It is difficult to recycle a large amount of iron resources in iron-rich red mud, and the calcification reduction-grinding method can realize the efficient separation of iron and aluminum components in red mud. In order to solve the problem that the liquid phase is easy to form during the calcification reduction process of iron-rich red mud, which leads to the melting of materials and the adhesion of equipment, a segmented calcification reduction-grinding technology route is proposed; the morphology, metalization rate, microstructure, growth law of metallic iron grains and related grinding indexes of calcification reduction products of iron-rich red mud under different temperature regimes are studied. The results show that the segmented calcification reduction roasting can complete the reaction process of iron oxide reduction to the formation of metallic iron and calcium-aluminum compounds at low temperature, and the aggregation and growth process of metallic iron particles at high temperature, and the formation of low melting point and high-temperature roasting can be separated to inhibit the formation of liquid phase. The first stage is roasted at 1 125 ℃ for 30 min and the second stage is roasted at 1 200 ℃ for 40 min, without obvious liquid phase formation during the roasting process, and the average particle size of the metal iron particles reaches 21.52 μm. After grinding, the TFe mass fraction and Fe recovery rate of reduced iron powder are obtained up to 92.84% and 78.68%, respectively. The results can provide a theoretical basis for the resource utilization of iron-rich red mud.