Physical Strength of Lime Pellets, 1998 International Chemical Recovery Conference Proceedings

The strength of limes from fluidized beds and rotary kilns was measured. It was found that lime agglomerates from fluidized beds have a higher strength. In order to explain that, pellets of lime mud or calcined lime mud formed at different compact pressures were heat treated in a laboratory furnace and then their strength was measured. The compact pressure ranged between 5 and 25 bars, the sintering temperature between 800 and 1200 °C and the sintering time between 30 and 150 minutes. The investigation showed that a higher pressure during compactation results in stronger lime agglomerates after sintering. This is probably because the co-ordination number will increase when the lime agglomerates are pressed closer to each other. Also, higher temperatures and longer sintering times give a stronger solid. If the lime mud was calcined before being pressed into pellets, the strength of the sintered pellets was much higher than if the pellets were formed out of lime mud and then calcined and sintered. The results may explain the higher strength of lime from a fluidized bed, where the lime mud is calcined instantaneously and, also, the lime is subject to high mechanical forces due to the turbulent conditions.