The reductive Bayer process creates favorable conditions for the synergistic smelting of aluminum and iron. However, the high-iron red mud generated by this process generally contains impurity elements such as Al, Si, and Ti, which are detrimental to iron smelting. Isomorphous substitution easily occurs between Ti4+ and Fe3+, which leads to significant difficulties in Ti-Fe separation and becomes a major challenge hindering the utilization of high-iron red mud as a raw material for ironmaking. In this study, targeting the high-iron red mud from the reductive Bayer process provided by a certain smelting plant, based on the occurrence characteristics of impurities such as aluminum, silicon, and titanium, technical research was carried out on the selective dissolution and removal of sodium silica slag in the high-iron red mud by weak acid, as well as the reduction and transformation of titanium-bearing hematite and the coordination dissolution of titanium. Under the optimized acid dissolution conditions, aluminum and silicon in the high-iron red mud were significantly removed. The dissolution rate of Si was approximately 80%, and the dissolution rate of Al was about 70%~80%. When the acid-dissolved red mud was jointly reduced and transformed by the titanium transformation agent of sodium alkali and iron powder, the coordination dissolution rate of titanium reached 36.7%. When the acid-dissolved red mud was jointly reduced and transformed by the titanium transformation agent of sodium alkali and hydrogen, the coordination dissolution rate of titanium reached 70%~80%. Additionally, it was observed that the wuestite phase and metallic iron phase, formed after the reductive transformation of acid-leached red mud, could be further converted into the siderite phase in the potassium bicarbonate solution used for coordinated titanium leaching. This study has opened up new ideas for the separation of titanium and iron when they are of isomorphous occurrence.