| Abstrakt: |
Abstract: In this study, Fourier transfor m infrared (FTIR) spectroscopy, differential scanning calorimetry (DSC) and thermogravimetry (TGA) are used as complementary techniques to investigate structural order and phase transformation associated with thermal decomposition of selected kaolins from South Africa and Cameroon. The samples exhibit poorly resolved, weak intensity OH stretching and bending vibrations of structural water, characteristic kaolinite dehydroxylation temperatures (500 - 560 °C), low to high mass loss (6.5 to 19.4 %) and asymmetrical DSC curves. The results infer poor to partially ordered structures associated wit h significant quartz and iron oxide contamination. Co mpared against other commercial kaolins, the studied samples show moderate to good potentials for use in structural ceramics and refractories. |
