Erbium (Er) is a silvery-white rare earth element with an atomic number of 68. It is a member of the lanthanide series on the periodic table. In its natural state, erbium is never found as a free metal; instead, it always occurs chemically combined with other elements in various minerals.
Natural Forms of Erbium
Erbium is typically found co-crystallized with other rare earth elements within complex mineral structures. These minerals are predominantly phosphates or carbonates. Xenotime, a yttrium phosphate mineral, is a significant source, often containing erbium alongside other heavy rare earth elements. Monazite, a phosphate mineral containing various rare earth elements, also hosts erbium, though it is more known for lighter rare earths. Bastnäsite, a fluorocarbonate mineral, is another common host for erbium, particularly in certain deposits.
Global Locations of Erbium Deposits
Erbium deposits are distributed globally, often concentrated in areas rich in other rare earth elements. China is the leading producer, with significant deposits, particularly ion-adsorption clays found in southern provinces like Jiangxi and Guangdong. These clay deposits are notable because rare earth elements in this state are relatively easier to extract. The United States has reserves, primarily at the Mountain Pass mine in California, which historically focused on bastnäsite. Australia also contributes to the global supply, with deposits like those in the Mount Weld region of Western Australia. Other countries with notable erbium production or reserves include Brazil and India, where it is often found in monazite sands. Russia and Vietnam also have significant rare earth deposits that contain erbium. These deposits are typically associated with larger mining operations targeting a broader spectrum of rare earth elements, as erbium rarely occurs in high concentrations on its own and is often a byproduct of mining for other, more abundant rare earths.
How Erbium is Obtained
The process of obtaining erbium begins with mining the ore that contains rare earth minerals. After extraction, the ore is crushed and ground to reduce particle size. This is followed by beneficiation, which involves physical and chemical treatments such as magnetic separation, flotation, and gravity concentration to separate the valuable minerals from waste material. This initial concentration increases the percentage of rare earth elements. The concentrated ore then proceeds to complex chemical separation processes. A common method is acid leaching, where strong acids dissolve the rare earth elements, leaving insoluble waste behind. To isolate erbium from the chemically similar rare earth elements, advanced techniques like solvent extraction or ion exchange are employed. Solvent extraction involves mixing the dissolved rare earths with an organic solvent that selectively binds to specific elements. Ion exchange uses resins to selectively absorb ions for purification.
Why Erbium is Valued
Erbium’s properties make it valuable across various high-tech applications. Its ability to absorb and emit light at specific wavelengths is useful in fiber optics. Erbium-doped fiber amplifiers (EDFAs) are integral components in telecommunication systems, boosting optical signals over long distances. Erbium is also used in lasers, especially in medical and industrial fields. These erbium-doped lasers are used for applications such as dermatology, dentistry, and rangefinders due to their specific emission wavelengths. Beyond optics, erbium finds application in phosphors for displays, contributing to vivid colors. In nuclear technology, erbium oxide serves as a neutron absorber in reactors, helping regulate the fission process. Erbium is also employed as a colorant, imparting a distinct pink hue to glass and ceramics.