SURFACE-AREA AND PORE-SIZE CHANGES DURING SINTERING OF CALCIUM-OXIDE PARTICLES

Changes in surface area and pore size during the sintering of CaO samples between 0.71 to 1 mm, were studied. Typical operating conditions in fluidized bed combustors (temperature between 973 and 1173 K and C02concentrations up to 15%) were chosen. The longest sintering time was 90 min. The decrease in the surface area with sintering time was described using an empirical equation deduced from the German-Munir model. Surface area reduction and increase in pore size was strongly affected by the presence of C02. Shrinkage of the CaO particles was not observed during sintering. The pore volume and porosity remain unaffected by sintering. A qualitative model, based on SEM microphotographs, for describing the sintering process was proposed. © 1991, Gordon and Breach Science Publishers S.A.