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Rare Earth Metals Are Found in Everything From Catalytic Convertors
Critical metals are defined mostly by governments as the raw materials essential to their economies, defence and for medical purposes and are also referred to as strategic metals.
Lists of such metals vary and are generally not widely publicised by governments but can include everything from bauxite, manganese, chromium, tin, cobalt, and platinum, which are sometimes stockpiled to ensure security of supply.
While the numbers of metals defined as strategic or critical varies there is one set of elements that are common to most lists and these are the 17 elements generally known as rare earth metals.
While strictly speaking they are not rare geographically, they are generally found as traces in other ores and what makes them rare is the difficulty of extracting them and processing them and the cost of doing so, which has hitherto made them uneconomic to produce.
An examples of a rare earth elements in common use is Cerium. One of the lanthanide group this is used as a catalytic converter to reduce carbon monoxide emissions in car exhaust fumes.
As an alloy with Lanthanum, iron oxide and magnesium oxide (plus small traces of neodymium and praseodymium) it provides the flint in cigarette lighters. Cerium is used in the walls of self-cleaning ovens and to polish glass surfaces.
Praesodymium, which is also one of the lanthanide group, was first identified by an Austrian scientist, Carl Auer von Welsbach, in 1885. It is an ingredient essential to high-intensity permanent magnets, used in electric motors, and is also used in the rechargeable batteries used in hybrid cars. Its properties also make it useful for producing special specialized yellow glass goggles used by glass blowers and welders and as a salt for colouring glass and ceramics.
Promethium was the last element of the rare earth lanthanide to be identified in 1945 and it is the only radioactive rare earth metal. It is used in atomic batteries for spacecraft and guided missiles.
AS many of these examples demonstrate we are often unaware of the presence of rare earth metals in the equipment that is around us in daily life and it is perhaps this fact that has raised the profile of these elements in the last couple of years.
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