Steel is one of the most important industrial materials, which mainly comes from the smelting of iron ore. In view of the huge steel consumption every year, the exploitation of vast reserves of siderite ores is significant for improving the self-sufficiency rate of iron ore resources and ensuring the strategic security of the iron and steel industries. This paper investigated the influence of temperature, time, and other parameters on the magnetic properties of roasted siderite ores using the method of suspended roasting and analyzed the washability of roasted ores under weak-magnetic-field conditions using the magnetic separation tube experiment. The findings of the study explained the iron phase transformation process, i.e., FeCO3 was transformed into Fe3O4 by suspension magnetization roasting. Furthermore, the saturation magnetization of the roasted ore increased in due time at a constant temperature range of 550-750 °C and a roasting time of less than 5 s. It also increased with increasing temperature and constant time. The roasted ore achieved the best magnetic characteristics after roasting at 750 °C for 5 s. After low-intensity magnetic separation, the iron grade of the concentrate changed to 55.12%, with a recovery rate of 90.34%. The study results provide a reference for the development and application of siderite suspension magnetization roasting technology.
Keywords: magnetic properties; magnetic separation; magnetite; magnetization roasting; siderite; suspended state.