Effect of microwave radiation on the magnetic properties of ludwigite and iron-boron separation

To effectively separate and recover the valuable elements iron and boron from ludwigite, this study investigated the magnetic properties and the magnetic separation efficiency. And the reactivity of boron component in the B-bearing tailing was studied. The results indicated that the saturation magnetization of ore samples was increased with the increase of microwave power and heating time. Under condition of 40 s with 4 kW, the saturation magnetization of ore samples increased from 12.73 emu/g for the raw ore to 24.70 emu/g for the treated ore, an increased of 94.03%. After magnetic separation, the grade and recovery rate of iron in the iron concentrate and the boron grade in the tailing for the treated sample with 4 kW for 40 s were increased by 19.74%, 31.46% and 86.46% in comparison with those of the untreated ore. The sample was heated to 600 °C at 4 kW and held for 20 min, the reactivity of boron component in the B-bearing tailing reached 86.68 wt%, which increased by 34.01% compared with that of the raw ore and 4.43% compared with that of the optimal traditional roasting value at 700 °C for 2 h, indicating that the roasting temperature and time were obviously decreased and the reactivity was significantly improved by the microwave radiation.