Production of High Carbon Ferrochromium Using Melt Circulation

Some fundamental studies related to the production of high carbon ferrochromium were summarized using melt circulation technology carried out in the School of Chemical Engineering at the University of Birmingham. These studies focused on the kinetics of chromite reduction in Fe-C(-Cr-Si) melts. The effects of feed mode,fluxes, amount and particle size of reductant, particle size of chromite, melt composition and the reduction temperature were investigated. The reduction mechanisms were discussed. The results showed that (1) the reduction rates of sintered chromite Pellets and non-compacted chromite powder in Fe-C(-Cr-Si) melts was generally very low,(2) addition of carbon in the non-compacted chromite feed greatly improved the reduction kinetics, (3) compaction of the carbon-chromite mixtures into composite Pellets further improved the reduction kinetics and (4) addition of lime in the composite Pellets increased the reduction rate, while the addition of silica may suppress the posihve effect of lime. It can be concluded that solid-state reduction, smelting reduction and dissolution proceed simultaneously during the reduction of compacted compostite pellets or non-compacted composite mixtures in Fe-C(-Cr-Si) melts,and the early stage of reduction is very likely to be controlled by either or both solid-state and/or gas diffusion through the oxide phases and/or the product layers.