Magnetite oxidation mechanism of the air-cooling stage for limonite ore magnetization roasting

Magnetization roasting is an effective method to process limonite ore. However, conventional water quenching technology primarily limits its industrial applications, particularly in regions with water shortages. In this study, the magnetite oxidation mechanism of the air-cooling stage during limonite ore magnetization roasting was investigated in detail. Oxidation roasting experiments of a synthetic magnetite were performed to investigate the effects of the oxidation temperature, oxidation time, and O-2 concentration in the air-cooling stage. The samples were characterized via X-ray diffraction, Mossbauer spectroscopy, simultaneous thermogravimetry and differential scanning calorimetry analysis, and vibrating sample magnetometry. The results showed that magnetite was oxidized to maghemite in a controlled air atmosphere, which was closely related to the oxidation temperature. Additionally, the generation of maghemite did not affect the subsequent magnetic separation owing to its ferrimagnetism. Therefore, as shown in this paper, air cooling is feasible for limonite magnetization roasting.

Automated summary

This study investigated the magnetite oxidation mechanism of the air-cooling stage during limonite ore magnetization roasting, and found that magnetite was oxidized to maghemite in a controlled air atmosphere, which did not affect the subsequent magnetic separation.