Cobalt: Essential for Batteries and Bright Blues

Centuries ago, miners in the Schneeberg mountains of modern-day Germany ran into a problem. They carved into the mountainside in search of metal-rich ore, specifically silver and nickel. But when they tried to smelt the ore into its valuable metal components, some impurity kept spoiling the process.

Being the Middle Ages, the miners blamed their smelting issues on troublesome kopelts or kopolds, a medieval German word for "gnome" or "goblin." According to legend, the kopolds lived in the Schneeberg mines and liked to prank humans by replacing the silver and nickel in their ore with a foul mineral that released poisonous fumes during the smelting process. They were also blamed for cave-ins.

As with all good ancient legends, the gnome story had a grain of truth to it. The silver and nickel smelting process was complicated by high levels naturally occurring cobalt in the Schneeberg rock. And a mineral called cobaltite contains arsenic and sulfur, which could be deadly if released in an airtight mine shaft.

Cobalt, the elemental metal, was first isolated and named in 1735 by the Swedish chemist Georg Brandt, an early critic of alchemy and probably not a fan of gnomes, either.

Although cobalt didn't get its name until the 18th century, cobalt-based pigments and dyes have been prized for their rich blue hue for millennia.

The Cobalt Institute says that pottery and glass containing cobalt-based glazes have been recovered from Egyptian tombs dating back at least 2,600 years. And the famous blue Chinese porcelain from the Tang (600-900 C.E.) and Ming (1350-1650 C.E.) dynasties were also glazed with cobalt-based minerals.

Pure cobalt is a shiny gray color, but it can be transformed into a bright blue powder by taking cobalt oxides and treating them with a process called calcination that exposes cobalt-rich minerals to temperatures in excess of 2,012 degrees F (1,100 degrees C). The striking color known as Cobalt Blue is made by heating cobalt oxide (Co₃O₄) with aluminum silicates at 2,192 degrees F (1,200 degrees C).

A host of other hues — mazarine blue, willow blue, blue-black — can be made by combining cobalt oxide with other minerals. Small amounts of blue cobalt hues are also used as a "decolorizer" to cancel out yellowish hints in glass from iron contamination.

Cobalt was almost exclusively used as an ingredient in pigments and paints up until the 20th century. In 1916, more than 70 percent of all cobalt mined and refined in the world, which was only 440 tons (400 metric tons), was used as oxides for colorings, according to the Cobalt Institute.

The rechargeable lithium ion batteries in your smartphone, tablet and electric vehicle run, at least in part, on cobalt. Cobalt is one of the key ingredients, along with other metals like lithium, nickel and manganese, inside these fast-charging, long-lasting batteries that power our digital lives. About 50 percent of the cobalt produced worldwide is used for rechargeable batteries.

Cobalt is found in the cathode (the positively charged electrode) of lithium ion batteries. When a lithium ion battery is charged, lithium ions flow from the cathode to the negatively charged anode, where they're stored. When the battery is discharged, the ions flow back to the cathode and electrons are released to power the phone or electric motor.

Cobalt has two innate properties that make it ideal for battery applications: thermal stability and high energy density. Cathodes made with cobalt won't overheat easily or catch fire, which is a major safety issue, and they'll also be able to store and transfer more energy. Cobalt is not only found in the cathodes of lithium ion batteries, but also in other popular rechargeable batteries like nickel-cadmium and nickel-metal hydride batteries.

Since cobalt currently makes up between 10 and 33 percent of rechargeable cathodes, the automobile industry is going to need a lot more cobalt to power the future of electric vehicles. One analysis predicts the cobalt demand from passenger vehicles alone to quadruple from more than 27,500 tons (25,000 metric tons) in 2020 to over 110,231 tons (100,000 metric tons) by 2025.

When aerospace engineers need a material that can withstand the intense heat inside a jet or rocket engine, they turn to "superalloys" made with cobalt.

Superalloys are high-performance metals that earn their flashy name from extremely high resistance to wear and heat. Nickel-based superalloys outperform cobalt alloys for stress resistance for temperatures reaching up to 1,706 degrees F (930 degrees C). Beyond that extreme temperature, cobalt-based super alloys really show their stuff.

Cobalt has a higher melting point than nickel and cobalt super alloys are more resistant to heat corrosion. That's why you'll find cobalt superalloys in the stationary fins of gas-turbine engines, which take the brunt of the intense heat generated by jet engines without wearing down and failing.

One of the main reasons that cobalt landed on the U.S. Department of Interior's list of "critical minerals" for national security is that half of the world's cobalt is mined in the Democratic Republic of Congo (DRC). As a report from the U.S. Geological Survey explains, DRC has a poor history of government corruption, human rights violations and environmental damage related to cobalt mining.

It's not only human rights groups like Amnesty International that are concerned with unsafe and unethical labor practices related to unregulated "artisanal" cobalt mining in the DRC. The political and environmental instability of DRC means that a huge chunk of the cobalt supply chain is vulnerable to disruption. If the high-tech economy relies on a steady supply of cobalt, largely to be used in rechargeable batteries, than troubles in the DRC could slow economic growth worldwide.

The USGS report also notes that China is the main refiner of cobalt and one of the biggest financial backers of large cobalt mining operations in the DRC. As it stands, the U.S. tech sector is hugely dependent on an unstable source in DRC and a contentious trade partner in China for its cobalt supply. Which accounts for the last fact on out list.

According to figures from 2015, the United States consumed 10 percent of the world's cobalt while producing less than 1 percent of the global cobalt supply.

Cobalt isn't everywhere, but it also isn't a particularly rare mineral — it ranks 32nd in abundance in the earth's crust. Only two mines in Canada and Morocco can extract pure cobalt ore, while the majority is extracted as a byproduct of copper and nickel mining. One of the world's richest cobalt deposits is in the Central African Copperbelt in the DRC.

The U.S., however, isn't blessed with a lot of high-grade cobalt deposits, which makes it trickier to mine profitably. The mining industry also has complained of a slow permitting process to allow for mineral exploration, both onshore and offshore. The Trump administration has directed the Department of Interior to speed up the permitting process in an effort to decrease America's reliance on foreign sources of critical minerals like cobalt.

Despite permitting and geological obstacles, there has been some progress in U.S. cobalt mining. In 2014, the Eagle Mine in Michigan's Upper Peninsula began mining nickel and copper with cobalt and other minerals as a byproduct. And America's first mine dedicated to cobalt is getting ready to go into production in 2020 in Idaho.