The effect of impurity in vanadium-rich solution on vanadium precipitation of VO2(B) by hydrothermal method

The effect of iron, aluminum, silicon and phosphorus in the vanadium-rich solution on the vanadium precipitation of VO2(B) by hydrothermal method were studied. Through the analysis of vanadium conversation efficiency, the content of V and impurity elements in precipitates and their existing form, product crystal structure and micromorphology, it is concluded that the effect following the order of P > Fe > Si > Al. As the impurity concentration increased, V content of the precipitates decreased to varying degrees, while impurity content increased. The exist of Al, Si, Fe and P could alter the diffraction peaks intensity of some crystal faces and the micromorphology of VO2(B). The high concentrations of Fe and P transformed the VO2(B) to Fe2.5V7.1O16 and Na0.45VOPO4 & sdot;1.58 H2O, respectively. V and P are easily combined by covalent bonds, affecting the precipitation of VO2(B). Silicon is adsorbed on the surface of the precipitate as silica gel, thereby reducing the purity of the precipitate. The influence of impurity elements in vanadium-rich solution on the precipitation of VO2(B) by hydrothermal method is studied, which will provide a theoretical basis for the application of the new process of vanadium precipitation by hydrothermal method.