Ferromolybdenum is an important iron molybdenum alloy, with a molybdenum content of 60-70%. It is the main source for molybdenum alloying of HSLA steel. The molybdenum is mined and is subsequently transformed into the molybdenum(VI) oxide MoO3. This oxide is mixed with iron oxide and aluminum and is reduced in the an aluminithermic reaction to molybdenum and iron. The ferromolybdenum can be purified by electron beam melting or used as it is. For alloying with steel the ferromolybdenum is added to molten steel before casting.