In the periodic table, there is a set of 17 metallic elements referred to as rare earth elements (REE). This group includes 15 lanthanides with the addition of scandium and yttrium.
What are Rare Earth Elements?
Rare earth elements are lustrous silvery-white soft heavy metals with many similar properties. Also known as rare earth metals or rare earth oxides, these elements can be found together in geologic deposits.
Rare earth elements are important components of many high-tech devices. They are essential to over 200 products across various applications, particularly consumer products like cellular phones, flat-screen monitors and televisions, electric and hybrid vehicles, and computer hard drives. They also have significant applications in defense systems, including radar and sonar systems, lasers, guidance systems, and electronic displays.
The amount of rare earth elements used in a product may not be an essential part of weight, value, or volume, but they are essential for the device to function. For example, magnets made of rare earth elements often represent only a small portion of the total weight, but without them, the spindle motors and voice coils of desktops and laptops would not be possible.
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Are REEs Really Scarce?
Geologically speaking, the rare earth elements are not really rare. The U.S. Geological Survey studied the "crystal abundance" of various elements and discovered that most rare earth elements are in the same order of magnitude as common metals like copper and zinc. As reported by Virginia Polytechnic Institute and State University professor Aaron Noble, rare earth elements are certainly not as rare as metals like platinum and gold.
This group of elements is fairly common, but they are very difficult to extract from their natural sources. This is because they are just not concentrated in a single place. In the U.S., there are about 0.005 ounces per pound (300 milligrams per kilogram) of rare earth elements across all shale.
Metals typically concentrate within the Earth's crust because of various geological processes, like the formation of mountains, hydrothermal activity, and lava flow. Rare earth elements have unusual chemistry, making them difficult to collect together under these conditions. Since their traces are spread across the planet, they become inefficient to mine.
In nature, metals exist as compounds known as ores, which contain metal particles connected to other nonmetallic substances (counterions) by strong ionic bonds. These bonds must be broken to extract the pure metal, and the counterions must be removed.
Rare earth elements have three positive charges and form strong ionic bonds with phosphate counterions, which possess three negative charges. Therefore, The strong attraction between the positive metal and the negative phosphate must be overcome during the extraction process.
This difficulty of extracting them in pure form gives the rare Earth elements their name. Experts are working on new methods to recycle and extract these valuable metals from old electronic devices and industrial wastes to reduce the pressure on current supplies. Others also try to reproduce new compounds' unusual magnetic and electronic properties to provide an alternative to rare earth elements. There is still no substitute for these elements despite the increasing demand for them.
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