Modeling of physical and chemical processes in the synthesis of foam glass of various modifications: phase analysis and prediction of properties

Abstract

To achieve effective thermal insulation of enclosing structures, it is necessary to increase the resistance to heat transfer through the use of advanced thermal insulation materials. A promising heat-insulating material is foam glass, which has a low thermal conductivity, high mechanical strength, frost resistance and low density. The physical properties of foam glass are determined by the structure of its macro- and microstructure, which depend on the temperature regime of synthesis and composition components. In the work, the choice of the optimal compositions of foam glass for correct comparison was carried out, a physicochemical model was developed, the qualitative and quantitative phase composition of foam glass samples was determined using the method of X-ray phase analysis to verify the results obtained. Based on the performed calculations of the composition of phases and components that are formed during the synthesis of various modifications of foam glass, the possible phases were determined using physicochemical models and methods for minimizing thermodynamic potentials. These methods make it possible to determine the equilibrium composition of a heterogeneous system and the thermodynamic parameters of processes. The reliability of the model is confirmed by the results of X-ray phase analysis, which showed the presence of phases obtained by calculation. The scientific novelty of the study lies in determining the features of the formation of crystalline phases during the synthesis of foam glass, taking into account the temperature-time conditions and composition. The study showed that the formation of the mineral composition of foam glass in the considered modifications is significantly affected by Na2B4O7∙10H2O and natural chalk. Additionally, microimpurities affect the formation of new aluminosilicate phases and the redistribution of the main chemical elements between the mineral components of foam glass. This also leads to changes in the density and composition of amorphous phases. An efficient model has been developed using the Gibbs isobaric-isothermal potential minimization method, numerical values of the number of probable phases and components formed during the synthesis of foam glass material have been obtained.