Fundamental processes in bath smelting: reactions of iron oxides with Fe-C melts

Reactions of Fe-C melts with wustite, hematite, and partially metallised iron oxide pellets were investigated experimentally. Effects of pellet size, shape, initial temperature, and degree of metallisation, as well as bath temperature (1473-1923 K), on the reactions were examined. Flash X-ray equipment was used to obtain several images of the reacting pellet and melt surface. The time for complete reaction tR was the same for both wustite and hematite pellets of equal weight at or above 1723 K, but longer than that for partially metallised pellets. The pellet shape or its initial temperature had no effect on the reactions. The value of tR decreased with increasing melt temperature, but the rate of reduction for temperatures below 1651 K, the onset of the melting point of wustite, was 5-100 lower than that for temperatures above 1651 K. The overall reaction of the process (at or above 1723 K) followed nth order reaction rate kinetics, with the order of reactions equalling 0.3-0.4. The apparent rate constant increased with increasing bath temperature and the calculated apparent activation energy of the process was 76.2 ± 27.7 kJ (mol O)-1.