Iron (Fe) is fundamentally the backbone of our industrialized world. Iron rarely exists in its pure, metallic form in nature. Instead, it is predominantly found as iron oxides, such as hematite (Fe2O3) and magnetite (Fe3O4), which are the primary constituents of iron ore.
These oxides are the essential raw material for metallurgy. The process of reducing these oxides in a blast furnace, typically using coke as a reductant, converts the iron oxide back into metallic iron, initially yielding pig iron. Conversely, the widespread corrosion of infrastructure is the reverse process: metallic iron reacts with oxygen and water to revert to iron oxides (rust).
While iron is a base element, steel is an alloy of iron and carbon that increases strength.
See also: Steelmaking