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.
With many REEs hosted in minerals with resistive properties, analytical method choice becomes crucial to ensure concentrations of REEs are not underestimated. ALS has a number of options for the analysis of REEs to achieve total recovery without comprising detection levels.
ALS’s super-trace ME-MS71L™ method employs a unique ammonium bi-fluoride (ABF) decomposition that leverages its high boiling point (239.5° C) to achieve complete recovery of REEs and refractory phases. The method is optimised to improve recoveries and stabilities of REEs, high field strength elements (HFSE) and key pathfinder elements.
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 |
The main minerals that are mined for REEs are bastnasite, monazite, loparite and laterite clays. All but the laterite clays are highly resistant to acid digestion, therefore necessitating a fusion decomposition for analysis.
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 |
CODE | ANALYTES & RANGES (ppm) | |||||
---|---|---|---|---|---|---|
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. |
Where lower detection limits are required, two methods are suitable: ME-MS89L™ for trace values from a sodium peroxide fusion, or ME-MS81 from lithium borate.
MORE INFORMATIONMethods for determining rock forming elements may be added to both the ME-MS81™ and ME-MS89L™ REE exploration methods.
MORE INFORMATION