Effect of average size and the amplitude of particle size distribution in filter cake dewatering

The amplitude and average size influence of particle size distribution in the deliquoring kinetics of calcium carbonate filter cakes in a defined particle range (38 to 125 mm) was studied. Narrow granulometry fractions, called pures, were prepared which were used to design blends; they had diferent standard deviations and ranges of particle size distribution. Experimental curves of liquid removal and gas flow were determined in function of dewatering time, for suspensions to 20% in weight. Pure fractions results show that while increasing particle size, the initial dewatering speed and gas flow increase, while equilibrium saturation diminishes. The most important blends results were defined in a qualitative manner. These indicate that initial dewatering speed and gas flow diminish, while equilibrium saturation increases when standard deviation and distribution ranges are increased.