The Study On The Reclamation Of Wastewater Discharged From Vanadium Extraction Process By Electrodialysis Technology

In this study, the detriment of ecological balance and human health caused by high salinity wastewater emissions is comprehensively reviewed. The treatment of high salinity wastewater technologies(mainly:biological, thermal, membrane method) which domestic and foreign, are summarized; The prospect of electrodialysis technology which is used to deal with high salinity wastewater, is explored.Wastewater discharged from vanadium extraction by steel plant (which contains high concentration of Sulfate and Vanadate) is taken as the research object and a zero discharge green chemical process(recover salt and recycle fresh water) is designed The work will focus on the following three topics. Firstly, the pretreatment of wastewater by ion exchange technology, including the selection of suitable resins and optimization the operating conditions of adsorption and desorption process. Secondly, the treatment of brine by ED was comprehensively investigated, including determining the operating demarcation point (concentrated and dilute cut-off point), and investigating the effects of types of membrane and current density on ED performance, such as the current efficiency, energy consumption, and water desalination recovery. Finally, the economic evaluation on the reclamation scheme was conducted on basis of the mentioned-above experiments for future possible industrialization and commercialization.The result of pretreatment showed that:compared with the resin 201*7, D301 resin is more appropriate in the recovery of vanadium. It can effectively recover vanadium and achieve the feed requirement of ED system. And comparing to 201* 7, the resin desorption recycling rate of D301 is better than former.while the concentration of NaOH is 3M, and the volume is 2 times than resin, the reasonable economic benefit can be achieved and desorption rate can reach to 88%. The experimental of ED showed that:the current efficiency and energy consumption of homogeneous membrane module is better than heterogeneous membrane module, no matter in the desalination process or salt enrichment process. However, the water recovery and desalination rate has little difference. So the total cost of heterogeneous membrane reactor is much lower than the foreign homogeneous membrane reactor due to the membrane cost, for example, when current density is 30 mA/cm2,salt production costs is Y 0.4172 per kg and Y 1.4330 per kg, respectively. The reclamation of wastewater discharged from Vanadium extraction process by ED has potential in broad applications.