7440-00-8

Usage

Uses

Used in Electronics:
Neodymium is used as a component in many of the most powerful magnets in the world, due to its strong magnetic properties.
Used in Alloys:
Neodymium is used as an alloying element in some types of steel, where it can make up to 18% of the composition. This addition increases the heat resistance and strength of the steel.
Used in Colored Glass:
Neodymium can be added to glass to produce violet-, red-, or gray-colored glass. Neodymium glass is used to calibrate spectrometers and other optical devices in astronomical and laboratory observation instruments.
Used in Astronomical Lenses and Lasers:
Neodymium salts are used in the production of artificial rubies, which are used in lasers. Additionally, neodymium is used in astronomical lenses to increase their heat resistance.
Used in Metallurgical Research:
Neodymium is used in metallurgical research for its properties and potential applications in various industries.
Used in Yttrium-Garnet Laser Dopants:
Neodymium is used as a dopant in yttrium-garnet lasers, enhancing their performance and capabilities.
Used in Gas Scavenger in Iron and Steel Manufacture:
Neodymium serves as a gas scavenger in the iron and steel manufacturing process, improving the quality of the final product.
Used in Cigarette-Lighter Flints:
Misch metal, which is composed of about 18% neodymium, is used in the production of cigarette-lighter flints.
Used in Ceramic Enamels and Glazes:
Neodymium salts are used as pigments for ceramic enamels and glazes, adding color and aesthetic appeal to various ceramic products.
Used in TV Tubes and Eyeglasses:
Neodymium is used as a color for TV tubes and as a tint for eyeglasses, enhancing their visual properties.
Used in Analytical Chemistry and Atomic Absorption Spectroscopy:
Neodymium plasma standard solution is used as a standard solution in analytical chemistry and atomic absorption spectroscopy, as well as a single-element standard solution for plasma emission spectrometry.

Isotopes

There are 47 isotopes of neodymium, seven of which are considered stable.Together the stable isotopes make up the total abundance in the Earth’s crust. Twoof these are radioactive but have such long half-lives that they are considered stablebecause they still exist on Earth. They are Nd-144 (half-life of 2.29×10+15 years) andNd-150 (half-life of 6.8×10+15years). All the other isotopes are synthetic and havehalf-lives ranging from 300 nanoseconds to 3.37 days.

Origin of Name

Derived from the two Greek words neos and didymos. When combined, they mean “new twin.”

Characteristics

As an element, neodymium is a soft silver-yellow metal. It is malleable and ductile. It canbe cut with a knife, machined, and formed into rods, sheets, powder, or ingots. Neodymiumcan form trivalent compounds (salts) that exhibit reddish or violet-like colors. Neodymium reacts with water to form Nd(OHO)3 and hydrogen (H2), which can explodeif exposed to a flame or spark. It is shipped and stored in containers of mineral oil.

History

In 1841 Mosander extracted from cerite a new rose-colored oxide, which he believed contained a new element. He named the element didymium, as it was an inseparable twin brother of lanthanum. In 1885 von Welsbach separated didymium into two new elemental components, neodymia and praseodymia, by repeated fractionation of ammonium didymium nitrate. While the free metal is in misch metal, long known and used as a pyrophoric alloy for light flints, the element was not isolated in relatively pure form until 1925. Neodymium is present in misch metal to the extent of about 18%. It is present in the minerals monazite and bastnasite, which are principal sources of rare-earth metals. The element may be obtained by separating neodymium salts from other rare earths by ion-exchange or solvent extraction techniques, and by reducing anhydrous halides such as NdF3 with calcium metal. Other separation techniques are possible. The metal has a bright silvery metallic luster. Neodymium is one of the more reactive rare-earth metals and quickly tarnishes in air, forming an oxide that splits off and exposes metal to oxidation. The metal, therefore, should be kept under light mineral oil or sealed in a plastic material. Neodymium exists in two allotropic forms, with a transformation from a double hexagonal to a body-centered cubic structure taking place at 863°C. Natural neodymium is a mixture of seven isotopes, one of which has a very long half-life. Twenty-seven other radioactive isotopes and isomers are recognized. Didymium, of which neodymium is a component, is used for coloring glass to make welder’s goggles. By itself, neodymium colors glass delicate shades ranging from pure violet through wine-red and warm gray. Light transmitted through such glass shows unusually sharp absorption bands. The glass has been used in astronomical work to produce sharp bands by which spectral lines may be calibrated. Glass containing neodymium can be used as a laser material to produce coherent light. Neodymium salts are also used as a colorant for enamels. The element is also being used with iron and boron to produce extremely strong magnets. These are the most compact magnets commercially available. The price of the metal is about $4/g. Neodymium has a low-to-moderate acute toxic rating. As with other rare earths, neodymium should be handled with care.

Production Methods

Neodymium is recovered mostly from mineral monazite and bastnasite, thetwo most abundant rare-earth minerals. Monazite is a rare earth-thorium phosphate usually containing between 9 to 20% neodymium. Bastnasite is a rare earth fluocarbonate ore containing 2 to 15% neodymium. Both ores are first cracked by heating with concentrated sulfuric acid or sodium hydroxide. The recovery process from monazite ore using sulfuric acid is described below:Heating the ore with sulfuric acid converts neodymium to its water soluble sulfate. The product mixture is treated with excess water to separate neodymium as soluble sulfate from the water-insoluble sulfates of other metals, as well as from other residues. If monazite is the starting material, thorium is separated from neodymium and other soluble rare earth sulfates by treating the solution with sodium pyrophosphate. This precipitates thorium pyrophosphate. Alternatively, thorium may be selectively precipitated as thorium hydroxide by partially neutralizing the solution with caustic soda at pH 3 to 4. The solution then is treated with ammonium oxalate to precipitate rare earth metals as their insoluble oxalates. The rare earth oxalates obtained are decomposed to oxides by calcining in the presence of air. Composition of individual oxides in such rare earth oxide mixture may vary with the source of ore and may contain neodymium oxide, as much as 18%.The oxalates obtained above, alternatively, are digested with sodium hydroxide converting the rare earth metals to hydroxides. Cerium forms a tetravalent hydroxide, Ce(OH)4, which is insoluble in dilute nitric acid. When dilute nitric acid is added to this rare earth hydroxide mixture, cerium(IV) hydroxide forms an insoluble basic nitrate, which is filtered out from the solution. Cerium also may be removed by several other procedures. One such method involves calcining rare earth hydroxides at 500°C in air. Cerium converts to tetravalent oxide, CeO2,while other lanthanides are oxidized to trivalent oxides. The oxides are dissolved in moderately concentrated nitric acid. Ceric nitrate so formed and any remaining thorium nitrate present is now removed from the nitrate solution by contact with tributyl phosphate in a countercurrentAfter removing cerium (and thorium), the nitric acid solution of rare earths is treated with ammonium nitrate. Lanthanum forms the least soluble double salt with ammonium nitrate, which may be removed from the solution by repeated crystallization. Neodymium is recovered from this solution as the double magnesium nitrate by continued fractionation.Three alternative methods may be mentioned here, which give high purity material and are less tedious than the one described above. These are (1) ion exchange, (2) metallothermic reduction, and (3) electrolysisIn the ion exchange process, the nitric acid solution of the rare earth oxides obtained above is passed through a sulfonated styrene-divinylbenzene copolymer or other cation exchange resin in the hydrogen form. The rare earths are selectively eluted by flowing down a chelating solution of ethylenediamine tetraacetic acid (EDTA), or citric acid, or nitrilotriacetate (NTA) through the loaded column. The most stable complexes are eluted first. Metal ions are selectively stripped out in successive stages.In the metallothermal reduction, the mixture of rare earth oxides obtained above is first converted to their halide salts. This is done by heating the oxidesat 300 to 400°C with dry and purified hydrogen fluoride, or preferably, by allowing dry hydrogen fluoride to pass over rare earth oxides and ammonium fluoride at 300-400°C. If chloride salt is desired, the oxides must be heated with ammonium chloride. For example, neodymium oxide may be converted to its fluoride or chloride:Nd2O3 + 6NH4F?HF → 2NdF3 + 6NH4F↑ + 3H2O↑Nd2O3 + 6NH4Cl → 2NdCl3 + 6NH3↑ + 3H2O↑Neodymium, along with lanthanum, cerium and praseodymium, has low melting points and high boiling points. The fluorides of these and other rare earth metals are placed under highly purified helium or argon atmosphere in a platinum, tantalum or tungsten crucible in a furnace. They are heated under this inert atmosphere or under vacuum at 1000 to 1500°C with an alkali or alkaline earth metal. The halides are reduced to their metals:2NdF3 + Ca → 2Nd + 3CaF2NdCl3 + 3Li → Nd + 3LiClThe crucible is allowed to cool and is held at a temperature slightly above the melting point of neodymium for a sufficient time to allow separation of the metal.In the electrolytic process, a fused mixture of anhydrous rare earth chlorides (obtained above) and sodium or potassium chloride is electrolyzed in an electrolytic cell at 800 to 900°C using graphite rods as the anode. The cell is constructed of iron, carbon or refractory linings. Molten metal settles to the bottom and is removed periodically.

Hazard

(Salts) Irritant to eyes and abraded skin

Hazard

Many of the compounds (salts) of neodymium are skin irritants and toxic if inhaled oringested. Some are explosive (e.g., neodymium nitrate [Nd(NO3)3]).

Safety Profile

Human systemic effects by intracerebral route: blood changes. It may be an anticoagulant lanthanoid. Care in handling is advised. Flammable in the form of dust when exposed to heat or flame. Slight explosion hazard in the form of dust when exposed to flame. Can react violently with air, halogens, N2.Violent reaction with phosphorus above 4OOOC. Many of its compounds are poisons.

InChI:InChI=1/Nd