Ceramics-Silikáty 51 (1) 24-29 (2007)

Chemically activated kaolinites after de-intercalation of formamide

M. Valášková, G. Simha Martynková, V. Matějka, G. Kratošová

Five well and poor ordered kaolinites were studied to explore structural changes of kaolinite/formamide intercalates and de-intercalates. These materials were evaluated using the X-ray powder diffraction (XRPD) supplement with scanning electron microscope (SEM), measurement of specific surface area (SSA) and particle size distribution (PSD). The XRPD of de-intercalated kaolinites exhibit: (1) diffractions of 7 A kaolinite, some remaining 10 A kaolinite/formamide complex and an additional 8.4 A phase, (2) lower one-layer thickness of de-intercalated 7 A kaolinite than before formamide treatment, (3) changes in the (02, 11) diffraction band indicating structural disorder in the a, b plane. The chemical activation of kaolinites using formamide creates kaolinites with smaller and more homogenous particles and higher SSA than were observed in the original ones.

Keywords: Powders-chemical preparation; De-intercalation; X-ray diffraction; Kaolinite, Structural application.