<p>The mineralogical characteristics of iron minerals in red mud produced through reductive Bayer digestion (RBD-RM) significantly differ from those in red mud generated by lime Bayer digestion (LBD-RM). These differences provide distinct separation characteristics of iron to RBD-RM. This study employed the Advanced Mineral Identification and Characterization System. A quantitative analysis and comparative examination were conducted on the mineralogical properties of iron minerals in both types of red mud. The study was performed at both the mineral particle and mineral grain levels. All primary iron mineral grain types in a red mud particle were treated as an aggregate at the mineral particle level.</p><p>The liberation of aggregates and the distribution of embedding minerals in RBD-RM were significantly better than those in LBD-RM. At the mineral grain level, hematite in RBD-RM predominantly exhibited high liberation degrees, whereas hematite in LBD-RM primarily demonstrated low liberation degrees. Furthermore, goethite in both types of red mud displayed similar liberation degrees. This indicates that the superior liberation of hematite at the mineral grain level in RBD-RM is the key factor contributing to the higher liberation of iron minerals at the mineral particle level. These differences make iron recovery from RBD-RM more conducive. In iron separation experiments, the yield rate, total iron grade, and iron recovery rate for concentrate derived from RBD-RM were 36.26, 60.34, and 64.16%, respectively. These indexes surpassed those of concentration achieved from LBD-RM by 14.86, 7.63, and 18.39%, respectively.</p> Graphical Abstract <p></p>