Kinetics Parameters Of The Thermal Dehydroxylation Of Gibbsite Al(oh)3 By Differential Thermal Analysis (dta)

In this present study, the thermal decomposition of gibbsite Al(OH)3 was studied by the Differential Thermal Analysis (DTA) technique under non-isothermal conditions, the gibbsite powder were carried out between room temperature to 900 °C using heating rates of 5, 10, 15 and 20 °C/min.The obtained DTA curves show two different peaks: the first peak is due to partial dehydroxylation of gibbsite and formation of boehmite, the value of the activation energy (EA) corresponds to 143 KJ/mol. The second peak corresponds to transformation of gibbsite to -Al2O3 phase, the activation energy (EA) was found around to 185 KJ/mol. The values of apparent activation were determined by Ozawa–Flynn–Wall (OFW), Boswell and Kissinger–Akahira–Sunose (KAS) methods and by applying the basic solid-state kinetic equations. The phases formed and the structural changes were investigated by differential thermogravimetry (DTG) and X-ray diffraction (XRD) for gibbsite powder treated at different temperatures from room temperature to 1100 °C.