V.N. Dokutovich, I. V. Korzun, N. K. Tkachev.
ABSTRACT
Salt mixtures are widely used in various fields of science and technology. To develop new ionic media and to find optimal compositions for practical use, it is necessary to study their phase diagrams. Currently, there is a number of significant gaps in understanding and description of the fusion diagrams of reciprocal salt mixtures. The LiF– MnCl2 salt mixture, which is one of the boundary binary systems in the Li, Mn || F, Cl reciprocal mixture, was chosen as the object of this study. The purpose of our study is to determine the solid-liquid phase equilibria in the LiF – MnCl2 system by the DTA and DSC methods, including the analysis of exchange reaction and the presentation of the fusibility diagram. For differential thermal analysis (DTA), we had to construct a thermal analyzer, in which hermetic ampoules made of stainless steel are used as containers. The XRD analysis of the solidified melts confirmed the presence of only two starting materials (lithium fluoride and manganese chloride), which is in good agreement with the results of the thermodynamic analysis of the 2LiF + MnCl2 = 2LiCl + MnF2 exchange reaction, which is shifted strongly to the left. The phase diagram of the LiF–MnCl2 system has the form of a simple binary system with eutectic point. The composition of the eutectic mixture is 0.547LiF–0.453MnCl2 and its melting point is equal to 734.2 K.
KEY WORDS:
phase diagram, reciprocal mixtures, DSC, DTA, lithium fluoride, manganese dichloride.
DOI: 10.31857/S0235010620050047