Phase Equilibria and Phase Diagram of the Quaternary NaOH–Na₃VO₄–Na₂WO₄–H₂O System at 278.15 K to 353.15 K

Abstract

The solid−liquid phase equilibria and phase diagrams for the quaternary NaOH−Na 3 VO 4 −Na 2 WO 4 −H 2 O system from 278.15 K to 353.15 K were investigated, and the compositions in the liquid phase and densities were measured experimentally with the isothermal equilibrium method. Na 3 VO 4 solubility is significantly affected by the temperature and NaOH concentration, and Na 2 WO 4 solubility is significantly affected by the NaOH concentration. The dry-salt phase diagram of the system consists of three crystallization zones (for which the solid phases are