Environmental friendly management of CRT glass by foaming with waste egg shells, calcite or dolomite

Panel (P) and funnel (F) glasses from Cathode Ray Tube (CRT) have been used to obtain glass foams by a simple and economic processing route, consisting of direct heating the glass powders at relatively low temperatures (650-750 °C) using different foaming agents (FA) such as egg shells, calcite, dolomite. Mixtures in different proportions of P and F glass powders were tested and the effects of composition and heat treatment temperature on the foaming behaviour were evaluated. Glass foams featuring apparent density and compressive strength values of 0.29 g/cm3 and 2.34 MPa, respectively, could be produced from a P/F ratio=1 with added 3 wt% of egg shells upon heat treating at 700 °C for 15 min. The P/F ratio was found to strongly influence the foaming behaviour and, consequently, the physical properties of the final foam glass. The relative performance of other foaming agents under a given set of experimental conditions revealed to be dependent on the type of glass (composition and thermal properties).