Study And Application On The Wastewater Treatment In Rare Earth Production Waste-of NdFeB Recovery Process

Fenton reagent was used to treat waste water of NdFeB waste recycling in this paper, The experiment studyed the COD removal rate in different initial pH, different reaction times, different FeSO4·7H2O dosage and different H2O2, dosage, the experiment shown that in the initial pH at4, reaction time2hour, FeSO4·7H2O dosage of0.006mol/L, H2O2dosage to2mL/L, the COD removal rate can reach above70%.As for the acidity of wastewater and the concentration of Fe2+is very large, this paper studyed a new method of using alkali to acclerate the coagulation and sedimentation to reducing wastewater’s COD to reducing the pressure of the follow-up Fenton oxidation. The pH of the wastewater callback to4to5after coagulation and sedimentation, and original pull-in the Fe2+to the Fenton oxidation system can achieve the requirements of Fenton oxidation. When pull-in raw water for50mL/L, pH of the wastewater for4to5, the COD removal efficiency above70%.Engineering operation shows that the raw water COD concentration of3200to3650mg/L by Fenton oxidation process, the COD concentration reduce to839-1130mg/L, COD removal efficiency can be maintained at between68.21and75.23%. The flotation process influent COD is701to992mg/L, while the effluent COD is438to736mg/L, the COD removal efficiency is17.20to39.69%. Activated carbon adsorption process influent COD is438to736mg/L, and the effluent COD is under40mg/L, the COD removal efficiency can up to92%. The COD removal efficiency can go up to99%by this entire system. The operation results show that the system is stable and efficient of processing NdFeB waste recycling wastewater, effluent quality can meet the emission requirements.