Environment, Materials

Niobium

Meeting demands, I will talk about niobium. I will talk about properties, reserves, extraction and applications.

Properties

It has a atomic number of 41 and atomic mass of 92,90637 u. This is a measure unit based in 12 carbon, 1 u is 1/12 of 12 carbon.

This element is ductile, in other words, can make wires with this metal, the melting point is 2477°C and the boiling point is 4744°C, stay bluish when exposed with the air in the environment temperature for long time and there are 18 isotopes.

Reserves

95% of reserves stay in Brazil according with this document.

Brazil leads the production followed by Canada.

The biggest brazilian reserves stay in the states of Minas Gerais, Goiás and Amazonas.

Extraction

In the environment, it is found in the following forms:

  • Niobite or columbite ((Fe,Mn)Nb_{2}O_{6}).

  • Pyrochlore ((Na,Ca)_{2}(Nb,Ta,Ti)_{2}O_{6}(OH,F)).

  • Euxenite ((Y,Ca,Ce,U,Th)(Nb,Ta,Ti)_{2}O_{6}).

In the mining land is sliced and shaved. Here is a open field mine.

The ore is taken to a stair to a processing plant.

After passing by grinding, magnetic separation, deaeration, flotation, calcification, acid leaching and drying, it is obtained the oxide (Nb_{2}O_{5}). An aluminum thermal reaction is made to get niobium and iron.

3Nb_{2}O_{5}+Fe_{2}O_{3}+12Al\rightarrow 6Nb+2Fe+6Al_{2}O_{3}

Environmental impact

In addiction to the impact caused by the mining activity, chemical residues are generated in the process of deaeration, flotation, and acid leaching. Niobium ores have radioactive elements like uranium and thorium, this graphic shows the concentration of radioactive materials in the process. Bigger concentration stay in leaching (lixiviado) and slag (escória).

Applications

The stainless steel with only 0,1% of niobium gain a great increase in mechanical resistance without harm weldability, tenacity and formability. This type of steel is used in pipelines, offshore oil platforms in deep water and naval construction.

This type of steel is used in truck’s chassis, wheels, escapement and vehicle’s bodyworks. It is also used in any application which require a high resistance steel.

The niobium can be painted by anodizing and is used in jewelry due to low toxicity.

Superconductors electromagnets use wires made of niobium-titanium alloy, are cooled with liquid nitrogen or liquid helium. Those electromagnets are used in magnetic resonance devices and particle accelerators.

The LHC, the biggest particle accelerator in the world, use superconductor cable made of niobium-titanium, here is a piece of the cable.

Niobium superalloy based in cobalt or nickel, which resist to high temperature, are used in components of gas turbines and jet engines to civilian and military aircraft.

Those superalloys also are components of space rockets. This part of liquid fuel engine of a rocket has niobium rings.

Here is the application percentage.

Some facts

  • When this metal was discovered it received the name columbium, so much that the niobite is also called columbite. The niobium become the official name in 1949;
  • The name came from greek mythology, Niobe daughter of king Tantalus. Being that the properties of niobium and tantalum are similar;
  • Usually niobium and tantalum are found and extracted together. It were believed before that both were the same element;
  • In the next post about environment, I will talk about tantalum.

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About Pedro Ney Stroski

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