An innovative technology for utilization of oolitic hematite via microwave fluidization pretreatment: Separation characteristics and mechanism

Oolitic hematite possesses the characteristics of large resource reserves, low iron grade, fine embedded particle size and complex mineral composition, which is difficult to be used efficiently through traditional beneficiation process. In this work, a new technology of microwave fluidization pretreatment (MFP) was proposed to strengthen the separation of oolitic hematite. Scanning electron microscope, vibrating sample magnetometer and laser particle size analyzer were used to explore the influence of MFP on roasting magnetic separation and leaching. The results presented that compared with conventional electric furnace pretreatment, the magnetism of roasting products has been significantly improved. The iron grade was increased from 56.88% to 58.72% and recovery was increased from 88.89% to 89.32% for magnetic separation concentrate. Phosphorus content of leaching residue was reduced from 0.17% to 0.11%, and phosphorus leaching rate was increased from 83.06% to 89.77% by MFP. MFP could strengthen microcrack formation and growth, increasing the specific surface area and the grindability of ore.