Almost all technological products we use on a daily basis contain a group of elements known as the rare-earth metals. Abundant in technology and deemed by US Department of Energy as “technology metals” due to the fact that they are used in all sorts of technologies ranging from computers and screens, networks, MRIs, batteries, magnets, automobiles and various types of special optical glasses, as well as a catalyst for oil refining. As a matter of fact, this a small sampling of examples, and the list goes on virtually touching every industry and modern technological devices.As an example of a technology that everyone is very familiar with is the smart-phone. A generic smart phone uses about 16 rare-earth metals! These metals give rise to striking colors such as green, blue and red due to their luminescent property. Additionally, rare-earth are responsible for making the smart-phones vibrate, are used in the speaker system, as well as in many of the electronic circuits that allow the phone to work. Although ubiquitous in usage, many people are not familiar with these elements and perhaps it is not a coincidence that their name on the periodic table table derives from the Greek, “lanthanein,” which means “hidden.” So what are rare-earth metals and what makes them so vital for our technological sustinance?
Rare-earth elements chemist Lieutenant Carl Axel Arrhenius found a black mineral which caught his eye in a small village in Sweden named Ytterby. Later, it was discovered that this black mineral contained a new oxide and was named yttria. Although the complete discovery of all the rare earth metals lasted around 160 years. This is due to the fact that these elements are found together in minerals, and their chemical composition is very similar but the methods for separating these elements chemically at that time where very lengthy and scientists could spent their entire career isolating one rare earth from another. Fortunately, with the Neil Bohr’s theory of the hydrogen atom allowed theoretical physicists and chemists to show that there were only 15 lanthanides as well as scandium and yttrium, which make up rare earth metals.
Rare-earth metals are found in the earth’s crust and although they are abundant, their concentration is low in the minerals and ores, which makes it hard to extract and their extraction may not always be economically viable. Additionally, the extraction of these metals and mining process has a negative environmental impact. Moreover, although several countries, including the US have deposits of rare-earth, as I’ve said previously not all deposits are economically viable to mine. Currently, China controls 80% of the export market for the rare-earth elements. Apple has recently said that it wants to use recycled rare-earth metals for its products. Thus, finding alternative ways for producing rare-earth metals may provide better environmental protection as well as less reliance on price fluctuations due to various import-export regulations and currency fluctuations.
Scientists at Idaho National Laboratory, Livermore National Laboratory, Rutgers university and UC Davis have reported to find a new way to produce rare-earth metals using organic bio-acids, such as acids from fruits, and by product of phosphoric acid production, known as phosphogypsum. Phosphoric acid has a slew of industrial uses and is widely produced, thus finding a way to extract rare-earth metals from this byproduct is viable option. Scientists used synthetic phosphogypsum which was produced in lab and had a controlled composition, and used various acids to understand which acid was best at separating rare-earths most efficiently. Surprisingly, bio-acids did the best job! The next step of this research would be to apply industrial grade phosphogypsum found as a by product to refine the results of this study as well as understand how different compositions of phosphogypsum affects the ability of rare-earth metals to be extracted.