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Rare earth elements

Rare earth elements

The rare earth elements (REEs) are the 15 lanthanides of the periodic table of elements, but often scandium and yttrium are included in the definition due to their similar chemical behaviour. The importance of this group of elements has grown in recent years due to use in a variety of industrial applications but particularly electronics, clean energy, and automobiles. Rare earth elements are found in two types of deposits: primary magmatic deposits and secondary concentration deposits, either by mechanical or chemical weathering.

REE

Analysis for rare earth element exploration

Accurate analysis is vital in rare earth element (REE) exploration, particularly because many REEs are contained within minerals that are highly resistant to conventional digestion methods. Choosing the right analytical technique is therefore crucial to avoid underestimating REE concentrations and to ensure reliable data for effective decision-making. At ALS, we offer a range of advanced analytical solutions designed to achieve total recovery of REEs without compromising detection limits or sensitivity.

Super-trace, total extraction REE & refractory minerals

Our ME-MS71L™ method employs a unique ammonium bifluoride (ABF) decomposition technique. By utilising the high boiling point of ABF (239.5°C), this approach enables near complete extraction of rare earth elements, including those locked within refractory mineral phases. The method has been carefully optimised to enhance recovery and stability not only of REEs but also of critical high field strength elements (HFSE) and key pathfinder elements, providing comprehensive geochemical insights essential for exploration success.



Code Analytes & Ranges (ppm)
ME-MS71L™
0.1g sample




Al 0.05-50% Eu 0.004-5,000 Mo 0.1-10,000 Ta 0.005-10,000
B 10-10,000 Fe 0.05-50% Na 0.05-10% Tb 0.001-5,000
Ba 1-10,000 Gd 0.004-5,000 Nb 0.02-10,000 Th 0.004-10,000
Be 0.03-1,000 Hf 0.008-10,000 Nd 0.04-10,000 Ti 0.0002-20%
Ca 0.01-50% Ho 0.002-5,000 P 0.002-20% Tm 0.001-5,000
Ce 0.1-10,000 K 0.05-25% Pb 0.5-10,000 U 0.01-10,000
Co 0.2-10,000 La 0.1-10,000 Pr 0.01-5,000 V 1-10,000
Cs 0.01-10,000 Li 1-10,000 Rb 0.05-10,000 W 0.2-10,000
Cu 2-10,000 Lu 0.001-5,000 Sc 0.04-10,000 Y 0.01-10,000
Dy 0.003-5,000 Mg 0.01-50% Sm 0.006-5,000 Yb 0.001-5,000
Er 0.002-5,000 Mn 0.005-50% Sr 0.4-10,000 Zr 0.5-10,000
 

REE Exploration in Clays

Rare earth elements (REEs) can be efficiently extracted from ionic adsorption clays through the use of ammonium sulphate leaching. These clays are formed through the natural weathering of REE-rich minerals, during which REE ions become loosely adsorbed onto clay surfaces. The leaching process releases these adsorbed ions without the need to dissolve the host mineral structure—offering a selective method for recovering REEs from weathered deposits.


Code Analytes & Ranges (ppm)
ME-MS19™
30g sample
 Al 5-250000 Fe 5-500000 Nb 0.005-500 Ta 0.005-500
B 10-10000 Gd 0.005-1000 Nd 0.05-10000 Tb 0.002-1000
Ba 0.5-10000 Hf 0.005-500 Ni 0.1-10000 Th 0.005-10000
Be 0.01-1000 Ho 0.002-1000 P 5-10000 Ti 5-100000
Ca 20-250000 K 20-100000 Pb 0.05-10000 Tm 0.002-1000
Ce 0.005-500 La 0.002-10000 Pr 0.004-1000 U 0.005-10000
Co 0.005-10000 Li 0.2-10000 Rb 0.05-10000 V 0.4-10000
Cs 0.005-500 Lu 0.002-1000 Sc 0.005-10000 W 0.01-10000
Cu 0.04-10000 Mg 1-250000 Si 10-10000 Y 0.005-500
Dy 0.005-1000 Mn 0.2-50000 Sm 0.004-1000 Yb 0.004-1000
Er 0.004-1000 Mo 0.01-10000 Sn 0.05-500 Zr 0.01-500
Eu 0.004-1000 Na 50-100000 Sr 0.03-10000    

Ore grade rare earth elements

The main minerals mined for REEs are bastnasite, monazite, loparite, and laterite clays. Except for laterite clays, these minerals are highly resistant to acid digestion, requiring fusion or ABF digestion for complete decomposition and accurate analysis.

Methods for ore grade REEs

ALS method ME-MS81h is suitable for ore grade REEs and is provided from a lithium borate fusion with ICP-MS analysis. The upper limit for the trace elements by this method range from 5,000 to 50,000 ppm, however, over-range analysis by ME-OGREE can determine concentrations up to 30%. Alternatively, where the lower detection limit is of lesser concern, fusion-XRF method ME_XRF30, which also includes loss on ignition as part of the analysis, may be suitable.



Code Analytes & Ranges (ppm)
ME-MS81h™
0.1g sample 		Ce* 3-50,000 Ho 0.05-5,000 Rb 1-50,000 Tm 0.05-5,000
Dy* 0.3-5,000 La* 3-50,000 Sm* 0.2-5,000 U 0.3-5,000
Er 0.2-5,000 Lu 0.05-5,000 Sn 5-50,000 W 5-50,000
Eu 0.2-5,000 Nb 1-5,000 Ta 0.5-5,000 Y 3-50,000
Gd* 0.3-5,000 Nd* 0.5-50,000 Tb* 0.05-5,000 Yb 0.2-5,000
Hf 1-50,000 Pr* 0.2-5,000 Th 0.3-5,000 Zr 10-50,000
*These elements may be determined up to 30% by ME-OGREE.


CODE ANALYTES & RANGES (%)
ME_XRF30
0.7g sample 		CeO2 0.01-50 Ho2O3 0.01-10 Sm2O3 0.01-10
Dy2O3 0.01-10 La2O3 0.01-50 Tb4O7 0.01-10
Er2O3 0.01-10 Lu2O3 0.01-10 Tm2O3 0.01-10
Eu2O3 0.01-10 Nd2O3 0.01-10 Y 0.01-10
Gd2O3 0.01-10 Pr6O11 0.01-10 Yb2O3 0.01-10
OA-GRA05x
ME-GRA05 		Loss on Ignition Furnace or Thermogravimetric Analyser (TGA).
1g sample.

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