### Theory:

Iron
Iron is the $$4th$$ most abundant element in the Earth’s crust. It is estimated that worldwide there are 800 billion tons of iron ore resources, containing more than 230 billion tons of iron. After copper, iron is the metal used by ancient man, which was most likely first discovered before the 5th millennium BC ($$5000 BC$$).

Common ores of iron are magnetite and hematite, and they usually occur in the rocks of the Earth crust. Other important ores of iron are titanomagnetite, and pisolitic ironstone. Iron ore is the key raw material for steel. Around $$98%$$ of the iron ore extracted is used for making various types of steel. Though pure iron ore is very soft, its strength is increased by adding a small amount of carbon and manganese.

Its low cost and high surface strength made it a key metal in engineering applications, such as the construction of machinery and machine tools, automobiles, construction of large ships, structural components of buildings, bridges etc. About $$90%$$ of all metal that is refined today is iron.

Iron ore is mined in over 50 countries. China, Australia, Brazil, India and Russia are the principal producers of iron ore, accounting for about $$85%$$ of the world’s total iron ore output. These countries are estimated to have $$70%$$ of the total reserves of the world. Jharkhand, Odisha, Madhya Pradesh, Chhattisgarh, Karnataka and Goa account for over $$95 per cent$$of the total reserves of India. Iron ores found at Kanjamalai in Tamil Nadu.