Thermal analysis of dehydroxylation of Algerian kaolinite

Thermal analysis techniques remain important tools amongst the large variety of methods used for analysis of the dehydroxylation of kaolinite. In the present study, the kinetics of dehydroxylation of Algerian kaolinite, wet ball milled for 5 h followed by attrition milling for 1 h, was investigated using differential thermal analysis (DTA) and thermogravimetry (TG). Experiments were carried out between room temperature and 1350 °C at heating rates of 5, 10 and 20 °C min-1. The temperature of dehydroxylation was found to be around 509 °C. The activation energy and frequency parameter evaluated through isothermal DTA treatment were 174.69 kJ mol-1 and 2.68 × 109 s-1, respectively. The activation energies evaluated through non-isothermal DTA and TG treatments were 177.32 and 177.75 kJ mol-1, respectively. Growth morphology parameters n and m were found to be almost equal to 1.5.