The effects of key redox smelting parameters, including anthracite addition amount, temperature, and holding time, on Zn migration behavior and toxicity characteristics were investigated. The results showed that CaSO₄ in leaching residue promoted the transformation of ZnFe₂O₄ into ZnS−FeS eutectic, hindering Zn recovery and contributing to contamination potential. At temperatures above 1573 K, the ZnS−FeS eutectic in the upper slag was oxidized by O₂/(O)_slag to form ZnO(s), then converted to chemically dissolved Zn, and finally reduced to Zn(g) by CO. Zn volatilization can be improved by pre-desulfurization or by increasing the oxygen potential. Under optimized conditions, the Zn residual content decreased to 0.22 wt.%, substantially lower than the industrial range of 1.0−3.0 wt.%, thereby reducing environmental hazards.