ALUMINO-SILICATE WASTES USED FOR MAKING CELLULAR GRAVEL BY NON-CONVENTIONAL DIRECT MICROWAVE HEATING METHOD

Abstract

Cellular gravel based on alumino-silicate wastes including residual clay brick recovered from construction demolition and fly ash resulted from coal burning in energy industry was experimentally made. The expanding process made with glycerin as a liquid organic material together water glass was obtained by direct electromagnetic wave warming without affecting the structural integrity of the product. The special effectiveness of the direct irradiation of the material led to extremely low specific electricity consumption (0.53-0.64 kWh/kg). The optimal version had the following characteristics: bulk denseness of 0.21 g·cm^-3, heat conductivity of 0.063 W·m^-1·K^-1, compression resistance of 3.9 MPa, flexural strength of 2.4 MPa, and cell dimension within the limits of 0.2-0.5 mm. The use of alumino-silicate wastes in association with direct microwave warming keeping the physical, thermal, mechanical and microstructural properties unchanged (almost similar to industrial products) constitutes the paper originality.