Alumina samples were produced by the thermal decomposition of hydrates of aluminium sulphate, nitrate and chloride. The kinetics of the chlorination were studied by means of isothermal TG measurements, using COCl2 as chlorinating agent. Apparent activation energies were determined in the temperature ranges where the reaction was controlled by chemical processes. The reaction rates related to unit surface area were similar for all the samples, and the isothermal TG curves could be described by the models of contracting cylinders and spheres. Below 700 K, however, the initial rates for samples prepared from AlCl3·6H2O were of an accelerating character, resembling an autocatalytic process. After this stage, the reaction rates stabilized at extremely high level as compared with the samples of other origins.
ASJC Scopus subject areas
- Chemical Engineering(all)