硅灰石制备多孔高比表面积二氧化硅机理探讨

通过对用硅灰石与盐酸反应制备多孔高比表面积SiO2最佳实验工艺条件的研究,确定了最佳试验工艺条件,即反应速度、反应时间、中和速度、反应最终pH值与SiO2比表面积的关系,探讨了其合成的机理。研究结果表明,当pH≤1.0时,硅灰石与盐酸反应生成大量稳定的硅酸溶胶;反应最终(pH＝4.0)使硅酸水解和缩聚以及Si—O与OH基团氢键的形成以适宜的速度进行,形成弱交联、网状、低密度的硅酸凝胶,最终产物SiO2的比表面积增大。

Mechanism of Silica Powder with Porous and Higher Specific Surface Area by Wollastonite

Through a series experiments,the best process conditions are ensured in the prepared porous SiO 2 powder with high surface area by wollastonite and acid.The optimum test condictions such as reac-tion rate,time,neutralization rate and relation between pH value and specific surface area of SiO 2 are determined.The synthetical mecha-nism is discussed.The results show that there exist a great deal of silicic acid sol with stable states during reaction when pH≤1.0.The hydrolysates and condensation polymers of silicic acid are obtained when pH=4.0,and the hydrogen bonds of Si-O and OH groups are formed in suitable rate,which can makes sol to gel with infirmness connection,reticulation and lower density,and surface area of silica powder is higher.