Ferro niobium is an important iron niobium alloy, with a niobium content of 60-70%. It is the main source for niobium alloying of HSLA steel and covers more than 80% of the world wide niobium production. The niobium is mined from pyrochlore deposits and is subsequently transformed into the niobium pentoxide Nb₂O₅. This oxide is mixed with iron oxide and aluminium and is reduced in an aluminothermic reaction to niobium and iron. The ferroniobium can be purified by electron beam melting or u  sed as it is. For alloying with steel the ferroniobium is added to molten steel before casting.