You have likely never paid much attention to tantalum when you've gazed at the periodic table. It sits there, in the middle of a sea of transition metals, kind of out of the way and in the corner.
And yet, tantalum is increasingly important in the 21st Century, because it plays a large role in making personal electronic devices smaller, and it naturally fights corrosion. Along with the increased demand for tantalum comes a human price, as tantalum resources funded portions of the Second Congo War, the bloodiest conflict since World War II.
Tantalum has the atomic number 73, snuggling the element between hafnium, niobium, and tungsten in the transition metal section of the periodic table. Discovered in the 19th Century, tantalum is named for Tantalus, a figure from Greek Mythology, who found himself doomed to spend eternity in a Saw-like torture scheme after death. An unknown force required Tantalus to stand in knee deep water, with delicious fruit handing overhead and just out of reach. The name refers to tantalum's own ability to be submerged in substances without being quenched.
In fact, tantalum's unusual characteristics led to its increased use in the late 20th and 21st Century. The element is extremely stable at temperatures lower than 150 degrees Celsius, and needs exposure to hydrofluoric acid, one of the nastier acids out there, to cause corrosion. This protection from corrosion is due to a natural protective layer created by oxides of tantalum on the surface of the the metal; making the element a perfect match for use in structures exposed to the the elements, like bridges and water tanks.
21st Century uses
Tantalum's primary 21st Century use comes in the creation of capacitors. Tantalum capacitors have an extremely high capacitance packed in a small volume — perfect for shrinking our electronic devices, or making additional room in them for larger processors or speakers. Tantalum is found in cell phones, dvd players, laptops, hard drives, and the PS3 — essentially almost any piece of home or industrial electronic equipment.
Tantalum is also used to create surface acoustic wave filters, devices used in cell phones and televisions to improve audio quality. The average cell phone has about 40 milligrams of tantalum inside — not a considerable amount, but one that adds up quickly thanks to the millions and millions of cell phones in use.
Tantalum capacitors experience an extremely low failure rate, making them perfect for use in medical equipment, including hearing aids and devices that you don't want to randomly fail, like pacemakers. Tantalum is not harmed by bodily fluids, and does not irritate the flesh of the implantee, making it a perfect metal from which to create hip, knee, and other orthopedic implants.
How to Mine It
Tantalum is rarely found in its elemental form — the element is often found with niobium and the radioactive elements thorium and uranium, and industrial processes are required to extract pure tantalum. South American and Australia account for over two-thirds of the world's tantalum production, with a single mine in Brazil accounting for 20% of the world's annual supply.
Increased use of tantalum in electronic devices has increased the cost of capacitor-grade tantalum over the past decade, with the refined form currently hovering around $300 a pound, while lower grade forms routinely sell for $100+ a pound.
Funding a civil war
"Coltan" is another name for columbite-tantalite, an ore containing a mix of niobium and tantalum. As we discussed yesterday, the Democratic Republic of the Congo (formerly Zaire) is extremely rich in coltan reserves, with rebels mining and then selling coltan to finance the civil war, with the majority of illegally mined coltan sold to China. The Second Congo War has claimed over 5.4 million lives, the bloodiest single conflict since World War II.
The Kahuzi-Biega National Park and the Okapi Wildlife Reserve are extremely fertile sources of coltan, with mining activities driving out endangered gorillas in these protected areas. Mining coltan in the Congo also brings along another problem — due to the distance from home or camps, miners often kill and eat gorillas they come across in order to survive, further endangering the animals.
Locals also seek out coltan, well aware of the financial gains lying in the surrounding area as they sift for the rock in riverbeds and remove leftover pieces from abandoned mines. One-third of children in the Congo quit school to mine for coltan, which has a negative impact on the region for generations.
Individuals receive around ten dollars for a pound of unprocessed coltan, a good deal of money for those looking for a way to feed their families. Not the healthiest or safest way to make a living — but one that will persist as long as demand for tantalum is high and the price of life is low.
Top image courtesy of FZD/Shutterstock.com
Images courtesy of WildlifeDirect, zazzle, and the Tantalum-Niobium International Study Center. Sources linked within the article.