硬硅钙石动态水热法合成及其微观形貌控制  

Dynamic Hydrothermal Synthesis and Morphology Control of Xonotlite

作　　者：郑骥[1] 倪文[1] 肖晋宜[1] 

机构地区：[1]北京科技大学土木与环境工程学院,北京100083

出　　处：《材料科学与工程学报》2008年第2期161-164,共4页Journal of Materials Science and Engineering

基　　金：国家高技术研究发展计划基金资助项目(2003AA302610)

摘　　要：使用粉石英和消石灰为原料，采用动态水热法合成了硬硅钙石，当氧氯化锆添加量Zr／（Ca＋Si）=0．02或白炭黑掺量占硅质原料总量12％，保温阶段搅拌速度200rpm时，合成硬硅钙石制品体积密度小于70kg·m^-2，达到保温绝热用材料超轻型水平。超轻制品显微分析结果表明，硬硅钙石纳米纤维相互交叉缠绕形成形状规则、大小均匀的球形团聚体，这种二次粒子平均粒径50～80μm，内部中空。形成中空二次粒子微观结构是获得超轻硬硅钙石制品的关键。ZP^4＋能与Ca^2＋发生置换反应，非晶质白炭黑比结晶质粉石英有着更高的反应活性，搅拌速度可控制扩散及传质速度，因此可通过调节氧氯化锆用量、白炭黑掺量和保温阶段搅拌速度来调节水热反应速度，从而有利于形成硬硅钙石中空二次粒子的微观结构。A xonotlite-type thermal insulating material with very low bulk density was prepared using natural mineral tripoli SiO2 and lime CaO as raw materials through a dynamic hydrothermal technique. Amorphous siliceous material carbon white, additive ZrOCI2 and stirring rate were studied to find out their effects on bulk density of prepared insulation products. When stirring rate in the constant temperature reaction period was 200rpm with Zr/（Ca＋ Si） molar ratio 0. 02, or when stirring rate was 200rpm and 12% tripoli was replaced with carbon white, bulk densities of synthesized xonotlite were less than 70kg · m^-3 in both conditions. The peculiar microstructure of these synthesized extremely light insulations was regular homogeneous hollow spherical secondary particles, with shell weaved by xonotlite nanocrystal fiber. Because Zr^4＋ released from additive ZrOCI2 can exchange with Ca^2＋ and amorphous carbon white has much higher reactivity than crystalline tripoli, each of them can adjust the dissolution, adsorption and diffusion reaction rates of hydrothermal process, resulting in the special hollow-secondary-particles morphology finally.

关 键 词：硬硅钙石 微观形貌 中空二次粒子 动态水热合成 

分 类 号：TQ170.7[化学工程—硅酸盐工业]