REE - WIKIPEDIA

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A table listing the seventeen rare earth elements, their atomic number and symbol, the etymology of their names, and their main usages (see also Applications of lanthanides) is provided here. Some of the rare earth elements are named after the scientists who discovered or elucidated their elemental properties, and some after their geographical discovery.

Z	Symbol	Name	Etymology	Selected applications
21	Sc	Scandium	from Latin Scandia (Scandinavia).	Light aluminium-scandium alloys for aerospace components, additive in metal-halide lamps and mercury-vapor lamps,[4] radioactive tracing agent in oil refineries
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, yttria-stabilized zirconia (YSZ), yttrium iron garnet (YIG) microwave filters,[4] energy-efficient light bulbs,[5] spark plugs, gas mantles, additive to steel
57	La	Lanthanum	from the Greek "lanthanein", meaning to be hidden.	High refractive index and alkali-resistant 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,[4] 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, didymium glass, ceramic capacitors
61	Pm	Promethium	after the Titan Prometheus, who brought fire to mortals.	Nuclear batteries
62	Sm	Samarium	after mine official, Vasili Samarsky-Bykhovets.	Rare-earth magnets, lasers, neutron capture, masers
63	Eu	Europium	after the continent of Europe.	Red and blue phosphors, lasers, mercury-vapor lamps, fluorescent 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, magnetostrictive alloys such as Galfenol, steel additive
65	Tb	Terbium	after the village of Ytterby, Sweden.	Green phosphors, lasers, fluorescent lamps, magnetostrictive alloys such as Terfenol-D
66	Dy	Dysprosium	from the Greek "dysprositos", meaning hard to get.	Rare-earth magnets, lasers, magnetostrictive alloys such as Terfenol-D
67	Ho	Holmium	after Stockholm (in Latin, "Holmia"), native city of one of its discoverers.	Lasers, wavelength calibration standards for optical spectrophotometers, magnets
68	Er	Erbium	after the village of Ytterby, Sweden.	Infrared lasers, vanadium steel, fiber-optic technology
69	Tm	Thulium	after the mythological northern land of Thule.	Portable X-ray machines, metal-halide lamps, lasers
70	Yb	Ytterbium	after the village of Ytterby, Sweden.	Infrared lasers, chemical reducing agent, decoy flares, stainless steel, stress gauges, nuclear medicine
71	Lu	Lutetium	after Lutetia, the city which later became Paris.	Positron emission tomography – PET scan detectors, high refractive index glass, lutetium tantalate hosts for phosphors

As defined by IUPAC, a rare earth element (REE) or rare earth metal is one of a set of seventeen chemical elements in the periodic table, specifically the fifteen lanthanides plus scandium and yttrium.[2] Scandium and yttrium are considered rare earth elements because they tend to occur in the same ore deposits as the lanthanides and exhibit similar chemical properties. Despite their name, rare earth elements (with the exception of the radioactive promethium) are relatively plentiful in the Earth's crust,
with cerium being the 25th most abundant element at 68 parts per million (similar to copper). However, because of their geochemical properties,
rare earth elements are typically dispersed and not often found concentrated as rare earth minerals in economically exploitable ore deposits.
It was the very scarcity of these minerals (previously called "earths") that led to the term "rare earth". The first such mineral discovered was
gadolinite, a compound of cerium, yttrium, iron, silicon and other elements. This mineral was extracted from a mine in the village of Ytterby in Sweden;
several of the rare earth elements bear names derived from this location.

Neodymium: very interesting material

Neodymium is a chemical element with the symbol Nd and atomic number 60. It is a soft silvery metal that tarnishes in air.
Neodymium was discovered in 1885 by the Austrian chemist Carl Auer von Welsbach. It is present in significant quantities
in the ore minerals monazite and bastnäsite. Neodymium is not found naturally in metallic form or unmixed with other lanthanides,
and it is usually refined for general use. Although neodymium is classed as a "rare earth", it is a fairly common element, no rarer than cobalt,
nickel, and copper, and is widely distributed in the Earth's crust.Most of the world's neodymium is mined in China.(where?)
Neodymium compounds were first commercially used as glass dyes in 1927, and they remain a popular additive in glasses.
The color of neodymium compounds—due to the Nd3+ ion—is often a reddish-purple but it changes with the type of lighting,
due to fluorescent effects. Some neodymium-doped glasses are also used in lasers that emit infrared light with wavelengths between 1047 and 1062 nanometers.
These have been used in extremely high power applications, such as experiments in inertial confinement fusion.
Neodymium is also used with various other substrate crystals, such as yttrium aluminum garnet in the Nd:YAG laser.
This laser usually emits infrared waves at a wavelength of about 1064 nanometers. The Nd:YAG laser is one of the most commonly used solid-state lasers.
Another chief use of neodymium is as the free pure element. It is used as a component in the alloys used to make high-strength neodymium magnets – powerful permanent magnets
These magnets are widely used in such products as microphones, professional loudspeakers, in-ear headphones, and computer hard disks
, where low magnet mass or volume, or strong magnetic fields are required. Larger neodymium magnets are used
in high power versus weight electric motors (for example in hybrid cars) and generators (for example aircraft and wind turbine electric generators).

History of neodynium

Neodymium was discovered by Baron Carl Auer von Welsbach, an Austrian chemist, in Vienna in 1885.
He separated neodymium, as well as the element praseodymium, from a material known as didymium by
means of fractional crystallization of the double ammonium nitrate tetrahydrates from nitric acid, while following
the separation by spectroscopic analysis; however, it was not isolated in relatively pure form until 1925.
The name neodymium is derived from the Greek words neos and didymos
Double nitrate crystallization was the means of commercial neodymium purification until the 1950s.
Lindsay Chemical Division was the first to commercialize large-scale ion-exchange purification of neodymium.
Starting in the 1950s, high purity (above 99%) neodymium was primarily obtained through an ion exchange process from monazite,
a mineral rich in rare earth elements. The metal itself is obtained through electrolysis of its halide salts. Currently, most neodymium is extracted from bastnäsite,
(Ce,La,Nd,Pr)CO3F, and purified by solvent extraction. Ion-exchange purification is reserved for preparing the highest purities (typically >99.99%).
The evolving technology, and improved purity of commercially available neodymium oxide, was reflected in the appearance of neodymium glass that resides
in collections today. Early neodymium glasses made in the 1930s have a more reddish or orange tinge than modern versions which are more cleanly purple,
due to the difficulties in removing the last traces of praseodymium in the era when manufacturing relied upon fractional crystallization technology.

PRODUCTION OF NEODYNIUM

Neodymium is never found in nature as the free element, but rather it occurs in ores such as monazite and bastnäsite that contain small amounts of all the rare earth metals.
The main mining areas are in China, the United States, Brazil, India, Sri Lanka, and Australia. The reserves of neodymium are estimated at about eight million tonnes.
Although it belongs to the rare earth metals, neodymium is not rare at all. Its abundance in the Earth crust is about 38 mg/kg,
which is the second highest among rare-earth elements, following cerium. The world's production of neodymium was about 7,000 tonnes in 2004.
The bulk of current production is from China, whose government has recently imposed strategic materials controls on the element,
raising some concerns in consuming countries and causing skyrocketing prices of neodymium and other rare-earth metals.
As of late 2011, 99% pure neodymium was traded in world markets for US$300–350 per kilogram, down from the mid-2011 peak of 500 dollard/kg.
Neodymium is typically 10–18% of the rare earth content of commercial deposits of the light rare earth element minerals bastnasite and monazite
With neodymium compounds being the most strongly colored for the trivalent lanthanides, that percentage of neodymium can occasionally dominate the coloration
of rare earth minerals—when competing chromophores are absent. It usually gives a pink coloration. Outstanding examples of this include monazite crystals from
the tin deposits in Llallagua, Bolivia; ancylite from Mont Saint-Hilaire, Quebec, Canada; or lanthanite from the Saucon Valley, Pennsylvania, US.
As with neodymium glasses, such minerals change their colors under the differing lighting conditions. The absorption bands of neodymium interact
with the visible emission spectrum of mercury vapor, with the unfiltered shortwave UV light causing neodymium-containing minerals to reflect a distinctive green color.
This can be observed with monazite-containing sands or bastnasite-containing ore.

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