Atomic number: 27
Group: transition metals
CAS number: 7440-48-4
Atomic mass: 58.933194
Density: 8.90 g / cm3
Mohs hardness: 5
Melting point: 1495 ° C
Boiling point: 2900 ° C
Cobalt is most commonly used in metallic form.
Most of the cobalt consumed is used in the manufacture of superalloys. These are metal formulations that are most commonly used in areas where resistance to extreme conditions is required, e.g. B. in components of jet engines or high-speed drills. Superalloys are also sometimes used in biomedical implants such as hip replacements, although these implants must be monitored for damage because metal nanoparticles generated by wear can be easily absorbed and distributed throughout the body. Cobalt in cobalamin, also known as vitamin B12, is an essential nutrient, but excess free cobalt ions in the body have toxic effects.
Cobalt is also used in other alloy applications. It is found in both alnico and samarium cobalt magnets, both of which are widely used in the industry. Cobalt is also found in combination with primary electrode metals in lithium-ion, nickel-cadmium, and nickel-metal hydride batteries. Because of its attractive appearance, extreme hardness and resistance to oxidation, cobalt can be used as a metal to clad other materials, either alone or as a base for other coatings such as porcelain enamels. Platinum used in jewelry making contains five percent cobalt as this makes an alloy suitable for highly detailed casting.
There are two other main uses of cobalt in industry. The first acts as a catalyst: cobalt compounds are used industrially to produce polymer precursors to remove sulfur-containing impurities from petroleum and to improve the adhesion of steel to rubber for the manufacture of steel belted tires. In addition, cobalt catalysts are added as drying agents for paints and varnishes and are used in a variety of other chemical processes, both on an industrial and laboratory scale. The second main application is as a binder in cemented carbides, where extremely hard materials are used in machining metals such as steel.
Finally, cobalt radioisotopes perform some notable functions. Cobalt-60 is a radioactive isotope that is used to generate gamma rays for the sterilization of food and medical supplies and for use in both medical radiation therapy and the production of industrial X-ray images. Cobalt-57 is used as a tracer in medical imaging, primarily to monitor vitamin B12 uptake.
The most important cobalt ores are cobaltite, erythritol, glaucodot and skutterudite, all of which are commercially exploited. However, a significant portion of the metal is also obtained through processing by-products of copper and nickel mining. Cobalt catalysts and cobalt alloy waste can also be recycled to produce high purity cobalt.