The combined process of multi-stage extraction-aerated distillation-heterogeneous ozone catalytic oxidation was used to treat high concentration organic wastewater from lithium hexafluorophosphate production.The feasibility of the combined process treating the said wastewater were investigated;besides,the influence of multistage extraction,aeration distillation and some other experimental parameters on treatment effect was discussed.The results showed that,when the volume ratio of extract phase to raffinate phase was 1∶ 10,the extraction time for each stage of three-stage extraction was 1.5 h,the mass concentration of COD in lithium hexafluorophosphate production wastewater decreased from 93 440 to below 2 372 mg/L.The mass concentration of COD in the effluent water decreased to 495 mg/L after 1 h of aerated distillation when the volume ratio of distillate to total solution was 7.8%.The mass concentration of COD in the effluent water from aeration distillation unit was reduced to 100 mg/L after heterogeneous ozone catalytic oxidation.The removal rate of COD by the said combined process reached 99.9%,and the pretreated wastewater could meet the requirements of subsequent treatment unit.
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