Iron and steel or siderometallurgy is the technique of processing iron ore to obtain different types of iron or its alloys such as steel. The process of transforming iron ore begins with its extraction in the mines. Iron is found in nature in the form of oxides, hydroxides, carbonates, silicates and sulfides. The most commonly used by the iron and steel industry are oxides, hydroxides and carbonates. The basic transformation processes are as follows:

• Oxides -> hematite (Fe2O3) and magnetite (Fe3O4).
• Hydroxides -> Limonite
• Carbonates -> Siderite or iron carbonate (FeCO3)

These minerals are found combined in rocks, which contain unwanted elements called gangue.