Hematite: the major ore of iron, iron(Ill) oxide

Blast furnace: a furnace for extracting metals (particularly iron) by reduction with carbon that uses hot air blasted in at the base of the furnace to raise the temperature

Limestone: a form of calcium carbonate (CaCO3)

Mineral: a naturally occurring rock containing a particular compound

Slag: a molten mixture of impurities, mainly calcium silicate, formed in the blast furnace

Reduction of iron ore to iron

Remove impurity

bauxite: the major ore of aluminium; a form of aluminium oxide, Al2O3

electrolyte: an ionic compound that will conduct electricity when it is molten or dissolved in water; electrolytes will not conduct electricity when solid

Cryolite: sodium aluminium fluoride (Na3AlF6, an ore of aluminium used in the extraction of aluminium to lower the operating temperature of the electrolytic cell；

• mining the ore • purification of the ore • electrolysis of the molten ore.

Rusting: the corrosion of iron and steel to form rust (hydrated iron(III) oxide)

Barrier methods

Galvanising

Sacrificial protection