Phase Equilibria in the Na+,Ba2+||Br–,$$\text{WO}_{4}^{{2-}}$$ Three-Component Reciprocal System

The article describes a study on the identification of possible phase equilibria in mutual geometrical images of five-component system of water and salt from sulfates, bicarbonates, potassium and calcium fluoride at 25 °C, followed by the construction of its phase diagram complex. Knowledge of the laws governing the structure of the phase complex of this system is necessary not only to obtain new scientific data as reference material, but also to contribute to the creation of optimal conditions for the utilization of liquid wastes of aluminum industrial production containing the system of salts that make up this system. To solve the problem, we used the translation method, which is based on the position according to which the dimension of the geometric images of the diagram of the original (private) system increases by one by adding a subsequent component, due to its concentration, i.e. are transformed. Since the investigated five-component system consists of five particular four-component systems, the addition of the fifth component to any of them is accompanied by transformations of the geometric images of all five four-component systems. Transformed geometric images according to their topological properties are broadcasted to the level of a five-component composition. At the level of the five-component composition, the transformed geometric images, in accordance with the Gibbs phase rule, intersect each other forming geometric images of a given level of componentness. Investigation of phase equilibria five-component water-salt reciprocal system of sulfates, bicarbonates, potassium and calcium fluorides and construction of its phase diagram with complex translation method (at 0°C) showed that it is characterized by fifteen divariant fields, thirteen monovariant curves, and four invariant points. On the basis of the obtained data, the complete closed phase diagram of the investigated system was constructed for the first time and, for the convenience of its reading, it is fragmented by the regions of divariant equilibria.Forcitation:Jabborov I., Soliev L., Nizomov I., Musodzonova J. Phase equilibria in system K,Са//SO4,HCO3,F-H2O at 25 °C. Izv. Vyssh. Uchebn. Zaved. Khim. Khim. Tekhnol. 2018. V. 61. N 3. P. 26-30

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Phase complex model of ternary reciprocal system Na+,Sr2+||WO42-,MoO42-

Butlerov Communications ◽

10.37952/roi-jbc-01/19-59-8-103 ◽

2019 ◽

Vol 59 (8) ◽

pp. 103-115

Author(s):

Alexander V. Burchakov ◽

Keyword(s):

Phase Equilibria ◽

Solid Solutions ◽

Binary Systems ◽

Reciprocal System ◽

Condensed State ◽

Continuous Series ◽

Algebraic Equations ◽

Reaction Products ◽

System Components ◽

Phase Complex

The paper presents the results of a theoretical study of the phase complex of a three-component reciprocal system consisting of sodium and strontium tungstates and molybdates. Previously, a literature review was conducted on data on phase equilibria in the condensed state of individual salts, binary faceting systems. In two Na2MoO4 – SrMoO4 and Na2WO4 – SrWO4 binary systems, a eutetic equilibrium is observed with the formation of solid phases corresponding to the system components, and in two other Na2MoO4 – Na2WO4 and SrMoO4 – SrWO4 binary systems, one phase of a continuous series of solid solutions crystallizes. Based on the mathematical model of the molar balance, one can uniquely determine the quantities of reaction products, the molecular formulas of solid solutions, and the equations of chemical reactions for an arbitrary mixture of system components. This model represents a set of algebraic equations by which the balance is calculated. To build a 3D computer model, the paper presents the equations for the conversion of coordinates from barycentric to Cartesian. The model is implemented in concentration-temperature coordinates using the KOMPAS-3D program using experimental data on the system. The model is built in two interpretations: based on data on the faceting elements and on the basis of all available data about the system. Comparison of the two models makes it possible to evaluate the predictive ability carried out using 3D modeling. From this comparison, it was found that using the 3D model it is possible to conduct a preliminary a priori forecast of phase equilibria in order to identify the structure of phase diagrams at the qualitative and quantitative levels. The projection of the crystallization polytherm onto the square of the compositions is represented by two fields of solid solutions – Na2MoxW1-xO4 and SrMoxW1-xO4. Isothermal and polythermal sections were constructed. The system implements di- and monovariant equilibria.

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