Stable Phase Equilibrium of the Aqueous Quaternary System (MgCl2+ MgSO4+ MgB6O10+H2O) at 323.15 K

ABSTRACT:

The solubilities and relevant physicochemical properties including density and pH values of the aqueous quaternary system (MgCl2+ MgSO4+ MgB6O10+H2O) at 323.15 K were determined for thefirst time with the method of isothermal dissolution. According to the experimental results, the dry-salt-phase diagram, water-phase diagram, and physicochemical properties versus composition diagrams were plotted. It was found that there are three three-salt cosaturated invariant points, seven univariant solubility isotherm curves, and five stable crystallization fields corresponding to bischofite (MgCl2, 6H2O, Bis), kieserite (MgSO4 3H2O, Kie), tetrahydrite (MgSO434H2O, Tet), hexahydrite (MgSO436H2O, Hex), and mcallisterite (Mg(B6O7)(OH)6 4.5H2O, Mca). Neither solid solution nor double salts were found. On the basis of the extended Harvie Weare (HW) model and its temperature-dependent equation, single-salt parametersβ

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