Thermodynamic Assessment and Process Development for Smelting Aluminosilicochrome from Technogenic Wastes of Ferroalloy and Coal Production

This study evaluated the production of aluminosilicochrome alloy (ASC) from technogenic wastes generated by ferroalloy and coal production. Chromite spinel dust from high-carbon ferrochrome gas cleaning, microsilica from ferrosilicon gas cleaning, and coal sludge as a reductant were used as raw materials. Thermodynamic modeling of the Fe–Cr–Si–Al–C–O system in HSC Chemistry 10 predicted that ASC formation is most favorable at 2000–2200 °C, where the metallic phase should contain (wt. %) 28.27–29.46 Cr, 35.21–36.06 Si, 10.14–11.89 Al, and 10.21–10.45 Fe. These predictions were tested by smelting a pre-agglomerated monocharge in a 100 kVA single-electrode electric arc furnace. The resulting alloy contained (wt. %) 24.23 Fe, 32.03 Si, 22.32 Cr, 18.70 Al, 0.36 C, 0.028 P, and 0.015 S. The experiments confirmed the formation of Si-, Cr-, and Al-rich ASC and demonstrated the feasibility of carbothermic production from these wastes. SEM-EDS revealed a multicomponent metallic matrix with pronounced microstructural heterogeneity and local redistribution of Fe, Si, Cr, and Al. Overall, the results support the use of fine technogenic wastes for producing a complex Fe–Cr–Si–Al alloy.