Journal of Chemical Engineering of Japan, Vol.51, No.7, 576-583, 2018
Component Separation in a Vibrating Fluidized Bed Based on Differences in Agglomeration Properties of Particles
The gas fluidization of three binary powder mixtures, viz. SiO2-ZnO, SiO2-Fe2O3, and ZnO-Fe2O3 were studied in a mechanically vibrating fluidized bed. The effects of the powder particle characteristics and their agglomeration (cohesiveness) properties on segregation in the fluidized bed were investigated. For SiO2-ZnO, large agglomerated particles with high ZnO contents were observed, which segregated to the bottom of the fluidization column. The underlying mechanism was found to be the following: low-cohesion and low-density SiO2 particles migrate to the upper layer through the channels because of gas flow. On the other hand, the large agglomerated particles with high ZnO contents are formed in the bottom layer because of the interparticle collisions due to vibrations, followed by sedimentation and segregation to the bottom. A similar phenomenon was observed for SiO2-Fe2O3. The ZnO-Fe2O3, which exhibited similar agglomeration properties and densities, formed agglomerated particles that contained the components in uniform amounts and ratios and did not segregate to the bottom. These results highlight the possibility of separation of component on a vibrating fluidized bed based on the differences in their agglomeration properties.