Optimization of chemical composition and microstructure of iron ore sinter for low-temperature drip of molten iron with high permeability

To discuss sinter condition for lowering dripping temperature of molten iron and enhancing reducibility, reduction behavior of sinter samples with extensive range of chemical composition was measured with reduction test under load. Basicity was found to have dominant influence on dripping temperature and should be in the range between 1.0 and 1.5. A further decrease in dripping temperature was achieved by decreasing Al2O3 content and increasing MgO content in sinter, which was related with low liquidus temperature, low viscosity and fast smelting-reduction of slag containing low FeCt content. In contrast, reducibility and mineralogy of sinter influenced softening-melting behavior as well. Increasing fine pores could improve softening-melting behavior as a result of enhancing reducibility. Finally optimized sinter, containing 1.0-1.5 basicity, low Al2O3 and high MgO content was proposed. This chemical composition of sinter could lower dripping temperature by 80degreesC with fairly high permeability of sinter layer compared to conventional sinter. Possibility of the further improvement of softening-melting behavior at a constant chemical composition with controlling sinter mineralogy was discussed.