Physicochemical Studies of Opoka as a Raw Material Component of Sodium Silicate Mixture for Subsequent Synthesis of Foam Glass Material Based on It

The present article presents the results of physical and chemical studies of opoka. In particular, the opoka was subjected to chemical analysis, X-ray phase, differential thermal analysis, scanning microscopy, and X-ray energy dispersive elemental microanalysis. The opoka was studied with the aim of using it as an available raw material for obtaining a sodium silicate mixture and, in the future, developing an energy-saving technology for obtaining a building heat-insulating and sound-insulating foam glass material based on it, using synthesis. As a result of the studies, the chemical composition of the opoka was determined, which is 69–80% represented by silica. The elemental composition of the opoka was established, which is represented by 94.25% oxides of Si, Al, and Fe. The presence of such oxides makes it an ideal raw material component of a silicate-sodium mixture for the subsequent synthesis of foam glass material from it. Experimental exploratory studies on the synthesis of foam glass based on opoka have been carried out. The experimentally obtained sample of foam glass material consists of 93.37% Si, Al, Mg, and Na oxides, has a porous structure with a pore size of 2–5 microns, an average density of 375 kg/m3, thermal conductivity of 0.063 W/(m °C) at 25 °C, and noise absorption of 51.6 Db.