Recovery a refractory oolitic hematite by magnetization roasting and magnetic separation

Orthogonal test was carried out to investigate effects of multiple factors during the magnetization roasting-magnetic separation process as follow: roasting temperature, time, ratio of reducing agent and magnetic field intensity. Significant order of those factors on grade of iron concentrate is obtained, and opportune condition for magnetic roasting is determined. As the condition that roasting temperature is 850 degrees C, time is 40min, ratio of reducing agent is m(coal)/m(ore)=12% and magnetic field intensity is 1800Gs, iron ore concentrate whose grade and recovery are 56.32% and 94.03%, respectively, is obtained. At last, through closed-circuit test including magnetization roasting, magnetic separation and reverse flotation, final result is obtained that iron concentrate with phosphorus and silicon are 0.18% and 2.63%, respectively, and its iron grade and recovery are 60.47% and 80.1%, respectively.