Niobium and Ferro-Niobium Production

H. K. D. H. Bhadeshia

Photographs courtesy of Dr Thomas Sourmail

The main production of niobium and an alloy or iron and niobium (ferroniobium) is at CBMM, Araxá, Brazil, where there are sufficient reserves to last for 500 years at current world consumption rates. The pyrochlore ore is mined simply by digging it out from open pits - at this stage it contains about 3% of Nb₂O₅. This is then enriched using the floatation process. The enriched ore is then reacted with aluminium to getter the oxygen and ferroniobium. Electron-beam refining is used to produce pure noibium. Most of the niobium produced is in the form of ferroniobium, which goes towards the production of huge quantities of microalloyed steels.

Many more photographs

The open cast mine	Floatation process ot enhance the niobium content of the ore
Hot ferroniobium	Ferroniobium
Packing tin cans of ferroniobium	Electron beam furnace for the refinement of niobium metal, producing 210 tonnes per annum
Electron beam refined niobium ingot

Iron-Niobium-Tantalum Ore from Brazil

Photographs by Mathew Peet, of an Fe-Ta-Nb ore from Brazil. The sample was brought to Cambridge by Professor Hamilton Abreu of the Universidade Federal do Ceara, Engenharia Metalurgica e de Materiais, Fortaleza. An amazing 45% of this ore is niobium.

Niobium was discovered first by Charles Hatchett in 1801; Anders Gustaf Ekeberg discovered tantalum in 1802.

Niobium Carbonitrides

Crystal Structure of Niobium Carbide

Niobium carbide has a cubic-F lattice with a motif of Nb at 0,0,0, and carbon at 0,0,0.5. The carbide is not strictly stoichiometric but is represented here as such, with a lattice parameter of 4.4691 nm.

Crystal structure of NbC in perspective.	Projection of the crystal structure of NbC along a 110 direction.
Projection of the crystal structure of NbC along a 111 type direction.	Projection of the crystal structure of NbC along a cube edge.
Movie 1 showing rotating unit cell. Movie 2 showing rotating unit cell. Movie 3 showing rotating unit cell. Crystalmaker file.

Publications

• "Local brittle zones and the role of niobium"
  Materials Science Forum 783-786 (2014) 2129-2135.
  H. K. D. H. Bhadeshia
  
• "Mechanism and kinetics of solid-state transformation in high-temperature processed linepipe steel"
  Metallurgical and Materials Transactions A 44 (2013) 5468-5477.
  P. Yan and H.K.D.H. Bhadeshia
  
• "Role of Niobium in Influencing Transformation of Microalloyed Austenite"
  Metallurgical and Materials Transactions A, Vol. 26A, 1995, pp. 21-30.
  C. Fossaert, G. Rees, T. Maurickx and H. K. D. H. Bhadeshia
• "The Effect of Niobium in Solid Solution on the Transformation Kinetics of Bainite"
  Materials Science and Engineering A, Vol. A194, 1995, pp. 179-186.
  G. Rees, J. Perdrix, T. Maurickx and H. K. D. H. Bhadeshia
• "Competitive Effects of Niobium and Niobium Carbides
  on the Kinetics of the Bainite Reaction"
  Proceedings of Solid-Solid Phase Transformations '94, 1994
  T. Maurickx, G. Rees and H. K. D. H. Bhadeshia
• "Modelling Precipitation of Niobium Carbide in Austenite: Multicomponent Diffusion, Capillarity and Coarsening"
  Materials Science and Technology, Vol. 17, 2001, 403-408.
  N. Fujita and H. K. D. H. Bhadeshia
• "Modelling M₆C Precipitation in Niobium-Alloyed Ferritic Stainless Steel"
  Metallurgical and Materials Transactions A, Vol. 33A, 2002, 3339-3347.
  N. Fujita, H. K. D. H. Bhadeshia and M. Kikuchi

Welding of high-strength pipeline steels

Niobium in construction steels

Niobium in stainless steels