Kinetics of smelting reduction of fluxed composite iron ore pellets

Abstract

Kinetic studies on smelting reduction of unreduced fluxed composite pellets (FCP) and fluxed composite pre-reduced iron ore pellets (FCRIP) have been carried out in an induction furnace. The pellets are charged into the slag layer floating on the carbon saturated molten iron bath in a graphite crucible. The slag basicity was however varied such that it has the same value as that of the pellets charged. The temperature of the slag is varied within the range of 1623K to 1823K for the pellets of basicity 2.0. Kinetic studies show a mixed kinetic model of both diffusion and chemical reaction controlled. While the smelting of FCRIP follows the model expressed as G(alpha) = 1-(2/3)(alpha) - (1-alpha)(2/3), the unreduced FCP pellets initially follow the diffusion controlled model of G(alpha) = alpha(2) followed by a chemical reaction controlled first order model of -In(1-alpha) at the latter stages of smelting reduction, where a denotes the degree of reduction. The basicity dependence on the kinetics is not very significant. Comparison of the activation energy values explains that the smelting reduction with pre-reduced pellets seems to be a rather less energy intensive process