Direct reduction of fluxed iron ore pellets made from coarse iron ore particles

Abstract

ABSTRACT The preparation of finer iron ore particles which can be used suitably in pelletization, decreases the binder requirement in the process, but increases the energy consumption during crushing and ball milling. Therefore, using relatively coarser iron ore particles with a suitable binder may help decrease energy input and slag volume. The present study was undertaken for the utilisation of iron ore fines in the range of −0.25 + 0.05 mm along with a suitable binder. Iron ore fines were classified into three size ranges (SR1(−0.25 + 0.1), SR2(−0.1 + 0.05) and SR3(−0.05)mm). Pellets of the above material were prepared using lime as a binder for basicity 0, 1 and 2 respectively, to observe hardening and reduction behaviour. Hardened pellets were characterised using cold crushing strength and porosity. Reduced pellets were characterised using XRD and SEM. It was observed that the cold crushing strength of hardened fluxed pellets decreased from 222 to 12 kg/pellet, and porosity increased from 30 to 43% with an increase in selected particle size. %Reduction increases from 89 to 99% with an increasing iron ore particle size. X-ray diffraction and scanning electron microscopy study confirms the increase in Fe content and iron whiskers growth in reduced pellets with increasing particle size. The optimum property was observed for the SR2 size range with the lime binder, which can produce highly reducible DRI (90–99%).