A Study on the Influence of Phosphorus on the Precipitation Behavior of Ammonium Vanadate

The mechanism of the influence of impurity phosphorus on the vanadium precipitation process is not clear. In this regard, the effect of phosphorus on the precipitation of vanadium from vanadium solutions with variable concentrations was investigated. The results showed that with the increase of P concentration, vanadium precipitation efficiency and V₂O₅ purity decreased gradually, and the decreasing trend of vanadium precipitation efficiency was more obvious in low concentration vanadium solution. The mechanism of phosphorus effect on vanadium precipitation was analyzed by Raman spectroscopy. It was found that the phosphorus in the solution reacted with vanadium to form P-V heteropolyacids, leading to a decrease in the content of H₂V₁₀O₂₈⁴⁻, thus reducing the precipitation efficiency of vanadium. The V-P-H₂O diagrams for vanadium solutions of different concentrations show that the lower the vanadium concentration, the more P-V heteropolyacids are formed, which leads to a lower H₂V₁₀O₂₈⁴⁻ content and a lower vanadium precipitation efficiency.