Present-day all-vanadium redox flow batteries(VRFBs)generally require high purity vanadium oxide as a raw ingredient.The chlorination procedure presents distinct technical advantages with regard to preparing high puri...Present-day all-vanadium redox flow batteries(VRFBs)generally require high purity vanadium oxide as a raw ingredient.The chlorination procedure presents distinct technical advantages with regard to preparing high purity vanadium pentoxide(V2O5)using vanadium oxytrichloride(VOCl3)as a highly pure intermediate.To efficiently prepare high purity V2Os from VOCl3,a single-step fluidized bed chemical vapor deposition(FBCVD)method was explored in the present work.Based on thermodynamic analyses,the direct and complete conversion of VOCl3 to V2O5 is difficult,and may result in a small amount of residual Cl in the product.Consequently,the effects of temperature and the H2O/VOCl3 molar ratio on the quantity of residual Cl were assessed.The Cl concentration was found to decrease with increasing temperature or increasing H2O/VOCl3 molar ratios.Additionally,Cl was determined to be present only in the form of Cl-V bonds,while Cl-H and Cl-Cl bonds were not detected in a V2O5 product made at 200℃with a H2O/VOCl3 molar ratio of 18.A Cl concentration of less than 0.05 wt%was obtained under the optimal synthesis conditions,demonstrating that the FBCVD method is a viable means of preparing high purity V2O5 via the gaseous hydrolysis of VOCl3.展开更多
The possibility and extent of the separation of impurity vanadium in titanium tetrachloride by means of adsorption with molecular sieves were studied. As ascertained by the experimental results, the adsorption of VOCl...The possibility and extent of the separation of impurity vanadium in titanium tetrachloride by means of adsorption with molecular sieves were studied. As ascertained by the experimental results, the adsorption of VOCl3 onto molecular sieve internal surface was controlled by the intraparticle diffusion of the molecules. Although all of the three kinds of molecular sieves used are competent for removing vanadium from titanium tetrachloride, type 4 A behaves more effectively than the others under the same conditions. After adsorption for nine stages, the concentration of vanadium in the product becomes as less as that of industrial standard level.展开更多
基金This work was supported by the National Natural Science Foundation of China(Project Nos.51774262,51504231,51504232,and 21736010)the Open Project of State Key Laboratory of Complex Nonferrous Metal Resources Clean Utilization(Project No.CNMRCUKF1704).
文摘Present-day all-vanadium redox flow batteries(VRFBs)generally require high purity vanadium oxide as a raw ingredient.The chlorination procedure presents distinct technical advantages with regard to preparing high purity vanadium pentoxide(V2O5)using vanadium oxytrichloride(VOCl3)as a highly pure intermediate.To efficiently prepare high purity V2Os from VOCl3,a single-step fluidized bed chemical vapor deposition(FBCVD)method was explored in the present work.Based on thermodynamic analyses,the direct and complete conversion of VOCl3 to V2O5 is difficult,and may result in a small amount of residual Cl in the product.Consequently,the effects of temperature and the H2O/VOCl3 molar ratio on the quantity of residual Cl were assessed.The Cl concentration was found to decrease with increasing temperature or increasing H2O/VOCl3 molar ratios.Additionally,Cl was determined to be present only in the form of Cl-V bonds,while Cl-H and Cl-Cl bonds were not detected in a V2O5 product made at 200℃with a H2O/VOCl3 molar ratio of 18.A Cl concentration of less than 0.05 wt%was obtained under the optimal synthesis conditions,demonstrating that the FBCVD method is a viable means of preparing high purity V2O5 via the gaseous hydrolysis of VOCl3.
文摘The possibility and extent of the separation of impurity vanadium in titanium tetrachloride by means of adsorption with molecular sieves were studied. As ascertained by the experimental results, the adsorption of VOCl3 onto molecular sieve internal surface was controlled by the intraparticle diffusion of the molecules. Although all of the three kinds of molecular sieves used are competent for removing vanadium from titanium tetrachloride, type 4 A behaves more effectively than the others under the same conditions. After adsorption for nine stages, the concentration of vanadium in the product becomes as less as that of industrial standard level.
