Morphology and reduction kinetics of fluxed iron ore pellets

The present paper describes studies of the reduction and sintering behaviou r, followed by examination of the structural changes taking place, during d irect reduction of fluxed composite (ore plus coal) pellets. The kinetics a nd morphological aspects of the direct reduction of fluxed composite pellet s are compared with those for the gaseous reduction of fluxed ore pellets w ithout carbon addition. It is shown that the chemical reaction is the rate limiting-factor for fluxed composite pellets, and the mass transport of rea ctant gas through the reaction product iron layer governs the overall reduc tion process in the case of fluxed ore pellets. Microscopic analysis of the fluxed composite pellets has indicated no tendency to form a reduction inh ibition iron shell towards the end of the reduction, as found in the case o f gaseous reduction of fluxed ore pellets under identical reduction process conditions. The effects of basicity, Fe/C, temperature, and other variable s on morphological and microstructural changes in the directly reduced flux ed composite pellets have been experimentally investigated in the present w ork. I&S/1422 (C) 2000 IoM Communications Ltd.