Peculiarities of foam glass synthesis from natural silica-containing raw materials

Abstract

The production of foamed silicate materials using foam glass technology promotes using of environmentally friendly fire-resistant heat-insulating materials. At the same time, it is urgent to search for different silicate materials, which could be used instead of common glass powder. A new promising way to produce foamed silicate materials is “hydrate” foaming. It is based on an interaction between SiO2 and alkali solution with a formation of sodium hydrosilicate mixture. Further heating leads to a water vapor release that forms the softened silicate mass. This study describes the technology of preparation and heat treatment of initial raw mixtures, their synthesis, the properties of the synthesized samples (density, porosity) and their internal structure. A comparative analysis of the processes occurring during the heat treatment of the initial diatomite and the developed compositions was performed. The processes occurring during foaming of foam glass using a “waterglass–glycerol” mixture were considered using differential thermal calorimetry. The role of each component of the mixture was revealed, and the perspective of their introduction was justified, as it allows obtaining a material with a density of 190 kg m−3.