Thursday, March 14, 2013

Rare Earth Elements

by akshiv, This post originally appeared at the Future Science Leaders blog.

When ever you look at the periodic table there are always two rows of elements at the bottom, the Lanthanide, and the Actinide series. What is so special about these guys? Why are they treated like the way the US treats Alaska and Hawaii. In fact, it is for the same reason that cartographers move a disembodied Alaska down, that chemists place the rare earth elements down there. It is for spacing. A table with the lanthanide and the actinide series placed in it would look like: 




The rare earth classification is given to only the Lanthanide series (sorry Actinides :( ) and also yttrium and scandium.
So, what is so special about this set of seventeen elements?
Well for starters a lot of them are ferromagnetic. This means that they naturally generate a magnet field. This is an important trait, so much so that numerous electronic engineers have taken advantage of this to make modern electronics better. Virtually every cellphone, laptop, and piece of fancy lab equipment contains some concoction. Everyone loves lasers right? These elements are required to make modern lasers. You know the super precise, micro machining, 3-D imaging, and missile seeking kind. Essentially, as we get better technology, we need more rare earth elements.
These elements are called rare earth elements because surprise, they are rare. Okay, in reality, they are not that rare. Most of them (except promethium) are abundant in the earth’s crust. They are rare because they are really dispersed in the crust and do not exist in large deposits where they can be mined or extracted in large quantities very easily. There do exist some of these magical deposit but they are scarce, making the elements hard to obtain and thus rare.
As we have established, are extremely important to our technology dependent 21st century societies and as the name would suggest quite rare. Where are the biggest supplies? What are we doing to get them out of the ground? These days more than 80% of the global supply of rare earth elements are mined in China. The government of China has promised to keep up production and continue to export this resource to the rest of the world. Obviously, the world will be a little uncomfortable with one nation in charge of an extremely valuable resource, and to avoid the problem of China gaining a monopoly, searches in Australia, Brazil, Canada, Denmark (Greenland), South Africa, Tanzania, and the United States are on going.
These metals have a dark side as well. Mining, refining, and even recycling of these metals can be extremely harmful for the environment. Aside from the huge amount of atmospheric carbon produced in global management of these metals, the chemicals needed to work with the metals are generally extremely toxic. On top of all of this these ores are generally found along with a slew of radioactive elements that used to be buried away in the earth’s crust.
The rare earth metals allow for great technological advances and are necessary for out modern societies, but as is the case with most things, we need to arrive at balance between what is good for us now and what will be good for us in the future. Below is a great visualization of the role of rare earth elements in our modern day societies.
About this contributor: I am in my final year of high school. I love playing ultimate frisbee, skiing and playing the clarinet/guitar. I am happiest when learning random trivia or stargazing. Learning for me is its own reward whether it is about the quantumly tiny or the cosmologically large.

1 comment:

  1. I'm impressed to say the least! Although it is much longer, I feel your writing surpasses some on the topic in well regarded scientific journals such as science news. Furthermore your use of graphics effectively organizes the topic in a way text often fails to produce. I am also interested in random knowledge but lack the desire to do anything with other than avoid having to look up information I could conceivably need. In that regard I applaud the effort you have obviously put into educating less generous seekers of knowledge like myself.

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