Table
1.
Summary
of
recent
literature
studying
the
use
of
scCO
2
extraction
for
the
recovery
of
REEs
REE
Source
REEs wt%
Chelating
agents
Pressure (MPa)
Temperature
(°C)
Residence
Time
(h)
Efficiency (%)
Pre-treatment/
Other Additions
Reference
Monazite concentrate
La
(15.2)
Ce
(30.6)
Pr
(3.4)
Nd
(13.0)
Sm
(1.4)
Eu
(0.06)
Gd
(0.8)
Tb
(0.09)
TBP(HNO
3
)HDEHP-HNO
3
20.27
45
1
La
(91.82)
Ce
(93.53)
Pr
(94.28)
Nd
(95.15)
Sm
(95.74) Eu(96.28)
Gd
(94.63)
Tb
(94.47)
Pre-treatment
with
NaCO
2
3
(Samsonov, Trofimov
et
al.
2015)
Monazite concentrate
La
(16.75)
Ce
(33.72)
Pr
(3.72)
Nd
(14.32)
Sm
(1.58)
Eu
(0.06)
Gd
(0.93)
Tb
(0.10)
D2EHPA-HNO
3
20.27
45
La
(72.80)
Ce
(92.30)
Pr
(92.6)
Nd
(94.8)
Sm
(99.39)
Eu
(99.49)
Gd
(98.76)
Tb
(98.88)
Pre-treatment
with
NaCO
2
3
(Samsonov, Trofimov
et
al.
2016)
Bastnasite concentrate
La
(20.7)
Ce
(34.1)
Pr
(3.0)
Nd
(8.0)
Sm
(0.6)
Eu
(0.2)
Gd
(0.2)
Tb
(0.1)
Ba
(4.3)
Ca
(0.9)
Sr
(4.2)
TBP/HNO
3
34
65
2
La
(72)
Ce
(96)
Pr
(88)
Nd
(90)
Roasted
at
730
°C
for
3
hrs
(Sinclair,
Baek
et
al.
2017)
1368 XXXI International Mineral Processing Congress 2024 Proceedings/Washington, DC/Sep 29–Oct 3