Textural properties of the medical Algo clay as influenced by calcination

A pharmaceutically available clay, Algo clay from the Tibet plateau, recommended for a large range of medical applications was investigated by X-ray diffraction (XRD), thermal analysis, scanning electron microscopy (SEM), nitrogen adsorption, particle size distribution measurements and electron paramagnetic resonance (EPR). The major crystalline phase was kaolinite, with layered structure confirmed by SEM analysis. The specific surface area of the clay was about 28 m2/g, the particle size < 100 nm and the average pore radius varied between 0.6 nm and 9.27 nm. Surface and structural effects after calcination at 700 °C and 1000 °C are reported.