Chapter 1.12 - Production of Ferroalloys

Abstract

Various alloys of iron with a high proportion of one or more other elements such as chromium, manganese, and silicon are known as ferroalloys. They are primarily used in the production of low-alloyed and stainless steels, other high-alloy steels, and cast-iron grades. They impart distinctive properties to these materials in their final use as products and components. On the other hand, ferroalloys serve important functions during the steelmaking process, for instance, for deoxidation and reduction purposes. The bulk ferroalloys, namely, Fe–Mn, Fe–Cr, and Fe–Si, are produced commercially by reduction smelting of their oxide minerals with coke or charcoal or another carbonaceous reductant in a submerged electric arc furnace and, to a lesser extent, by a metallic reductant such as silicon and aluminum. In general, the overall reduction reactions are highly endothermic, thus requiring large thermal energy inputs in the form of electricity. Details on the submerged arc furnace production of major ferroalloys, ferrochromium, manganese alloys, and silicon alloys are provided along with their fundamentals. General process description, energy saving approaches, emissions, and control as well as future trends are briefly included. The high energy consumption and CO2 emissions are the main issues which need rapid mitigation. Especially, decarbonization of ferroalloy production will be extremely challenging.