*2.3. Sample Analysis and Testing*

The phase composition of iron ore was evaluated by PANalytical XPert PRO MPD XRD (Panaco, Almelo, Netherlands)with Cu target, K radiation, and 40 kV operating voltage. The chemical component of roasted ore was determined by IRIS Advantage Radial inductively coupled plasma atomic emission spectrometry (ICP-AES, Thermo Elemental, Massachusetts, America), and the physicochemical properties of the roasted ore were analyzed by FEI Nova NanoSEM400 (FEI, Hillsboro, America) scanning electron microscopy (SEM), coupled with energy-dispersive X-ray spectroscopy (EDS, FEI, Hillsboro, America).
