Enhancement of magnetization roasting of hematite ore by high voltage pulse discharge

Abstract

High voltage pulse discharge (HVPD) is a new type of crushing technology with good application. Existing studies have focused on the crushing characteristics, with less reports on follow-up work. This study magnetization roasts hematite ore after mechanical crushing and HVPD, analyzing the difference in the roasting effect between the two crushing methods by establishing a new system of HVPD-magnetization roasting. For a roasting temperature of 500 °C, roasting time of 30 min and number of pulses of 100 times, the grade and recovery of magnetic separation concentrate obtained from HVPD products after secondary separation were 64.69% and 82.05% respectively, which were 0.28 and 1.96 percentage higher than those of mechanical crushing. X-ray diffraction (XRD), vibrating sample magnetometry (VSM), Brunauer-Emmett-Teller (BET), scanning electron microscopy and energy dispersive spectroscopy (SEM-EDS) were used to analyze the process and showed that the specific surface area, pore volume and average pore size of the HVPD products were improved. Grain boundary fracture and burn marks were present in the HVPD products.