Preparation Of High Purity Vanadium Pentoxide By Purification Of Polyammonium Vanadate

High purity vanadium pentoxide has been widely used in chemical catalysis,aerospace,electrochemical industry.In particular,the high purity vanadium pentoxide substituted VOSO₄ for the preparation of all vanadium electrolytes,Vanadium battery had gradually become a focus of attention.It is likely to introduce the whole new energy industry into the era of vanadium batteries and triggered the rapid growth of the market of high purity vanadium pentoxide.Industry grade ammonium polyorthovanadate was used as raw material in this paper,the method of MP-AES testing the Si,P,Al and Cr in the vanadate was discussed.0.5mol/L sulfuric acid was selected as the medium,spectral background correction and matrix matching were used to eliminate the interference factors.The result showed that Al,Si,and Cr element concentration were within the range of 1.0⁷.0?g/mL,the P was0.2¹.4?g/mL,the calibration curve was linear and the linearly dependent coefficient all larger than 0.999,The detection limit of low,linear range was wide,operation was simple and cost was low,It provided a basis for the convenience of follow-up studies.Alum was confirmed as remover of Si and P by screening.The effects of pH value,alum addition amount N?mass ratio of alum and Si?,reaction time,reaction temperature,and settlement time on silicon removal rate,phosphorus removal rate and vanadium loss rate were investigated.The result showed that the best conditions were N was 0.9,pH value was 9.0,teaction time was 60min,reaction temperature was 60?and settlement time was 60min,the silicon removal rate was 98.96%,the phosphorus removal rate was86.90%,the vanadium loss rate was 3.67%.Sodium hydrosulfide was confirmed as remover of Cr by screening.The result showed that the chrome removal rate was 96.44%under the conditions of sodium hydrosulfide dosage?mass ratio of sodium hydrosulfide and chrome?was 5:1,pH value was 8.0,reaction time was 90min,reaction temperature was 60?and settlement time was 60min,the vanadium loss rate was 7.53%.The product was analyzed and characterized with MP-AES,XRD and SEM,it showed that the content of vanadium pentoxide was 99.33%,content of chrome was 0.138%,and the crystals of vanadium pentoxide were not dispersed and viscous particle,and were piled as irregular pie structures.It couldn't get the high purity vanadium oxide.Contrasted ten anion exchange resins effects on vanadium-chromium separation,the 202-IISC resin was best.The pH value,adsorption temperature,adsorption time were investigated in static adsorption experiment,the best conditions of vanadium-chromium separation were pH value was 9,adsorption temperature was 298K,adsorption time was 20h.In the dynamic adsorption experiment,the flow rate was1BV/h,the concentration of chrome effluent began to be greater than chrome in vanadium solution before exchange when adsorption effluent was 120mL?C/C₀>1?,it showed that vanadium could replace the chrome that adsorbing on 202-IISC resin.When NaOH concentration was 1mol/L,flow rate was 2BV/h,the content of vanadium pentoxide in the desorption solution was 45.96g/L,and the chrome was 5.2mg/L,the desorption rate of vanadium was 98.03%.the high purity vanadium pentoxide was prepared by traditional vanadium precipitation and roasting decomposition.the product was analyzed and characterized with MP-AES,XRD and SEM,The product is high pure vanadium pentoxide,the content of vanadium pentoxide was 99.86%,content of silicon was 0.0022%,content of phosphorus was 0.0004%,content of chrome was0.0008%,the yied was 95.25%,and the crystal has a cuboid structure,about 2?m in length,with good permeability.