Iron

Abstract

Abstract Iron, the fourth most abundant element in the earth's crust, is the world's least expensive, most useful metal. Iron is alloyed with other elements for commercial applications. Iron‐bearing minerals of economic importance are hematite, magnetite, goethite, siderite, ilmenite, and pyrite. These ores can be beneficiated through crushing, grinding, magnetic separation, flotation, electrostatic separation, roasting, sintering, or pelletizing. Iron oxides in the form of pellet, lump, and/or sinter are fed along with coke and limestone into the blast furnace wherein the iron oxide is reduced and melted into hot metal (pig iron); the pig iron is further refined in an oxygen converter to make steel. New technologies are being developed as alternatives to the blast furnace for reducing iron oxide. These include direct reduction and direct smelting processes. In the foundry, ferrous scrap can be melted along with coke in a cupola or induction furnace to make cast iron. Cast iron can be classified into gray, white, malleable, or ductile iron.