Niobium Production

Niobium metal can be produced by electrolysis of molten potassium niobium heptafluoride, or by reduction of potassium niobium heptafluoride with sodium metal or niobium pentoxide with aluminum metal. Pure niobium is used in electronic tubes to remove residual gases. Doping steel with niobium improves the oxidation resistance of steel at high temperatures and improves the welding properties of steel. Niobium is also used in the manufacture of high-temperature cermets.
The mined ore undergoes a separation process to separate tantalum pentoxide (Ta2O5) and niobium pentoxide (Nb2O5) from the other minerals. The first step in the process is a reaction with hydrofluoric acid:
Ta2O5+ 14 HF → 2 H2[TaF7] + 5 H2O
Nb2O5+ 10 HF → 2 H2[NbOF5] + 3 H2O
Jean-Charles Galisa de Marinha invented industrial-scale separation methods that take advantage of the differences in water solubility possessed by the fluoride complexes of niobium and tantalum. The new method then uses an organic solvent similar to cyclohexanone to extract the fluoride from an aqueous solution, and then water to extract the niobium and tantalum complexes separately from the organic solvent. The addition of potassium fluoride precipitates the niobium into the potassium fluoride complex, while the addition of ammonia precipitates niobium pentoxide:
H2[NbOF5] + 2 KF → K2[NbOF5] ↓ + 2 HF

Then:
2 H2[NbOF5] + 10 NH4OH → Nb2O5↓ + 10 NH4F + 7 H2O
There are several methods of reduction from the compound to the metallic state. One is the electrolysis of a molten mixture of K2[NbOF5] and sodium chloride, and the other is the reduction of niobium fluoride with sodium. This method yields niobium metal of high purity. In large-scale production, the reduction of Nb2O5 is generally carried out using hydrogen or carbon. Another method utilizes an aluminothermic reaction in which iron oxide and niobium oxide react with aluminum:
3 Nb2O5 + Fe2O3 + 12 Al → 6 Nb + 2 Fe + 6 Al2O3
A small amount of an oxidizing additive similar to sodium nitrate can enhance the above reaction. This produces aluminum oxide and ferro-niobium alloys, the latter of which can be used in steel production. Ferro Niobium typically contains 60% to 70% niobium. Without the addition of iron oxide, the aluminothermal reaction produces niobium metal, but only after a purification process to produce high-purity niobium alloys with superconducting properties. The method used by the world's two largest niobium distributors is vacuum electron beam melting.
As of 2013, the Brazilian Metallurgical and Mining Company Limited (Portuguese: Cia. Brasileira de Metalurgia & Mineração) controls 85% of the world's niobium production. The U.S. Geological Survey estimates that niobium production rose from 38,700 tons in 2005 to 44,500 tons in 2006. The global inventory of niobium resources is estimated at 4.4 million tons. Between 1995 and 2005, production more than doubled from 17,800 tons, and between 2009 and 2011, production remained steady at 63,000 tons per year.