钾铯基地聚合物前驱体水热合成块体铯榴石

Hydrothermal synthesis of bulk pollucite through(K,Cs)-geopolymer

以偏高岭土为铝、硅源,以硅酸钾铯溶液为碱激发剂,无需添加任何沸石晶种和表面活性剂,室温制备了钾铯基地聚合物前驱体。将所制备钾铯基地聚合物前驱体在密闭蒸压反应釜环境中(180℃,0.8 MPa)水热晶化8h,制备得到了块体铯榴石。研究结果表明,钾铯基地聚合物前驱体为无定形物质;经水热晶化处理后,铯含量较高的样品中出现了铯榴石晶体,说明地聚合物凝胶原位转化为铯榴石晶体颗粒。原位转化生成的铯榴石晶体颗粒被地聚合物凝胶包裹和粘结,使得块体材料具有较高抗压强度。

（K ,Cs）-geopolymer precursors have been synthesized by using metakaolin （MK） and potassium cesi-um silicate solutions as raw materials without any zeolites and surfactants. And the bulk pollucite mateials were obtained by the hydrothermal crystallization of （K , Cs）-geopolymer precursors under hydrothermal conditions of 180 °C and 0.8 MPa for 8 h. Results show the amorphous nature of （K , Cs）-geopolymer precursors. And the crystals with pollucite structure in the samples with higher content of Cs indicates the in-situ transformation of （K , Cs）-geopolymer gels under hydrothermal conditions. The in-situ formed pollucite particles could be bonded by non-transformed geopolymer gels to construct the bulk pollucite with high compressive strength.