Preliminary hydrogen reduction of iron from complex iron-bearing ores and subsequent liquid-phase separation

• A hydrogen-based selective reduction route for complex iron-bearing ores is proposed and validated. • Process parameters enabling selective iron and Fe-Ni reduction were experimentally established. • Liquid-phase separation after hydrogen reduction ensures effective metal-slag partitioning. • The process allows treatment of refractory and low-grade ores without intensive beneficiation. • The proposed technology offers reduced energy demand and lower carbon emissions. . This study presents the results of selective hydrogen reduction of metals from complex iron-bearing manganese and nickel ores followed by liquid-phase separation of the reduction products. Iron–manganese and nickel ores from deposits of the Republic of Kazakhstan with a complex phase composition containing Fe, Mn, Ni, and Si oxides were investigated. Solid-state reduction was performed in a vertical high-temperature furnace at 800-1100°C with an isothermal holding time of 60 min in a hydrogen atmosphere (99.99%) at a flow rate of 0.5 L/min. The results demonstrate selective reduction of iron in iron–manganese ores and simultaneous reduction of iron and nickel in nickel ores, while manganese predominantly remains in the oxide state. Phase and elemental analyses of the reduced products were carried out using X-ray diffraction and scanning electron microscopy with energy-dispersive spectroscopy. The formation of a metallic phase was observed at 800°C, whereas increasing the temperature to 900°C led to a higher degree of iron reduction. Subsequent smelting of the pre-reduced materials at 1650°C for 5 min enabled effective liquid-phase separation into metallic and slag phases. The proposed combination of hydrogen-based selective reduction and liquid-phase separation represents an efficient and low-carbon engineering approach for processing complex and refractory iron-bearing ores.