The iron and steel industry faces increasing pressure to reduce CO \(_{2}\) emissions, which requires a shift away from conventional fossil fuel reductants. Hydrogen-based direct reduced iron (H \(_{2}\) -DRI) is a potential alternative, as it produces iron without direct carbon participation. However, a critical challenge arises since the melting temperature of H \(_{2}\) -DRI is similar to that of pure Fe, which hinders efficient Electric Smelting Furnace (ESF) operation. To overcome this limitation, controlled carbon addition is necessary to lower the melting temperature of H \(_{2}\) -DRI. In the present study, the melting behavior of H \(_{2}\) -DRI with different reduction degrees (RDs) was investigated by blending Coke Dry Quenching dust (CDQ) or Graphite (GR) with fluxing agents (CaO). Melting experiments were carried out using in situ Confocal Scanning Laser Microscopy (CSLM) up to 1585 \(^{\circ} \) C under a purified Ar atmosphere. The results revealed that carbon addition facilitated the formation of liquid Fe at lower temperatures. Nevertheless, even with sufficient carbon addition, only partial melting was observed and the porous DRI structure was retained. Acidic gangue components prevent structural collapse by reacting with carbon to form stable oxides, whereas CaO addition promoted melting by neutralizing acidic components. Subsequently, thermodynamic calculations were conducted to optimize conditions for rapid and complete melting of H \(_{2}\) -DRI. The optimized condition enabled H \(_{2}\) -DRI melting near 1400 \(^{\circ} \) C, significantly lower than the melting point of pure Fe. These findings demonstrate the feasibility of reducing energy consumption in ESF operations through appropriate carburization and flux addition strategies, thereby contributing to more sustainable iron and steelmaking.
