Preparation of potassium and metakaolin based geopolymer foam with millimeter sized open pores for hydrogen recombining catalyst supports

A method to control the millimeter-sized open porosity in geopolymer foam was attempted to produce hydrogen recombining supports for radioactive waste canisters. The raw materials were mixed with silicon powder as a foaming agent. Geopolymer foams with open porosities as high as 81% were obtained by a water bath treatment before pouring the slurry into the mold. The increase in the open porosity of geopolymer foam was observed by an increase in the water bath treatment time. It was thought that the viscosity of slurry increase induced the pores trapped inside the geopolymer foam and connected to form millimeter-sized and open pores. It was concluded that a simple method with a foaming agent and a water bath treatment to prepare geopolymer foams with high open porosity was developed. (author)