Cobalt

Cobalt is a chemical element with the symbol Co and atomic number 27. It is a hard, gray metal often found mixed with other elements in the ground.

People have used cobalt for thousands of years to make beautiful blue colors in jewelry, paints, and glass.

Today, most cobalt comes from mining copper and nickel. The Democratic Republic of the Congo makes most of the world’s cobalt.

Cobalt is important for making lithium-ion batteries, strong mixtures of metals called alloys, and bright blue colors for glass, ceramics, paints, and more. It is also used in the oil industry. In nature, cobalt is a key part of Vitamin B₁₂, which helps all animals stay healthy.

Characteristics

Cobalt is a ferromagnetic metal that is strongly magnetic. It is 8.9 times heavier than water and can stay magnetic even at very high temperatures. Cobalt can form different crystal shapes, and these shapes usually mix together.

Cobalt does not rust easily because a thin layer of oxide protects it. However, it can react with certain gases and elements. When heated with oxygen, it forms a new compound. It also reacts with elements like fluorine, chlorine, and bromine to make other 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. In water, a simple +2 compound creates a pink color. Adding chloride makes the color turn blue. When heated, cobalt can form different oxides.

Some special compounds of cobalt with elements like fluorine show unique behaviors. There are also four main compounds where cobalt has a +2 charge combined with fluorine, chlorine, bromine, or iodine.

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

Main article: Organocobalt chemistry

Cobalt has special compounds that act like a well-known compound called ferrocene, but with cobalt instead of iron. Cobalt is also 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.

Etymology

See also: Gnome § Cobalt ore

Many stories tell us where the word "cobalt" came from. One story says it was named after "kobelt". This was a term used by German miners in the 1500s. They used this word for a tricky kind of ore. This ore was harmful and gave off bad gases, but people used it for blue coloring. 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 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 thought the ore's name might come from ideas about spirits or demons in mines.

Other ideas say the word might come from old words meaning "house ruler" or a type of bucket used in mining.

History

Cobalt compounds have been used for centuries to color glass, glazes, and ceramics blue. 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 German word from the 1500s. Swedish chemist Georg Brandt discovered cobalt around 1735. He showed it was a new element, different from other metals. He proved that cobalt made glass blue, not bismuth as people once thought. Cobalt was the first metal found since ancient times.

In the 1800s, much of the world's cobalt was used to make 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. This helped scientists learn more about atoms. Today, cobalt is very important for batteries and other modern technologies.

Occurrence

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

In nature, cobalt is usually mixed with other elements. It combines with sulfur and arsenic to make minerals such as 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 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 take in cobalt from the soil, and this cobalt is then inhaled when the tobacco is smoked.

Production

See also: Cobalt extraction

Cobalt is mostly found in ores like cobaltite, erythrite, glaucodot, and skutterudite. However, most cobalt comes from mining nickel and copper. Because it is a by-product, the amount of cobalt we get depends on how much nickel and copper we mine.

There are few places where cobalt is mined 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. 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 is a lot of cobalt in the world. The Democratic Republic of the Congo (DRC) makes most of the world's cobalt. Experts think we will need more cobalt in the future.

Democratic Republic of the Congo

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

Changes in mining rules helped the DRC become the top cobalt producer. The Mukondo Mountain project could be one of the richest cobalt places in the world.

In 2016, China owned some of the cobalt mines in Congo, which helps China control a lot of the world's cobalt. Some people worry about how miners work in Congo’s mines. There have been concerns about children working in mines, which is not fair or safe for them. Companies like Apple Inc. try 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.

Canada makes cobalt when they mine nickel. In 2023, Canada sold a lot of cobalt and cobalt products.

Cuba

Canada’s Sherritt International works with cobalt ores from nickel deposits in the Moa mines in Cuba.

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. The Indonesian government wanted to build a strong supply chain for electric vehicles.

Applications

In 2016, about 116,000 tonnes of cobalt was used. Cobalt helps make special mixtures of metals and batteries.

Alloys

Cobalt-based metal mixes are very important. They stay strong at high temperatures, so they are good for airplane engine parts. These mixes also don’t rust easily, which makes them great for medical tools, like parts for hips and knees. They are also used in dentistry and to make strong magnets and special metals for jewelry.

Batteries

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

Catalysts

Cobalt can help make certain chemicals. It is used to turn oils into paint and to clean up fuels.

Pigments and coloring

Long ago, cobalt was used to make blue colors in glass and paint. Today, special blue paints still use cobalt because the color stays bright.

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 bad for health if you have too much of it.

If a person weighs about 100 kilograms, having around 20 grams of cobalt can be harmful.

In the past, using small amounts of cobalt in beer caused heart problems for some people. Cobalt may also cause breathing or skin problems if it is breathed in or touched. Some health groups think cobalt might possibly cause cancer.