EXPANDING RESIDUAL CLEAR FLAT GLASS WITH COAL POWDER IN OXIDANT ATMOSPHERE OF THE OVEN USING WATER GLASS SOLUTION

Abstract

Porous material based on residual glass was non-conventionally made using anthracite as a pore-forming agent under the conditions of an oven with oxidizing atmosphere. Water glass as a protective agent for carbon particles avoiding their early oxidation and manganese dioxide (MnO₂) as an oxygen-supplier contributed to obtaining cellular glass with excellent physical, thermal, mechanical, and morphological features. The best specimen made by microwave heating at 790 ℃ using 1 % anthracite, 11.5 % water glass, 1.8 % MnO₂, and 5 % water allowed creating a product with excellent heat-insulating features (apparent density of 0.21 g·cm^-3, heat conductivity of 0.039 W·m^-1·K^-1), and acceptable compressive resistance (2.3 MPa), the microstructural appearance being homogeneous with uniformly distributed pores with very low dimensions (0.1-0.4 mm).