Introduction
Cobalt is a transition metal appearing in the fourth period of the periodic table between iron and nickel. Â It is a shiny, grey, brittle metal with a close packed hexagonal (CPH) crystal structure at room temperature.
The metal is rarely used as a structural material in the pure form but almost always as an alloy or a component of another system. Â The physico-chemical properties of cobalt allow for a hard wearing, wear-resistant metal with unique valency properties. Â These qualities make it unsubstitutable in a number of key sustainable and strategic applications.
History of Cobalt Uses
Colorings from cobalt oxides and silicates have been used to color pottery and glass for at least 2600 years and this was the main use of cobalt up to the 20th Century. Â Cobalt metal itself was isolated in 1735 by G. Brandt, a Swedish scientist, and its metallic uses based on Co-Cr alloys, and super alloys in general, stem from the work of Elwood Haynes in the early 1900’s.
Cobalt has increasingly been used in specialized applications where it is difficult to substitute with alternative materials. Â In some applications cobalt is essential, such as in medical diagnostics, pharmaceuticals and fermentation processes (e.g. bio-mass).
Demand has moved towards chemical applications as a result of the large increase in demand for rechargeable batteries.  In 2011, cobalt was recognized as ‘critical’ in the EU and strategically important in the USA.
Innovation and Cobalt
Cobalt confers exceptional properties to many different applications, as shown in the figure below, including:
- catalysts for more efficient chemical processing and cleaner fuels.
- rechargeable batteries to help increase current density and recharge-ability.
- propagate vaccines and enable diagnostics within healthcare.
- improve magnetic qualities (particularly at elevated temperature).
- enhance pigment color and increase drying of paints.
- help rubber adhere to steel bracing in tires.
- improve anti-corrosion properties of alloys and augment surface treatment.
- enhance digital storage and increase digital processing.
- provide hard metals for cutting, drilling, and grinding.
There are many other uses and applications of cobalt and its compounds and as a result, cobalt is widely considered the technology enabling metal.
Cobalt Applications
It is difficult to find a sector that doesn’t include cobalt, though it is only used in relatively small quantities in each application. The figure below shows cobalt consumption by end use in 2016.  The following is a brief discussion of cobalt applications in order of decreasing consumption.