Liquid-solid equilibria in quinary system Na+, Mg2+/Cl-, SO42-, NO3--H2O at 298.15 K

in order to develop the nitrate deposits found close to Lop Nur in the Xinjiang region in China, the solubilities of the system Na+, Mg2+/Cl-, SO42-, NO3--H2O and its subsystems, the quaternary systems Na+, Mg2+/SO42-, NO3-, -H2O and Mg2+/Cl-, SO2-4, NO3-H2O, were studied at 298.15 K. The phase diagrams were plotted according to the solubilities achieved. In the equilibrium phase diagram of Mg2+/Cl-, SO42-, NO3--H2O there are two invariant points, five univariant curves and four regions of crystallization: Mg(NO3)(2)center dot 6H(2)O,MgCl2 center dot 6H(2)O, MgSO4 center dot 7H(2)O and MgSO4 center dot(1-6)H2O. In the equilibrium phase diagram of Na+, Mg2+/SO42-, NO3-H2O, there are five invariant points, eleven univariant curves and seven regions of crystallization: Na2SO4, Na2SO4 center dot 10H(2)O, NaNO3, MgSO4 center dot Na2SO4 center dot 4H(2)O, NaNO3 center dot Na2SO4 center dot 2H(2)O, Mg(NO3)(2)center dot 6H(2)O and MgSO4 center dot 7H(2)O. In the equilibrium 4, NO3 center dot H2O system, there are six invariant points, and ten regions of crystallization: NaCl, phase diagram of the Na+, Mg2+/Cl-, SO2NaNO3, Na2SO4, Na2SO4 center dot 10H(2)O, MgSO4 center dot Na2SO4 center dot 4H(2)O, NaNO3 center dot Na2SO4 center dot 2H(2)O, Mg(NO3)(2)center dot, Mg(NO3)(2)center dot 6H(2)O, MgSO4(NO3)(2)H2O and MgSO4 center dot 7H(2)O. (C) 2007 Elsevier Ltd. All rights reserved.