A NEW TYPE OF NONVARIANT POINTS IN MULTICOMPONENT SOLUBILITY DIAGRAMS BY THE EXAMPLE OF THE Na, Ni // Cl, SO – HO SYSTEM

Existence of a new type of nonvariant points on isotherm-isobaric solubility diagrams of multicomponent systems is described. Realization of such nonvariant points is directly related to crystallization of solid phases based on pure solvents at temperatures below the crystallization temperatures of the latter in single-component systems. A type of nonvariant processes occurring at these points during isothermal evaporation of the solvent and stability of monovariant equilibria in the nearest neighborhood of nonvariant points are considered. Characteristic examples of realization of such nonvariant equilibria are presented by the example of three- and four-component (mutual) water-salt systems.