Lithium sulfate: Calorimetric determination of the temperatures and enthalpies of high-temperature phase transitions

Abstract

Using a high-temperature Calvet calorimeter as a differential enthalpic analyser Li 2SO 4 was investigated in the temperature range 800–1200 K. One transformation in the solid state was observed at 847 K with a corresponding enthalpy increment of 24.2 kJ mol −1. The solid-liquid transition was found to occur at 1131 K with an enthalpy of fusion of 7.74 kJ mol −1. Furthermore, the analysis of the corresponding thermograms supports the presence of the premelting effect which was evidenced by other techniques. A critical comparison with previous results in the literature is given.