WHAT ARE RARE EARTHS?
“Rare earth elements” (REEs) refers to a group of seventeen unique chemical elements: the lanthanides, which are comprised of fifteen elements, plus scandium and yttrium which are grouped alongside the lanthanides on account of their similar physical and chemical properties”.
REEs are often separated into two sub-groups based on atomic weight. The first of these sub-groups, the light REEs, is comprised of lanthanum, cerium, praseodymium, neodymium and samarium (atomic number 57 to 62). The second sub-group, the heavy REEs, is comprised of the lanthanides with an atomic number ranging from 63 to 71: europium, gadolinium, terbium, holmium, erbium, thulium, ytterbium, lutetium as well as scandium and yttrium (atomic numbers 21 and 39). The unique chemical and physical properties of REEs have positioned them as a critical material across a number of rapidly evolving markets and industrial applications.
Rare Earth Elements are present in most devices we use on a daily basis: they are used in the fabrication of our smartphones, notebooks, tablets and even the vehicles we use for transportation. Also, these minerals are used to elaborate wind turbines, medical lasers and sensible defense equipment, becoming the most strategic minerals in the world.
The vital role Rare Earth play in the manufacturing of hybrid and electric vehicles, along with other REE dependent industries, has prompted many countries to seek sustainable long term suppliers. This is not surprising giving the fact that in regions like North America, the Rare Earth industry contributes almost $800 mm USD directly to the economy (2013 data), making a significant effect on economic flows.
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The Rare Earth have many scientific and industrial uses. Their compounds are used as catalysts in the production of petroleum and synthetic products. Rare Earths are used in lamps, lasers, magnets, phosphors, motion picture projectors, and X-ray intensifying screens. A pyrophoric mixed rare-earth alloy called Mischmetall (50% Ce, 25% La, 25% other light lanthanides) or misch metal is combined with iron to make flints for cigarette lighters. The addition of <1% Mischmetall or lanthanide silicides improves the strength and workability of low alloy steels.
Rare Earths share the following common properties:
- Silvery-white metals that tarnish when exposed to air, forming their oxides.
- Relatively soft metals. Hardness increases somewhat with higher atomic number.
- Moving from left to right across the period (increasing atomic number), the radius of each lanthanide 3+ ion steadily decreases. This is referred to as ‘lanthanide contraction’.
- High melting points and boiling points.
- Very reactive.
- React with water to liberate hydrogen (H2), slowly in cold/quickly upon heating. Lanthanides commonly bind to water.
- React with H+ (dilute acid) to release H2 (rapidly at room temperature).
- React in an exothermic reaction with H2.
- Burn easily in air.
- They are strong reducing agents.
- Their compounds are generally ionic.
- At elevated temperatures, many rare earths ignite and burn vigorously.
- Most rare earth compounds are strongly paramagnetic.
- Many rare earth compounds fluoresce strongly under ultraviolet light.
- Lanthanide ions tend to be pale colors, resulting from weak, narrow, forbidden f x f optical transitions.
- The magnetic moments of the lanthanide and iron ions oppose each other.
- The lanthanides react readily with most nonmetals and form binaries on heating with most nonmetals.
- The coordination numbers of lanthanides are high (greater than 6; usually 8 or 9 or as high as 12).
RARE EARTHS INDUSTRY
Rare earths demand is driven, in large part, by two of the fastest-growing sectors on the planet: energy and high technology. In the energy square, neodymium, praseodymium, and dysprosium are used in the manufacturing of rechargeable batteries, hybrid/electric cars, and wind turbines.
Cerium and lanthanum are used in fluid cracking catalysts and catalytic converters. In the high tech sector, elements like europium and yttrium are used in flat panel displays, lasers and radars.
Neodymium, praseodymium, yttrium, europium and terbium have substitutes but they are not as effective and other elements have none at all in specific applications. Unlike base metals, new applications are also being constantly developed for rare earths given their unique attributes.
- Permanent Magnet demand is forecast to increase due to emerging green technologies of wind turbines and new energy vehicles, leading a strong growth in Praseodymium and Neodymium.
- Neodymium, Praseodymium and Dysprosium demand will grow strongly until 2030. From 2020 through 2025 the rate of global demand growth will accelerate, resulting in major annual demand increases by 2025 that can only be satisfied by the continuous and accelerated development of new mines – Adamas Intelligence.
- Demand for NdFeB magnets in end-use products such as windmills, electric motors, electric bikes and external hard disk drives to increase significantly. – Adamas Intelligence.
- The global REE magnet market is expected to grow (from 2016) at a compound annual rate of 13.2% to reach $41.41 billion by 2022 – Infoholic Research.