2859
Coalescence in Fluidized Bed Flotation: Understanding the
Interplay Between Chemistry and Hydrodynamics
Anna Skliar
Julius Kruttschnitt Mineral Research Centre, University of Queensland, Brisbane, Australia
Isabella Verster, Unzile Yenial Arslan, Gordon Forbes, Liza Forbes
Julius Kruttschnitt Mineral Research Centre, University of Queensland, Brisbane, Australia
ARC Centre of Excellence on Eco-Efficient Beneficiation of Minerals, University of Newcastle, Callaghan, Australia
ABSTRACT: Fluidised bed flotation devices, such as the Eriez HydroFloat ®, were explicitly developed for
efficient coarse particle recovery. The low turbulence environment in fluidised bed flotation minimises particle
detachment and improves coarse particle recovery. The hydrodynamic environment of fluidised bed flotation
is a significant departure from that in conventional mechanical flotation cells. In this environment, bubble
size and bubble coalescence are significantly affected. The bubbles need to be bigger to improve buoyancy for
heavier particles, and the bubble/bubble collision rates are reduced considerably in quiescent conditions. The
overall goal of this work is to gain an understanding of the coalescence mechanisms, specifically within the novel
hydrodynamic environment created by a fluidised bed flotation system.
To establish the practical relationship between process chemistry and hydrodynamics, we examine bubble size
as a function of coalescence, which is influenced by fluidised bed hydrodynamic parameters such as airflow and
chemical parameters such as frother concentration. The results showed that fluidised bed flotation follows the
same trends as those established earlier for conventional flotation. However, significantly higher frother dosages
are required to achieve CCC in a fluidised bed environment.
Keywords: HydroFloat ®, coarse particle flotation, bubble surface area flux, flotation chemistry, bubble size,
coalescence.
INTRODUCTION
With the depletion of high-grade ore deposits, the min-
erals processing industry had to adapt its technologies to
extract low-grade, finely disseminated ores. It is possible to
effectively treat ores with minerals of interest content lower
than 1% and even less for by-product minerals (Nkuna,
Ijoma, Matambo et al., 2022). However, treating these
ores requires intense comminution to liberate minerals
sufficiently. Comminution is one of the most energy-inten-
sive operations in the beneficiation process. This presents
substantial challenges to the minerals processing industry
regarding financial expenditure and adverse environmental
impact due to the high greenhouse gas emissions. Therefore,
downstream processing of coarse particles, particularly with
flotation, became a focus of extensive research and technol-
ogy development.
Coalescence in Fluidized Bed Flotation: Understanding the
Interplay Between Chemistry and Hydrodynamics
Anna Skliar
Julius Kruttschnitt Mineral Research Centre, University of Queensland, Brisbane, Australia
Isabella Verster, Unzile Yenial Arslan, Gordon Forbes, Liza Forbes
Julius Kruttschnitt Mineral Research Centre, University of Queensland, Brisbane, Australia
ARC Centre of Excellence on Eco-Efficient Beneficiation of Minerals, University of Newcastle, Callaghan, Australia
ABSTRACT: Fluidised bed flotation devices, such as the Eriez HydroFloat ®, were explicitly developed for
efficient coarse particle recovery. The low turbulence environment in fluidised bed flotation minimises particle
detachment and improves coarse particle recovery. The hydrodynamic environment of fluidised bed flotation
is a significant departure from that in conventional mechanical flotation cells. In this environment, bubble
size and bubble coalescence are significantly affected. The bubbles need to be bigger to improve buoyancy for
heavier particles, and the bubble/bubble collision rates are reduced considerably in quiescent conditions. The
overall goal of this work is to gain an understanding of the coalescence mechanisms, specifically within the novel
hydrodynamic environment created by a fluidised bed flotation system.
To establish the practical relationship between process chemistry and hydrodynamics, we examine bubble size
as a function of coalescence, which is influenced by fluidised bed hydrodynamic parameters such as airflow and
chemical parameters such as frother concentration. The results showed that fluidised bed flotation follows the
same trends as those established earlier for conventional flotation. However, significantly higher frother dosages
are required to achieve CCC in a fluidised bed environment.
Keywords: HydroFloat ®, coarse particle flotation, bubble surface area flux, flotation chemistry, bubble size,
coalescence.
INTRODUCTION
With the depletion of high-grade ore deposits, the min-
erals processing industry had to adapt its technologies to
extract low-grade, finely disseminated ores. It is possible to
effectively treat ores with minerals of interest content lower
than 1% and even less for by-product minerals (Nkuna,
Ijoma, Matambo et al., 2022). However, treating these
ores requires intense comminution to liberate minerals
sufficiently. Comminution is one of the most energy-inten-
sive operations in the beneficiation process. This presents
substantial challenges to the minerals processing industry
regarding financial expenditure and adverse environmental
impact due to the high greenhouse gas emissions. Therefore,
downstream processing of coarse particles, particularly with
flotation, became a focus of extensive research and technol-
ogy development.