Iron is mostly used to create steel, an alloy of iron and carbon, according to Jefferson Lab. Iron also plays an important role in producing chlorophyll in plants and serves as an essential component of hemoglobin, the substance in red blood cells that transports oxygen. Iron sulfate is used for treating the blood disease anemia.
Iron is one of the most abundant metals, comprising almost 5.6 percent of the Earth's crust and almost all of the Earth's core. Some of the mineral sources of iron are hermatite, magnetite, taconite, limonite and siderite.
The Royal Society of Chemistry notes that iron is the cheapest and most useful of all metals. It is generally used in making steel, which is used in civil engineering and the manufacturing industry. Ordinary carbon steel contains 0.1 percent carbon for mild steel and up to 2 percent carbon for high carbon steels, along with small amounts of other elements. Wrought iron is tough, malleable and less fusible compared to pure iron.
Pig iron is impure iron that is directly obtained from the blast furnace and contains around 3 percent carbon with varying amounts of manganese, phosphorus, silicon and sulfur. This type of iron is hard, brittle and fairly fusible, and it is typically used to create other alloys, such as steel. Iron is also used in making magnets.