Efficient recovery of zinc material from zinc reductive smelting flue gas via vapor condensation

The inherent susceptibility of zinc vapor Zn (g) to oxidation during conventional pyrometallurgical zinc production fundamentally limits direct metallic zinc recovery. This study developed an innovative multi-field controlling condensation technique to address this challenge through synergistic regulation of atmospheric composition (Zn (g) -CO₂-CO-N₂ system), thermal gradients, and concentration fields in smelting operations. Combining thermodynamic simulations with pilot experiments, the oxidation inhibition mechanisms were systematically elucidated, quantitative relationships between operational parameters and zinc recovery efficiency were established. Thermodynamic analysis revealed that increasing the reaction temperature, elevating CO and zinc vapor concentrations in the gas phase, and reducing H 2 O and SO 2 contents can effectively inhibit zinc vapor oxidation. Experimental validation demonstrated exceptional zinc vapor oxidation inhibition rates of 95.7–99.1 % under optimized conditions: 1050 °C reaction temperature, CO/CO₂ ratios of 3.0–5.0, 0.34 mL/min zinc vapor flux, 610–625 °C condensation temperature, and 60 min retention time without H 2 O and SO 2 . Additionally, this methodology enables precise morphological control of condensed products, achieving tunable zinc crystal structures ranging from dendritic to compact granular morphologies through strategic manipulation of condensation kinetics. This breakthrough establishes a robust technical pathway for sustainable zinc recovery from smelting off-gases while providing fundamental insights into vapor-phase metal purification strategies.