The phase and density diagrams of the systems MgCl2–MgB4O7–H2O and KCl–K2B4O7–H2O at 273 K

Resumo

The method of isothermal dissolution was used to study the solubilities and the densities of the two systems MgCl₂–MgB₄O₇–H₂O and KCl–K₂B₄O₇–H₂O at 273 K. By the X-ray diffraction the equilibrium solids were determined. The phase diagrams and density versus composition diagrams of the systems MgCl₂–MgB₄O₇–H₂O and KCl–K₂B₄O₇–H₂O at 273 K were plotted. The both diagrams are consisted of one invariant, two stable solubility isothermal curves and two crystallization fields. The crystallization fields for the system MgCl₂–MgB₄O₇–H₂O corresponds to MgB₄O₇ · 9H₂O and MgCl₂ · 6H₂O. Those for the system KCl–K₂B₄O₇–H₂O corresponds to K₂B₄O₇ · 4H₂O and KCl.