Study on Vanadium Precipitation by Hydrolysis of Chromium-vanadium Solution

With the solution containing 17.86 g/L of vanadium and 15.96 g/L of chromium as the raw material,vanadium precipitation through hydrolysis was carried out in this work.The effects of pH value,temperature,time,chromium and sodium concentrations in the solution on the vanadium precipitation rate were investigated.The results show that a vanadium precipitation rate of 91.61% can be obtained at the pH value of 1.8 and the temperature above 95 ℃ for 60 min.At 1.7～17 g/L of chromium concentration in the solution,the precipitation rate of vanadium increases with increase of the chromium concentration,and 97.5% of vanadium precipitation rate can be achieved at 17 g/L of chromium concentration.However,the vanadium precipitation rate decreases with the chromium concentration exceeding 17 g/L,with the precipitation rate decreased to 95% at 25 g/L of chromium concentration.Furthermore,the rate of vanadium precipitation decreases obviously with increase of the sodium concentration（35.2～90 g/L） in the solution.Hence chromium with a proper concentration in the solution is favor for vanadium precipitation via hydrolysis,while sodium in the solution is adverse to vanadium precipitation.