Abstract: The stimulated flotation wastewater containing butyl xanthate was treated by O₃/H₂O₂ process.Effects of O₃ dosage，H₂O₂ dosage，pH value，initial solution concentration and common ions on wastewater COD_Cr removal were investigated.Reaction mechanism of removal of butyl xanthate by O₃/H₂O₂ was studied by addition of tertiary butanol and using of UV-Vis absorption spectrum.The results showed that，COD_Cr removal rate can be reached 60.25% at 100 L/h of ozone dosage，1 000 mg/L of H₂O₂ dosage，pH 6.8 and 2 h of reaction time to 400 mg/L butyl xanthate.COD_Crremoval is inhibited by introduction of CO2-3 and SO2-4.COD_Crremoval rate is accelerated by introduction of Cu2+ and Zn2+.O₃/H₂O₂process followed a hydroxyl radical type mechanism.

Key words: Floation wastewater, Butyl xanthate, O₃/H₂O₂, Hydroxyl radicals