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Trevor M. RiedemannManager, MPC Rare Earth Materials Section122 Metals Development BuildingAmes LaboratoryAmes, IA 50011-3020Phone: 515-294-1366Fax: 515-294-8727E-mail: [email protected]
2011
Materials Preparation CenterA US Department of Energy Specialized Research Center
High Purity Rare Earth Metals Preparation
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.
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Lawrence L. JonesDirector, MPC121 Metals Development BuildingAmes LaboratoryAmes, IA 50011-3020Phone: 515-294-5236Fax: 515-294-8727E-mail: [email protected]
Thomas A. LograssoDivision DirectorDivision of Materials Science & Engineering124 Metals Development BuildingAmes, IA 50011-3020Phone: 515-294-8425Fax: 515-294-8727E-mail: [email protected]
Acknowledgements
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. SchmidtChapter 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 11 th 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.
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Acknowledgements
1794 J. Gadolin first reports their existence1804 M.H. Klaproth isolated ceria1827 Preparation of first REM (Ce)
…
1931 Preparation of “reasonably pure” metal by electrolysis1937 Pure enough to determine crystal structures
1947 Separation adjacent RE by ion exchange.
1950’s Spedding and Daane – developed “Ames Process”
41787 – 1987 Two Hundred Years of Rare EarthsRare Earth Information Center IS-RIC 10Institute for Physical Research and TechnologyIowa State UniversityK.A. Gschneidner Jr & J. Capellen, ed.
The Rare Earths - A very Brief History
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.
51787 – 1987 Two Hundred Years of Rare EarthsRare Earth Information Center IS-RIC 10Institute for Physical Research and TechnologyIowa State UniversityK.A. Gschneidner Jr & J. Capellen, ed.
The Rare Earths - Etymology
6US Geological Survey Fact Sheet 087-02Rare Earth Elements – Critical Resources for High TechnologyGordon B. Haxel, James B. Hedrick, and Greta J. Orris
The Rare Earths - Abundance
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Y2O3 La2O3 CeO2 Pr6O11 Nd2O3 Sm2O3 Eu2O3 Gd2O3 Tb4O7 Dy2O3 Ho2O3 Er2O3 Tm2O3 Yb2O3 Lu2O3
III / IV
III / IV
III / IV
UPDATE ON THE GLOBAL RARE EARTH INDUSTRY:Prospect for Magnetic Rare Earth Materials 2004 China Magnet SymposiumGlobal Markets and Business OpportunitiesMay 17-21, 2004, Xi’an, ChinaConstantine E. Karayannopoulos
High Purity Oxide Prices
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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 11/2010La 99% US$/kg 1.60 3.10 7.75 6.25 61.00Ce 99% US$/kg 1.57 2.50 4.35 4.50 49.00Pr 99% US$/kg 7.44 28.00 27.00 14.00 72.00Nd 99% US$/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 341.00 555.00 650.00 350.00 605.00Dy 99% US$/kg 31.00 85.00 110.00 100.00 295.00
Source: Metal Pages
High Purity Oxide Prices
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Sc Y La Ce Pr Nd Sm Eu Gd Tb Dy Ho Er Tm Yb Lu0
500
1000
1500
2000
2500
3000
3500
4000Boiling PointMelting Point
The Rare Earths - Physical Properties
(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
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R2O3 + 6HF 2RF3 + 3H2O
3Ca + 2RF3 2R + 3CaF2
R2O3 + 2La La2O3 + 2R
The Rare Earths - Ames Process
Impurity Sources:Oxygen: Incomplete oxide conversion
Calcium reductantAtmosphere (handling and processing)
N, C, & H: Adsorbed on oxide/fluorideCalcium reductantTantalum CrucibleAtmosphere
Ca & F: Reductant and incomplete reduction (10% excess Ca is used in Rx)Insufficient vacuum casting
Fe, Co, Ni & Cu: Tantalum CrucibleImpurities in oxide & HFContamination of oxide during handling
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?Ames Process = High purity
Cross Contamination in Processing Line
Foundry vs Chip Fab
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Ames Commercial
99.996 99.99
99.99 99.96
99.9 99.2
115 150 175 555660 3105 2100 N/T
How Pure?
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Impurity Ingot Distilled Distilled DistilledH 7400 6800 22200 945C n.a. n.a. n.a. 132N 810 8000 1070 91O 10900 28800 34400 665Fe 156 117 60 14La 200 120 35 1Ta 5000 9 0 11Total mag. RE 68 86 112 17at% 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 PurificationTechnology and New Functional Materials Creation of Rare Earth Metals, Society of Non-Traditional Technology, Tokyo, Japan (1989) pp 13-29 K.A. Gschneidner, Jr.
Impurities affect the basic properties of pure metals (and alloys)Lattice parametersCrystal structureMelting pointHardnessStrengthResistivitySusceptibilityGrain growthMagnetic domain wall motion
Stoichiometry of alloy is shiftedSecond phase can form and change the properties.
Crystal GrowthOxygen as impurity in crystal growth of intermetallics, D. Souptel, W. Lo¨ ser, W. Gruner, G. Behr, Journal of Crystal Growth 307 (2007) 410–420
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Impurities may mask theINTRINSIC behavior of the pure metal or alloy material
Why do we need High Purity Metals?
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Why do we need High Purity Metals?
Temperature (K)
-ΔS
m (
J/kg
K)
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 gadoliniumMaterials 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 AlloysUS Patent: 6,589,366 B1 (2003)
Impurities are suppressing a structural transition from orthorhombic to monoclinic
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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. alCrystal 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 tomassive changes in pressure, magnetic fields, or chemical impurities.
Why do we need High Purity Metals?
High Purity Oxides
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Praseodymium OxidePr6O11
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
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Triple Distilled commercial Ca has ~2000 – 5000 ppm oxygen
Inputs: Calcium Reductant
Distilled under He pp to remove oxygen
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• 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 Days900 g/run
Ce 1900g CaLu 505g Ca
Distilled under He pp to remove oxygen
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Alumina
Magnesia
Quartz
Zirconia
Graphite
Iron
XXXXXX
Inputs: Tantalum10” x 14” x 0.030” = $1081.00
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ASTM B708 – 05 R05200, unalloyed tantalum, electron-beam furnace or vacuum-arc melt, or bothASTM B708 – 05 R05400, unalloyed tantalum, powder-metallurgy consolidation
Element R05200 R05400C 0.010 0.010O 0.015 0.03N 0.010 0.010H 0.0015 0.0015Fe 0.010 0.010Mo 0.020 0.010Nb 0.100 0.010Ni 0.010 0.010Si 0.005 0.010Ti 0.010 0.010W 0.05 0.010
Cleanest Ta: PickledAnnealed2000ºC degassed
Inputs: Tantalum
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Purity range from 99% to 99.99%
Parameter Level †HF 99.95 wt%H2SO4 100 wt ppmSO2 50 wt ppmH2O 200 wt ppmAs 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)
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Yb Eu Sm Tm Dy Ho Er Sc Gd Tb Y Lu Ce La Pr Nd0
500
1000
1500
2000
2500
3000
3500
4000
Boiling PointMelting Point
The Rare Earths - Physical Properties
1 2 3 4
Vapor Pressure at Melting PointTm 73.4 mm HgCe 3.6(10)-12 mm Hg
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Ames Process – Flow Diagram1
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4
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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
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Sm, Eu, Tm and Yb
① Dry Oxide Removes H2O and CO2
② Machine lanthanum chips③ Mix oxide and La chips (in dry box)
④ Pack in crucible (in dry box)
⑤ Load into induction furnace⑥ Heat under vacuum.⑦ Hold for 8 hours⑧ Perform a low temp sublimation.⑨ Strip Ta from sublimate mass⑩ Europium is extruded.
Ames Process – Procedure
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Ames Process
Sublimed Ytterbium Metal
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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.
Ames Process – Flow Diagram
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La, Ce, Nd and Pr
① Dry Oxide② LT/HT Fluorination of oxide③ Heat mixture of Ca & REF3 ④ Cool, remove slag⑤ Total of three reductions in same crucible⑥ Vacuum cast at high temperature⑦ Cool to just above melting point.
Hold to precipitate tantalum
⑧ Decant or “pour” RE into thin wall crucible⑨ Machine off crucible⑩ Arc cast into ingots
Ames Process – Procedure
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Ames Process: Low Temp Fluorination
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Ames Process
Reduction Step
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Ames Process
Post Reduction
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Ames Process
Pour/Decant Step
35
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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.
Ames Process – Flow Diagram
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Sc, Dy, Ho and Er
① Dry oxide② LT Fluorination of oxide③ Heat mixture of Ca & REF3 ④ Cool, remove slag⑤ Total of three reductions in same crucible
Excluding Sc
⑥ Vacuum cast Metal loss occurs
⑦ Sublimate to purify⑧ Machine off crucible⑨ Arc cast into ingots
Ames Process – Procedure
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Ames Process
Reduction Step
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Dysprosium metal (as Reduced)
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Ames Process
Sublimation Step
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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
Ames Process – Flow Diagram
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Erosion of Ta by Refluxing During Distillation
44Scandium At MP ~ 3.2 at.% Ta (11.8 wt%)Cerium, At MP ~ 0.10 at% Ta
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Hey! What about me!
Ames Process – Flow Diagram
High Purity Fluorides
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Praseodymium Fluoride PrF3 “Topped”YF3 LaF3 CeF3 PrF3 NdF3 SmF3 EuF3 GdF3 TbF3 DyF3 HoF3 ErF3 TmF3 YbF3 LuF3
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Commercial: R2O3 + 6NH4HF2 2RF3 + 3NH3 + 3H2O450ºC
• 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
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RF3 + HF(anhydrous) RF3 + (H2O, other trace)
Metal T Al Si Cr Fe Ni CuLa - 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 5.1Yes 0.5 <9 0.6 10 6.6 2.6
Tb - 2 10 1 19 4 3.6Yes 0.5 <0.2 0.3 18 3 5.0
M.P.
High Purity Fluorides
Beaudry, B.J. & P.E. Palmer
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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
Ames Process = High Purity
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Start with pure inputsKeep them pure
Semper Fidelis
