The Treatment Of Lead And Zinc Smelting Wastewater By Fe-C Micro-electrolysis And Flocculation

As a highly polluting industry in non-ferrous metals industry, the wastewater of Lead and zinc smelting containing heavy metal pollutants pose a serious threat to the ecological environment. The wastewater of Lead and zinc smelting mainly characterize in having low pH and high concentrate Cu, Zn, Pb, As, F oins. The main treatment methods for the lead and zinc smelting wastewater contain precipitation, sulfide precipitation and ferrite, however, it is difficult to produce the sediment and reuse the useful resources. In other hand, these methods could lead secondary pollution that hard to deal with and need high cost. In view of the adverse effects of lead and zinc smelting wastewater on the environment, it is called out for a tremendous amount of research to be conducted to identify robust new methods of purifying water.The comparison study about the effects of single iron and micro-electrolysis combined with flocculation on wastewater treatment were researched by experiments. To evaluate the effect and influence factors on Pb2+, Zn2+ oins separately, the artifical wastewater was used after using the Mengzi Mining Limited wastewater. The results showed that Fe-C micro-electrolysis is more effective than a single iron. While the Pb2+ and Zn2+ removal efficiencies of artifical wastewater were 77.81% and 21.33% respectely by iron and the date for actual wastewater were 78.67% and 20.41%, the efficiencies by Fe-C micro-electrolysis can reach to 98.25% and 56% for artifical wastewater,97.88% and 47.29% for actual wastewater. After the flocculation following the Fe-C micro-electrolysis treatment, the removal efficiencies of can reach to 99.82% and 99.81% for artifical wastewater respectively, and can reach to 99.90% and 99.84% for actual wastewater. The optimum conditions of the actual wastewater by the coupling micro-electrolysis flocculation treatment as follow:pH 3,40 mesh(Fe-C size), Fe-C ratio 2:1, retention time 40min, flocculation pH 9, stirring time 10min, stationary time 60min, aeration 90 min. The Pb2+ and Zn2+ removal rates were 99.90% and 99.84% at the optimum conditions as the effluent concentration was 0.088mg/L and 0.25 mg/L, which can match the national standards. The actual waste water also can match the national effluent standards after micro-electrolysis coupling flocculation treatment.The reaction mechanism and the metal deposition order for the Fe-C before and after treatment were analyzed by the SEM,EDS and XRD. The mechanism of micro-electrolysis was analyzed by the different between the single iron and Fe-C micro-electrolysis. The impact of impurity ions on the Fe-C micro-electrolysis was also analized by the difference between the artificial solution and actual wastewater. The experimental have a same result with the instrumental anlysis.The structure of micro-electrolysis reactor and the wastewater treatment process were design under the experimental conditions. The operating costs estimate result of 5% acid lead and zinc smelting wastewater showed that it needed 53 yuan for per cubic wastewater. Compared with other tratement methods, the Fe-C micro-electrolysis needs lower cost and easier process, which indicating that the it can be use as a viability application.The micro-electrolysis flocculation obtained ideal results in actual use of dealing with lead and zinc smelting wastewater. It also provided a new method and new technology for how to handle the hot potato of the smelting wastewater of lead and zinc in China.