(1. Key Laboratory of Mineralogy and Metallogeny, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China;
2. Guangdong Provincial Key Laboratory of Mineral Physics and Materials, Guangzhou 510640, China;
3. University of Chinese Academy of Sciences, Beijing 100049, China)

Abstract: Compared with homogeneous synthesis technology, heterogeneous synthesis can promote the nucleation and subsequently accelerate the growth of secondary minerals by providing a local environment with super-saturation of ion concentration and a relatively lower energy barrier. In the present study, a series of samples were synthesized by altering Si/Al ratio (fixing the Mg/(Si+Al) =3∶4), reaction temperature and time. Characteristic reflections of phyllosilicate were recorded in XRD patterns of the resulting products with d(060)≥0.153 nm, indicating a successful synthesis of saponite. The well-crystallized saponite was obtained in the initial Si/Al ratio range of 5.43–7.89, and their crystallinities increased with increasing reaction temperature and time. At a temperature of 160℃, brucite and analcime formed as impurities, resulting from the low dissolution ability of brucite and the excess of Si4+ and Al3+ in the solution. Both of them disappeared with extension of reaction time. At a temperature of 300℃, a small amount of chrysotile was formed, corresponding to the rapid release of Mg2+.

Keywords: saponite; heterogeneous hydrothermal synthesis; influence factor; chrysotile

Email: zhangdan@gig.ac.cn

ACTA MINERALOGICA SINICA Vol. 36, No. 2, 2016, Page 241-246