Original Article

Smelter to close the raw material gap in green steel production

Primetals Technologies, Linz, Austria

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Received: 12 September 2025
Accepted: 7 January 2026

Abstract

The transition to green steel production faces a critical challenge: the raw material gap caused by the limited availability of high-grade iron ores required for direct reduction (DR) and electric arc furnace (EAF) steelmaking routes. Most globally available iron ores are lower grade, which, when processed in an EAF, leads to excessive slag formation, reduced yield and productivity, and increased energy consumption. Moreover, valorization of EAF slag for high value applications remains an unresolved issue. To address these limitations, a two-step process combining a Smelter and a basic oxygen furnace (BOF) is proposed. The Smelter enables efficient melting and final reduction of low-grade DRI under reducing conditions, achieving high iron yield and producing slag suitable for cement applications. The BOF refines the hot metal without altering existing plant logistics, avoiding costly re-certification. This configuration accommodates various DRI forms and metallization degrees, offering flexibility in DRI feedstock and energy optimization between DR and Smelter operations. Process validation tests in a 600 kg Smelter demonstrated successful processing of different DRI types and carbon carriers, achieving carbon contents above 3.5% in the hot metal and FeO levels below 1.5% in slag. Modeling indicates that the Smelter–BOF route can reduce CO₂ emissions by up to 78% compared to the conventional BF–BOF route when powered by renewable electricity. Furthermore, the Smelter provides a pathway for steelmaking slag valorization, enabling recovery of metallic fractions and modification of mineral phases for cement use. In conclusion, the Smelter–BOF route offers a promising solution to close the raw material gap in green steelmaking, supporting decarbonization, resource efficiency, and circular economy principles. Ongoing industrial projects, including Hy4Smelt and HYREX, confirm the feasibility of upscaling this technology for commercial deployment.