Alumina-Iron Separation of High Alumina Iron Ore by Carbothermic Reduction and Magnetic Separation

Abstract

The carbothermic reduction of high alumina iron ore in the absence/presence of sodium carbonate (Na2CO3) was carried out for alumina-iron separation by wet magnetic separation. Sodium carbonate is found to be capable of improving the separation of alumina and iron, as well as increasing the particle size of metallic iron significantly. When the high alumina ore briquettes were reduced at 1050°C for 80 min, the average particle size of metallic iron was approximately 100 μm in the presence of sodium carbonate, which is bigger than the size of 50 μm in the absence of sodium carbonate. Compared with the absence of sodium carbonate, the Al2O3 content of iron concentrate decreased from 4.33% to 1.29%, while the Al2O3 removal rate increased from 43.70% to 83.37% with the addition of 9% sodium carbonate. Experimental evidence showed that Na2CO3 reacted with Al2O3 and SiO2 to form sodium silicate, aluminum silicate, and sodium aluminosilicate, and decreased the content of Fe in the slags, which improved the separation between the alumina and iron during the magnetic separation.Color versions of one or more of the figures in the article can be found online at www.tandfonline.com/lsst.