Birdwood kaolinite: a highly ordered kaolinite that is difficult to intercalate—an XRD, SEM and Raman spectroscopic study

The intercalation of a highly ordered kaolinite from Birdwood, South Australia, has been studied using a combination of electron microscopy, X-ray diffraction and Raman microscopy. Highly ordered kaolinites normally intercalate easily and to a high degree. The kaolinite under study was found to intercalate acetamide and formamide with difficulty and more than 18 days were required to achieve more than 20% intercalation. Further treatment did not improve the degree of intercalation past 60%. The difficulty of intercalation is attributed to the co-existence of two kaolinite phases, a highly ordered (with a Hinckley index>1.3) and a highly disordered kaolinite, the latter material appears to coat the highly ordered kaolinite thereby limiting the intercalation. The presence of two forms of silica and a dickite were identified in the sample using X-ray diffraction.