The ternary system H2O-NH4NO3-Mg(NO3)(2): Isotherms -25, -14, 0, 30 and 45degrees C

The solid-liquid equilibria of the ternary system H2O-NH4NO3-Mg(NO3)(2) wer e studied by using two synthetic methods: conductimetric measurements and i soplethic thermal analysis. Five isotherms at -25, -14, 0, 30 and 45 degree s C were entirely determined. The solid phases which appear below 0 degrees C are (i) ice, Mg(NO3)(2). 9H(2)O, Mg(NO3)(2). 6H(2)O alpha and variety V of ammonium nitrate at -25 degrees C (ii) ice, Mg(NO3)(2). 6H(2)O alpha and variety IV of ammonium nitrate at -14 degrees C. Above this latter tempera ture, two solid phases only present equilibria with the liquid phase: the h exahydrate of magnesium nitrate and the variety IV of ammonium nitrate at 0 and 30 degrees C, the hexahydrate of magnesium nitrate and the variety III of ammonium nitrate at 45 degrees C. By using isoplethic thermal analysis at 30 degrees C, a metastable phase appears in the ternary system : Mg(NO3) (2). 6H(2)O beta. (C) 2000 Elsevier Science B.V All rights reserved.