What is Niobium and Where Do I Use It?
- Niobium (Nb), formerly known as Columbium (Cb), is a soft, silvery transition metal. It has chemical properties very similar to Tantalum (Ta) making it difficult to distinguish the two and it was only confirmed as a separate element by Charles Hatchett in 1801.
- It is most commonly found as pyrochlore - (Na,Ca)2Nb2O6(OH,F) and most of the niobium mined is sold as ferroniobium, an alloy of niobium and iron.
- Over 90% of Nb is used in steels. Its principal use is as a grain refiner, where very small additions (200-1,000 g/t), significantly increases both steel strength and toughness simultaneously. These high strength steels are mostly used in structures, pipelines and automotive applications.
- Nb has a high melting point and low density relative to other refractory metals, which make it an important alloying addition in “superalloys” for use in high temperature applications, particularly where weight is an important factor such as aircraft engines and rocket motors.
- Its superconducting properties also make it an important element in the production of components for superconducting magnets, used in products such as MRI scanners and in particle accelerators including the Large Hadron Collider at CERN.
Where is Niobium Produced?
- Niobium is the 35th most abundant element in the earth’s crust at a concentration of about 8 ppm. The two largest production sites for niobium are in Brazil with the third largest mine in Canada.
- The bulk of the niobium extracted is concentrated by flotation and then converted to ferro-niobium (FeNb) by aluminothermic reduction followed by electron beam refining.
Specific issues for Niobium
- In excess of 90% of the world’s niobium is produced from two mines in Brazil, despite a wide dispersion of deposits globally. This concentration of supply was identified as a risk by the European Commission in compiling the list of Critical Raw Materials for the EU.
- Its physical and chemical properties give it applications in several important areas, such as high strength steels. Ironically, using Nb reduces the need to use larger additions of other elements which are either more expensive or also classified as critical.
- The use of high strength niobium-bearing steels also brings environmental benefits, primarily associated with light weighting, which is often overlooked by policy makers. This results in a reduced consumption of steel, welding consumables and transportation costs (reducing CO2 emissions).