This study investigates the exothermic effects and viscosity properties of multicomponent oxide melts during the high-temperature reduction of low-grade Cr–Mn ores. Unlike previous thermodynamic-focused research, this work provides experimental evidence of transient exothermic responses and correlates them with melt properties. High-temperature experiments identified pronounced exothermic effects in the 800–1600 °C range. Phase analysis (XRD, SEM–EDS) confirmed effective Cr and Mn reduction into Fe–Cr–Mn–Si alloys with minimal residual oxides in the slag. Effective viscosity, measured via the electrovibrational method at 1400–1650 °C, decreased monotonically with temperature. Arrhenius analysis was applied to determine activation energies and crystallization onset temperatures (Tcr). The results indicate low viscosity and high thermal stability of the slags, ensuring efficient metal–slag separation. These findings confirm the technological feasibility of using low-grade ores for Fe–Cr–Mn alloy production and provide a basis for optimizing industrial smelting.
This study investigates the possibility of producing a complex W–Mo–Cr-containing alloy via metallothermic reduction of oxide concentrates in the presence of direct reduced iron (DRI) in an induction furnace under atmospheric conditions. A complex FeAlSiCa alloy was used as a reductant due to its high exothermicity and combined reducing potential. Thermodynamic analysis showed that the reduction of WO3 and MoO3 is more favorable compared to Cr2O3, which is reflected in the temperature profiles of the process. Experimental results confirmed that the addition of FeAlSiCa leads to intensive exothermic reactions and promotes melt formation. The estimated apparent recovery of W and Mo reached up to ~99%, while Cr estimated apparent recovery remained lower (up to ~70%) due to its higher thermodynamic stability and kinetic limitations. Microstructural analysis revealed a heterogeneous structure consisting of an Fe-based matrix and W–Mo-rich phases, including characteristic “fishbone” morphologies. An increase in reductant amount led to higher Si content in the alloy, indicating the need for composition optimization. The results demonstrate the feasibility of direct complex alloying as an alternative to conventional ferroalloy-based methods and highlight the potential for developing resource-efficient and low-carbon metallurgical technologies.
The study investigates the technology of direct Cr alloying of steel in an induction furnace using Cr-containing oxide raw materials and an FeAlSiCa metallothermic reducing agent under atmospheric conditions. The experimental design included four charge variants: scrap-based, DRI-based, A-series (50% scrap/50% DRI), and B-series (75% scrap/25% DRI). For A-series and B-series, the FeAlSiCa content was varied from the baseline value to reduced levels of −10% and −20%. The results demonstrate that Cr recovery strongly depends on the metallic component of the charge. The highest Cr recovery (up to 83%) was consistently achieved for the DRI-based charge, while mixed charges showed intermediate values depending on the DRI fraction and reducer amount. Reduction in FeAlSiCa content led to a decrease in Si transfer to steel, but was accompanied by lower Cr recovery. The produced steels were characterized by a uniform distribution of alloying elements, low impurity levels (S, P < 0.03%), and the formation of a dense, non-disintegrating slag. The results confirm that direct Cr alloying in an induction furnace can be effectively implemented under atmospheric conditions without vacuum or protective gas atmosphere, while the presence of DRI plays a key role in enhancing Cr assimilation.