The chemical element cobalt
The chemical element cobalt has a silvery or bluish white color. The element was discovered in 1935 by George Brandt (Greenwood, Norman and Alan 135). Erythrite, smaltite, and cobaltite are the main ores and sources of cobalt. The byproducts of the mining and processing of iron, copper, lead, and nickel can also be used to obtain cobalt (Barceloux, Donald and Barceloux 201). There is more proof that cobalt may be discovered in meteorites. Since its discovery, cobalt has been used by numerous industries for a variety of tasks, such as creating super-alloys and serving as a blue coloring element in paintings and ceramics. Cobalt refers to a chemical element denoted by the symbol Co. It belongs to periodic number four and group 9 of transition metal in the periodic table. Cobalt has an atomic number of 27 in addition to 27 protons in the atom's nucleus. It has an atomic mass of 58.9332 g.mol -1. Cobalt has oxidation states ranging from negative three (-3) to positive four (+4). However, cobalt has two most common states of oxidation +3 and +2 (Greenwood, Norman and Alan 142).
Physical Properties
Cobalt is a ferromagnetic, brittle, hard metal with a bluish-white or silver-white color. According to Pauling, Cobalt has an electronegativity of 1.8. The density of Cobalt is 8.9g/cm3. It has a melting and boiling point of 2723℉/1495℃ and 5301℉/2927℃ respectively. The freezing point of Cobalt is 1495℃. At room temperature, Cobalt is solid (Barceloux, Donald and Barceloux 203).
Cobalt Isotopes
Cobalt has eight primary isotopes namely; 59Co, 60Co, 57Co, 56Co, 58Co, 55Co, 61Co, 62Co. 59Co (59-Co) cobalt naturally occurs and is a stable isotope. Since it is stable, it is non-radioactive. The radioactive isotopes are 60Co, 57Co, 56Co, 58Co, 55Co, 61Co, 62Co. Radioisotopes of Cobalt are naturally unstable, and thus they dissipate energy. Examples of radioactive Co isotopes include 60Co isotope with a half-life of approximately 5.2714 years, 56-Co has a half-life of approximately 77.27days, whereas the half-lives of 57Co and 58Co isotopes are 271.79 days and 77.27 days respectively (Barceloux, Donald and Barceloux 204). The other remaining radioactive isotopes have decay lives less than eighteen hours, for example, isotope 55Co has a half-life of 17.53 hours. Cobalt radioactive isotopes have four meta states having less than fifteen-minute half-life. The half-life of isotopes denotes the time taken by radioactive elements to decay or decompose. The atomic weight of Cobalt isotopes ranges from 73 amu to 50 amu. The common decay mode before the most naturally stable isotope is electron capture, while the primary mode after 59Co isotope is beta decay. In addition to primary isotopes, the total Cobalt isotopes are twenty-six (Barceloux, Donald and Barceloux 204).
Chemical Properties
Cobalt element reacts moderately. It slowly reacts Oxygen in the air. Cobalt reacts with a lot of acids leading to the production of hydrogen gas but does not react with (H2O) water at room temperature. It reacts with elements to form compounds such as cobalt black, cobalt blue (Co(AlO2)2), cobalt (II) fluoride, cobalt ammonium phosphate, cobalt (II) oxide, cobalt violet, cobalt potassium nitrate, and cobalt sulfide (Barceloux, Donald and Barceloux 212). Compounds of Cobalt have a wide range of industrial applications, especially as catalysts and coloring/dying materials.
Abundance of Cobalt
Cobalt element is highly abundant. Research indicates that there are about ten to thirty parts per million of Cobalt abundance. Naturally, mineral ores such as erythrite, smaltite, skutterudite, linnaeite, cobaltite, and chloranthite have abundant cobalt. The major countries with naturally occurring Cobalt include Brazil, Zambia, Canada, Democratic Republic of Congo, Canada, and Russia. Numerous transition metals such as Cobalt can be found on the bed floors of deep oceans. Estimated earth natural abundance of Cobalt is 2.5x10 mg/kg while oceanic abundance estimate is 2x10-5mg/L.
History of Cobalt
Cobalt was previously used in the 16th century in Germany. The word Cobalt originated from a German Phrase Kobold which means evil spirit or goblin. Kobold described ores of Cobalt, which when smelted produces a poisonous arsenic trioxide due to their silver content. Cobalt was used to make blue dyes for glazes and pottery. Babylonian and Egyptian potters used Cobalt compounds as dyes since 1450 B.C (Barceloux, Donald and Barceloux 201).However, the first isolation of copper from its ore was in 1735. George Brandt, a Swedish chemist, discovered Cobalt element. Brandt discovered Cobalt while trying to prove that the ability of particular minerals to color pottery products and glass was due to an element which was unknown and not element bismuth, as most people commonly believed during that period (Cotton, Albert et al. 55). Thus, he was able to prove that the blue coloring element that was thought to be bismuth was Cobalt.
Industry Uses and Facts of Cobalt
Cobalt has many industrial uses. They are used as superalloys, for example, stellite alloy. These alloys are highly resistant to wear, corrosion, and high temperatures. Superalloys of Cobalt are used in the manufacture of jet engine turbine blades, gun barrels, and exhaust valves. Another industrial use of Cobalt is the creation of wear resistant alloys such as Vitallium used in medicine as dental implants as well as knees and hips prosthetic. Cobalt acts as a binding material for hard metals such as cemented carbide (Faucon, Olivier and Bastien 236). Additionally, Cobalt is used in the production of magnets like samarium-cobalt and AlNiCo magnets. Isotopes of Cobalt such as 60Co have various uses in medicine. Lastly, Co chemicals are used as catalysts, coloring pigments and decolorizers in glass, ceramic, and petrochemical industries (Faucon, Olivier and Bastien 235).
Leading Producer and Cost
The leading producer and seller of refined Cobalt are China. Other countries which produce a lot of Cobalt include Canada, Zambia, DR Congo, Russia, and Brazil. The cost of Cobalt per pound is $31.75 (Faucon, Olivier and Bastien 233).
Works Cited
Barceloux, Donald G., and Donald Barceloux. “Cobalt.” Journal of Toxicology: Clinical Toxicology 37.2 (1999): 201-216.
Cotton, Albert F., et al. Advanced inorganic chemistry. Wiley, 1999.
Greenwood, Norman Neill, and Alan Earnshaw. Chemistry of the Elements. Elsevier, 2012.
Faucon, Michel-Pierre, Olivier Pourret, and Bastien Lange. “Element Case Studies: Cobalt and Copper.” Agromining: Farming for Metals. Springer, Cham, (201). 233-239.
