Separation of aluminium and preparation of powdered DRI from lateritic iron ore based on direct reduction process

Lateritic iron ore has not been used effectively due to excess content of multiple metals. In this work, separation of aluminium from a high-aluminium lateritic iron ore was achieved by the process of 'direct reduction with sodium sulfate-magnetic separation', with a powdered direct reduced iron ( DRI) produced. It is found that the presence of 12% sodium sulphate during reductive roasting significantly improves separation of iron and aluminium in magnetic separation: the total iron grade ( TFe) of powdered DRI increases from 80.6 to 92.0% and the Al2O3 content decreases from 9.8 to 1.3% correspondingly. The presence of sodium sulphate results in formation of sodium aluminosilicates instead of FeAlO2. Moreover, sodium sulphate significantly promotes growth of metallic iron grains which is beneficial to sufficient liberation and separation of metallic iron grains from gangue minerals in grinding and magnetic separation.