TRIBOCHEMISTRY AND KINETICS OF AL-2(SO4)(3)CENTER-DOT-XH2O DECOMPOSITION

The thermal decomposition of tribochemically activated Al-2(SO4)(3).xH (2)O was studied by TG, DTA and EMF methods. For some of the intermedi ate solids, X-ray diffraction and IR-spectroscopy were applied to lear n more about the reaction mechanism. Thermal and EMP studies confirmed that, even after mechanical activation of Al-2(SO4)(3).xH(2)O, Al2O(S O4)(2) is formed as an intermediate. Isothermal kinetic experiments de monstrated that the thermochemical sulphurization of inactivated Al-2( SO4)(3).xH(2)O has an activation energy of 102.2 kJ.mol(-1) in the tem perature range 850-890 K. The activation energy for activated Al-2(SO4 )(3).xH(2)O in the range 850-890 K is 55.0 kJ.mol(-1). The time of the rmal decomposition is almost halved when Al-2(SO4)(3).xH(2)O is activa ted mechanically. The results permit conclusions concerning the effici ency of the tribochemical activation of Al-2(SO4)(3).xH(2)O and the ch emical and kinetic mechanisms of the desulphurization process.