METHOD OF RESEARCH OF SOLUBILITY IN MULTI-COMPONENT WATER-SALT SYSTEMS Russian patent published in 2008 - IPC G01N33/18 G01N31/00 

FIELD: physical and chemical analysis.

SUBSTANCE: method involves experimental determination of the composition of an equilibrium liquid phase of an initial component mixture having an optimum composition, measurement of any easily measurable physical property of the liquid phase after equilibrium is reached in a known initial mixture of components located strictly at sections of the composition triangle; the composition property diagram is plotted, a system of intercrossing lines is obtained, with the number of lines equal to the number of fields dissected by the selected section, the functional line intersection points determine borders of fields with different phase states. Solid phases are identified by the intersection points of limit nodes entering the same solid phase, defined by the coordinates of experimentally determined compositions of nonvariant liquid phases, borders in delimiting systems, and apexes of nonvariant areas of isohydric sections of a system without isolation, separation, or additional identification of bottom phases; the nonvariant area border orientation relative to the sides of the salt (anhydrous) concentration figure of the section of the system under research determines the type of phase interaction in it, while the parallelism of these borders to the sides of the concentration figure of the isohydric section is a sign of crystallisation from the nonvariant solution of anhydrous salt components, which compose this concentration figure, and the absence of parallelism of the borders of the nonvariant area to the sides of the concentration figure of the isohydric section is a sign of formation of a new solid phase or crystallohydrates in the system. If a new solid phase is found, the initial system is triangulated accordingly, all compositions of nonvariant solutions saturated also with this solid phase, and coordinates of apexes of the corresponding nonvariant isohydric areas are determined experimentally, the obtained results are combined to determine the compositions of all equilibrium solid phases in order to confirm the phase interaction types in the subsystems obtained and prove the absence of any other solid phases without isolating them from the liquid phase.

EFFECT: simplification of and increased reliability and informativity of determination.

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