Abstract :
The solid–liquid equilibria of the ternary system H2O-NH4NO3-Mg(NO3)2 were studied by using two synthetic methods: conductimetric measurements and isoplethic thermal analysis. Five isotherms at −25, −14, 0, 30 and 45°C were entirely determined. The solid phases which appear below 0°C are (i) ice, Mg(NO3)2·9H2O, Mg(NO3)2·6H2Oα and variety V of ammonium nitrate at −25°C (ii) ice, Mg(NO3)2·6H2Oα and variety IV of ammonium nitrate at −14°C. Above this latter temperature, two solid phases only present equilibria with the liquid phase: the hexahydrate of magnesium nitrate and the variety IV of ammonium nitrate at 0 and 30°C, the hexahydrate of magnesium nitrate and the variety III of ammonium nitrate at 45°C. By using isoplethic thermal analysis at 30°C, a metastable phase appears in the ternary system : Mg(NO3)2·6H2Oβ.
