1. Trevor M. Riedemann
Manager, MPC Rare Earth Materials Section
122 Metals Development Building
Ames Laboratory
Ames, IA 50011-3020
Phone: 515-294-1366
Fax: 515-294-8727
E-mail: riedemann@ameslab.gov
Materials Preparation Center
A US Department of Energy Specialized Research Center
High Purity Rare Earth Metals
Preparation

2. The Materials Preparation Center (MPC) is a U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, Division
of Materials Sciences & Engineering specialized research center located at the Ames Laboratory. MPC operations are primarily
funded by the Materials Discovery, Design, & Synthesis team's Synthesis & Processing Science core research activity.
2
Lawrence L. Jones
Director, MPC
121 Metals Development Building
Ames Laboratory
Ames, IA 50011-3020
Phone: 515-294-5236
Fax: 515-294-8727
E-mail: jonesll@ameslab.gov
Thomas A. Lograsso
Division Director
Division of Materials Science & Engineering
124 Metals Development Building
Ames, IA 50011-3020
Phone: 515-294-8425
Fax: 515-294-8727
E-mail: lograsso@ameslab.gov
Acknowledgements

3. The Rare Earths, F.H Spedding & A.H. Daane, eds.
(1961) John Wiley & Sons.
Chapter 6 – Preparation of the Rare Earth Fluorides, O.N. Carlson & F.A. Schmidt
Chapter 8 – Metallothermic Preparation of Rare Earth Metals, A.H. Daane
Beaudry, B.J. & P.E. Palmer, (1974) “The use of inert atmospheres in the preparation and handling
of high purity rare earth metals” Haschke, J.M, and H.A. Eich, eds. Proceedings of the 11th
Rare Earth Research Conference (CONF-741002, Part 2, NTIS, Springfield, Virginia 22151) pp
612-620
Handbook on the Physics and Chemistry of Rare Earths, Vol 1 – Metals,
(1978) K.A.Gschneidner, Jr. & L.R. Eyring, eds.
Chapter 2 – Preparation and Basic Properties of the Rare Earth metals,
B.J. Beaudry & K.A. Gschneidner
A Lanthanide Lanthology, Part I & II, B.T. Kilbourn
(1993) Molycorp. Inc.
3
Acknowledgements

4. 1794 J. Gadolin first reports their existence
1804 M.H. Klaproth isolated ceria
1827 Preparation of first REM (Ce)
…
1931 Preparation of “reasonably pure” metal by electrolysis
1937 Pure enough to determine crystal structures
1947 Separation adjacent RE by ion exchange.
1950’s Spedding and Daane – developed “Ames Process”
4
1787 – 1987 Two Hundred Years of Rare Earths
Rare Earth Information Center IS-RIC 10
Institute for Physical Research and Technology
Iowa State University
K.A. Gschneidner Jr & J. Capellen, ed.
The Rare Earths - A very Brief History

5. Z Symbol Name Etymology
21 Sc Scandium Latin Scandia (Scandinavia)
39 Y Yttrium Ytterby, Sweden, where the first ore was discovered.
57 La Lanthanum Greek "lanthanein", meaning to be hidden.
58 Ce Cerium For the dwarf planet Ceres.
59 Pr Praseodymium Greek "prasios” leek-green, &"didymos", meaning twin.
60 Nd Neodymium Greek "neos” new, and "didymos", meaning twin.
61 Pm Promethium Titan Prometheus, who brought fire to mortals.
62 Sm Samarium Vasili Samarsky-Bykhovets, who discovered samarskite.
63 Eu Europium For the continent of Europe.
64 Gd Gadolinium Johan Gadolin (1760–1852), to honor his study of REE.
65 Tb Terbium Ytterby, Sweden.
66 Dy Dysprosium Greek "dysprositos", meaning hard to get.
67 Ho Holmium Stockholm (in Latin, "Holmia”)
68 Er Erbium Ytterby, Sweden.
69 Tm Thulium For the mythological northern land of Thule.
70 Yb Ytterbium Ytterby, Sweden.
71 Lu Lutetium Lutetia, the city which later became Paris.
5
1787 – 1987 Two Hundred Years of Rare Earths
Rare Earth Information Center IS-RIC 10
Institute for Physical Research and Technology
Iowa State University
K.A. Gschneidner Jr & J. Capellen, ed.
The Rare Earths - Etymology

6. 6
US Geological Survey Fact Sheet 087-02
Rare Earth Elements – Critical Resources for High Technology
Gordon B. Haxel, James B. Hedrick, and Greta J. Orris
The Rare Earths - Abundance

7. 7
Y2O3
La2O3
CeO2
Pr6O11
Nd2O3
Sm2O3
Eu2O3
Gd2O3
Tb4O7
Dy2O3
Ho2O3
Er2O3
Tm2O3
Yb2O3
Lu2O3
III / IV
III / IV
III / IV
often hits very hard when the money r uns out while operators are under the
illusion of profitability.
Figure 2 shows price histories for Pr, Nd, Tb and Dy oxides and Nd metal,
with prices normalized to the beginning of 1995. Please keep in mind that this
chart is based on Chinese export prices, which are not necessarily related to
prices for products where additional value was added outside of China. I will
keep referring to this figure and will return to it later for a more in-depth
discussion about cycles.
Figure 2. Price History for Selected Rare Earths
0%
50%
100%
150%
200%
250%
1995 1996 1997 1998 1999 2000 2001 2002 2003 2004
Nd Oxide
Pr Oxide
Dy Oxide
Tb Oxide
Nd Metal
UPDATE ON THE GLOBAL RARE EARTH INDUSTRY:
Prospect for Magnetic Rare Earth Materials 2004 China Magnet Symposium
Global Markets and Business Opportunities
May 17-21, 2004, Xi’an, China
Constantine E. Karayannopoulos
High Purity Oxide Prices

8. 8
Y2O3
La2O3
CeO2
Pr6O11
Nd2O3
Sm2O3
Eu2O3
Gd2O3
Tb4O7
Dy2O3
Ho2O3
Er2O3
Tm2O3
Yb2O3
Lu2O3
III / IV
III / IV
III / IV
2004 2007 2008 2009 11/2010
La 99% US$/kg 1.60 3.10 7.75 6.25 61.00
Ce 99% US$/kg 1.57 2.50 4.35 4.50 49.00
Pr 99% US$/kg 7.44 28.00 27.00 14.00 72.00
Nd 99% US$/kg 5.64 29.00 27.00 14.00 77.00
Eu 99% US$/kg 292.00 300.00 475.00 450.00 630.00
Tb 99% US$/kg 341.00 555.00 650.00 350.00 605.00
Dy 99% US$/kg 31.00 85.00 110.00 100.00 295.00
Source: Metal Pages
High Purity Oxide Prices

9. 9
0
500
1000
1500
2000
2500
3000
3500
4000
Sc Y La Ce Pr Nd Sm Eu Gd Tb Dy Ho Er Tm Yb Lu
Boiling Point
Melting Point
The Rare Earths - Physical Properties

10. (1) High purity oxides from Ion-Exchange
(2) Preparation of anhydrous RE-fluorides
(3) Metallothermic reduction by Ca metal
(4) Metallothermic reduction by La metal
10
R2O3 + 6HF  2RF3 + 3H2O
3Ca + 2RF3  2R + 3CaF2
R2O3 + 2La  La2O3 + 2R
The Rare Earths - Ames Process

11. Impurity Sources:
Oxygen: Incomplete oxide conversion
Calcium reductant
Atmosphere (handling and processing)
N, C, & H: Adsorbed on oxide/fluoride
Calcium reductant
Tantalum Crucible
Atmosphere
Ca & F: Reductant and incomplete reduction (10% excess Ca is used in Rx)
Insufficient vacuum casting
Fe, Co, Ni & Cu: Tantalum Crucible
Impurities in oxide & HF
Contamination of oxide during handling
11
?Ames Process = High purity
Cross Contamination
in Processing Line
Foundry vs Chip Fab

12. 12
Ames Commercial
99.996 99.99
99.99 99.96
99.9 99.2
115 150 175 555
660 3105 2100 N/T
How Pure?

13. 13
Impurity Ingot Distilled Distilled Distilled
H 7400 6800 22200 945
C n.a. n.a. n.a. 132
N 810 8000 1070 91
O 10900 28800 34400 665
Fe 156 117 60 14
La 200 120 35 1
Ta 5000 9 0 11
Total mag. RE 68 86 112 17
at% pure <97.5 <95.6 <94.2 <99.81
Anlaysis of three commercial Tb samples and MPC Tb (ppm at).
Source A Source D MPC
Semiquantitative MS for 25 elements (H,N and O by vacuum fusion)
High purity Rare Earth Metals – Do We Need Them?
Proc. of the first Symposium Rare Metals Forum, Extra-High Purification
Technology and New Functional Materials Creation of Rare Earth Metals,
Society of Non-Traditional Technology, Tokyo, Japan (1989) pp 13-29
K.A. Gschneidner, Jr.

14. Impurities affect the basic properties of pure metals (and alloys)
Lattice parameters
Crystal structure
Melting point
Hardness
Strength
Resistivity
Susceptibility
Grain growth
Magnetic domain wall motion
Stoichiometry of alloy is shifted
Second phase can form and change the properties.
Crystal Growth
Oxygen as impurity in crystal growth of intermetallics, D. Souptel, W. Lo¨ ser, W. Gruner, G. Behr, Journal of Crystal Growth 307 (2007) 410–420
14
Impurities may mask the
INTRINSIC behavior of the
pure metal or alloy material
Why do we need High Purity Metals?

15. 15
Why do we need High Purity Metals?
Temperature (K)
-ΔSm(J/kgK) Gd5Si2Ge2: 0 – 5 T
V. K. Pecharsky and K. A. Gschneidner, Jr.
Giant Magnetocaloric Effect in Gd5Si2Ge2
Physical Review Letters 78 (1997) No. 23
T. Zhang , et. Al (Sichuan University)
The structure and magnetocaloric effect of rapidly
quenched Gd5Si2Ge2 alloy with low-purity gadolinium
Materials Letters 61 (2007) 440–443
K. A. Gschneidner, Jr., et al.
Method of Making Active Magentic Refrigerant,
Colossal Magnetostriction and Giant
Magentoresistive Materials Based on Gd-Si-Ge Alloys
US Patent: 6,589,366 B1 (2003)
Impurities are suppressing a
structural transition from
orthorhombic to monoclinic

16. 16
Y. Matsumoto, et al.
Quantum Criticality Without Tuning in the Mixed Valence
Compound -YbAlB4.
Science, 2011; 331 (6015)
S. Nakatsuji, et al.
Superconductivity and quantum criticality in the heavy-fermion
system –YbAlB4
Nature Physics 4, 603 - 607 (2008)
Robin T. Macaluso, et. al
Crystal Structure and Physical Properties of Polymorphs of LnAlB4
(Ln = Yb, Lu)
Chem. Mater., 2007, 19 (8), pp 1918–1922
An exotic new superconductor based on the element
ytterbium displays unusual properties that could change
how scientists understand and create materials for
superconductors and electronics. Beta-YbAlB4, can
reach a quantum critical, without being subject to
massive changes in pressure, magnetic fields,
or chemical impurities.
Why do we need High Purity Metals?

17. High Purity Oxides
17
Praseodymium Oxide
Pr6O11
99.999% pure
<10 ppm REM
GARBAGE IN = GARBAGE OUT
Y2O3
La2O3
CeO2
Pr6O11
Nd2O3
Sm2O3
Eu2O3
Gd2O3
Tb4O7
Dy2O3
Ho2O3
Er2O3
Tm2O3
Yb2O3
Lu2O3
III / IV
III / IV
III / IV
Inputs: Oxides

18. 18
Triple Distilled commercial Ca has ~2000 – 5000 ppm oxygen
Inputs: Calcium Reductant

19. 19
• Oxygen content is lowered <10 ppm
• Glove box protected
• Ca readily picks up O from H2O
• >1000 ppm from air in 5 minutes
The effect of handing the Ca in air
results in a 30-fold increase in O content
in Cerium metal (BJB)
6 Days
900 g/run
Ce 1900g Ca
Lu 505g Ca

20. 20
Alumina
Magnesia
Quartz
Zirconia
Graphite
Iron
X
X
X
X
X
X
Inputs: Tantalum
10” x 14” x 0.030” = $1081.00

21. 21
ASTM B708 – 05 R05200, unalloyed tantalum, electron-beam furnace or vacuum-arc melt, or both
ASTM B708 – 05 R05400, unalloyed tantalum, powder-metallurgy consolidation
Element R05200 R05400
C 0.010 0.010
O 0.015 0.03
N 0.010 0.010
H 0.0015 0.0015
Fe 0.010 0.010
Mo 0.020 0.010
Nb 0.100 0.010
Ni 0.010 0.010
Si 0.005 0.010
Ti 0.010 0.010
W 0.05 0.010
Cleanest Ta: Pickled
Annealed
2000ºC degassed
Inputs: Tantalum

22. 22
Purity range from 99% to 99.99%
Parameter Level †
HF 99.95 wt%
H2SO4 100 wt ppm
SO2 50 wt ppm
H2O 200 wt ppm
As 25 wt ppm
Hydrofluosilicic 0.05 mol %*
†Honeywell Specifications
*Handbook of Compressed Gasses, 4th ed. (1999) H2SiF6
Not a lot of impurities to worry about…but…..
Nasty Stuff
Inputs: Hydrofluoric Acid (HF)

23. 23
0
500
1000
1500
2000
2500
3000
3500
4000
Yb Eu Sm Tm Dy Ho Er Sc Gd Tb Y Lu Ce La Pr Nd
Boiling Point
Melting Point
The Rare Earths - Physical Properties
1 2 3 4
Vapor Pressure at Melting Point
Tm 73.4 mm Hg
Ce 3.6(10)-12 mm Hg

24. 24
REO
Ion Exchange
HP REO
Sm, Eu,
Tm, Yb
Oxides
La, Ce,
Pr, Nd
Oxides
La Rx/
Sublimate
Vacuum Cast &
Tantalum
Precipitation
ReductionLTF
may be topped
REM
REM
Sc, Dy,
Ho, Er
Oxides
Sublimate
Vacuum
Cast
Reduction
LTF
never topped
REM
Y, Gd,
Tb, Lu
Oxides
Distill
Vacuum
Cast
ReductionLTF
should be topped
REM
HTF,
Topping
Sublimate
HTF,
Topping
Pour
Ames Process – Flow Diagram
1
2
3
4

25. REO
Ion Exchange
HP REO
Sm, Eu,
Tm, Yb
Oxides
La, Ce,
Pr, Nd
Oxides
La Rx/
Sublimate
Vacuum Cast &
Tantalum
Precipitation
ReductionLTF
may be topped
REM
REM
Sc, Dy,
Ho, Er
Oxides
Sublimate
Vacuum
Cast
Reduction
LTF
never topped
REM
Y, Gd,
Tb, Lu
Oxides
Distill
Vacuum
Cast
ReductionLTF
should be topped
REM
HTF,
Topping
Sublimate
HTF,
Topping
Pour
25
Sm, Eu, Tm and Yb
• Low Boiling Points
• Reduction by Lanthanum from Oxide
• Easily purified by Sublimation
• Sm, Eu, Tm and Yb can be melted in Ta
crucibles without Ta contamination
Tm is very difficult to arc melt due to
~74mm vapor pressure at its melting point
Ames Process – Flow Diagram

26. 26
Sm, Eu, Tm and Yb
① Dry Oxide Removes H2O and CO2
② Machine lanthanum chips
③ Mix oxide and La chips (in dry box)
④ Pack in crucible (in dry box)
⑤ Load into induction furnace
⑥ Heat under vacuum.
⑦ Hold for 8 hours
⑧ Perform a low temp sublimation.
⑨ Strip Ta from sublimate mass
⑩ Europium is extruded.
REO
Ion Exchange
HP REO
Sm, Eu,
Tm, Yb
Oxides
La, Ce,
Pr, Nd
Oxides
La Rx/
Sublimate
Vacuum Cast &
Tantalum
Precipitation
ReductionLTF
may be topped
REM
REM
Sc, Dy,
Ho, Er
Oxides
Sublimate
Vacuum
Cast
Reduction
LTF
never topped
REM
Y, Gd,
Tb, Lu
Oxides
Distill
Vacuum
Cast
ReductionLTF
should be topped
REM
HTF,
Topping
Sublimate
HTF,
Topping
Pour
Ames Process – Procedure

27. 27
REO
Ion Exchange
HP REO
Sm, Eu,
Tm, Yb
Oxides
La, Ce,
Pr, Nd
Oxides
La Rx/
Sublimate
Vacuum Cast &
Tantalum
Precipitation
ReductionLTF
may be topped
REM
REM
Sc, Dy,
Ho, Er
Oxides
Sublimate
Vacuum
Cast
Reduction
LTF
never topped
REM
Y, Gd,
Tb, Lu
Oxides
Distill
Vacuum
Cast
ReductionLTF
should be topped
REM
HTF,
Topping
Sublimate
HTF,
Topping
Pour
Ames Process

28. 28

29. 29
La, Ce, Nd and Pr
• Low Melting but high Boiling Points
• Volatile impurities (Ca & F) can be
quantitatively removed by vacuum
casting without loss of metal
• Ta solubility at M.P. is low therefore Ta
dissolved during vacuum casting can be
removed by precipitation.
REO
Ion Exchange
HP REO
Sm, Eu,
Tm, Yb
Oxides
La, Ce,
Pr, Nd
Oxides
La Rx/
Sublimate
Vacuum Cast &
Tantalum
Precipitation
ReductionLTF
may be topped
REM
REM
Sc, Dy,
Ho, Er
Oxides
Sublimate
Vacuum
Cast
Reduction
LTF
never topped
REM
Y, Gd,
Tb, Lu
Oxides
Distill
Vacuum
Cast
ReductionLTF
should be topped
REM
HTF,
Topping
Sublimate
HTF,
Topping
Pour
Ames Process – Flow Diagram

30. 30
La, Ce, Nd and Pr
① Dry Oxide
② LT/HT Fluorination of oxide
③ Heat mixture of Ca & REF3
④ Cool, remove slag
⑤ Total of three reductions in same crucible
⑥ Vacuum cast at high temperature
⑦ Cool to just above melting point.
Hold to precipitate tantalum
⑧ Decant or “pour” RE into thin wall crucible
⑨ Machine off crucible
⑩ Arc cast into ingots
REO
Ion Exchange
HP REO
Sm, Eu,
Tm, Yb
Oxides
La, Ce,
Pr, Nd
Oxides
La Rx/
Sublimate
Vacuum Cast &
Tantalum
Precipitation
ReductionLTF
may be topped
REM
REM
Sc, Dy,
Ho, Er
Oxides
Sublimate
Vacuum
Cast
Reduction
LTF
never topped
REM
Y, Gd,
Tb, Lu
Oxides
Distill
Vacuum
Cast
ReductionLTF
should be topped
REM
HTF,
Topping
Sublimate
HTF,
Topping
Pour
Ames Process – Procedure

31. 31
Ames Process: Low Temp Fluorination

32. 32
REO
Ion Exchange
HP REO
Sm, Eu,
Tm, Yb
Oxides
La, Ce,
Pr, Nd
Oxides
La Rx/
Sublimate
Vacuum Cast &
Tantalum
Precipitation
ReductionLTF
may be topped
REM
REM
Sc, Dy,
Ho, Er
Oxides
Sublimate
Vacuum
Cast
Reduction
LTF
never topped
REM
Y, Gd,
Tb, Lu
Oxides
Distill
Vacuum
Cast
ReductionLTF
should be topped
REM
HTF,
Topping
Sublimate
HTF,
Topping
Pour
Ames Process
Reduction Step

33. 33
Ames Process
REO
Ion Exchange
HP REO
Sm, Eu,
Tm, Yb
Oxides
La, Ce,
Pr, Nd
Oxides
La Rx/
Sublimate
Vacuum Cast &
Tantalum
Precipitation
ReductionLTF
may be topped
REM
REM
Sc, Dy,
Ho, Er
Oxides
Sublimate
Vacuum
Cast
Reduction
LTF
never topped
REM
Y, Gd,
Tb, Lu
Oxides
Distill
Vacuum
Cast
ReductionLTF
should be topped
REM
HTF,
Topping
Sublimate
HTF,
Topping
Pour
Post Reduction

34. 34
REO
Ion Exchange
HP REO
Sm, Eu,
Tm, Yb
Oxides
La, Ce,
Pr, Nd
Oxides
La Rx/
Sublimate
Vacuum Cast &
Tantalum
Precipitation
ReductionLTF
may be topped
REM
REM
Sc, Dy,
Ho, Er
Oxides
Sublimate
Vacuum
Cast
Reduction
LTF
never topped
REM
Y, Gd,
Tb, Lu
Oxides
Distill
Vacuum
Cast
ReductionLTF
should be topped
REM
HTF,
Topping
Sublimate
HTF,
Topping
Pour
Ames Process
Pour/Decant Step

35. 35

36. 36
Sc, Dy, Ho and Er
• High Melting and low to intermediate
Boiling Points.
• To remove F impurity thru vacuum
casting, must loose up to 30% of metal
• Easily purified with respect to O, N, C, Ta
and other non-volatile impurities by
sublimation.
REO
Ion Exchange
HP REO
Sm, Eu,
Tm, Yb
Oxides
La, Ce,
Pr, Nd
Oxides
La Rx/
Sublimate
Vacuum Cast &
Tantalum
Precipitation
ReductionLTF
may be topped
REM
REM
Sc, Dy,
Ho, Er
Oxides
Sublimate
Vacuum
Cast
Reduction
LTF
never topped
REM
Y, Gd,
Tb, Lu
Oxides
Distill
Vacuum
Cast
ReductionLTF
should be topped
REM
HTF,
Topping
Sublimate
HTF,
Topping
Pour
Ames Process – Flow Diagram

37. 37
Sc, Dy, Ho and Er
① Dry oxide
② LT Fluorination of oxide
③ Heat mixture of Ca & REF3
④ Cool, remove slag
⑤ Total of three reductions in same crucible
Excluding Sc
⑥ Vacuum cast Metal loss occurs
⑦ Sublimate to purify
⑧ Machine off crucible
⑨ Arc cast into ingots
REO
Ion Exchange
HP REO
Sm, Eu,
Tm, Yb
Oxides
La, Ce,
Pr, Nd
Oxides
La Rx/
Sublimate
Vacuum Cast &
Tantalum
Precipitation
ReductionLTF
may be topped
REM
REM
Sc, Dy,
Ho, Er
Oxides
Sublimate
Vacuum
Cast
Reduction
LTF
never topped
REM
Y, Gd,
Tb, Lu
Oxides
Distill
Vacuum
Cast
ReductionLTF
should be topped
REM
HTF,
Topping
Sublimate
HTF,
Topping
Pour
Ames Process – Procedure

38. 38
REO
Ion Exchange
HP REO
Sm, Eu,
Tm, Yb
Oxides
La, Ce,
Pr, Nd
Oxides
La Rx/
Sublimate
Vacuum Cast &
Tantalum
Precipitation
ReductionLTF
may be topped
REM
REM
Sc, Dy,
Ho, Er
Oxides
Sublimate
Vacuum
Cast
Reduction
LTF
never topped
REM
Y, Gd,
Tb, Lu
Oxides
Distill
Vacuum
Cast
ReductionLTF
should be topped
REM
HTF,
Topping
Sublimate
HTF,
Topping
Pour
Ames Process
Reduction Step

39. 39
Dysprosium metal (as Reduced)

40. 40
REO
Ion Exchange
HP REO
Sm, Eu,
Tm, Yb
Oxides
La, Ce,
Pr, Nd
Oxides
La Rx/
Sublimate
Vacuum Cast &
Tantalum
Precipitation
ReductionLTF
may be topped
REM
REM
Sc, Dy,
Ho, Er
Oxides
Sublimate
Vacuum
Cast
Reduction
LTF
never topped
REM
Y, Gd,
Tb, Lu
Oxides
Distill
Vacuum
Cast
ReductionLTF
should be topped
REM
HTF,
Topping
Sublimate
HTF,
Topping
Pour
Ames Process
Sublimation Step

41. 41

42. 42
Y, Gd, Tb and Lu
• High Melting and High Boiling Points.
• Volatile impurities (Ca & F) can be
removed by vacuum casting without
significant loss of metal
• Ta solubility at MP is high, but can be
removed by distillation.
• Slow distillations will reduce O, N, C
slightly
REO
Ion Exchange
HP REO
Sm, Eu,
Tm, Yb
Oxides
La, Ce,
Pr, Nd
Oxides
La Rx/
Sublimate
Vacuum Cast &
Tantalum
Precipitation
ReductionLTF
may be topped
REM
REM
Sc, Dy,
Ho, Er
Oxides
Sublimate
Vacuum
Cast
Reduction
LTF
never topped
REM
Y, Gd,
Tb, Lu
Oxides
Distill
Vacuum
Cast
ReductionLTF
should be topped
REM
HTF,
Topping
Sublimate
HTF,
Topping
Pour
Ames Process – Flow Diagram

43. 43

44. 44Scandium At MP ~ 3.2 at.% Ta (11.8 wt%)
Cerium, At MP ~ 0.10 at% Ta

45. REO
Ion Exchange
HP REO
Sm, Eu,
Tm, Yb
Oxides
La, Ce,
Pr, Nd
Oxides
La Rx/
Sublimate
Vacuum Cast &
Tantalum
Precipitation
ReductionLTF
may be topped
REM
REM
Sc, Dy,
Ho, Er
Oxides
Sublimate
Vacuum
Cast
Reduction
LTF
never topped
REM
Y, Gd,
Tb, Lu
Oxides
Distill
Vacuum
Cast
ReductionLTF
should be topped
REM
HTF,
Topping
Sublimate
HTF,
Topping
Pour
45
Hey! What about me!
Ames Process – Flow Diagram

46. High Purity Fluorides
46
Praseodymium Fluoride PrF3 “Topped”YF3
LaF3
CeF3
PrF3
NdF3
SmF3
EuF3
GdF3
TbF3
DyF3
HoF3
ErF3
TmF3
YbF3
LuF3

47. 47
Commercial: R2O3 + 6NH4HF2  2RF3 + 3NH3 + 3H2O
450ºC
• 1000 to 5000 ppm residual O
• Also a source of N impurity
Ames LT: R2O3 + 6HF(anhydrous) + Ar  2RF3 + 3H2O + Ar
650ºC
• 10 to 1000 ppm residual O
• Pt lined furnace eliminated source
of transition metal impurities.
RF3 + HF(anhydrous)  RF3 + H2OAmes HT “Topped”:
• <10 ppm residual O
• Some reduction of transition metals
La – Nd, Gd, Tb, Lu
M.P.
High Purity Fluorides

48. 48
RF3 + HF(anhydrous)  RF3 + (H2O, other trace)
Metal T Al Si Cr Fe Ni Cu
La - 20 60 9.5 66 15 2.9
Yes 0.5 3 0.1 15 1.0 0.5
Ce - 4.0 30 1.1 40 10 5.1
Yes 0.5 <9 0.6 10 6.6 2.6
Tb - 2 10 1 19 4 3.6
Yes 0.5 <0.2 0.3 18 3 5.0
M.P.
High Purity Fluorides
Beaudry, B.J. & P.E. Palmer

49. 49

50. 50
La Ce Pr Nd Gd Tb Lu Y
(1) 7800 5020 7000 9000 12770 27500
(2) 3040 2900 2500 2700
(3) 3040 3070
(4) 204 260 254 480 735 745 1145 2170
(5) 304 130 260 307 245 440 430 145
Oxygen content in AT PPM of selected REM prepared from
various grades of fluorides and calcium.
(1) Typical commercial purity
(2) Fluoride prepared by NH4HF2 and reduced with purified calcium
(4) Low-temp fluoride, purified calcium, handled in glove box
(5) Topped fluoride, purified calcium, handled in glove box
(3) Topped fluoride, purified calcium, handled in air
Beaudry, B.J. & P.E. Palmer

51. Ames Process = High Purity
51
Start with pure inputs
Keep them pure
Semper Fidelis