Recycling of Rare Earths Koen Binnemans KU Leuven – University of Leuven (Belgium)
1
H
Rare earths in the periodic table
3
4
Li
Be
11
12
Lanthanides = La-Yb, Lu (4f-elements) Rare Earths = Lanthanides + Sc, Y
Na Mg 19
K
REEs = rare-earth elements 23
24
V
Cr Mn Fe Co Ni
41
42
20
21
25
44
27
45
46
29
30
5
6
7
8
9
B
C
N
O
F Ne
14
15
16
17
Si
P
S
Cl Ar
31
32
33
34
35
47
48
49
39
40
Zr Nb Mo Tc Ru Rh Pd Ag Cd In
71
72
56
87
Fr
88
77
78
Ta W Re Os Ir
Pt
73
74
110
80
111
105
Db Sg Bh Hs Mt Ds Rg Cn
89
58
59
Ce Pr 90
91
60
61
62
63
64
81
65
50
51
52
Sn Sb Te 82
83
Pb Bi
84
53
I 85
Po At
54
Xe 86
Rn
112
104
Rf
108
109
79
Au Hg Tl
103
57
107
76
Ra Lr
La
106
75
36
Cu Zn Ga Ge As Se Br Kr
Y
55
18
13
38
Cs Ba Lu Hf
10
Al
Rb Sr
37
43
26
28
22
Ca Sc Ti
2
He
66
67
68
69
70
Nd Pm Sm Eu Gd Tb Dy Ho Er Tm Yb 92
Ac Th Pa U
93
94
95
96
97
98
Np Pu Am Cm Bk Cf
99
100
101
102
Es Fm Md No
1
Why recycling of rare earths? • Efficient use of natural resources • Supply of critical raw materials • Balance problem (specific for REEs)
Source: report US Department of Energy(2010)
Balance problem • Balance problem = demand and supply of the individual rare-earth elements (REEs) have to be equal at any time • Became an issue when applications shifted from the use of mixed rare earths to pure rare earths • Of importance for REE manufacturers • Concept introduced by P. Falconnet (Rhone-Poulenc) J. Less-Common Metals 111 (1985) 9.
2
Early applications: mixed rare earths • Mainly lanthanum and cerium • Catalyst industry – Stabilization Stabili ation of zeolites eolites for fluid fl id cracking catalysts (FCC) during steam regeneration • Metallurgy (mischmetall) – Graphite nodularization in cast iron – Ultimate desulfurization of steels – Lighter flints made of iron-mischmetall alloy – Grain g growth inhibition in light g metals – Battery alloys (NiMH) • Glass industry – Polishing powder (CeO2)
Modern applications: pure rare earths • Permanent magnets – NdFeB (Nd,Pr,Dy) – SmCo ((Sm)) ((< 2% of market)) • Phosphors – Phosphors for trichromatic fluorescent lamps (Y, Eu, Tb, La, Ce) – Phosphors for CRTs (color television, computer monitors (Eu,Y) – X-ray intensifying screens (Gd,La,Tb) • Glass industry – Optical glass (La)
3
Evolution of supply and demand of REOs
• Yearly production: about 125,000 tons of REOs • Total production numbers do not reflect availability of individual REEs
REE content of selected minerals (%) Bastnasite Mountain Pass, USA
Xenotime Lehat, Malaysia 1.2 3.1 0.5 1.6 1.1
Low Y RE laterite Xunwu, China 43.4 2.4 9.0 31.7 3.9
Loparite Kola Peninsula Russia 25.0 50.5 5.0 15.0 0.7
