Solubility of Sodium Chromate in the NaOH-CH3OH-H2O System from (278.15 to 343.15) K

The solubility of sodium chromate in the NaOH-CH3OH-H2O system have been measured using the static analytical method at temperatures of (303.15, 313.15, 323.15, and 333.15) K. The measured results were respectively correlated by the Apelblat equation, the empirical equation, and the lambda-h equation. Meanwhile, it was found that the liquid-liquid phase separation, also termed as oiling out, will happen under certain conditions. The relationship between the steady-state critical temperature and solvent composition was studied systematically using FBRM. The results show that the solubility of sodium chromate increases with increasing temperature and decreases with increasing concentration of sodium hydroxide, respectively. Three models were employed to correlate the experimental data, which fit the data well. Moreover, the Apelblat equation for the system has less deviations than the lambda-h equation and the empirical equation. The results also show that the steady state critical oiling-out temperature increases with the increase of methanol mass fraction.