The Coltan is a mineral not itself but the contraction of the name of two minerals: columbite, an ore of niobium (or columbium ) and tantalite, an ore of tantalum . Therefore, the coltan is formed by the mixture of columbite, a mixture of niobium oxide, iron and manganese [(Fe, Mn) Nb 2 O 6 ] and tantalite which is composed of tantalum oxide, iron and manganese [(Fe, Mn) Ta 2 O 6 ] in any proportion.
The world's leading producers of this rare mineral are Australia, Brazil, Canada and especially some African countries like Republic of the Congo and Rwanda, although the reserve base are virtually unknown to them. The value of the niobium used in 2006 was 118 million U.S. dollars and 164 million tantalum. Spain has a deficit of niobium and tantalum.
Their exploitation in Africa has been and is, linked to armed conflicts to gain control of this material, operation under conditions of semi-slavery, environmental disaster with serious repercussions on the local fauna in protected species (gorillas, elephants), and even serious health problems associated with the archaic and subhuman farming methods. Very recently revealed an additional problem, which could have serious consequences related to artisanal mining of coltan in the Democratic Republic of Congo. Elements such as uranium, thorium and radium, among others, can appear in exotic mineral phases associated with coltan, or are even present in the structure crystal of columbite and tantalite. In the last issue of 2007 issue Journal of Radiological Protection, scientists from the Department of Physics and Institute of Nuclear Sciences, University of Nairobi have shown very high doses of radiation Congolese workers engaged traditional way to the extraction of coltan.
The tantalum is a chemical element with atomic number 73 which is placed in Group 5 of the periodic table of elements. Its symbol is Ta. It is of a metal of the third transition series. Is an inert metal, and this is the reason for the origin of its name. Tantalus in Greek mythology is the son of Jupiter and a nymph ruled the kingdom of Phrygia . It is said that Tantalus so loved humans that he was accused of revealing secrets of the gods themselves. For this reason was condemned by them to suffer the torment of thirst, consisting of spending eternity with the body immersed in water to the jaw, so that every time you bend your head to try to drink, the water level down. This is also what happens to the tantalum, which does not get wet inside, is unresponsive, or the water or acids.
Tantalum is a metal superconductor, ultrarrefractarias properties (minerals able to withstand very high temperatures), is a phenomenal capacitor (stores temporary electric charge and releases it when needed), and present a high resistance corrosion and general disruption.
Tantalum is used mainly in the production of capacitors. Tantalum electrolytic capacitor is a capacitor type present in virtually all electronic devices currently on the market: mobile phones computers, plasma screens, game consoles, digital cameras, mp3 and mp4, or high-tech devices, such as artificial satellites sent into space. These devices are becoming smaller, thinner and reliable thanks in large part to the use of tantalum electrolytic capacitors that have replaced traditional electrolytic capacitors. Although most electronic devices can operate with normal electrolytic capacitors (aluminum), tantalum electrolytic capacitors with values \u200b\u200bmore accurate electrical capacity, support higher temperatures and are much smaller. This makes ideal for today's demands for miniaturization of electronic devices we use routinely.
The fact that the niobium and tantalum appear together in nature much more difficult their separation and the discovery of the former. In Greek mythology, Niobe is the daughter of Tantalus, and as the Niobium was discovered in the mineral which had previously been discovered tantalum, it was felt that chemistry was his daughter. This element was called for over 100 years of two ways: niobium and columbium .
Columbia was the name of its first discoverer, the English chemist Charles Hatchett , originally given to this in 1801, and this name remained in use in American magazines , while in Europe was used niobium, a name that gave her a second discoverer, the German chemist Heinrich Rose in 1846. To put end this confusion, the European name of niobium was officially adopted in 1950 by the Union for Pure and Applied Chemistry (IUPAC), despite the chronological precedence of the American name of columbium . However, this alleged decision against American interests contained a deception, because to change the accepted IUPAC name tungsten instead of wolfram in deference to American usage. Today it continues to use the name of Columbia in the United States.
The niobium is a chemical element with atomic number 41 located in Group 5 of the periodic table of elements. Is symbolized as Nb . Is a second transition metal. The properties of niobium are very similar to those of tantalum. Although resistance to corrosion is not as good as that of tantalum, the lowest price and greater availability make the niobium attractive to use less accurate, such as coatings in chemical plants. The most important application is as an alloying element for the construction of machines and high pressure pipelines. It is also used superalloys that require high temperatures, such as in the turbines of jet engines and exhaust pipes of cars. In the field of electrical superconductivity titanium alloys used to build supercooled electromagnets used in magnetic resonance imaging.
Sources: El Pais, Wikipedia and " The name and symbol of the chemical elements (Ed. Synthesis) ."
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