Cobalt

Cobalt is a chemical element with the symbol Co and atomic number 27. It is a hard, gray metal that is usually found combined with other elements in the Earth’s crust. People have used cobalt-based blue pigments for thousands of years in jewelry, paints, and glass because of its beautiful color.

Today, most cobalt is made as a by-product when mining copper and nickel. The Democratic Republic of the Congo produces most of the world’s cobalt. In 2024, over 300,000 tons were made, with the DRC providing more than 80% of it.

Cobalt is very important for making lithium-ion batteries, strong and wear-resistant alloys, and bright blue colors in glass, ceramics, inks, paints, and varnishes. It is also used in the petroleum industry to help clean up oil and prevent pollution. In nature, cobalt is a key part of Vitamin B₁₂, which all animals need to stay healthy.

Characteristics

Cobalt is a ferromagnetic metal that is strongly magnetic. It has a density of 8.9 times that of water and can stay magnetic up to very high temperatures. Cobalt can form different crystal shapes, and these shapes usually mix together.

Cobalt does not easily rust because a thin layer of oxide protects it. However, it can react with certain gases and elements. When heated with oxygen, it forms a compound that can lose oxygen at very high temperatures. It also reacts with elements like fluorine, chlorine, and bromine to form new compounds. Cobalt does not react with hydrogen or nitrogen gas, even when heated, but it does react with elements like boron, carbon, and phosphorus. At normal temperatures, cobalt reacts slowly with strong acids and with moist air, but not with dry air.

Compounds

See also: Category:Cobalt compounds

Cobalt can form many different compounds. Common forms include states where cobalt has a +2 or +3 charge, though it can have charges from -3 to +5. In water, a simple +2 compound creates a pink color. Adding chloride makes the color turn intensely blue. When heated, cobalt can form different oxides, some of which are green, brown, or blue.

Some special compounds of cobalt with elements like fluorine show unique behaviors. For example, cobalt(III) fluoride stays stable even though it reacts strongly with water. There are also four main compounds where cobalt has a +2 charge combined with fluorine, chlorine, bromine, or iodine, and these can also exist in forms that include water.

Cobalt can also form complexes with ammonia and similar molecules. One famous scientist, Alfred Werner, studied these deeply and won a Nobel Prize for his work. Cobalt also forms compounds with softer molecules like triphenylphosphine, linking to more complex metal compounds.

Main article: Organocobalt chemistry

Cobalt has special compounds that act like a well-known compound called ferrocene, but with cobalt instead of iron. Cobalt also helps in important chemical reactions and is part of vitamin B₁₂, the only vitamin that contains a metal atom.

Isotopes

Main article: Isotopes of cobalt

There is only one stable type of cobalt found in nature, called ⁵⁹Co. Scientists have made 22 other types of cobalt that do not stay the same over time, called radioactive isotopes. The most stable of these changes back into another element in about 5 years, while others change much faster—some in just seconds.

These different types of cobalt range from ⁵⁰Co to ⁷⁸Co. The lighter ones change by taking in particles, while the heavier ones change by sending out particles. These changes create either iron or nickel. The ⁵⁹Co type can be studied using special tools to see its tiny changes.

Etymology

See also: Gnome § Cobalt ore

Many stories exist about where the word "cobalt" came from. One story says it was named after "kobelt", a term used by German miners in the 1500s for a tricky type of ore. This ore was harmful and gave off bad gases, but people had used it for blue coloring for a long time. At the time, German miners did not know how to turn this ore into metal.

A well-known writer named Georgius Agricola wrote about this type of ore, calling it cobaltum. He also wrote about a harmful spirit called "kobel". Some people thought the ore was named after this spirit. Later writers and dictionaries suggested the ore's name might come from ideas about spirits or demons in mines.

Other ideas about the word's origin include links to old words meaning "house ruler" or even a type of bucket used in mining.

History

Cobalt compounds have been used for centuries to give glass, glazes, and ceramics a beautiful blue color. People have found cobalt in old sculptures from Egypt, jewelry from Persia, ruins from Pompeii, and ancient China from the Tang dynasty and Ming dynasty.

The word cobalt may come from a 16th-century German word for a type of ore. Swedish chemist Georg Brandt discovered cobalt around 1735, showing it was a new element different from other metals. He proved that cobalt was what made glass blue, not bismuth as people thought before. Cobalt was the first metal discovered since ancient times.

In the 19th century, much of the world's cobalt was made into blue paint in Norway. Later, big cobalt mines were found in New Caledonia, Ontario, Canada, and the Katanga Province in the Congo. In 1938, scientists discovered a special form of cobalt called cobalt-60, which later helped learn more about how atoms change. Today, cobalt is very important for batteries and other modern technologies.

Occurrence

Cobalt is created in big star explosions called supernovae and makes up a tiny part, about 0.0029% of the Earth's crust. It is often found together with nickel. Both can be found in special iron from space called meteoric iron, though cobalt is less common there.

In nature, cobalt is usually mixed with other elements. It combines with sulfur and arsenic to form minerals like cobaltite (CoAsS), safflorite (CoAs₂), glaucodot ((Co,Fe)AsS), and skutterudite (CoAs₃). These minerals can change when they meet air and water, turning into pink stones like erythrite and spherocobaltite.

Small bits of cobalt can be found in rocks, soil, plants, and animals. Very tiny amounts of cobalt have even been found in samples from deep holes dug in the Earth and in rocks brought back from the Moon.

Cobalt can also be found in tobacco smoke. Plants that make tobacco absorb cobalt from the soil, and this cobalt is then inhaled when the tobacco is smoked.

Production

See also: Cobalt extraction

Cobalt is mainly found in ores like cobaltite, erythrite, glaucodot, and skutterudite, but most of it comes as a by-product when mining and processing nickel and copper. Because cobalt is often a by-product, how much of it we get depends on how much nickel and copper we mine.

There are not many places where cobalt is found by itself, but some rare spots, like in Morocco, have cobalt ores that are mined directly. To get cobalt from ores, different methods are used, such as froth flotation, which helps separate cobalt from other materials. These processes turn the ores into cobalt oxide (Co₃O₄), which can then be changed into metal using special reactions or in a blast furnace.

Extraction

See also: Cobalt extraction

The United States Geological Survey says there are about 11 million metric tons of cobalt available worldwide. The Democratic Republic of the Congo (DRC) makes most of the world's cobalt, about 63% of it. By 2025, this could rise to 73% if plans by companies like Glencore work out. Experts think that by 2030, we will need 47 times more cobalt than we did in 2017.

Democratic Republic of the Congo

See also: Mining industry of the Democratic Republic of the Congo

Changes to mining rules in Congo in 2002 brought new money into copper and cobalt projects. By 2005, the DRC was the top cobalt producer, thanks to copper deposits in its Katanga Province. The Mukondo Mountain project, run by the Central African Mining and Exploration Company (CAMEC), might be the richest cobalt spot in the world. In 2008, it made about a third of all cobalt produced globally. In July 2009, CAMEC agreed to sell all its cobalt from Mukondo Mountain to a Chinese company.

In 2016, China owned over 10% of cobalt mining in Congo, which helps China control much of the world's cobalt supply. This has worried other countries who want to rely less on China. There have also been concerns about how miners work and treat people in Congo’s mines.

Glencore’s Mutanda Mine sent out 24,500 tons of cobalt in 2016, a big part of Congo’s output and nearly a quarter of all cobalt made worldwide. Glencore stopped Mutanda for two years late in 2019 but has since restarted its Katanga Mining project, which should make 300,000 tons of copper and 20,000 tons of cobalt by 2019.

In February 2018, experts said the DRC is “the Saudi Arabia of the electric vehicle age” because of its cobalt, which is key for the lithium-ion batteries in electric vehicles.

On 9 March 2018, the DRC’s leader Joseph Kabila changed the mining rules, making cobalt and coltan “important metals.” The rules changed for good on 4 December 2018.

In February 2025, the DRC stopped cobalt exports for four months because the price dropped very low. The DRC gives about 75% of the world’s cobalt. The China Molybdenum Company (CMOC) is a big player there, making about 40% of the world’s cobalt. In the past year, CMOC doubled its output from two mines in the DRC.

There are worries about how some miners work in Congo. Some miners use simple tools and work unsafe jobs, which can hurt or even kill them. There have also been reports of children working in mines, which is not fair or safe for them. Companies like Apple Inc. have tried to make sure their cobalt does not come from places where children work.

Canada

In 2017, some companies planned to look for old silver and cobalt mines in Cobalt, Ontario, where they think there is a lot of cobalt.

Canada makes cobalt as a by-product of nickel mining. In 2023, Canada made more than 5,000 tons of cobalt, with most coming from Newfoundland and Labrador and some from Ontario, Manitoba, and Quebec. In 2023, Canada sold $568 million worth of cobalt and cobalt products.

Cuba

Canada’s Sherritt International works with cobalt ores from nickel deposits in the Moa mines in Cuba. Cuba has several mines in Mayarí, Camagüey, and Pinar del Río. Because of investments by Sherritt International, Cuba became third in cobalt reserves in 2019, just before Canada.

Indonesia

Indonesia started making cobalt in 2021 as a by-product of nickel production. By 2022, it became the world’s second-largest cobalt producer. Experts think Indonesia could make up 20% of the world’s cobalt by 2030. Cobalt production grew from 1,300 tons in 2015 to 20,500 tons in 2024 because the Indonesian government wanted to build a strong supply chain for electric vehicles. In 2020, Indonesia banned cobalt exports, which brought in more foreign money to process nickel and cobalt there.

Applications

In 2016, about 116,000 tonnes of cobalt was used. Cobalt is useful in making special mixtures of metals called alloys and in some rechargeable batteries.

Alloys

Cobalt-based mixes of metals have been very important. They stay strong at high temperatures, so they are good for parts in airplane engines. These mixes also don’t rust or wear down easily, which makes them great for medical tools that last a long time, like parts for hips and knees. Some of these mixes are also used in dentistry. They can also be used to make strong magnets and special metals for jewelry.

Batteries

One important use of cobalt is in batteries, especially in older ones used in things like phones and computers. Newer batteries for electric cars use less cobalt, and scientists are working on ways to make batteries without cobalt at all.

Catalysts

Cobalt can help make certain chemicals. It is used to help turn some oils into paint and to clean up fuels by removing unwanted substances.

Pigments and coloring

Long ago, cobalt was used to make blue colors in glass and paint. Even today, special blue paints still use cobalt because the color stays bright for a long time.

Radioisotopes

A special kind of cobalt called Cobalt-60 gives off safe levels of radiation that doctors use to treat sickness and to clean medical tools. It is also used to check if metals are strong enough for building.

Magnetic materials

Because cobalt can stick to magnets and keep its magnetic properties even when very hot, it is used to make strong magnets for computers, sensors, and machines that picture the inside of our bodies.

Other uses

Cobalt is also used to make metals look shiny and strong, and it can be a base for special coatings used on things like pottery.

Biological role

Cobalt is important for all animals because it helps their bodies use energy. It is a main part of a vitamin called B₁₂, which animals need to stay healthy. Special tiny living things called bacteria in the stomachs of some animals, like cows, change cobalt into this important vitamin. Animals that eat grass need a small amount of cobalt in the soil to stay healthy.

When we eat foods with vitamin B₁₂, our bodies get all the cobalt we need. But for some animals like cows and sheep, cobalt is very important too. Long ago, farmers found that animals got sick when the soil didn’t have enough cobalt. Scientists learned they could help these animals by giving them small pellets with cobalt, which the animals could keep in their stomachs to stay healthy.

Health issues

Cobalt can be harmful to health if taken in large amounts. For a person weighing about 100 kilograms, a harmful amount would be around 20 grams.

Long-term exposure to smaller amounts of cobalt has caused health problems, such as heart issues linked to adding cobalt to beer in the past. Cobalt may also cause breathing and skin problems when inhaled or touched. It is also thought to possibly cause cancer, according to health research groups.