Abstract
The release of valuable minerals from the associated gangues is called liberation. Good liberation is essential to the subsequent separation stage. Selective liberation is advantageous to improve the degree of liberation. Oolitic hematite is one of the typical refractory iron ores in China, and its resources are abundant. However, owing to its fine dissemination and complex mineralogical texture, the conventional grinding processes are inefficient in improving the selective liberation of oolitic hematite. In this study, microwave processing and acid leaching were used to assist the liberation of oolitic hematite. The assisted liberation of the oolitic hematite mechanisms of microwave processing and acid leaching were studied by using scanning electron microscope (SEM), X-ray diffraction (XRD), BET specific surface area detection method (BET) and the transflective microscope method. The results indicated that microwave processing can reduce the mechanical strength of oolitic hematite and improve the liberation of hematite, and acid leaching can improve the microwave-assisted liberation efficiency and reduce the content of phosphorus in the grinding product. Compared to direct grinding, the liberation of hematite increased by 54.80% in the grinding product, and especially, the fractions of −0.038-mm and 0.05–0.074 mm increased significantly; however, there was no obvious change in other grain sizes, and the dephosphorization ratio reached 47.20% after microwave processing and acid leaching. After the two stages, the iron grade and recovery of the magnetic separation product increased by 14.26% and 34.62%, respectively, and the dephosphorization ratio reached 88.59%. It is demonstrated that microwave processing and acid leaching comprise an efficient method to improve the liberation of hematite and the dephosphorization ratio of oolitic hematite. The two-stage treatment can achieve selective liberation of oolitic hematite, which is beneficial to the following magnetic separation.
Highlights
As a typical refractory iron ore, high-phosphorus oolitic hematite is distributed widely and is an abundant resource worldwide
The images show that there were fractures generated after microwave processing, and the number of fractures was largest at a microwave power of 2.5 kW
After microwave processing and acid leaching, the iron grade, recovery of iron and dephosphorization ratio of the magnetic separation product increased by 14.26%, 34.62% and 43.49%, respectively, in comparison with direct grinding
Summary
As a typical refractory iron ore, high-phosphorus oolitic hematite is distributed widely and is an abundant resource worldwide. The reason why is that the complex structure and fine-grained dissemination of oolitic hematite make it very difficult to liberate [5]. Mineral liberation has stimulated great interest in the field of mineral processing, especially in complex minerals’. Size reduction is an important method of liberating valuable minerals from their associated gangues [7,8]. The degree of liberation is a more important indicator than size reduction when characterizing the liberation in mineral processing [9]. A perfect liberation forms fractures along the grain boundary of the valuable mineral and gangues, which is described as selective liberation. If selective liberation is achieved, the subsequent separation stage would become easier and more economical. Wang et al found that the electrical comminution product was better liberated than in the conventional comminution, and that the process made the stage consuming less energy [11]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
