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8/14/2019 Extractive Met RE
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Extractive Metallurgy of
the Rare EarthsFathi Habashi
Department of Mining, Metallurgical, andMaterials Engineering
Laval University, Quebec [email protected]
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Rare Earths in the Periodic Table
Pr Nd Pm Sm Eu Gd Tb D y Ho Er Tm Yb LuLa Ce57 58 59 60 61 62 63 64 65 66 67 68 69 70 71
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1 2
H He3 4 5 6 7 8 9 10
Li Be B C N O F Ne11 12 13 15 16 17 18
Na g Al Si P S Cl Ar19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36
K Ca Sc Ti V Cr Mn Fe Co Ni Cu Zn Ga Ge As Se Br Kr 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54
Rb Sr Y Zr Nb Mo Tc Ru Rh Pd g Cd In Sn Sb Te I Xe55 56 57 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86
Cs Ba a Hf Ta W Re Os Ir Pt Au g Tl Pb Bi Po At Rn87 88 89
Fr Ra c
58 59 60 61 62 63 64 65 66 67 68 69 70 71
Ce Pr Nd Pm Sm Eu Gd Tb y Ho Er Tm Yb Lu90 91 92 93 94 95 96 97 98 99 100 101 102 103
Th Pa U p Pu Am Cm Bk Cf Es Fm Md No Lw **Actinides
INNER TRANSITION METALS
PERIODIC TABLEMonatomic
LESS TYPICAL
*Lanthanides
Vertical & Horizontal
METALS
MET LLOI S
m ar ty
MET LS NONMET LS
Vertical Similarity
CovalentTRANSITION METALS
Horizontal Similarity
TYPICAL METALS
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RAW MATERIAL
Monazite and xenotime: phosphates
Bastnasite: fluorocarbonate
Phosphate rock
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Other complex minerals
Euxenite (Y,Ce)(Nb,Ta,Ti)2O6 Samarskite (Y,Ce)4(Nb,Ta,Ti)2O6 Fergusonite (Y)(Nb,Ti,Ta)O4 Betafite (U,Ca,Y,Ce2(Nb,Ta,Ti)2O6(OH)
Pyrochlor (Na,Ca,Ce)2(NbTa,Ti)2(O,OH,F)7
Loparite (Na,Ca, Ce)2(Nb,Ta,Ti)
2O
6
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Rare earths in China
[1] Associated with iron ore in Baotou, Inner
Mongolia Autonomous Region, northern
China
[2] Associated with clay in Guandzhou,
Guandong Province in southern China
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Home of rare earths welcomes you
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Relative abundance
Rare earths 10-4 %
Similar to arsenic, antimony, molybdenum,
tungsten, beryllium, tantalum, and
germanium
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Monazite and Xenotime
The minerals monazite and xenotime are lanthanidephosphate containing some thorium and small amountsof uranium. They differ slightly in crystal structure andthe individual lanthanides occur in different proportions.
Monazite is widely distributed in the Earths crust andoccurs in small proportions in granites. When such rocksare weathered, grains of monazite are carried by waters,then deposited at the mouths of rivers, together with theheavier constituents of the parent rock, to form black
sands. Monazite occur mainly in Brazil, India, Australia, and
USA, xinotime occurs mainly in South East Asiaassociated with alluvial tin deposits.
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Physical properties of lanthanide minerals
Monazite Xinotime
Color Yellow to red
brown
Pale yellow to
brownish green
Specific gravity 4.95.5 4.54.6
Hardness, Mohs 5 4.5
Crystal structure Monoclinic Tetragonal
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Lanthanide
oxide
Monazite
%
Xenotime
%
Bastnasite
%
Light La2O3CeO2Pr6O11Nd2O3
23.0
46.5
5.1
18.4
93
0.5
5.0
0.7
2.2
8.4
32.0
49.0
4.4
13.5
98.9
Heavy Sm2O3Eu2O3Gd2O3Tb4O7Dy2O3Ho2O3
Er2O3Tm2O3Yb2O3Lu2O3Y2O3
2.3
0.07
1.7
0.16
0.52
0.09
0.130.013
0.061
0.006
2
7
1.9
0.2
4.0
1.0
8.7
2.1
5.40.9
6.2
0.4
60.8
91.6
0.5
0.1
0.3
0.01
0.03
0.01
0.010.2
0.01
0.1
0.1
1.37
Composition of lanthanides in monazite, xenotime, and bastnasite
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RECOVERY: Monazite, xenotime
Monazite
concentrate
Digestion
H2SO4
Dissolution
Filtration
Residue
SiO2TiO2ZrSiO4
Leaching
NaOH
Filtration
Crystallization Na3PO4 10H2O
Residue :
hydroxides of
U, Th, R.E.
Monazite
concentrate
H2O
Solution
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Acid method:
2LnPO4+ 3H2SO4 Ln2(SO4)3+ 2H3PO4
Alkali method:LnPO4+ 3NaOH Ln(OH)3+ Na3PO4
Hydroxides of uranium, thorium, and
lanthanides, containing small amounts ofphosphate; it is dissolved in acid for furtherseparation.
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Bastnasite
Bastnasite is a fluorocarbonate:
Ln2(CO3)3, LnF3
or LnFCO3.
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Bastnasite
In the Molycorp process, the mineral is
concentrated to 60% by flotation and thencalcined, converting the cerium to the
tetravalent state.
It is then treated with hydrochloric acid,
which causes only the trivalent rare earth
elements to go into solution, leavingbehind 6580% CeO2
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Bastnasite
The scheme of separation of the lanthanides from leachsolution of bastnasite concentrates by extraction withD2EHPA.
Cerium is already separated in the leaching step since it
is transformed into soluble cerium(IV) compound and isrecovered from the residue.
Each extraction step includes numerous stages ofcontact with the extractant and the stripping agent undercertain conditions of organic/aqueous ratio, and
extractant and stripping agent concentrations. The plant is computerized and is fully automated.
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MolyCorp process
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Production
Tonnage wise, phosphate rock is the most
important source of rare earths as
compared with the other material.
About 18 million tons of igneous rock are
treated annually while only 30 000 tons of
monazite and xenotime.
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During the manufacture of phosphoric acidabout 70% of the rare earths is lost in thegypsum.
However, if acidulation is conducted by nitric
acid all will go into solution and can berecovered by organic solvents.
In Finland, the lanthanides were recoveredcommercially by Kemira Oy from phosphate rock
during 19651972 using organic solvents. It is believed that a similar operation is inexistence in Russia.
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Nitric acid leaching
Norsk Hydro
BASF
Etc. ================================
Can be conducted in heaps
================================
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New separation technology
No more fractional crystallization
Ion exchange
Solvent extraction
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Rare earths and nuclear reactors
Rare earths arefission products
[atomic weight140]
They absorbneutrons andmust be removed
Ce 144 product ofatomic bombs
[t 285 days]
N f th
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New uses of rare earths
TV screens
Special magnets
Special alloys
Catalysts
ElectronicsGlass and ceramics
h k
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Thank
s
athi Habashi