Rare earth elements are a set of 17 chemical elements. These elements are not exactly rare, but are relatively plentiful in Earth’s crust. In fact cerium, one of such elements, is the 25th most abundant element. But these elements are called rare because they tend to occur together in nature and hence are difficult to separate.
The first rare earth element Herbium, renamed Gadolimite in 1800, was discovered in 1787 at a quarry in the village of Ytterby, Sweden. Cerium was the second rare earth element discovered in 1803 in Sweden. By now total 17 rare earth elements have been discovered across the globe.
Rare earth elements are extracted from the minerals, namely, bastnasite, monazite, loparite and lateritic ion-absorption clays.
Except scandium, all rare-earth elements are heavier than iron and thus are believed to have been produced by supernova nucleosynthesis or the S-process in asymptotic giant branch stars.
Until 1948, most of the world’s rare earth elements came from placer sand deposits in India and Brazil. In the 1950s South Africa was the world’s main source of such elements. From 1960s to 1980s California was the leading producer. As of today, China is the top producer. She produces over 95% of world’s supply. China has over recent years curtailed production and export of rare earth elements in order to encourage domestic extraction and secure preferential use of those materials by Chinese manufacturers. This has led other countries to explore alternative sources. Recycling is also a significant option. In Japan and France rare earth elements are being extracted from used electronics, fluorescent lamps, magnets and batteries.
List of 17 Rare Earth Elements and their Uses
Below is produced a list of all 17 rare earth elements and their respective uses in industry and medicine.
- Neodymium – It is used for making powerful magnets for loudspeakers and computer hard drives. Magnets containing neodymium are also used in wind turbines and hybrid cars, ceramics, electric motors of electric automobiles.
- Lanthanum – It is used in manufacturing camera and telescope lenses, such carbon lighting applications as studio lighting and cinema projection, hydrogen stores. Used as a catalyst for oil refineries.
- Cerium – Industrial use in catalytic converters in cars enabling them to run at high temperatures, playing a crucial role in the chemical reactions in the converter, in the process of refining crude oil, polishing powder, as a catalyst for self-cleaning ovens.
- Praseodymium – Used in creating strong metals for aircraft engines. It is a component of a special sort of glass used to make visors to protect welders/glass-makers. It is a core material for carbon arc lighting.
- Gadolinium – Utilized in X-ray and MRI scanning system, in television screens, to be used possibly for developing more efficient refrigeration systems, computer memories, steel additive.
- Yttrium – Used in making lasers, super-conductors, microwave filters, energy-efficient light bulbs, gas mantles, spark plugs. It is used in cancer treatment as well.
- Terbium – Used in making magnets, lasers, naval sonar systems, stabilizer of fuel cells.
- Europium – Used in making red and blue phosphors, lasers, mercury-vapor lamps, fluorescent lamps, as an NMR relaxation agent.
- Samarium – Used in making lasers, masers, nuclear reactors’ control rods.
- Dysprosium – Used in making magnets, lasers, disk drives.
- Holmium – Lasers, spectrophotometers, magnets are made with the use of this element.
- Erbium – Erbium used in manufacture of infrared lasers, vandalium, steel, fiber optics.
- Thulium – of use in making lasers, portable X-Ray machines.
- Lutetium – Industrially used in scanning, high-refractive index glass, LED bulbs.
- Promethium – Used in making nuclear batteries, luminous paint.
- Scandium – Widely applied in making light aluminum alloys for aerospace components, radio-active tracing agent in oil-refineries, mercury vapor lamps.
- Ytterbium – Industrial use in making lasers, steel, nuclear medicines, earthquake monitoring.
Mining, refining and recycling of rare earths have serious environmental consequences. Thorium and uranium commonly occur in rare earth elements ores. Extraction therefore is accompanied by radio active slurry. Release of toxic wastes into the general water-supply has been reported in China.
Environment Question for UPSC from the above Article:
What are rare earth elements? Are they hazardous for the environment? Elucidate.