Co - Cobalt
|Chemical Element||Cobalt||Melting Point °C||1495|
|Chemical Symbol||Co||Boiling Point °C||2870|
|Atomic Number||27||Density g/cm3||8.9|
Cobalt is a hard, shiny and greyish metal, appearing in the first long period of the Periodic Table between iron and nickel. Today, cobalt has many strategic and irreplaceable industrial uses as a result of its unique properties: a high melting point (1495°C) and retaining its strength to a high temperature; being ferromagnetic with a high thermo-stability and being multivalent, thus enhancing catalytic action. Cobalt is the 33rd most abundant element in the Earth’s crust, and global reserves are estimated at around 7 million tonnes.
The name cobalt derives from the German word Kobald, which means an evil goblin or spirit. Cobalt occurred in the German Schneeberg mountains together with nickel and silver. If problems or accidents occurred whilst mining for silver, they were often blamed on the ‘kobolds’ and only later was it discovered that the cobalt ore was often the cause of the problems. While smelting the ore smaltite, which is in fact cobalt arsenide (CoAs2), poisonous fumes where let off and this led miners to believe that the ore was cursed by evil spirits.
Cobalt has been used to color pottery and glass from a least 2,600 BC and cobalt-containing glazes have been found in Egyptian tombs of that period. Chinese pottery from the Tang (600-900AD) and Ming (1350-1650) dynasties also contained blue colors made from cobalt containing minerals. The metal itself was not discovered until 1735 when G. Brandt, a Swedish scientist, came across it whilst analyzing a dark blue ore which he obtained from a local copper workings. 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. By 1916 global production was 554 tonnes, of which 400 tonnes was in oxide form. The metallic uses of cobalt quickly grew with the work of Elwood Haynes on Stellite (R) alloys, the development of Alnico magnets in Japan, and the use of cobalt to bind tungsten carbide in Germany; applications which are still very much in use today.
Cobalt is not found as a native metal but in nickel-bearing laterites or nickel / copper sulphide deposits. This means that cobalt is usually produced as a by-product of nickel and copper mining activities. Of current production sources, approximately 64% of cobalt production is copper related, 33% is nickel related and only 3% is produced by primary cobalt operations. The main reserves are found in the southern part of the Democratic Republic of Congo (DRC), an area which currently holds close to half of the world’s cobalt reserves. Australia, Cuba, Zambia, New Caledonia, Canada, Russia and Brazil hold much of the balance of global cobalt reserves. Currently global refined cobalt output is estimated at just over 80,000 MT, of which approximately 52% is in chemical form and 48% in metallic form. Approximately 49,000 MT, or 61% of global output, is originally mined and (semi) refined in the DRC and of the world’s five largest cobalt refiners, four are heavily dependent on DRC sourced refining materials. China’s share of global cobalt production has grown dramatically in recent years, contributing some 33,000 MT or 41% of global refined output.
Cobalt has a diverse range of important metallurgical and chemical uses, which varies from aircraft engines to rechargeable batteries. It is also found in industrial chemical processes, where its unique catalytic properties can be used for such applications as desulphurisation of hydrocarbons, the removal of nitrous oxide and the emerging technology of converting natural gas to liquid hydrocarbons. Base industry also utilises the advantages that cobalt can bring to the hard metal industry where hard wearing metals and alloys allow the manufacture 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. By improving wear and durability this can also improve operating efficiencies by extending the operating life and reducing friction. Furthermore, cobalt’s versatile physical and chemical properties make it a vital ingredient in the colouring of pigments and ceramics, electroplating and the manufacture of vehicle tyres, paint driers, permanent magnets, synthetic diamonds and animal feed.
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