD patterns of bastnaesite samples at different roasting
temperatures
pH
value Recovery
(%)
Intensity
(a.u.)