(Solid + liquid) equilibria in the quinary system image at 288 K

The solubilities and densities of the solid–liquid equilibrium in the quinary system Na+, Mg2+, image, B4O72−–H2O at 288 K were studied experimentally using the method of isothermal solution saturation. On the basis of the experimental data, the dry salt phase diagram, water content diagram and Mg2+ content diagram of the quinary system were constructed. In the equilibrium phase diagram of the quinary Na+,Mg2+, image, B4O72−−H2O system at 288 K, there are seven invariant points, fourteen univariant curves, and eight fields of crystallization (saturated with MgB4O7dot operator9H2O) corresponding to Na2B4O7dot operator10H2O, K2B4O7dot operator4H2O, K2SO4, Na2SO4dot operator10H2O, MgSO4dot operator7H2O, K2SO4dot operatorMgSO4dot operator6H2O, Na2SO4dot operatorMgSO4dot operator4H2O, and Na2SO4dot operator3K2SO4. The experimental results show that sulfates have larger solubilities than borates in the quinary Na+, Mg2+, image, B4O72−–H2O system at 288 K.