Abstract
Controlled transformation Rate Thermal Analysis (CRTA) has been used to study the thermal decomposition of a talc sample. The vacuum conditions and low rate of decomposition used in the present study has enabled to understand and quantify the decomposition in terms of the different brucite and talc sheets of the present mineral sample with chlorite impurity. Two mains decomposition steps at 500- 650 degrees C and 650-1000 degrees C respectively were identified using CRTA, FTIR, XRD, SEM and BET analyses of heated talc at various temperatures. The first decomposition step, having the major duration, can be attributed to the deshydroxylation of the layers brucitic of chlorite while the second stage is due to the dehydroxylation of the layers mica (OH) of chlorite and of those of talc (OH). This result is in good agreement with the structure of both minerals (talc/chlorite) and also the arrangement of the hydroxyl groups.