Solid–Vapor Equilibria under Desolvation of Solid Solutions. Topological Isomorphism with Phase Diagrams of Polymorphic Solid Solutions

This paper provides a proof for the operation of analogues of the three Gibbs–Konovalov laws (Gibbs–Roozeboom rules) in solid–vapor phase diagrams of ternary systems under the conditions of solid solutions desolvation in the absence of liquid phases. The diagrams under consideration are shown to feature topological isomorphism to phase diagrams of polymorphic transformations of solid solutions in binary systems, for which analogues of the Gibbs–Konovalov laws are also formulated. The proof is based on the application of generalized van der Waals differential equations to the phase equilibrium shift, written in the metrics of the incomplete and complete Gibbs potentials of solid phases of variable composition. The applicability of the laws (rules) analogues is shown for a number of model systems. A method is proposed for the separation and purification of salt components of solid solutions based on the laws recognized for the phase diagrams of solid solutions desolvation.