Crystallization behavior and mechanical properties of high open porosity dolomite hollow microspheres filled hybrid geopolymer foams

A novel kind of hybrid geopolymer cellular composite foam (DM/KGP) with multi-scale pores was produced by adding dolomite hollow microspheres into geopolymeric matrix via hydrogen peroxide. Effects of the dolomite type, foaming agent (H₂O₂) and microsphere content, high-temperature treatment on the microstructure, pore structure and mechanical properties of final foams were investigated. The DM/KGPs were composed of amorphous phase. The total and open porosity of samples reached ~88.8 vol% and 82.1 vol%, respectively. Compression strength of the foams decreased with increasing the content of H₂O₂, while it had the diametric increase when the DMs content increased. After high-temperature treatment, DM/KGPs were converted to DMs/leucite ceramic foams, which also showed good strength (4.49 MPa) and high open porosity (77.0 vol%). This fresh geopolymer foams could have great potential in membrane supports, catalysis and filtration applications.