Neodymium
27.13 %
12.18%
23.8 %
8.3%
17.19 %
{ syn. }
5.76%
{ syn. }
5.64%
Attention
Neodymium ( Nomenclature recommendation was temporarily neodymium ) is a chemical element with the element symbol Nd and atomic number 60 in the periodic table it is in the group of lanthanides and also making it one of the metals of the rare earths. The element name is derived from the Greek words neos νέος 'new' and δίδυμος didymos, twin ' ( as a twin of lanthanum ) from. The metal is mainly used for strong magnets.
- 6.1 oxides
- 6.2 halides
- 6.3 Other compounds
- 6.4 Other substances
History
1841 Carl Gustav Mosander extracted the rare earth Didym of lanthanum oxide. Per Teodor Cleve in 1874 remarked that it was all about two elements in Didym. In 1879 Lecoq de Boisbaudran samarium isolated from Didym, which he won from the mineral Samarskite. In 1885, Carl Auer von Welsbach, to separate Didym in praseodymium and neodymium, are the salts of different colors. Pure metallic neodymium was shown until 1925.
Occurrence
Neodymium occurs naturally only in chemical compounds associated with other lanthanides, preferably minerals,:
- Monazite (Ce, La, Th, Nd, Y) PO4
- Bastnaesite ( (Ce, La, Th, Nd, Y) ( CO 3) F)
- Mixed metal contains up to 18% neodymium.
The main supplier with 97 % of world production is China. This leads to significant environmental problems there. " In the separation of neodymium from the sponsored rock creates toxic waste, radioactive uranium and thorium also is released during the degradation process. These substances are at least partially into the groundwater, thus contaminate flora and fauna considerably and are classified as harmful to human health ". Other commercially exploitable deposits are found in Australia.
Extraction and production
As with all lanthanides ores are first concentrated by flotation, subsequently converted to their halides and metals are separated by fractional crystallization, ion exchange or extraction.
After separation of the complex oxide is converted to the Neodymbegleiter neodymium (III ) fluoride with hydrogen fluoride, followed by reduction with calcium to form calcium fluoride to neodymium. Calcium residues and impurities are separated off by melting in a vacuum. The production by electrolysis of Neodymhalogeniden is now used rarely.
The Chinese government has announced to introduce more stringent environmental requirements and strengthen the fight against illegal mines. Early June 2011, it seems to have come to a first implementation of this intention. According to reports the Financial Times, the state-owned producer (Baotou Steel Rare Earth) receives a monopoly on the extraction and processing of rare earths. 35 licensed establishments are closed and compensated nine other non-licensed establishments should be closed and not compensated. In the United States is currently the Mount Weld mine reactivated the Mountain Pass mine in California and Australia. Both mines are certified by Öko -Institut eV, acceptable environmental protection systems. However, there are also plans for the combined mining of rare earths in Greenland, where the toxic residues to be dumped in lakes.
Properties
Physical Properties
The silvery white lustrous metal is one of the lanthanides and rare earth metals. It's in the air a bit more corrosion resistant than europium, lanthanum, cerium, praseodymium, or, but readily forms an oxide layer of pink -violet, which can flake in the air.
Chemical Properties
At high temperatures, the sesquioxide Nd2O3 Neodymium burns. It reacts with water to form hydrogen to the Neodymhydroxid Nd (OH ) 3 With hydrogen is transformed to the hydride NdH2. In addition to the main valence / oxidation number 3 come under special conditions, the oxidation numbers 2 and 4.
Use
- Neodymium -iron- boron compounds for the production of the strongest magnets. They are used for magnetic resonance imaging, micro-motors and hard drives ( positioning of the write heads ), permanent magnet rotors (eg, stepper and servo motors, efficient permanent-magnet DC machines, for example, in some types of wind turbines (about one sixth ), for driving electric and hybrid vehicles as well as model - drives), linear motors for positioning, such as CNC machines, high-quality speakers and headphones. Compared with the samarium -cobalt magnets, they are stronger and much cheaper, but also much more sensitive to heat.
- Neodymium salts for coloring enamel
- Blue Porcelain Color
- Neodymium ( III) oxide on the glass color. It produces very warm purple to maroon and gray tones. Such glasses have sharp absorption bands and are used in astronomy to calibrate.
- Deinking of ferrous glass
- UV-absorbing glass ( solar control glass )
- Part of the industrially widely used neodymium -YAG laser
- Neodymoxiddotiertes barium titanate for capacitor dielectrics
- Because of its pyrophoric properties as an alloy partner with cerium in flint
- For the production of neodymium - catalyzed polybutadiene rubber (Nd -PBR )
Compounds
Oxides
- Neodymium (III ) oxide ( Nd2O3 )
Halides
- Neodymium (III ) fluoride ( NdF3 )
- Neodymium ( III ) chloride ( NdCl3 ), anhydrous
- Neodymium ( III ) bromide ( NdBr3 ), anhydrous, two modifications
- Neodymium ( II ) bromide ( NdBr2 ), only anhydrous
- Neodymium ( II, III ) bromide ( Nd4Br9 ), only anhydrous
- Neodymium ( III ) iodide ( NdI3 ), anhydrous
Other compounds
- Neodymium ( III ) nitrate ( Nd ( NO3) 3 · 6H 2 O )
- Neodymium ( III) sulfate ( Nd2 (SO4) 3 · 8 H 2 O)
- Neodymium ( III) acetate ( Nd ( C2H3O2 ) 3)
Neodymium ( III) chloride
Neodymium ( III) sulfate, nitrate and chloride in the solution
Other substances
Neodymium -iron-boron ( Nd2Fe14B ) is the material currently the strongest permanent magnets can be made from the. You reach a remanence of up to 1.4 Tesla. The coercivity jHc varies in the range 870-2750 kA / m.