A novel pneumatic dry high-intensity magnetic separator for the beneficiation of fine-grained hematite

Abstract

This study focuses on the development of a novel pneumatic dry high-intensity magnetic separator (PDHIMS) (maximum magnetic induction of 2 T) to enhance the efficiency of separating hematite ore fines. Force analysis of the novel separator demonstrated that it can potentially reduce the lower size limit of hematite dry beneficiation from 58 μm to 10 μm. A series of experiments of mixed samples, such as hematite–quartz/feldspar/chlorite/augite indicated that PDHIMS is successful in achieving highly selective separation of hematite particles fine to 13 μm, overcoming the slime coating of −13 μm quartz particles on the surface of −150 + 38 μm hematite particles, and improving the separation efficiency between hematite and poorly intergrown particles (or magnetic gangues). Energy dispersive spectrometer (EDS) and microscopic imaging of the concentrate confirmed that −13 μm particles form stable aggregates and cannot be disrupted by the employed aerodynamic field in PDHIMS, resulting in a notable entrapment of quartz particles within the concentrate. Lastly, the induced roll magnetic separators (IRMS) with gravity feed and airflow feed were selected as the objects compared with the PDHIMS. The comparison revealed that PGHIMS exhibits a marked superiority in eliminating slime coatings from coarser magnetic products.