Metastable Equilibrium in Quaternary System Li2SO4 ＋ K2SO4＋Li2CO3 ＋ K2CO3 ＋ H2O at 288 K

Metastable equilibrium solubilities and densities of the Li2SO4 ＋ K2SO4 ＋ Li2CO3 ＋ K2CO3 ＋ H2O system at 288 K were determined experimentally by using the isothermal evaporation method. According to the experimental data, the metastable equilibrium solubility phase diagram was constructed. In the phase diagram, there are three invariant points, seven univariant curves, and five fields of crystallization： Li2SO4· H2O2,K2SO4, Li2CO3, K2CO3 · 3/ 2H2O and K2SO4· Li2SO4. The double salt K2SO4 · Li2SO4 was found in the metastable equilibria. Lithium carbonate（ Li2CO3 ） has the smallest solubility in the quaternary system.