Cobalt
Cobalt is a bluish-gray, shiny, brittle metallic element. Its atomic number is 27 and its symbol is Co. It belongs to a group of elements called the transition metals. It has magnetic properties like iron. Cobalt is a known human toxin and carcinogen, whose dosage may occur by ingestion, inhalation or skin contact.
| Previous Element: Iron Next Element: Nickel |
| |
| Physical Properties | ||
|---|---|---|
| Color | bluish-white | |
| Phase at Room Temp. | solid | |
| Density (g/cm3) | 8.9 | |
| Hardness (Mohs) | --- | |
|
Melting Point (K) |
1768.2 | |
|
Boiling Point (K) |
3373 | |
| Heat of Fusion (kJ/mol) | 15.2 | |
| Heat of Vaporization (kJ/mol) | 381 | |
| Heat of Atomization (kJ/mol) | 425 | |
| Thermal Conductivity (J/m sec K) | 100 | |
| Electrical Conductivity (1/mohm cm) | 160.256 | |
| Source | Co sulfides & arsenides | |
| Atomic Properties | ||
| Electron Configuration | [Ar]4s23d7 | |
|
Number of Isotopes |
33 (1 natural) | |
| Electron Affinity (kJ/mol) | 63.8 | |
| First Ionization Energy (kJ/mol) | 758.4 | |
| Second Ionization Energy (kJ/mol) | 1646 | |
| Third Ionization Energy (kJ/mol) | 3232.2 | |
| Electronegativity | 1.88 | |
| Polarizability (Å3) | , | |
| Atomic Weight | 58.93 | |
| Atomic Volume (cm3/mol) | 6.6 | |
| Ionic Radius2- (pm) | --- | |
| Ionic Radius1- (pm) | --- | |
| Atomic Radius (pm) | 125 | |
| Ionic Radius1+ (pm) | --- | |
| Ionic Radius2+ (pm) | 83.8 | |
| Ionic Radius3+ (pm) | 71.8 | |
| Common Oxidation Numbers | +2, +3 | |
| Other Oxid. Numbers | -1, +1, +4, +5 | |
| Abundance | ||
| In Earth's Crust (mg/kg) | 2.50×101 | |
| In Earth's Ocean (mg/L) | 2.0×10-5 | |
| In Human Body (%) | ? | |
| Regulatory / Health | ||
| CAS Number | 7440-48-4 | |
| OSHA Permissible Exposure Limit (PEL) | No limit | |
| OSHA PEL Vacated 1989 | No limit | |
|
NIOSH Recommended Exposure Limit (REL) |
No limit | |
|
Sources: |
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Ancient civilizations in Egypt and Mesopotamia used a substance to color glass a beautiful deep blue. In 1735, the Swedish scientist Georg Brandt set out to prove that this color was due not to the element bismuth, as people believed, but to a new and unidentified element. He is credited with the discovery of this new element, which he named cobalt.
Cobalt is one of the elements that is very important to life, including human life and health. Vitamin B-12 contains cobalt. In areas where there is little cobalt in the soil, farmers have to provide salt blocks containing cobalt for their animals to lick in order to provide enough cobalt in their diet.
Cobalt is also found in iron-nickel meteorites.
Contents
Name
Cobalt was named after the German word kobald which means goblin or evil spirit believed to cause health problems for silver and copper miners.
Sources and refining
It is estimated that there are about one million tons of cobalt ore in the United States. Minnesota has the largest resources, but other ore resources are found in Alaska, California, Idaho, Missouri, Montana and Oregon. The identified cobalt resources in the world total about 15 million tons. Most are found in Australia, Canada, Congo, Russia, and Zambia, with Congo producing most ot the raw ore. Most refining is done in China..
The ocean floor has nodules of metals that form when hot water from deep in the Earth comes into contact with the cold ocean water. These nodules are mostly manganese and so are called manganese nodules. It is estimated that there are millions of tons of cobalt in these nodules. Presently, we do not have the technology to retrieve these nodules at a reasonable cost.
All of the primary cobalt used in the U.S. is imported. Cobalt is imported into the United States in the form of cobalt metal, cobalt salts, and cobalt oxide. The imports come from Norway, Finland, Canada, Russia, and other nations. China is the premier refiner of cobalt, producing over six time the quantity of cobalt as the number two country, Finland.
Uses
Cobalt has been used by civilizations for centuries to create beautiful deep blue glass, ceramics, pottery and tiles. In a similar way, it is being used to make paint pigments.
In addition to these traditional uses, cobalt is used in a number of industrial applications. Cobalt is a major component in the production of electric vehicle batteries, comprising ten to sixty percent of the cathodes. Due to poor environmental controls in Congo, as well as known exploitation of child labour, there has been a concerted effort in the USA to produce batteries with lower cobalt content; between 2016 to 2020, the US Energy Department undertook an aggressive effort, with the successful outcome of producing electric car batteries as low as ten percent cobalt. This outcome is also desirable due to known human toxic and carcinogenic effects. Editors have found no evidence the Biden Department of Energy is continuing this program to reduce cobalt content for electric vehicle batteries; the only ongoing statement from the 2021 US administration is a pledge to obtain most of the cobalt sourcing to China and other foreign nations, reducing jobs for miners in the USA. In any case the most commonly used lithium cobalt batteries are made in china and require about 7300 kg of carbon in manufacture of a single battery, thus making most electric vehicles more carbon polluting than a hybrid vehicle or even a fuel efficient internal combustion vehicle, when full life cycle carbon emissions are considered.(Dai et al, 2019)
When cobalt is alloyed with other metals, very strong magnets are created. Super-alloys containing cobalt are used in the production of jet engines and gas turbine engines for energy generation. These super-alloys account for nearly half of the cobalt used each year. Some cobalt is used to make cutting and wear-resistant materials.
A manmade isotope of cobalt, cobalt-60, produces gamma rays. This is used for sterilization of medical supplies and foods, for industrial testing.
There is growing concern about the availability of cobalt, due to potential increasing demand for production of electric vehicles.
Substitutes and Alternative Sources
At times, cobalt prices rise significantly and there is concern about the amount of cobalt easily available around the world. As a result, industries have tried to conserve cobalt consumption. There are some replacements for cobalt, but they don’t always work as well as cobalt. For example, nickel-iron or neodymium-iron-boron alloys can be used to make strong magnets. Nickel and special ceramics can be used to make cutting and wear-resistant materials. Nickel-base alloys containing little or no cobalt can be used in jet engines. Manganese, iron, cerium, or zirconium can be used in paint driers.
References
- Common Minerals and Their Uses, Mineral Information Institute.
- Qiang Dai, Jarod Kelly, Linda Gaines and Michael Wang (2019) Life Cycle Analysis of Lithium-Ion Batteries for Automotive Applications. Systems Assessment Group, Energy Systems Division, Argonne National Laboratory, DuPage County, Argonne, IL 60439, USA. Batteries 2019, 5(2), 48; https://doi.org/10.3390/batteries5020048
- Leyssens L, Vinck B, Van Der Straeten C, Wuyts F, Maes L (15 July 2017). "Cobalt toxicity in humans—A review of the potential sources and systemic health effects". Toxicology. 387: 43–56. doi:10.1016/j.tox.2017.05.015. hdl:10044/1/51711. PMID 28572025.
- Ernest Schneyder and Trevor Hunnicut. (May 25, 2021) In a blow to US mining, Biden plans to source metals for electric vehicles from other countries. Reuters
- More than 170 Mineral Photographs, Mineral Information Institute.
