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How does direct reduction make iron from ore without melting the metal?

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How iron is turned into steel — iron processing Iron ore is one of the most abundant elements on Earth, and one of its primary uses is in the production of steel. When combined with carbon, iron changes character completely and becomes the alloy steel.

Direct reduction (DR) is an iron-making process that extracts iron from ore at temperatures below the melting point of the materials involved. Unlike traditional blast furnace methods that melt the charge to separate iron from slag, direct reduction relies on chemical processes to remove oxygen from the ore while it remains in a solid state.12

In common gas-based direct reduction processes, such as the Midrex method, a gas reformer converts natural gas (methane) into a mixture of carbon monoxide and hydrogen. These gases are fed into a shaft furnace where they react with descending iron ore pellets at approximately 850° C (1,550° F). This chemical reduction strips the oxygen from the iron oxide, resulting in a porous, spongelike product known as direct-reduced iron (DRI).13

Because the metal is never melted during this process, the gangue (impurities) remains within the DRI and must be removed during a subsequent steelmaking stage. Consequently, this method is most effective when using high-grade ores or pellets made from superconcentrates.1