Guopeng Chen,Junsheng Yuan,Zilong Liu,Ming Lei,Bin Li
The solid–liquid equilibria in the LiBr–MgBr2–KBr–H2O system was measured, along with its two subsystems, LiBr–MgBr2–H2O and MgBr2–KBr–H2O, at 308.15 and 288.15 K using the isothermal dissolution equilibrium method. The stable phase diagrams of the three systems at 308.15 and 288.15 K were plotted. For the ternary LiBr–MgBr2–H2O system, two univariant curves, one ternary invariant point, and two crystallization fields, the fields being MgBr2·6H2O and LiBr·2H2O, were identified. The ternary system MgBr2–KBr–H2O contained three univariant curves, two ternary invariant points, and three crystallization fields corresponding to KBr, KBr·MgBr2·6H2O, and MgBr2·6H2O. From the stable phase diagram of the quaternary system, five univariant curves, four crystallization fields, and two invariant points were observed. The corresponding solids of the four crystallization fields were KBr, LiBr·2H2O, KBr·MgBr2·6H2O, and MgBr2·6H2O. The quaternary phase diagrams at 288.15 and 308.15 K had similar shapes, and the shapes of each crystallization field were identical. The crystallization field of KBr was larger than the other crystallization fields. With an increase in temperature, the crystallization field of KBr became smaller and that of LiBr became larger.
The solubilities of the LiBr−NaBr−KBr−H 2 O system and its subsystems LiBr−NaBr−H 2 O and LiBr−KBr−H 2 O were investigated at 288.15 K by the isothermal dissolution equilibrium method, and the corresponding phase diagrams were plotted, respectively. In the three systems, neither solid solution nor double salt was found. For the first subsystem LiBr−NaBr−H 2 O, there are two invariant points, three dissolution equilibrium curves, and three crystallization regions, which are LiBr·2H 2 O, NaBr·2H 2 O, and NaBr. An invariant point, two dissolution equilibrium curves, and two crystallization regions, which are LiBr·2H 2 O and KBr, constitute the stable phase diagram of the second subsystem LiBr−KBr−H 2 O. The phase diagram of the quaternary system LiBr−NaBr−KBr−H 2 O consists of two invariant points, five solubility curves, and four regions in which are LiBr·2H 2 O, NaBr, NaBr·2H 2 O, and KBr.