EXPANDED GLASS EXPERIMENTALLY MADE FROM RESIDUAL GLASS, ALUMINUM NITRIDE, AND MANGANESE DIOXIDE THROUGH MICROWAVE IRRADIATION HEATING

Abstract

An expanding agent (aluminum nitride) from the carbide and nitride group, less used in the cellular glass manufacturing process, was tested together with manganese dioxide in the experiment presented in the paper. The powder mixture of recycled residual glass and the two mentioned additives was thermally sintered and expanded by predominantly direct microwave irradiation at temperatures between 820-850 ºC. The remarkable energy efficiency of the original heating technique allowed obtaining very economic specific energy consumptions between 0.80-0.95 kWh/kg. The optimal products had the apparent density between 0.35-0.43 g cm^-3, porosity between 79.5-83.3 %, heat conductivity between 0.080-0.094 W (mK)^-1, and compression strength in the range 4.0-6.7 MPa. The cellular material has the characteristics required for its using as a thermal insulation material in the building sector.