Liquid-solid Equilibria in Quinary System Na +, K +, Mg 2+//Cl −, NO −3 −H 2O at 25 °C

Abstract

The solubilities of the quinary system Na +, K +, Mg 2+//Cl −, NO − 3 -H 2O and its two quaternary subsystems, Na +, K +, Mg 2+//NO − 3 -H 2O and K +, Mg 2+//Cl −, NO − 3 -H 2O, were studied by isothermal method at 25(C and their phase diagrams were plotted. In the equilibrium phase diagram of quaternary system Na +, K +, Mg 2+//NO − 3 -H 2O, there are one invariant point, three univariant curves and three regions of crystallization with one salt: NaNO 3, KNO 3 and Mg(NO 3) 2·6H 2O. In the equilibrium phase diagram of quaternary system K +, Mg 2+//Cl −, NO − 3 -H 2O, there are three invariant points, seven univariant curves and five regions of crystallization with one salt: KNO 3, KCl, Mg(NO 3) 2·6H 2O, MgCl 2·6H 2O and KCl·MgCl 2·6H 2O. In the equilibrium phase diagram of the quinary system Na +, K +, Mg 2+//Cl −, NO − 3 -H 2O, there are four invariant points, and seven regions of crystallization with one salt: NaCl, KCl, NaNO 3, KCl·MgCl 2·6H 2O, KNO 3, MgCl 2·6H 2O and Mg(NO 3) 2·6H 2O.