Effects of temperature, reaction time and reducing agent content on the synthesis of macroporous foam glasses from waste funnel glasses

In this paper, the microstructures of cellular materials (foam glasses) synthesized from lead containing waste cathode ray tube glasses (funnel CRT glasses) are only investigated. This synthetic approach is a possible method for recycling PbO containing glasses (20-22 wt.%). In the present work, foam glasses were prepared using various concentrations of SiC or TiN as the reducing agent for various temperatures and reaction times. The reaction between the reducing agent and the lead oxide in the glasses produces a gaseous phase in the network (CO2 and N-2 for SiC and TiN, respectively) and metallic lead. The gas expands, which results in a cellular structure, i.e., a porous body. Scanning electron microscopy was used with mercury porosimetry to study the microstructures of the resulting cellular materials as well as to determine their pore diameters and pore size distributions, and check for the presence of connecting "windows". We correlate these intrinsic parameters with the elaboration parameters with the aim of optimizing the material synthesis process. (c) 2005 Elsevier B.V. All rights reserved.