Study on Vanadium Precipitation from Solution Containing High Concentration Sodium Vanadate by Hydrolysis

Process of vanadium precipitation by hydrolysis is closely related to the properties of vanadiumcontaining solution such as the content of impurities,concentration of vanadium species,temperature and pH value of the solution. Vanadium pentoxide with purity > 99.5% satisfying the application requirements was obtained by the processes of silicon removal from high concentration sodium vanadate solution,vanadium precipitation by hydrolysis and sodium removal. The optimum process parameters for silicon removal from high concentration sodium vanadate solution are shown as follows: the molar ratio of aluminum sulfate to silicon in the solution is 1.0,the temperature and time for silicon removal is respectively 95 ℃ and 60 min,and the pH value of vanadium solution is 10.0. More than 99.0% of vanadium recovery rate can be obtained by vanadium precipitation with optimum vanadium concentration of 50 g/L,pH value of 2.5 and temperature of 90 ℃.