화학공학소재연구정보센터
Fluid Phase Equilibria, Vol.408, 115-122, 2016
Phase equilibrium of the quaternary system K2SO4-MgSO4-(NH4)(2)SO4-H2O at 25 degrees C
The solubilities of the quaternary system K2SO4-MgSO4-(NH4)(2)SO4-H2O were measured by isothermal method at 25 degrees C and their dry salt phase diagrams were plotted. The results indicated that, at 25 degrees C, the solubility phase diagram of this quaternary system consists of seven crystallization regions, those are single-salt crystallization region MgSO4 center dot 7H(2)O, (NH4)(2)SO4, and K2SO4, complex salt crystallization region MgSO4 center dot(NH4)(2)SO4 center dot 6H(2)O, MgSO4 center dot K2SO4 center dot 6H(2)O, solid solution crystallization region (K1-n, NH4n)(2)SO4 (n:0.143-0.893) and (K1-n, NH4O)(2)SO4 center dot MgSO4 center dot 6H(2)O (n:0.552-0.973), respectively. The extended Pitzer model was derived and applied to the phase equilibrium calculation of system K2SO4-MgSO4-(NH4)(2)SO4-H2O and its sub-systems at 25 degrees C. The results showed that the calculated values were consistent with experimental results well. The study on the quaternary system K2SO4-MgSO4-(NH4)(2)SO4-H2O provides a foundation for the N-Mg-K-S compound fertilizers preparation. (C) 2015 Elsevier B.V. All rights reserved.