Mechanism and experiment of iron recovery from tailings by suspension magnetization roasting

• Published in: Separation science and technology Vol. 60; no. 12; pp. 1575 - 1588
• Main Authors: Qi, Lei, Zhu, Kun, Gong, Minghui, Wang, Feiwang, Wu, Liwei, Dai, Huixin
• Format: Journal Article
• Language: English
• Published: Taylor & Francis 13.08.2025
• Subjects: efficient utilization; Iron tailings; magnetic separation; suspension magnetization roasting
• ISSN: 0149-6395; 1520-5754
• DOI: 10.1080/01496395.2025.2506499

As an industrial solid waste with large output and storage capacity, the green and efficient recycling technology of iron tailings has always been the current research difficulty. Suspended magnetization roasting can further improve the utilization rate of iron tailings by changing the occurrence state of iron in iron tailings, so it has become a research hotspot in the reuse technology of iron tailings resources. However, there are few implementation examples of this method and there are still some problems in industrial application. Based on the existing research, this paper uses the method of suspension magnetization roasting-magnetic separation to recover the valuable mineral limonite (Fe 2 O 3 · nH 2 O) in a tailings pond sample in Dali, Yunnan Province through a combination of mechanism analysis and experimental verification. Mechanism analysis indicates that by controlling the reaction conditions, Fe 2 O 3 can be almost completely converted to Fe 3 O 4 , thereby increasing the magnetic difference between valuable minerals and gangue minerals. Experimental results show that under the optimal conditions of CO concentration at 25%, total gas volume at 500 mL/min, a reducing agent ratio of CO: H 2  = 1:3, roasting temperature at 803 K, roasting time at 25 min, magnetic field intensity I at 1700Gs, and magnetic field intensity II at 2100Gs, the tailings sample with an iron grade of 23.76% can be transformed into iron concentrate with an iron grade of 57.75%. The separation indices achieved are a recovery rate of 69.54% and a yield of 34.52%. Experimental results such as chemical composition analysis, XRD detection, and iron phase analysis confirm that Fe 2 O 3 in the original tailings sample is almost completely converted to Fe 3 O 4 , consistent with the mechanism analysis results. The efficient utilization of this iron tailings resource has been successfully realized, consistent with the results of mechanism analysis, the efficient utilization of iron tailings resources has been successfully realized, which provides a certain reference for the efficient utilization of new technologies of iron tailings, and also has certain reference significance for the industrial application of suspension magnetization roasting.