Recent studies on the decomposition of the dolomite group by thermal analysis

Abstract Recent thermoanalytical investigations of the decomposition of the dolomite group are reviewed. Dolomite shows two DTA endotherms in CO 2 due to a two-step decomposition. It is well established that the higher decomposition temperature is very sensitive to atmospheric CO 2 partial pressure. However, there has been much discussion on whether or not the lower decomposition temperature depends on CO 2 pressure. Recent studies confirm that the lower decomposition temperature is shifted to a lower temperature on increasing CO 2 pressure, so that the lower and higher decomposition temperatures are shifted in opposite directions with changing CO 2 pressure. Regarding the mechanism of formation from dolomite in CO 2 , a direct formation theory is supported. The decomposition mechanisms of ferroandolomite-ankerite and kutnahorite are much discussed. Recent studies indicate that these minerals decompose in two steps in a similar manner to dolomite itself in the atmosphere, in which the O 2 partial pressure is sufficiently low to maintain both Mn and Fe as bivalent cations. In addition, recent investigations on the effects on salts on the decomposition mechanism of dolomite are briefly reviewed.