Solubility investigations in the quaternary NaOH–Na3VO4–Na2CrO4–H2O system at 40 and 80 °C

In a new vanadium production process using concentrated alkaline solution as reaction media, the effective separation of Na3VO4 and Na2CrO4 plays an important role. The mutual salt solubility data in the NaOH–Na3VO4–Na2CrO4–H2O system at 40 and 80 °C therefore were measured and compared with ternary NaOH–Na3VO4–H2O and NaOH–Na2CrO4–H2O subsystems, respectively. With the crystallization areas discussed in detail, a strategy for effective separation of Na3VO4 and Na2CrO4 from the NaOH–Na3VO4–Na2CrO4–H2O quaternary system has been proposed.