2005 Volume 45 Issue 4 Pages 587-593
A sinter ore has fine pores as well as macro pores and cavities in it. These mesoscopic porosity distributions have close relationship with reduction of loading capacity for sinter ores as well as their strength and stiffness. In addition, since the gaseous reduction reaction is enhanced by open meso-pores, meso-porous configuration becomes very important in the design of sinter ores. Multi-level modeling with use of artificial unit cells is proposed to aim at the meso-porous microstructure design. The phase filed method with finite element modeling provides us a reliable tool to control the size, shape and distribution of meso-pores and to consider their effects on the mechanical and thermal properties of sinter ores. Meso-porous hematite is employed as a targeting sinter ore to describe actual meso-porous microstructure by comparing the experimentally measured Young's moduli with the theoretically predicted elastic properties. Microstructure with uniform distribution of isolated meso-pores provides the upper bound on the Young's modulus. Reduction of Young's moduli in experiments below this upper bound is caused by irregular shaping and coalescence of meso-pores during sintering. Unit-cell modeling with irregularly shaped and inter-connected meso-pores, provides an actual upper bound for measured elastic properties of sinter ores. Variation of thermal conductivity with the average porosity is also estimated as a master curve for optimum sintering process design.