Solid-Liquid Phase Equilibria of the Quaternary System (NaCl + NH4Cl + SrCl2 + H2O) and Subsystem (NaCl + NH4Cl + H2O) at 288.15 K and 0.1 MPa

Solid-liquid phase equilibria of the quaternary system (NaCl + NH4Cl + SrCl2 + H2O) and its subsystem are very important for the separation of ammonium and strontium salts from oilfield brines. In this paper, the solubilities of the quaternary system (NaCl + NH4Cl + SrCl2 + H2O) and its subsystem (NaCl + NH4Cl + H2O) at 288.15 K and 0.1 MPa were determined by the isothermal solution equilibrium method. The experimental results show that the (NaCl + NH4Cl + H2O) system contains one invariant point and two single salt crystallization zones corresponding to NaCl and NH4Cl. The crystallization zone of NH4Cl was larger than that of NaCl. The quaternary system (NaCl + NH4Cl + SrCl2 + H2O) contains one invariant points, three univariate solubility curves, and three single salt crystallization regions corresponding to NaCl, NH4Cl, and SrCl2 & sdot;6H(2)O.