Cobalt

Cobalt is a transition metal with the chemical symbol Co and atomic number 27. It is a hard, lustrous, silver-grey element found naturally in the Earth’s crust, usually in association with iron and nickel ores. Cobalt is essential to modern industry and everyday technology due to its unique magnetic, chemical, and high-temperature properties. It plays a pivotal role in batteries, aerospace materials, medical applications, pigments, and catalysts, making it both an industrially and economically significant element in the 21st century.

Background and Properties

Cobalt has been known since antiquity, though it was first isolated as a pure metal in 1735 by the Swedish chemist Georg Brandt, who demonstrated that cobalt was responsible for the blue colouring of glass and ceramics previously attributed to bismuth.
Physically, cobalt is a ferromagnetic metal, retaining magnetism even at high temperatures (up to 1,115 °C, known as its Curie point). It is tough, ductile, and resistant to oxidation and corrosion. Chemically, it forms compounds in the +2 and +3 oxidation states, with cobalt(II) compounds being the most common in industry. Cobalt’s ability to form complex compounds with organic and inorganic ligands makes it highly versatile for use in catalysts, pigments, and electrochemical systems.
Naturally, cobalt occurs in minerals such as cobaltite (CoAsS), erythrite (Co₃(AsO₄)₂·8H₂O), and as a by-product of nickel and copper mining. Major producing countries include the Democratic Republic of Congo (DRC), Russia, Australia, Canada, and Indonesia.

Everyday Applications

Cobalt is not only vital in industrial sectors but also found, directly or indirectly, in numerous everyday technologies and activities.
1. Rechargeable BatteriesCobalt is a critical component in lithium-ion batteries, which power smartphones, laptops, electric vehicles (EVs), and portable electronics. It is used primarily in the cathode material—such as lithium cobalt oxide (LiCoO₂)—to improve energy density, stability, and battery life. Although newer technologies aim to reduce cobalt content, it remains indispensable for maintaining battery performance and safety.
2. Medical and Health UsesThe radioactive isotope Cobalt-60 is widely used in medicine for radiotherapy in the treatment of cancer. It emits high-energy gamma rays that can target and destroy malignant cells. Additionally, Cobalt-60 is used for sterilising medical instruments and food irradiation, which helps extend shelf life by eliminating microorganisms.
In nutrition, cobalt forms part of vitamin B₁₂ (cobalamin), an essential nutrient for human health involved in red blood cell formation and neurological function. Deficiency in vitamin B₁₂ can lead to anaemia and nervous system disorders.
3. Everyday Tools and Household ProductsCobalt’s hardness and wear resistance make it suitable for cutting tools, drill bits, and magnets. Cobalt-based alloys, such as stellite, are used in razor blades, turbine blades, and valves for their high strength and resistance to corrosion. In household applications, cobalt pigments are responsible for the rich blue colour seen in ceramics, glass, and paints—commonly referred to as “cobalt blue”.

Industrial Applications

1. Aerospace and SuperalloysCobalt is integral to the production of superalloys, which maintain strength and stability at extremely high temperatures. These alloys are essential in jet engines, gas turbines, and rocket components. Cobalt’s ability to resist heat and oxidation makes it ideal for components that must endure intense operational stress, contributing significantly to aviation safety and performance.
2. Catalysts and Chemical IndustryCobalt-based catalysts are used extensively in petroleum refining, synthetic fuel production, and chemical synthesis. They accelerate reactions such as hydrogenation and Fischer–Tropsch processes, converting carbon monoxide and hydrogen into hydrocarbons. In addition, cobalt compounds serve as catalysts in the manufacture of plastics, paints, and detergents.
3. Magnets and ElectronicsCobalt’s ferromagnetic properties make it a vital component in permanent magnets, particularly alnico (aluminium–nickel–cobalt) and samarium–cobalt magnets. These are used in electric motors, magnetic sensors, data storage devices, loudspeakers, and wind turbines. In electronics, cobalt contributes to efficient power conversion and improved magnetic storage capacity.
4. Hard Metals and Surface CoatingsCobalt is used as a binder in cemented carbides (such as tungsten carbide), forming extremely hard materials employed in cutting and mining tools. Cobalt coatings and plating enhance the wear resistance and appearance of metal parts, offering protection against corrosion and extending their service life.

Economic Importance

Cobalt is a strategic metal, central to emerging technologies and clean energy systems. Global demand has surged with the expansion of the electric vehicle and renewable energy sectors. The battery industry alone accounts for more than half of cobalt consumption, while aerospace, medical, and industrial uses share the remainder.
The Democratic Republic of Congo dominates global cobalt supply, producing over 70% of the world’s output. This geographic concentration has raised concerns over supply security, ethical mining practices, and market volatility. Many nations and corporations are investing in recycling, alternative chemistries, and diversified sourcing to reduce dependence on single-region production.
Economically, cobalt prices have shown considerable fluctuation due to political instability, changing demand, and environmental regulations. As a result, cobalt is classified as a critical raw material by several economic blocs, including the European Union and the United States, owing to its high economic importance and supply risk.

Environmental and Ethical Considerations

While cobalt is indispensable for modern technologies, its extraction often presents environmental and humanitarian challenges. Large-scale mining operations, particularly in the DRC, have been criticised for unsafe working conditions, child labour, and ecological damage. Growing awareness of these issues has led to the development of responsible sourcing initiatives, traceability systems, and ethical certification schemes aimed at ensuring that cobalt used in products is mined and processed sustainably.
From an environmental standpoint, cobalt recycling from used batteries and industrial scrap is increasingly important. Efficient recycling technologies can recover cobalt and other valuable metals, reducing the need for new mining and minimising environmental impact.