What is the process of extracting iron from its ore?

Iron is extracted from its ore, haematite, in a process involving reduction, smelting, and purification.

The extraction of iron from its ore is a long and subdued process, that helps in separating the useful components from the waste materials such as slag. The process begins with the crushing of the raw ore, which is the haematite. The ore is then concentrated by removing impurities like soil etc. This process is called beneficiation.

Following this, the concentrated iron ore is then subjected to a process known as smelting. Smelting is a form of extractive metallurgy to produce a metal from its ore. Smelting uses heat and a chemical reducing agent to decompose the ore, driving off other elements as gases or slag and leaving just the metal behind. The reducing agent is commonly a source of carbon such as coke, or in earlier times, charcoal. The carbon (or carbon monoxide derived from it) removes oxygen from the ore, leaving behind the elemental metal. The carbon is thus oxidised in two stages, producing first carbon monoxide and then carbon dioxide. As most ores are impure, it is often necessary to use flux, such as limestone, to remove the accompanying rock gangue as slag.

The iron produced in this way always contains a low percentage of carbon and is known as wrought iron. It is quite soft and easily worked and has little structural strength. It was once used to make decorative gates and railings, but these days mild steel is normally used instead.

The final step in the process is the purification of the iron. This is done by oxidising the impurities in the iron such as sulphur, phosphorus, silicon, manganese, and carbon, which forms a slag on top of the iron that can be removed. The end product is pure iron, which can be used for various industrial applications.