摘要
The equilibrium solubilities of 5(NH4)O·12WO3·5H2O (APT·5H2O) were determined at the terminal ammonia concentration of 2 mol/L at 87-95℃. Experimental data were regressed. The linear functional relation between the solubility of APT- 5H2O and the temperature (t /℃) is given as y = - 588.08 + 7.28t. The solubility of the species as a function of the terminal ammonia concentration (x / mol · L-1) is also achieved: y = 36.76 + 18.86x. The solubility of APT · 5H2O produced by ion-exchange method in China is much lower, which is due to much lower silica, much higher NH4Cl, and a small amount of APT · 7H2O with low solubility in the APT crystals. APT · 7H2O forms because of a large amount of NH4Cl and the low activity of water in the crystallization.
The equilibrium solubilities of 5(NH4)O·12WO3·5H2O (APT·5H2O) were determined at the terminal ammonia concentration of 2 mol/L at 87-95℃. Experimental data were regressed. The linear functional relation between the solubility of APT- 5H2O and the temperature (t /℃) is given as y = - 588.08 + 7.28t. The solubility of the species as a function of the terminal ammonia concentration (x / mol · L-1) is also achieved: y = 36.76 + 18.86x. The solubility of APT · 5H2O produced by ion-exchange method in China is much lower, which is due to much lower silica, much higher NH4Cl, and a small amount of APT · 7H2O with low solubility in the APT crystals. APT · 7H2O forms because of a large amount of NH4Cl and the low activity of water in the crystallization.
