A novel method to prepare high-purity V2O5 from Na3VO4 solution

The current study presents a novel method to prepare high-purity V2O5 from Na3VO4 solution. This process characterizes Na3VO4 calcification separation, Ca10V6O25 ammoniation and solubilization, NH4VO3 crystallization, and vanadium precipitation, which achieves elemental V migration from the Na3VO4–Ca10V6O25–NH4VO3–V2O5 phase, finally obtaining high-purity V2O5. The influencing factors of the preparation process were investigated, and the results showed that vanadium was released from Na3VO4 solution to synthesize Ca10V6O25 in the first stage under the most suitable conditions (Ca/V molar ratio of 1.8, and a concentration of NaOH less than 160 g/L). In the second stage, the leaching efficiency of vanadium reached 95% at optimal conditions (NH4+/V molar ratio was 1.2, reaction temperature and time were 90 °C and 30 min, respectively). In the third stage, NH4VO3 yield and crystal size reached maximum values under optimal conditions (feed rate, crystallization temperature, and the power factor of the circulating pump were 6 m3/h, 30 °C, and 80% respectively). Finally, high-purity V2O5 was prepared via a series of large particle NH4VO3 post-treatments. In addition, the ICP analysis confirmed that the purity of the generated V2O5 was more than 99.5%.