Thermodynamic Considerations in the production of Bulk Ferro Alloys (Fe-Mn, Fe-Cr and Fe-Si

The above mentioned ferro alloys are produced commercially by reduction smelting of their oxide minerals with, coke or charcoal in a submerged arc furnace and, to a lesser extent, by a metallic reductant such as aluminium. In general, the overall reduction reactions are highly endothermic, thus, requiring large thermal energy inputs.

In this paper, the thermodynamic principles. underlining reduction smelting of oxides are discussed with the help of free energy-temperature (Ellingham), diagram with a focus on the role of direct reduction, the smelting temp-eratures required for a given oxide mineral, the thermal energy requirements, the suitability of carbon as redu-ctant, the alloy grade and inpurity levels, the slag-
metal equilibria and the formation of carbides.