Abstract
In the practice of complex theoretical research of multicomponent systems, the so-called thermodynamic-diagram method of analysis is known, which significantly simplifies the study of phase transformations in multicomponent systems by dividing them into thermodynamically stable elementary partial subsystems of equal dimensionality as the main ones. Thermodynamic-diagram analysis combines the thermodynamic assessment of chemical interactions between components in the studied system with a geometric diagram. Such a combination, as studies of the physicochemical principles of refractories and ferroalloys production have shown, proves to be productive in interpreting chemical interactions in complex systems.