Thermite Reaction
A highly exothermic reaction in which aluminium powder reduces a metal oxide to the molten metal.
Formula / equation
Fe₂O₃ + 2Al → 2Fe + Al₂O₃
Unit
kJ/mol
In depth
Aluminium's very high affinity for oxygen releases about 850 kJ/mol, enough to raise the iron above its 1538 °C melting point. The reaction needs a magnesium fuse to overcome its large activation energy but then proceeds without any external oxygen supply.
Examples in the real world
Welding railway track in the field; producing manganese and chromium from their oxides on an industrial scale.