Economics of Rare Earths: the Balance Problem

Transcription

1 Economics of Rare Earths: the Balance Problem Koen Binnemans, Peter Tom Jones, Karel Van Acker, Johan Eyckmans KU Leuven University of Leuven (Belgium)

2 Definition Balance problem = demand and supply of the individual rare-earth elements (REEs) have to be equal at any time Also called: Balancing problem 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.

3 Early applications: mixed rare earths Mainly lanthanum and cerium Catalyst industry Stabilization of zeolites for fluid 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 growth inhibition in light metals Battery alloys (NiMH) Glass industry Polishing powder (CeO 2 )

4 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)

5 REE usage by application 5

6 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 6

7 Availability of individual REOs Production volumes of purified Ho, Er, Tm, Yb, Lu oxides are very small Source: US Department of Energy, Critical Materials Strategy, 2010

8 Relative abundance of rare earths Source: US Geological Survey 8

9 Rare-earth minerals Name Idealized Composition Primary Rare-Earth Content Allanite (Ca,Fe 2+ )(R,Al,Fe 3+ ) 3 Si 3 O 13 H R = light lanthanides Apatite Ca 5 (PO 4 ) 3 F R = light lanthanides Bastnasite RCO 3 F R = light lanthanides (60-70%) Euxenite R(Nb,Ta)TiO 6 xh 2 O R = heavy lanthanides plus Y (15-43%) Fluorite CaF 2 R = heavy lanthanides plus Y Gadolinite R 2 (Fe 2+,Be) 3 Si 2 O 10 R = heavy lanthanides plus Y (34-65%) Laterite clays SiO 2, Al 2 O 3, Fe 2 O 3 R = heavy lanthanides plus Y Loparite (R,Na,Sr,Ca)(Ti,Nb,Ta,Fe 3+ )O 3 R = light lanthanides (32-34%) Monazite RPO 4 R = light lanthanides (50-78%) Perovskite CaTiO 3 R = light lanthanides Sphene CaTiSiO 4 X 2 (X = ½O 2-, or F - ) R = light lanthanides Xenotime RPO 4 R = heavy lanthanides plus Y (54-65%) Zircon ZrSiO 4 R both light and heavy lanthanides plus Y

10 REE content of selected minerals (%) REE Bastnasite Mountain Pass, USA Bastnasite Bayan Obo, China Monazite Mt. Weld, Australia Xenotime Lehat, Malaysia High Y RE laterite Longnan, China Low Y RE laterite Xunwu, China Loparite Kola Peninsula Russia La Ce Pr Nd Sm Eu Trace Gd < Tb < Trace Trace Dy Trace 0.6 Ho 0.01 Trace Trace Trace 0.7 Er 0.01 Trace Trace Trace 0.8 Tm 0.01 Trace Trace 0.1 Yb 0.01 Trace Lu Trace Trace Y 0.1 Trace <

11 Consequence of REE abundances To get 1 ton of Eu 2 O 3 from bastnäsite, one needs to produce (and sell) the following amounts of REOs (tons): La 2 O CeO Pr 6 O Nd 2 O Sm 2 O Gd 2 O Y 2 O Ref.: P. Falconnet, Basic and Applied Aspects of Rare Earths, 1989 (Venice Italy) p. 27

12 Balance problem Ideal situation: perfect balance between demand and production of all REE elements Market in balance corresponds to lowest price for any REE: production costs are shared by all elements Market in balance is very difficult to obtain, because of changes in demand by changes in applications Compromise between two alternatives: Adjusting overall production to optimize production costs: creates surpluses of some REEs and shortages of other REEs (increases price of elements high in demand) Increasing overall production to meet demand of all REEs and stockpiling other REEs (increases overall price) Ref: P. Falconnet, J. Less-Common Met. 111 (1985) 9

13 Balance problem: solutions New applications have to be found for REEs that are produced in excess In case of choice, use for a given application the element that is available in excess e.g. Partial replacement of Nd by Pr in NdFeB magnets Process all REE ores to extract critical metals e.g. Nd-depleted mischmetall How will REE recycling influence balance problem? (research at KU Leuven)

14 Neodymium-driven LREE market Present light REE market is driven by demand for Nd for NdFeB magnets (about 25,000 tons in 2011) Sufficient quantities of REE ores have to be mined to produce at least 25,000 tons of Nd Ce, Pr, Sm are produced in excess (stockpiled) La is in balance thanks to use in NiMH batteries Pr can be used as an admixture in NdFeB magnets (but not Sm) More SmCo magnets could be produced, but high price of Co is a problem New applications for Ce, Pr and Sm needed

15 Dysprosium-driven HREE market Heavy rare earths are produced in much smaller quantities than light ones Present heavy REE market is driven by demand for Dy for NdFeB magnets (about 1,600 tons in 2011) Supply equals demand for Eu, Y, Er Shortage of Tb (use of stockpiles) Excess of Gd and of Ho,Tm,Yb,Lu (stockpiled) Excess of Gd will turn into shortage if magnetic refrigerators become popular New applications needed for Ho,Tm,Yb,Lu (no large-scale separations of these elements)

16 Rapidly changing REE market New applications can bring REE market rapidly out of balance Presently: market driven by Nd and Dy Before 1985: No Nd metal produced in industrial quantities No industrial applications for Dy 1980s: market driven by Sm (SmCo magnets) 1960s-1970s: market driven by Eu (color TV screens) Future: market driven by Gd? (magnetic refrigeration)

17 Conclusions Availability of REEs is determined not only by production volumes of REE ores, but also by natural abundances of individual REEs Matching supply and demand of all REEs is a challenge (balance problem) Present market is driven by Nd and Dy demand Situation could change rapidly by introduction of new applications Active search for applications that can consume stockpiled REEs REE recycling can have an influence on balance problem

18 Thank you!