RARE EARTH ELEMENTS
What Are Rare Earth Elements (REEs)?
Rare earth elements are a group of seventeen chemical elements that occur together in the periodic table (see image). The group consists of yttrium and the 15 lanthanide elements (lanthanum, cerium, praseodymium, neodymium, promethium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, and lutetium). Scandium is found in most rare earth element deposits and is sometimes classified as a rare earth element. The International Union of Pure and Applied Chemistry includes scandium in their rare earth element definition.
The rare earth elements are all metals, and the group is often referred to as the "rare earth metals." These metals have many similar properties, and that often causes them to be found together in geologic deposits. They are also referred to as "rare earth oxides" because many of them are typically sold as oxide compounds.
Uses of Rare Earth Elements
Rare earth metals and alloys that contain them are used in many devices that people use every day such as computer memory, DVDs, rechargeable batteries, cell phones, catalytic converters, magnets, fluorescent lighting and much more.
During the past twenty years, there has been an explosion in demand for many items that require rare earth metals. Twenty years ago very few people owned a mobile phone, but today over 5 billion people own a mobile device.  The use of rare earth elements in computers has grown almost as fast as cell phones.
Many rechargeable batteries are made with rare earth compounds. Demand for the batteries is being driven by demand for portable electronic devices such as cell phones, readers, portable computers, and cameras.
Several pounds of rare earth compounds are in batteries that power every electric vehicle and hybrid-electric vehicle.