Study on Mineral Phase Transformation Behavior in Sealed Reduction Electric Furnace for High-Iron Red Mud and Mechanisms of Efficient Co-Recovery of Iron and Aluminum

High-iron red mud presents a major obstacle to comprehensive resource utilization, as iron and aluminum minerals form tightly interwoven and encapsulated structures that resist conventional separation, hindering efficient co-recovery of these valuable elements. This study aimed to address this bottleneck by developing an effective strategy for iron–aluminum separation and synergistic recovery. A reduction smelting process was conducted in a sealed electric furnace using internally carbon-containing red mud pellets, enabling phase reconstruction to regulate aluminum-bearing phases while achieving iron–aluminum separation. XRD and SEM analysis verified that iron oxides were reduced to metallic iron with recovery exceeding 98%, and aluminum-bearing phases were selectively converted into active α-Al2O3 and mainly dodecacalcium hepta-aluminate (Ca12Al14O33) in the slag. Under optimized Bayer leaching conditions (150 g/L NaOH, 240 °C, 90 min, liquid-to-solid ratio 6:1), aluminum extraction exceeded 60%, comparable to conventional red mud processing. This work overcomes the technical barrier of iron–aluminum co-recovery from high-iron red mud, offering a practical and efficient route for its sustainable valorization.