How is iron extracted from its ore?
The uses of iron are innumerable. It is probably the most important metal for the human race, which has discovered its uncountable uses since 3500 B.C.
Pure iron, a grayish white metal, is scarce on Earth. It is only available in fallen meteorites. Apart from that, the iron on earth is found as a combination with other minerals. The most common form of iron is the oxides. Iron is extracted from the ore containing the maximum amount of iron. This is found near the surface of the Earth.
Iron ore is converted to iron by various processes. The most common process is the use of a blast furnace to extract pig iron. Pig iron comprises of about 92-94% iron and about 3-5% of carbon along with other impurities. Pig iron has limited uses, so it is sent to steel plants where the content of carbon is further reduced. The iron is then combined with manganese, nickel and other such elements that help it acquire certain specific properties.
Process: Iron ore is extracted from the best ores, which is ore with the highest iron content. These are then crushed and sorted by magnetization and other processes. Only the purest parts are taken to the blast furnace. After this processing, the ore is blended with another ore and then burnt in the blast furnace. The blast furnace is a tower shaped steel structure, lined with heat resisting bricks. When the mixture enters through the top of the furnace, very hot air is blown in through nozzles. The hot air makes the coke burn. Carbon in the coke reacts with oxygen in the air and forms carbon monoxide. This carbon monoxide reacts with the ore and forms pure iron and carbon dioxide. The pure iron is then separated from the impurities called slag at the bottom of the furnace. It is then extracted. Most of the gases are siphoned off to a gas cleaning plant where they are cleaned and made ready for other reactions.
This process in the blast furnace can continue up to years at a time till the blast furnace is in need of repairs or maintenance.