Kinetics of oxidation of CaS particles in the regime of low SO2 release

✍ Scribed by Gregorio Marbán; Marta Garcı́a-Calzada; Antonio B. Fuertes

• Book ID: 104108024
• Publisher: Elsevier Science
• Year: 1999
• Tongue: English
• Weight: 359 KB
• Volume: 54
• Category: Article
• ISSN: 0009-2509
• DOI: 10.1016/s0009-2509(98)00210-3

✦ Synopsis

The influence of temperature and oxygen partial pressure on the oxidation of pure CaS particles (`"18.6 m) in the regime of low SO release (¹(890°C for p -"0.21 atm, or ¹(840°C at any oxygen partial pressure) has been studied by means of thermogravimetric analysis. The kinetics of the process was analysed with the unreacted core model. After a short period of chemical control, the process is governed by solid-state diffusion through the product layer. The effective diffusivity of oxygen in the CaSO lattice decreases with conversion and is a function of temperature and oxygen partial pressure. This dependence can be explained by a grain boundary diffusion mechanism. This is thought to proceed via migration of Ca> and S\ ions from the CaS/CaSO interface to the particle surface, where the ions are oxidised to CaSO by gaseous oxygen.