Abstract. The mineral and elemental composition, crystal structure and particle size distribution of kaolin clays have been determined to ascertain its industrial significance. The mineral composition is evaluated by X-Ray Fluorescence (XRF), crystalline structure by X-Ray Diffraction (XRD) and particle size distribution using low angle laser light scattering (LALLS) technique. The results shows the presence of eight elements expressed in percentages in form of their oxides as: SiO 2, Al 2 O 3, Fe 2 O 3, MgO, CaO, K 2 O, TiO 2 and P 2 O 5. Five crystalline structures are revealed by XRD result. The particle size distribution shows that kaolin particles are mainly in the range of 25-35 µm, while few particles have size distribution varied between 0.4-0.75 μm. The report is found to be in agreement with other researchers.

Biodegradable films from tapioca starch (TPS) were formed by tape casting. The impact of glycerol (0, 5, 10, 15 and 20%) on the mechanical properties was investigated. The increase in glycerol content reduces the tensile strength while increasing the elongation at break. The varying concentrations of glycerol led to changes in tapioca starch edible film properties, potentially affecting film performances. The merging and increase in the intensity of absorption between 3700-3300 cm-1 as a result of increase in glycerol proportion is due to possible interaction of the OH groups in TPS and glycerol thereby increasing intermolecular H-bond.

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The effect of milling on structure of kaolinite-urea intercalates were studied. Untreated and treated kaolinite samples were examined by Field scanning electron microscopy (FESEM), X-ray powder diffraction (XRPD) and Fourier transform infrared (FT-IR) spectroscopy. The basal spacing of kaolinite measured by X-ray powder diffraction (XRPD) increased from 1.02 to 3.62 nm after intercalation by urea. Significantly, nature of intercalation was reached through formation of hydrogen bonds between urea and both Si-O and AlOH groups of the interlayer surface of kaolinite.

Raw kaolin was refluxed by sulphuric acid in variable concentrations of 2 M, 4 M, 6 M and 8 M. The morphology and elemental compositions of the acid-leached kaolin were analyse by Field Scanning Electron Microscopy (FESEM) and Energy Dispersive X-ray analysis (EDX) respectively. The disintegration and leaching of Al 3+ ions of the clay are determined by FESEM studies. The acid treatment increases the silicon content and decreases aluminium content as revealed by EDX analysis. The leaching of Al 3+ ions increases with gradual increase in concentration of the acid. Therefore, kaolin reflux with acid at lower strength (2 M and 4 M) are more dispersed and more industrially useful than that which is treated at higher acid strength.