Combined Use of Solid and Liquid Foaming Agents for Making Cellular Glass Aggregate-Microwave Assisted

A cellular glass aggregate with excellent heat insulation properties and mechanical strength was designed and tested under conditions of using unconventional microwave heating method. Sodium carbonate and glycerol were utilized as simultaneous expanding agents. Green post-consumer drinking glass was the predominant raw material in the mixture that contained also kaolin and water glass. The optimal cellular glass product had bulk density of 0.22 g·cm-3, heat conductivity of 0.062 W·m-1·K-1, and compression strength of 6.9 MPa. The process energy efficiency was excellent, the specific energy consumption being of 0.86 kWh·kg-1. The originality of the work consists in choosing sodium carbonate as a foaming agent together with glycerol and applying the own technique of mixed heating (direct and indirect) with microwaves.