Effect of dolomite on reduction swelling property of iron ore pellets

The effect of various dosages of dolomites on the reduction swelling property of iron ore pellets was studied. Experimental results show that the reduction swelling index (RSI) decreases from 13.35% to 4.0%, while the porosity of roasted pellets increases from 35% to 40% with increasing the dolomite dosage from 0 to 10.5%. Meanwhile, the content of magnesium ferrite with high melting temperature, as well as the stability of magnetite (Fe3O4) in the roasted pellets, increases with increasing the magnesium oxide (MgO) content from dolomite. The reasons for the decrease of RSI rely on the absence of crystal transformation from Fe2O3 to Fe3O4, the increased porosity of roasted pellet, and the suppression of phase transition of 2CaO·SiO2 resulted from the incorporation of magnesium into calcium silicate.