Above: Periodic table of elements with the rare earth elements circled in red (original image by Armtuk, adapted by Steven Watt)
Did you know? The magnet industry accounts for 25% of the total global demand for rare earth minerals.
From smartphones and GPS receivers to hybrid electric vehicles and wind turbines, the latest high-tech devices all have one thing in common: rare earth minerals. These natural resources have unique properties that are needed to manufacture the tiny internal components in a wide range of devices. Unfortunately, the production of these minerals is also a significant source of pollution.
A rare earth mineral is made of one or more rare earth elements (REEs). The REE group includes the 15 lanthanide elements in the second-last row of the periodic table, as well as yttrium and scandium in the third column (group IIIB), making a total of 17 REEs.
Did you know? Equipping wind turbines with direct-drive generators containing large amounts of rare earth magnets can increase efficiency by 25% compared to gear-driven generators.
Elements grouped together on the periodic table display similar electron configurations, resulting in shared chemical properties. REEs are no exception: they are all strong magnets and have high levels of electrical conductivity. These characteristics, along with being strong and lightweight, are why they are essential for so many modern electronics, including medical and military equipment.
Despite their name, rare earth minerals are actually abundant in Earth’s crust. However, they are typically dispersed throughout ore deposits rather than concentrated in one place. That means a lot of digging is needed to get a relatively small amount.
And since the REEs are chemically very similar, they have similar melting points and very small differences in solubility. This makes it more difficult to separate and purify the different elements, a problem made worse by the fact that REEs are often found together. As a result, processing REEs usually involves techniques that can cause significant pollution, especially when environmental safeguards are not used. For example, solvent extraction processes require the use of strong, damaging acids.
Did you know? Tiny rare earth magnets are so amazingly strong that it would be impossible for you to pull one off of your fridge.
In China, rare earth mineral processing produces around 25 million tons of wastewater each year, water that is laced with cancer-causing heavy metals. In fact, China accounts for 97% of the global output of rare earth minerals, and the Chinese are finding it increasingly difficult to satisfy rising global demand. As a result, prices are rising.
Recently, the search for new natural sources of REEs has led investors and manufacturers to Jamaica. It appears this Caribbean island can at least provide a short-term solution to the supply problem. However, regardless of where they rare earth minerals are mined, environmental risks remain.
Did you know? A miniature magnet made of neodymium is what causes your cellphone to vibrate when you receive a call.
Scientists have also begun to synthesize artificial rare earth substitutes in the lab. They do this by combining other elements in ways that mimic the properties of rare earth minerals. Some companies, such as Honda, have also begun recycling rare earth metals.
As the mining industry and manufacturers begin to explore solutions, what responsibility do you think consumers of high-tech devices should take for the pollution associated with rare earth minerals?
Textbooks and scholarly publications
- Jones AP, Wall F, Williams CT. 1996. Rare Earth Minerals: Chemistry, Origin and Ore Deposits. Springer, New York, NY.
Mining industry publications