Vitrocrystalline foams produced from glass and oyster shell wastes

In this work discarded glass bottles (GB) of different colors and oyster shells, OS (1-15 wt%) as pore forming agent were used to produce vitrocrystalline foams. Homogenized powders of the formulated compositions were uniaxially pressed (20 MPa) and the obtained compacts were fired at different temperatures (800-950 °C) and holding times (30-120 min), in order to investigate the effect of the oyster shell additions on the microstructure and properties of the processed vitrocrystalline foams. The best ratio between the used wastes and resulting porosity was obtained for a composition containing 91 wt% GB and 9 wt% OS fired at 900 °C in the 30-120 min holding time range (optimized thermal cycle). In this case, porosity varied from 81% to 91% while the thermal conductivity and compressive strength varied between 0.057 and 0.077 W/m K and from 1.00 to 2.33 MPa, respectively.