Metastable Equilibria of the Quinary System Li~+,Na~+//CO_3~(2-),SO_4~(2-),B_4O_7~(2-)-H_2O 288 K

An experimental study on metastable equilibria of the quinary system Li+,Na+//CO32-,SO42-,B4O72--H2O at 288 K was done by the isothermal evaporation method. Metastable equilibrium solubilities and densities of the solution were determined experimentally. Using the experimental data, the metastable equilibrium phase diagram and the density-composition diagram were plotted, respectively. The experimental results of the metastable equilibria show that the double salt Na3Li(SO4)2·6H2O formed in the quinary system Li+,Na+//CO32-,SO42-,B4O72--H2O at 288 K. The metastable equilibrium phase diagram has four invariant points, nine univariant curves, six fields of crystallization saturated with Li2CO3 corresponding to LiBO2·8H2O, Na2B4O7·10H2O, Na2CO3·10H2O, Na2SO4, Na3Li(SO4)2·6H2O and Li2SO4·H2O.