Preparation And Properties Of Fly Ash/Metakaolin Geopolymer Materials

Geopolymer material is a kind of inorganic high polymer material, with three-dimensional network structure, which is made of silicon oxygen tetrahedrons and aluminum oxygen tetrahedrons through oxygen atoms.There are many advantages, as simple in preparation process, abundant raw material sources, low energy consumption, low pollution, room temperature preparation, strong corrosion resistance and durability, good heat resistance and high mechanical performance, It is fully consistent with the policy of eliminating backward production capacity and developing new erergy, which is referred in the "Twelfth Tive-year" plan, therefore, geopolymer material has a good application prospect in industrial production and daily life. Alkali activated metakaolin geopolymer materials, metakaolin geopolymeric lightweight foaming insulation materials, fly ash/metakaolin geopolymer materials, fly ash/metakaolin geopolymeric lightweight foaming insulation materials were prepared with kaolin, fly ash, water glass, hydrogen peroxide as main raw materials, respectively. The technological parameters of the geopolymer materials were optimized. The main results were as follows:The properties of prepared metakaolin geopolymer materials are best when Kaolin was heated under800℃for2hours, n(H2O)/n(Al2O3)=13.02, modulus of water glass of1.2, slurry mixing time of25minutes, curing way is wet curing, curing temperature of80℃, curing time of48hours, the placement time of exciting agent of12hours, Si/Al ratio of2.1, and the corresponding compressive strength reaches86.53MPa(7days).The compressive strength of fly ash/metakaolin geopolymer materials is50MPa when the dosage of fly ash is40wt%and liquid-solid ratio is0.2.The properties of prepared metakaolin geopolymeric lightweight foaming insulation materials are best when hydrogen peroxide content is0.25wt%, stearic acid content is0.75wt%, curing temperature is25℃, modulus of water glass is1.2and water glass content is50%, and the corresponding compressive strength and bulk density are8.8MPa and0.72g/cm3, respectively. The thermal conductivity of the metakaolin geopolymeric lightweight foaming insulation materials can reach0.1W/(m·k).Foaming effect of hydrogen peroxide solution is better than that of aluminum powder, Steadying bubble effect of sodium dodecyl sulfate acid is better than that of stearic acid, The properties of prepared fly ash/metakaolin geopolymeric lightweight foaming insulation materials are best when Hydrogen peroxide content is0.5%, sodium dodecyl sulfate acid content is0.75%, and the corresponding compressive strength and bulk density are9.26MPa,0.83g/cm3, respectively, and the porosity distribution of the fly ash/metakaolin geopolymeric lightweight foaming insulation materials is very uniform, pore size is very small, The thermal conductivity can reach0.18W/(m·k), which shows a very good insulation effect.