Particle evolution during the decomposition of CdCO3

Particle evolution during and following the decomposition of cadmium carbonate was investigated using surface area and crystallite size analyses. Surface area results of decompositions at temperatures ranging from 523 to 775 K showed a maximum corresponding to the total decomposition of the carbonate. The maxima for vacuum and air decomposition occurred at 583 and 613 K, respectively. Crystallite size analyses showed that the sizes of the CdO resulting from the air decomposition of CdCO₃ at low temperatures was significantly larger than the corresponding values obtained for vacuum decomposition. These observations suggest that CdCO₃ sinters favourably in air before decomposition, leading to larger CdO crystallites after decomposition. After complete dissociation, the evolution of CdO particles is the same for vacuum and air decomposition, indicating that the sintering of CdO is essentially the same under these two conditions.