Effect of microwave irradiation on the grinding and magnetic separation characteristics of vanadium titano-magnetite

Abstract

In this study, the influence of microwave irradiation on the grinding characteristics and magnetic separation of vanadium titano-magnetite (VTM) was investigated, including the effects of microwave power, microwave irradiation time, and particle size of VTM. The particle size distribution of the ground product and Fe grade in magnetic fraction of the untreated and microwave-treated VTM were obtained. Grinding experiment showed that the microwave irradiation could improve the grindability of VTM, thus increasing the specific rate of breakage (S1) value and the weight percentage of the fine ground product significantly. With increasing microwave irradiation time and particle size of VTM, the increment in grindability of VTM was improved. No obvious difference was observed in the particle size distribution of the fine ground product between the untreated and microwave-treated VTM. The magnetic separation tests confirmed that the Fe grade of the magnetic fraction increased from 51.70% for untreated VTM to 53.78% by microwave irradiation. According to X-ray diffraction (XRD), Fourier transform infrared (FT-IR) and scanning electron microscopy (SEM) analyses, the dominant mechanisms that improved the grindability and liberation of VTM under microwave irradiation included the microwave selective heating the valuable mineral within the VTM and the micro-fractures between mineral and gangue that were induced by the thermal stress.