Cobalt – the Technology Enabling Metal
For some 5,000years cobalt has been at the service of man, initially providing the famous blue pigment in glazes back in ancient Egypt but now recognised as an important technology enabling metal where energy, efficiency and environmental benefits are the order of the day. Cobalt has a diverse range of important uses from aircraft engines to rechargeable batteries, which are so important in the development sustainable energy policies for the future. It is also found in industrial chemical processes where its unique catalytic properties can be used for such applications as desulphurisation of hydrocarbons, which is crucial to clean fuel technology, and also removal of nitrous oxide to ensure that emissions of this greenhouse gas are minimised. Its catalytic qualities are also used in the emerging technology of converting natural gas to liquid hydrocarbons, thus using carbon based resources more efficiently. Base industry also utilises the advantages that cobalt can bring to the hard metal industry where hard wearing metals and alloys allow the manufacturer of highly effective cutting tools for a broad range of industrial applications. The high temperature resistance, hardness and wear characteristics of cobalt when alloyed with other metals can also be put to good use not only in gas turbines but also as hard surfacing in critical applications where working environments are aggressive (hot, pressurised and acidic for example). By improving wear and durability this can also improve operating efficiencies by extending operating life and reducing friction. So versatile is cobalt that having imparted great physical attributes to many industrial applications it can also be as subtle as enabling digital storage. As yet another example of its versatility, cobalt is also an oligo element, being essential for growth and vitality in animals and humans as it is a crucial constituent in the synthesis of vitamin B12. Because animals are susceptible to cobalt deficiency this element is introduced into animal feed supplements when necessary.
So where is this extraordinary metal to be seen in action? Well it works best in conjunction with other metals and promotes chemical reactions, so cobalt is not obvious in its applications, but this versatile and technology enabling metal delivers the goods in many everyday and industrial situations. In particular it will be at the heart of the drive for alternative and renewable energy systems, whether as a hard wearing alloy in wind and wave generators, as a subtle catalyst used for ‘splitting’ water in the newly developing solar energy technologies or helping power electric vehicles of the future. In fact it is difficult to know what part of our lives is not affected in some way by cobalt and we at the Cobalt Development Institute work to ensure that cobalt and cobalt compounds are used in a responsible and sustainable manner in keeping with good product stewardship.
About Cobalt
Cobalt is one of the world's essential elements. Of all elements, 27 are essential to man. Cobalt is one. It has many strategic and irreplaceable industrial uses but it is as the central component of Vitamin B12 that it is VITAL. Cobalt has many uses based on several of its unique properties:
- It has a high melting point (1493°C) and retains its strength to a high temperature - Cutting tools, superalloys, surface coating, high speed steels, cemented carbides, diamond tooling
- Cobalt is ferromagnetic (nickel and iron are as well) and retains this property to 1100°C, a higher temperature (Curie Point) than any other material - Alnico magnets, recording tape, soft magnetic materials, samarium cobalt, NdBFe + cobalt
- Cobalt in conjunction with silica, etc., produces intense blue colours - Cobalt Blue in paints, glazes, enamels, etc.
- Cobalt is multivalent - Catalytic action is enhanced - OXO reaction, Fischer-Tropsch, oil desulphurisation, paint and ink driers, tyre adhesives
Sources of Cobalt
Cobalt is not a particularly rare metal and it ranks 33 in abundance. It is however widely scattered in the Earth’s crust but is found in potentially exploitable quantities in several countries, 17 of which currently produce. Cobalt is only extracted alone from the Moroccan and Canadian Arsenide ores. It is normally associated with copper or nickel. In 2003 about 44% of world production came from nickel ores.
Table 1 - Where Cobalt is Mined - shows the current situation. Significant resources of cobalt are also present in the deep-sea nodules and crusts which occur in the Mid-Pacific and are estimated to contain anywhere from 2.5-10 million tonnes of cobalt. At a world production level of 59,000 tonnes, this is 60 to 230 years of usage. Current land sources are estimated at over 100 years, so no long-term shortage is in sight.
|
Country
|
Mined
|
Refined
|
Approx. Refined Qty
|
|
Australia
|
×
|
×
|
4,100
|
|
Botswana
|
×
|
|
|
|
Brazil
|
×
|
×
|
1,400
|
|
Belgium
|
|
×
|
2,600*
|
|
Canada
|
×
|
×
|
4,700
|
|
China
|
×
|
×
|
33,000
|
|
Cuba
|
×
|
|
|
|
France
|
|
×
|
300
|
|
Finland
|
|
×
|
9,300
|
|
India
|
|
×
|
1,200
|
|
Japan
|
|
×
|
1,950
|
|
Morocco
|
×
|
×
|
1,550
|
|
New Caledonia
|
×
|
|
|
|
Norway
|
|
×
|
3,200
|
|
Russia
|
×
|
×
|
2,450
|
|
South Africa
|
×
|
×
|
500
|
|
Uganda
|
x
|
x
|
600
|
|
D.R.C.
|
×
|
×
|
4,200
|
|
Zambia
|
×
|
×
|
5,000
|
|
TOTAL
|
76,050(Tonnes) **
|
|
* Including cobalt produced by facilities in China and ** refers to 2010 production levels
Main properties
Cobalt is a transition metal appearing in the first long period of the Periodic Table between iron and nickel.
The ground state atom is s22s22p63s23d74s2
This leads to cobalt’s commonest valency, i.e. Co2+, by removal of the two 4s electrons. Other valencies exist however in some complex salts and mixed valencies occur in Co3O4 for example (Co2+ and Co3+).
Cobalt is shiny, grey, brittle metal with a close packed hexagonal (CPH) crystal structure at room temperature but which changes at 421°C to a face centred cubic form. 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
|
Physical Constants of Pure Metal Co
|
|
Density
|
- 8.85 g/cm3
|
|
Melting Point
|
- 1493oC (2719oF)
|
|
Boiling Point
|
- 3100oC (5612oF)
|
|
Coeff. of Linear Expansion
|
= 10-6 per oC = 12.5 (to 100oC)
|
|
Coeff. of Volume Expansion
|
= 10-6 per oC = 35.6 (to 100oC)
|
|
Transition temp. CPH to FCC
|
- ~421oC
|
|
Curie Point
|
- 1121oC
|
|
Atomic Number
|
- 27
|
|
Valencies
|
- 2 + 3
|
|
Saturation Induction
|
- 18,700 Gauss (1.87T)
|
|
Cobalt uses
The use of cobalt goes back to 2-3000 BC. Although it had not been identified, its addition to glass to give traditional cobalt blue was known. The name however seems to arise from the Erzgebirge region of Saxony which was a silver mining area. The term “Kobald” applied to spirits (gnomes) who frequented the mines causing trouble (as per “gremlins” in air force slang). The problems were due to cobalt interfering with the silver smelting and causing some respiratory problems with the miners (cobalt here is arsenical). The term seems to have passed to and been held by the metal but the stories are varied.
The main use of cobalt remained as a colouring agent right up to the 20th Century and in fact, before 1914, cobalt was really only available or used as the oxide.
The modern uses blossomed with the work of Elwood Haynes on StelliteR alloys, the development of Alnico magnets in Japan, and the use of cobalt to bind tungsten carbide in Germany. These uses are outlined in the 'Cobalt Facts' section of the website.
Disclaimer
Information on this website is provided for information purposes only. Great care has been taken to maintain the accuracy of the information provided on this website. However, the Cobalt Development Institute (CDI), its members, staff and contributors do not represent or warrant its suitability for any general or specific use and assume no liability of any kind in connection with the provision of the said information and no action should be taken without seeking independent full professional advice.
We cannot accept responsibility for losses occasioned by any persons acting or refraining from acting as a result of material contained on this website.
|
|
|