Thermal Decomposition of Siderite Ore in Different Flowing Atmospheres: Phase Transformation and Magnetism

Siderite ore (FeCO3) is an important iron ore resource that is widely distributed around the world. However, it is difficult to process using conventional methods owing to the low iron grade, easy sliming, and high impurity content. Based on the mechanism of thermal decomposition, the combination of metallurgy and processing is a promising method to process siderite ore. In this study, experiments on thermal decomposition were performed using a fluidization reactor in flowing atmospheres of N-2, CO, and CO2. The phase transformation and magnetism were characterized via X-ray diffraction, Mossbauer spectroscopy, and vibrating sample magnetometry. The results indicated that the thermal decomposition of siderite ore exhibited significant differences in various atmospheres, particularly for the phase transformation and magnetism, which primarily depended on a two-step function: FeCO3 -> FeO + CO2 -> Fe3O4 + CO. It has implications for the utilization of siderite ore resources.