Phase equilibria in the quinary system KCl-KBr-K2SO4-K2B4O7-H2O at 323 K and 348 K were studied by isothermal solution saturation method.The solubilities and densities of the solution in this system were determined experimentally.Using the experimental data

the phase diagrams of the quinary system were obtained(saturated with K2SO4).The quinary system is a solid solution.It comprises one univariant curve and two crystallization fields(saturated with K2SO4)

i.e.

solid solution K(Cl

Br) and K2B4O7·4H2O

and does not have invariant point.K2B4O7·4H2O has larger crystallization fields

while solid solution K(Cl

Br) has smaller crystallization fields.It is also found that KBr has the salting-out effect on KCl.The density of the solution increases with the increase of KBr concentration and decreases with the increase of KCl concentration.Compared with the stable phase diagrams at 323 K and 348 K

the crystallization fields of K2B4O7·4H2O is small at 348 K

whereas the crystallization field of solid solution K(Cl

Br) is large.