Research Of Extracting V₂O₅from The Converter Vanadium Slag With Novel Process

In this paper the "ammonium sulfate melting-sulfuric acid leaching-extraction-reverse extraction-vanadium precipitation" method was adopted on Chengde-Steel converter vanadium slag to obtain V2O5. XRD, XRF and ICP-AES analysis were used and the main research contents were listed as follows:the influence of addition amount of ammonium sulfate and potassium hydrogen sulfate, roasting temperature and holding time on leaching rate of vanadium during the process of roasting; the influence of liquid-solid ratio, sulfuric acid volume fraction, leaching temperature, leaching time on the leaching rate of vanadium slag during the process of leaching; the influence of pH, organic phase volume fraction, phase volume ratio and extraction time on the extraction rate of vanadium during the process of extraction; the technical conditions needed in the process of reverse extraction and vanadium precipitation.(1) The optimal conditions of roasting experiment are:converter vanadium slag/ammonium sulfate/potassium hydrogen sulfate is1:8:0.67in mass ration, roasting at350℃for36min. In these conditions, the leaching rate of V, Fe and Ti from converter vanadium slag is69.0%,66.5%and30.5%, respectively.(2) The optimal conditions of sulfuric acid leaching experiment are:the liquid-solid ratio is8:1, sulfuric acid volume fraction is12%, leaching at95℃for5h. In these conditions, the leaching rate of V is97.0%.(3) The optimal conditions of extraction experiment are:pH of leaching liquid is3.25, organic phase volume fraction is15%P204+5%TBP+80%sulfonated kerosene, phase volume ratio is1:1, extracting time is10min. In these conditions, the extraction rate of vanadium in leached liquid is96.5%.(4) The optimal conditions of reverse extraction experiment are:1.5%mol/L H2SO4, extraction liquid:dilute sulfuric acid=1:1, reverse extraction time for10min. In these conditions, the reverse extraction rate of V, Fe and Ti in extracted liquid is92.6%,4.6%and1.1%, respectively. (5) The optimal conditions of vanadium precipitation experiment are:pH at8.25, heating at85℃and stirring for1h. In these conditions, the precipitation rate of vanadium in extracted liquid is94.0%.(6) The optimal conditions of the preparation of V2O5are:calcining at550℃for2h in muffle after washing and drying. In these conditions the purity of V2O5is over90%.