Solid-liquid phase equilibria of H2O-Mn(H2PO2)2-MnCl2-NaCl, H2O-Mn(H2PO2)2-MnCl2 and (H2O-NaCl- MnCl2 systems at 323.15 K

Abstract

The solid–liquid phase equilibria (SLE) and densities of H2O–NaCl– –MnCl2–Mn(H2PO2)2 quaternary system and H2O–NaCl–MnCl2 and H2O– –MnCl2–Mn(H2PO2)2 ternary systems were investigated at 323.15 K by the isothermal solution saturation method. The analyses of the liquid and solid phases were used to determine the composition of the solid phase using the Schreinemakers graphic method. The ternary systems contain one invariant point, two invariant curves and two crystallization regions. In the quaternary system, there is one invariant point, three invariant curves and three crystallization areas corresponding to NaCl, MnCl2⋅4H2O and Mn(H2PO2)⋅2H2O. The crystallization area of Mn(H2PO2)2⋅H2O, being the largest in comparison with those of other salts, occupied 80.75 % of the total crystallization area.

Keywords

• manganese hypophosphite
• manganese chloride
• ternary system
• schreinmakers method
• density