Research On Extracting High-purity Vanadium Pentoxide From Acid Leaching Solution And Reutilization Of Vanadium Tailings

By now, ion exchange and solvent extraction are the most widely studied topic to recover vanadium pentoxide with high purity from acid leaching solution containing vanadium. These two methods can both make the vanadium and the impurities in the leaching solution separated from each other, howerer, solvent extraction is more appropriate to recover vanadium from acid leaching solution due to its characteristics of better selectivity, higher purity products, lower production costs, environmentally-friendly extracting agent.Considering the solution chemistry of acid leaching solution and its characteristics of low concentration of vanadium, various impurities, this study established a special extraction system which was appropriate for the purification and enrichment of acid leaching solution. On this basis, a new-fashioned extraction technology, adding washing procedure of loaded organic phase between traditional extraction process and stripping process, has been developed to separate the vanadium from acid leaching solution.The extraction, washing and stripping processes were detailedly researched in this study and the optimal technological parameters were obtained. Under the condition of10%N235+5%TBP+85%Sulfonated kerosene, duration of oscillation for2minutes, A:O=1:1, the extraction rate of vanadium reached96.42%; washing loss rate was as low as1.36%when0.3mol/L Na?SO4was used to wash the loaded organic phase, at the same time, the stripping rate of vanadium reached up to97.71%under the condition of0.25mol/LNa2CO3, A:O=1:2, duration of oscillation for3minutes. the vanadium and the impurity were effectively separated because the concentration of vanadium in the strip solution was enriched from7.46g/L up to14.50g/L, meanwhile, the detrimental impurity concentration(Fe) was as low as0.015g/L.Precipitation of vanadium by acidic ammonium salt was systematically researched and the optimal technological parameters were obtained. Under the optimal condition, the purity of final product V2O5can reach as high as99.9915%, which satisfied the standard of high purity vanadium pentoxide.Finally, in allusion to the mineral properties of acid leaching extracted vanadium tailings, the feasibility of extracted vanadium tailings returning to the blast furnace process and the reductibility of iron minerals in extracted vanadium tailings were studied through the perspective of effective use of second resource. Under the condition of20%coal, reducing temperature at1100℃, reducing time for1.5h, metallization rate of iron reached as high as91.42%.