Meeting demands, I will talk about niobium. I will talk about properties, reserves, extraction, and applications.
Properties
It has an atomic number of 41 and an atomic mass of 92,90637 u. This is a measuring unit based on 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 to the air in the environment temperature for a long time and there are 18 isotopes.
Reserves
95% of reserves stay in Brazil according to 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 mining, the land is sliced and shaved. Here is an 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, 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 addition 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 gains a great increase in mechanical resistance without harm to weldability, tenacity, and formability. This type of steel is used in pipelines, and offshore oil platforms in deep water and naval construction.
This type of steel is used in truck chassis, wheels, escapement, and vehicle bodyworks. It is also used in any application which requires high resistance steel.
The niobium can be painted by anodizing and is used in jewelry due to its low toxicity.
Superconductor electromagnets use wires made of niobium-titanium alloy and are cooled with liquid nitrogen or liquid helium. These electromagnets are used in magnetic resonance devices and particle accelerators.
The LHC, the biggest particle accelerator in the world, uses superconductor cables made of niobium-titanium, here is a piece of the cable.
Niobium superalloy based in cobalt or nickel, which resist high temperature, are used in components of gas turbines and jet engines for civilian and military aircraft.
Those superalloys also are components of space rockets. This part of the 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 was believed before that both were the same element;
- In the next post about environment, I will talk about tantalum.
