Beneficiation of goethite iron ore through magnetizing roasting followed by magnetic separation

Abstract

The present study is carried out to recover iron value from low grade goethite iron ore. The method is based on coal based magnetization roasting followed by magnetic separation. The effect of temperature, residence time and magnetic field intensity on grade and recovery of iron ore have been studied. The magnetizing roasting was carried out at 700°C, 800°C and 900°C for different residual time viz., 10, 20, 30, 40, 50 and 60 minutes. The production obtained from magnetizing roasting was then separated in wet high intensity magnetic separator (WHIMS) at different magnetic field of 2000 gauss, 4000 gauss and 6000 gauss. The result obtained at 900°C roasting temperature for 50 minute followed by magnetic separation at 2000 gauss shows optimum Fe grade of 59.20% and recovery is 68.23%, this grade and recovery of iron ore increases with increase of temperature and time. However, the grade and recovery of iron ore decreases during prolonged roasting at 900°C. The recovery increases with increasing in magnetic field but the grade is decreasing. In the present study, the as received goethite iron ore and concentrate ore have been examined using optical microscopy to know the phases present and change of phase during processing.