Investigation Interfacial Wetting Behavior of Copper Matte/Slag/Fe₃O₄ Enriched Intermediate Layer During High Temperature Smelting

The presence of wetting behavior between the Fe₃O₄-enriched intermediate layer (inter-layer) and matte during the copper smelting process is a critical factor that retards the aggregation, growth, and settling of matte droplets. Recognizing the significance of interfacial phenomena in evaluating phase separation, this paper reveals the retardation mechanism exerted by the inter-layer on matte through an analysis of interfacial wetting behavior and interfacial tension (IFT). The formation and ionic structure retardation of the inter-layer were examined from thermodynamic properties and melt structure perspectives, respectively. Results indicate that specific microscopic forms of retardation involve matte being wrapped around or adhered to Fe₃O₄ spinel within the inter-layer. The wettability differences between matte and various phases were further clarified by measuring IFT using both sessile–drop and floating drop methods. A positive correlation exists between high-grade matte and IFT, while a negative correlation is observed with respect to the Fe/SiO₂ ratio in slag. The aggregation of surface-active elements such as O, Fe, S at the interface along with diffusion behaviors among melt phases represent key mechanisms for reducing IFT. Analysis results confirm that strong wettability between Fe₃O₄ and matte in the inter-layer contributes significantly to matte retardation behavior. This study offers new insights into understanding mass transfer dynamics across interfaces involving heterogeneous phases in copper smelting.