Laboratory Testing Of Rare Earth Elements (REEs)

Jun 19 2013

Rare earth elements (REEs) or rare earth metals are a group of seventeen chemical elements in the periodic table, in particular the fifteen lanthanides as well as yttrium and scandium as defined by the International Union of Pure and Applied Chemistry (IUPAC). Yttrium and scandium are considered rare earth elements as they tend to occur in the same ore deposits as the lanthanides and exhibit similar chemical properties. Actually rare earth elements are neither earth nor rare. The name dates back to the 18^th and 19^th centuries when the elements were initially isolated out of minerals which were rare themselves. This gave them the name rare earth although the elements are quite common mixed in tiny concentrations into rock worldwide.

Hence rare earth elements excepting radioactive promethium are relatively plentiful in the earth’s crust with cerium being the 25^th most abundant element at 68 ppm similar to copper. However, due to their geochemical characteristics, rare earth elements are very dispersed and not usually found concentrated as rare earth minerals in economically exploitable ore deposits.

Description of Certain Rare Earth Elements

Certain rare earth elements used by LSM Analytical include:

Gadolonite – This was the first such mineral discovered which is a compound of yttrium, cerium, iron, silicon and other elements. The extraction of this mineral was done from a mine in Ytterby village in Sweden and as seen from our table several of the rare earth elements bear names derived from this location. In spite of being considerably low profile, rare earth elements are critical to the way one lives and responsible for helping in miniaturizing headphones and computers, powering hybrid cars and many more.
Cerium – This is a highly familiar substance especially in LSM Analytical and the parent company LSM, since it plays a major role in the glass polishing business known as optical surface technologies(OST). OST is the leading European producer of cerium oxide-based glass polishing powders and this high- performance material is used in a variety of polishing application from decorative to high-technology. Architectural mirrors, glass, computer and television screens, glasses, lenses and cathode ray tubes are few of the surfaces that benefit from cerium’s ability to deliver a defect-free.
Neodymium – It is also known as the little giant and is the most costly and sought-after rare earths. In the past it was not very easy to carry your favorite music along and rare earth elements changed that completely. The key is magnets, which are everywhere from headphones to hard drives to anything that includes a tiny electric motor. In case there is a magnet that needs to spin may be magnets are involved. The production of a strong magnetic field used to require a big heavy magnet resulting in big naturally heavy pieces of technology. In the late 70s, Sony introduced the Walkman was then a very small portable music player. Sony can shrink the form of the product only due to smaller, stronger magnets specifically those made from the rare earth element samarium.
Samarium - based magnets have largely been replaced by magnets made with neodymium at present. These magnets are responsible for miniaturizing gadgetry and also play a major role in making necessarily heavy-weight technology cheaper and lighter, for example oil drills and wind turbines.
Europium – This was the first isolated high-purity rare earth element to enter the public marketplace in 1967 as a source of color red in TV sets. Red phosphors had before the source of red on screen but did not produce a very bright color. Europium phosphors made the picture to really pop.
Lanthanum – This was first discovered in 1893 and is another example of a rare earth element responsible for a step-change in technology. When compared to silver or lead there is more lanthanum on this planet and it is the second most abundant rare earth element, but initially there were not a lot of uses for it. Lanathum extracted in the 1970s and '80s normally went into stockpile however today every Prius hybrid car on the road carries with it about 10 lbs of lanthanum. Nickel-lanthanum hydride batteries, a big breakthrough in battery technology pack more power into a more compact area and around two times more efficient as the standard lead-acid car battery. Most Prius owners will not know when they use this rare earth element daily since the car's battery is referred to as ‘nickel-metal hydride.’ The ‘metal in question is lanthanum.

Table of Applications

The applications of the different rare earth elements are provided in the table below:

Z	Symbol	Name	Etymology	Selected applications
21	Sc	Scandium	from Latin Scandia (Scandinavia), where the first rare earth ore was discovered.	Light aluminium-scandium alloy for aerospace components, additive in Mercury-vapor lamps.
39	Y	Yttrium	after the village of Ytterby, Sweden, where the first rare earth ore was discovered.	Yttrium aluminium garnet (YAG) laser, yttrium vanadate (YVO4) as host for europium in TV red phosphor, YBCO high-temperature superconductors, (YSZ), yttrium iron garnet (YIG) microwave filters, energy-efficient light bulbs.
57	La	Lanthanum	from the Greek "lanthanein", meaning to be hidden.	High refractive index glass, flint, hydrogen storage, battery-electrodes, camera lenses, fluid catalytic cracking catalyst for oil refineries.
58	Ce	Cerium	after the dwarf planet Ceres, named after the Roman goddess of agriculture.	Chemical oxidizing agent, polishing powder, yellow colors in glass and ceramics, catalyst for self-cleaning ovens, fluid catalytic cracking catalyst for oil refineries, ferrocerium flints for lighters.
59	Pr	Praseodymium	from the Greek "prasios", meaning leek-green, and "didymos", meaning twin.	Rare-earth magnets, lasers, core material for carbon arc lighting, colorant in glasses and enamels, additive in didymium glass used in welding goggles, ferrocerium firesteel (flint) products.
60	Nd	Neodymium	from the Greek "neos", meaning new, and "didymos", meaning twin.	Rare-earth magnets, lasers, violet colors in glass and ceramics, ceramic capacitors.
61	Pm	Promethium	after the Titan Prometheus, who brought fire to mortals.	Nuclear batteries.
62	Sm	Samarium	after Vasili Samarsky-Bykhovets, who discovered the rare earth ore samarskite.	Rare-earth magnets, lasers, neutron capture, masers.
63	Eu	Europium	after the continent of Europe.	Red and blue phosphors, lasers, mercury-vapor lamps, NMR relaxation agent.
64	Gd	Gadolinium	after Johan Gadolin (1760–1852), to honor his investigation of rare earths.	Rare-earth magnets, high refractive index glass or garnets, lasers, X-ray tubes, computer memories, neutron capture, MRI contrast agent, NMR relaxation agent.
65	Tb	Terbium	after the village of Ytterby, Sweden.	Green phosphors, lasers, fluorescent lamps.
66	Dy	Dysprosium	from the Greek "dysprositos", meaning hard to get.	Rare-earth magnets, lasers.
67	Ho	Holmium	after Stockholm (in Latin, "Holmia"), native city of one of its discoverers.	Lasers.
68	Er	Erbium	after the village of Ytterby, Sweden.	Lasers, vanadium steel.
69	Tm	Thulium	after the mythological northern land of Thule.	Portable X-ray machines.
70	Yb	Ytterbium	after the village of Ytterby, Sweden.	Infrared lasers, chemical reducing agent.
71	Lu	Lutetium	after Lutetia, the city which later became Paris.	Positron emission tomography - PET Scan detectors, high refractive index glass.

Conclusion

The following rare earth elements are assayed by LSM Analytical : La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy,Ho, Er, Tm, Yb, Lu

Their chemical composition from 100% to 0.05% is determined by XRF and 0.05% to ppm levels by ICP-OES. Surface area can be determined by BET and particle size distribution by laser diffractions (Malvern). LSM Analytical has Flexible Scope Accreditation by which they are prepared and equipped to develop any further chemical or physical testing that customers may require.

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