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Upgrading of positively buoyant particles using an inverted reflux classifier

conference contribution
posted on 2025-05-12, 10:06 authored by A. Kiani, Zi Qiang ZhouZi Qiang Zhou, Kevin GalvinKevin Galvin
Cenospheres are hollow alumina silicate microshells found in fly ash. They are positively buoyant in water, thus allowing gravity-separation to be used to separate these low density particles from negatively buoyant fly ash particles. However, very low feed grade, of order 1%, and small particle diameter, typically less than 150 μmm, make achieving a reasonable throughput per unit vessel area difficult for conventional gravity-separation systems. In this study an Inverted Reflux Classifier (IRC) was used for the first time to recover and concentrate cenospheres from a real fly ash feed obtained from a coal fired power station. This novel, single stage, device consists of a system of parallel inclined channels, located beneath a partially enclosed vertical fluidizing chamber. The channels enhance the segregation rate of the cenospheres from the fly ash, permitting a greater downwards fluidization to aid the desliming of fine fly ash particles from the overflow product. The device was fed at a solids flux of about 2.6 t/m2h. A product grade of 75% was achieved from a feed with a grade of only 0.53%, corresponding to an upgrade of 142. Here, the recovery of the cenospheres was 41%. By increasing the overflow product rate, a significantly higher recovery of 64% was achieved, but at a much lower upgrade of 33. In both cases most of the losses were attributed to fine cenosphere particles, less than 50 μmm, being entrained to the underflow.

History

Source title

Chemeca 2013: Challenging Tomorrow: Proceedings

Name of conference

Chemeca 2013: Challenging Tomorrow

Location

Brisbane, Qld

Start date

2013-09-29

End date

2013-10-02

Pagination

357-362

Publisher

Engineers Australia

Place published

Barton, ACT

Language

  • en, English

College/Research Centre

Faculty of Engineering and Built Environment

School

School of Engineering

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