The utilization of bauxite residue (BR) through iron oxide reduction and leachable alumina phaseformation by hydrogen reduction were studied experimentally. Three different types of pellets weremade: one from bauxite residue, and the other two via calcite addition with varying CaCO3 amounts.All pellets were isothermally reduced by H2 gas in a thermogravimetry furnace at constant temperatureunder fixed hydrogen flow rate and retention times. X-ray diffraction (XRD) and Scanning electronmicroscopy (SEM), coupled with Energy dispersive spectroscopy (EDS), were used for the phaseand microstructural analysis. It was found that the formation of dominant phases during reduction isdependent on the reduction temperature and the quantity of CaCO3 addition. The relative intensity ofiron is constant for all reduced pellets at constant reduction temperature. There is no mayenite phasein the reduced BR pellets, but with the addition of calcite, a small amount of mayenite phase starts toappear, which increases with more calcite addition. In addition, similar metallic iron recoveries wereobserved for all reduced pellets, while the calcite-added ones had better composition for further aluminarecovery.