Abstract Iron is the most useful metal. It is the base element for steel, an iron-based alloy, the most important metallic material in use. Iron production goes back to 1300 B.C., and the technologies were steadily further developed. The blast furnace is today the dominating process for converting iron ore to metallic iron. Alternative technologies are direct and smelting reduction processes. The production of iron is energy intensive and is today based on fossil energy. The production of iron for steelmaking is responsible for 6% of the global greenhouse gas emissions.