Phase Tree, Prediction of Crystallizing Phases, and Description of Chemical Interaction in the NaF–KF–MgF₂ System

The ternary system NaF–KF–MgF₂ has been divided into simplexes by a geometric method and a phase tree has been constructed, which has a linear structure and comprises four stable triangles separated by three stable secants. The phase tree has been used to predict the number and composition of crystallizing phases for stable elements of the system. Chemical interaction in the ternary system has been described using the ion balance method. The compounds located on the binary sides of the composition triangle have made it possible to obtain quadrangles with diagonals whose intersection points correspond to exchange reactions—main reactions in the system. Experimental data obtained by thermogravimetry confirm that reactions occur on the sides and in the composition triangle.