Phase transformation in solid-state reaction of MgO−V2O5 binary system and dissolution behavior of products

The solid-state reaction behavior of MgO−V2O5 mixtures with different molar ratios was explored. The solubility of the solid-state reaction products (magnesium vanadates) in water at 25−55 °C was measured using the isothermal solution saturation method. The dissolution behavior and kinetics of the magnesium vanadates in dilute sulfuric acid were also investigated. The results showed that the molar ratio of MgO to V2O5 and roasting temperature significantly influenced the phase transformation of the solid-state reaction product. MgV2O6 exhibits the highest solubility in water, followed by Mg2V2O7 and Mg3V2O8. The dissolution rate of magnesium vanadates in dilute sulfuric was significantly increased with the decrease of pH from 4.0 to 2.5 and the temperature increase from 30 to 70 °C. The dissolution of magnesium vanadate can be described using a second-order pseudo-homogeneous reaction model.