Forecasting state diagrams two-component salt systems

Abstract

The article proposes a method for forecasting and approximate calculating the two-component systems characteristics state diagrams. The results for 200 salt systems with a common cation and 100 with a common anion systems statistical analysis of fase diagrams are presented. In this paper, the authors propose to consider two signs of the eutectic points presence in binary systems and a method for approximate calculation the eutectic point temperature and concentration values. The first criterion for the presence or absence of eutectic points in the system is determined using specific, isobaric heat capacities of the components. The second criterion is based on the well-known fact that entropy values difference for components of eutectic systems are greater than entropy differences for components of systems with continuous series of solid solutions. A method for approximate calculating the temperatures values and the composition of two-component salt systems eutectic points, in which there is no intermediate chemical interaction between the components, is given. A comparative analysis of the calculations results according to the methodology proposed by the authors and the eutectics thermodynamic characteristics values obtained using the Schroeder-Le Chatelier equation is carried out. The adequacy of the proposed model for the analysis and determination of the thermodynamic characteristics of two-component salt systems is confirmed by the calculations results of the eutectics composition and temperatures of 120 two-component systems with average errors, which amounted to 6% in concentrations and 7% in temperatures. Based on the proposed approximation procedure, a calculation program in the Pascal language was created in the Delphi visual environment with a user interface. One of the advantages of this environment is that the executable modules of programs created in it do not require equipping the computer with additional software, except for the presence of an operating system.