Kinetics and mechanism of smelting reduction of fluxed chromite Part 2 Chromite–flux pellets in Fe–C–Si melts

Experimental studies on the smelting reduction of fluxed chromite pellets in Fe–C–Si melts were carried out at 1508–1590°C under an initial atmosphere of argon. The reduction was found to be favoured by high temperatures, high melt C contents and a high addition of lime or silica to the pellets. An increase in melt Si content from 0 to 1·5%, however, resulted in a limited effect. Two reaction schemes are proposed to interpret the mechanisms of the smelting reduction of fluxed chromite pellets in Fe–C–Si melts. It is shown that the initial stage up to 10%reduction is principally controlled by mass transfer of oxygen in the metal phase with an apparent activation energy of 78·4 kJ mol^-1 of oxygen. In the later stages, however, mass transfer in the slag phase is likely to be rate limiting, with an apparent activation energy of 449 kJ mol^-1 of CrO.