SiO_2包覆超细CaCO_3的结构和机理分析

Mechanism and structure analysis of SiO_2-coated CaCO_3 superfine particles.

合成了表面包覆 Si O2 的超细 Ca CO3 。通过 XPS,XRD对包覆表面层结构的分析 ,证实了 Si O2 以无定形包覆于 Ca CO3 表面 ,并在其表面形成了 Si- O- Ca键。对 Si O2 包覆超细 Ca CO3 的机理分析结果可知 :Na2 Si O3 的加入量是影响包覆效率的重要因素 ,由于硅酸易自聚 ,控制 Si O2 与 Ca CO3 的重量比约为4 %～ 5 %时为包覆的最佳点 ;Ca CO3 晶粒度大小影响分散性能 ,进而影响包覆效率 ,分散性能好的包覆效率较高。

The superfine particles of CaCO\-3 coated by SiO\-2 has been studied. By XPS and XRD analysis, it has been confirmed that the SiO\-2 layer is present as amorphous phase, and is formed via Si-O-Ca bond on the surface. Further studies show that the amount of Na\-2SiO\-3 added into the system plays an important role in the coating efficiency. The optimistic ratio of the SiO\-2 to CaCO\-3 has been found to be 4%-5% for the self\|polymerization of H\-2SiO\-3. It has been concluded that the better condition of CaCO\-3 dispersion is influenced by grain size, which may contribute to the better coating efficiency.