Direct Reduction (DRI / HBI)

Direct reduction (DR) produces solid or hot metallic iron from iron ore without melting, by reacting iron oxide with a reducing gas — primarily hydrogen (H₂) and carbon monoxide (CO) — at temperatures of 700–1,100 °C. Because no melting occurs, the product retains the shape of the ore pellets used as feedstock, earning it the name sponge iron. The commercial names DRI (directly reduced iron) and HBI (hot briquetted iron) refer to the same metallurgical product in different physical forms.

Global DRI production reached approximately 120 million tonnes in 2023, accounting for roughly 6–7% of total primary iron production. The route is growing rapidly, driven by two structural forces: the proliferation of EAF steelmaking in regions with cheap natural gas (Middle East, North Africa, India), and the recognition that gas-based DR — and ultimately hydrogen-based DR — represents the most credible low-carbon pathway to primary steelmaking.

Unlike the blast furnace, direct reduction plants are not continuous 24-7 operations tied to a fixed footprint. Shaft furnaces of 0.5–2.5 Mt/year capacity can be built modularly, started and stopped more flexibly than blast furnaces, and can in principle switch between natural gas and hydrogen as the reductant — making them the cornerstone of every major steel producer's long-term decarbonisation roadmap.