INVESTIGATION OF GIBBSITE INTO BOEHMITE BY DSC ANALYSIS

The dehydroxylation of gibbsite into boehmite was investigated by mean s of DSC analysis under non-isothermal conditions in the temperature r ange 453-673 K at heating rates from 2.5 to 20.0 K min(-1). Mathematic al analysis of the experimental DSC curves revealed the mechanism and kinetics of the gibbsite dehydroxylation process. The kinetic curves a lpha = f(t) and alpha = f(T) are sigmoidal in shape; their inflection points and the nu(m) point of the curves nu = f(t) and nu = f(T) are i nterrelated and as defined by the concept of a stationary point. The a ctivation energy for the first stage of gibbsite dehydroxylation in th e temperature range 453-673 K is 132.92 +/- 8.33-142.26 +/- 8.33 kJ mo l(-1).