Study on mixing and segregation behaviors in particulate fluidized bed system for mineral processing

Abstract

In order to identify the mixing and segregation behaviors in a mineral processing operation, present study aimed on the hydrodynamics of solid–liquid fluidization. The study was carried out in a fluidization column with tapings at different height of the bed to collect the sample. The binary particles considered in this study are hematite (4800kg/m3) and quartz (2600kg/m3) at different size fractions in the range of average size 87×10−6m to 400×10−6m. It is observed that for various binary mixtures, both quartz and hematite particles share the equal composition by mass (50%) at a particular height of fluidized bed, referred as “locus point” of mixing. Study indicates that the mixing zone volume will increase for a continuous fluidized bed plant operation. It is observed that the number of locus points varies from 1 to 3 signifying their dependency on the size ratios of binary mixture. Whenever, the difference in terminal velocity between quartz and hematite particles approaches to zero, mixing is enhanced. Further, the present study is extended to find the segregation index for the different size ratios of quartz and hematite particles. It is evident that depending on the size ratios, various regions such as complete segregation, partial mixing and complete mixing can be observed.