Decomposition of CaS particles at ambient conditions

Decomposition of CaS particles (18.6 mu m size) at ambient conditions was i nvestigated by means of potentiometric analysis, TG, SEM-EDX and XRD techni ques. The thermodynamics of the process was also studied. The results show that well dispersed CaS particles are decomposed provoking a high H2S relea se to the atmosphere during the first two days of decomposition. This relea se was evaluated to be in the range 61-72 mol% on initial sulphur basis. Th e remaining solid consists of a 66 mol% calcium carbonate, 22 mol% calcium sulphate and 12 mol% elemental sulphur. Trace amounts of thiosulphate were also detected by XRD analysis. The formation mechanisms of the different sp ecies are discussed. SEM photographs of decomposed CaS pellets revealed tha t the decomposition process is diffusion controlled for high loads of parti cles. (C) 2000 Elsevier Science Ltd. All rights reserved.